The relative economic of screening for colorectal cancer, breast cancer and cervical cancer

Critical Reviews in Oncology/Hematology 32 (1999) 133–144

The relative economics of screening for colorectal cancer, breastcancer and cervical cancer

Dorte Gyrd-Hansen*Institute of Public Health, Uni6ersity of Southern Denmark, Odense Uni6ersity, Winsløwparken 19,3, 5000 Odense C, Denmark

Accepted 8 December 1998

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

2. Presenting the screening programmes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

2.1. Colorectal cancer screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

2.2. Breast cancer screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

2.3. Cervical cancer screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

2.4. A comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

3. Modelling the cost-effectiveness of screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

4. Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

6. Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

Biography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

This paper compares the cost-effectiveness of mam-mography screening, colorectal cancer screening usingthe unhydrated Hemoccult II (H-II) test and cervicalcancer screening using the Pap-smear test. Emphasishas been on shedding some light on the unique charac-teristics of each of these programmes. This comparativeevaluation illustrates that although the breast cancerscreening and cervical cancer screening programmes aremore effective in detecting cancers, colorectal cancerscreening using the unhydrated H-II test is overall morecost-effective. This paper suggests that in a Danishsetting, it would be optimal to introduce annual col-orectal cancer screening of the 50–74 year olds alongwith biennial mammography targeted at the 50–69 yearolds and cervical cancer screening every 4 years for the25–59 year olds.

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1. Introduction

In recent decades potential methods of screening forearly stage cancers diseases have surfaced. The interestin developing such screening methods has been fur-naced by a wish to reduce the mortality rate of cancerdiseases. Although survival rates have improved forcolorectal cancer, mammae cancer and cervical cancereven when these are detected at the clinical stage, it hasbeen shown that detecting these cancers at a yet un-symptomatic stage can reduce mortality rates further.

Several randomised controlled trials have beenlaunched in order to measure the magnitude of theeffect of early detection on the mortality rates of col-orectal cancer and mammae cancer. Recently, the re-sults of two randomised trials on the early detection ofcolorectal cancer were published, which showed thatcolorectal cancer mortality was reduced by 15–18%

* Tel.: +45-65503059; fax: +45-65918296.E-mail address: [email protected] (D. Gyrd-Hansen)

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D. Coyle et al. / Critical Re6iews in Oncology/Hematology 32 (1999) 133-144134

[1,2] amongst the test group. Both trials applied theunhydrated Hemoccult II test (H-II), which is one ofseveral fecal occult blood tests (FOBT) that have beendeveloped for potential use in population screeningprogrammes for detection of colorectal neoplasms.

The effect of mammography for the early detectionof breast cancer has likewise been analysed in a seriesof randomised trials. A recent meta-analysis [3] basedon various clinical trials shows that the relative risk forwomen aged 50–74 offered screening mammographycompared with those who do not is significantly lowerthan 1.

The main test used to screen for cervical cancer isthe Papanicolaou smear developed by Dr GeorgePapanicolaou in the 1930s and introduced forwidespread screening in the 1940s. While thePap-smear test has never been subject to randomisedtrials, comparison of regions in which the test has beenused with regions in which such screening has nottaken place, have shown that this test has a significantimpact on the mortality of cervical cancer [4].

In previous works we modelled the effects ofscreening for colorectal cancer, cervical cancer andmammae cancer [5–7]. In this paper we present acomparative analysis, where the work from theprevious publications are presented together, in orderto demonstrate the relative efficacy and cost-effectiveness of the unhydrated Hemoccult II test,one-view mammography and the Pap-smear test. Thecost-effectiveness of each of these screening proceduresis a function of the characteristics of the tests and thenatural history of the cancer diseases as well as thepopulation incidence of the disease. The aim of thispaper is to provide the reader with an intuitiveunderstanding of the relative merits of the screeningtests, and to illustrate the relative economics of suchscreening programmes. The discussion is largely basedon a Danish setting using Danish incidence rates and,to the extent possible, test characteristics as these havebeen observed in Denmark. Unfortunately, Danishdata were not always available, making it necessary toseek other data sources primarily data from Swedishand Dutch screening programmes. Incidence rates dohowever vary across countries, as do the methods ofperforming and analysing tests. The cost-effectivenessresults presented in this paper should be interpretedwith this in mind.

Below, we discuss each screening procedure in turnand present parameter values used in the modellingwork. This is followed by a direct comparison of thethree types of screening programmes illustratingrelative advantages and disadvantages. Next, we turnto the economics of each type of screening programme.This section is based on previously performed analyses,and hence focus is largely on results. Finally, webroadly outline how policy makers could distribute

resources amongst programmes in order to maximisethe effect of investments in these preventiveinterventions.

2. Presenting the screening programmes

The aim of this paper is to demonstrate the relativecost-effectiveness of FOBT screening for colorectalcancer, cervical cancer screening using the Pap-smeartest, and mammography screening in a Danish setting.The model used for all three evaluations is a statisticalmodel originally developed by Day and Walter [8].Variables such as mean sojourn time, sensitivity rateand age dependent incidence rates, are inputs into asimulation process, where the number of cancers detected per age group at each screening round areestimated for hypothetical screening programmes withvarying screening intervals and target groups. Eachmodel parameter will influence the results of thecost-effectiveness analysis. This section introduces thesecore parameters and presents the parameter valuesused in the model.

2.1. Colorectal cancer screening

The incidence of colorectal cancer in the Danishpopulation rises with age. Amongst 50–54 year oldsthe incidence is 50 per 100 000, but it rises to as muchas 318 per 100 000 for the older age group of 70–74year olds. Consequently, the target group for screeninghas been the older age groups. Clinical trials haveinvited the +45 year olds, but since the observeddetection rates amongst 45–49 year olds have beenminimal [1], the focus of this paper’s discussion will bethe 50–74 year olds.

One objective of fecal occult blood screening is thedetection and treatment of carcinomas at the earliestpossible stage, when patient prognosis is the mostfavourable. FOB screening, however, is also capable ofdetecting adenomas, or benign tumors, because thesetoo possess a capacity to bleed. The extent to whichscreening programmes have an effect on mortality ratesis highly dependent on the screening test’s ability todetect cancers earlier. The latency period signifies thetime period in which the cancer is detectable by thescreening test but not yet clinically detectable. Themaximum lead time obtainable is hence the latencyperiod. This period, as well as the sensitivity rate, arecharacteristics of the screening test. Although oftenestimated independently of each other, these parametersshould in principle be estimated simultaneously [8,9].This was done in a recent article [10] using screeningdata from the randomised trial on Funen. The meanlatency period was estimated to be 2.1 years (assumingan exponential distribution) and the sensitivity estimate

D. Coyle et al. / Critical Re6iews in Oncology/Hematology 32 (1999) 133-144 135

was 62.1%. These values were used to estimate theeffectiveness of colorectal cancer screening.

Sensitivity and specifity, along with estimates of thelatency period, are vital parameters in determining theeffectiveness and cost-effectiveness of screening pro-grammes. The Hemoccult II test is characterised by alow sensitivity and a short sojourn time which rendersit less (cost) effective. It does however obtain a highlevel of specificity which reduces monetary as well asmore intangible costs of the programme. The specificityof the unhydrated Hemoccult II test is 99–99.5% [1,2];an estimate of 99% was used in the analysis.

In recent publications two randomised trials haveshown that colorectal cancer screening using the H-IItest has an effect on overall mortality [1,2]. The presenteconomic analysis is based on the results of the Danishtrial [1], since the aim is to judge the economic implica-tions of introducing such a programme in a Danishsetting. The Funen randomised population study wasset up in 1985. The first screening round ended in 1986when 20 672 persons had done the test (67%). Duringthe study period of 10 years 481 persons with colorectalcancer were found in the group allocated to screeningand 483 in the control group. The main outcome of thestudy was a colorectal cancer mortality ratio of 0.82(95% CI:0.68–0.99). The decrease in colorectal cancerdeaths in the test group in Funen is a result of earlydetection and can be explained by a colorectal cancermortality of 15.7% amongst patients with cancers de-tected by the screening test after the 10 years of follow-up. Within the same follow-up period the disease-specific mortality rate amongst cancer patients in thecontrol group is 51.5%. This indicates that 35.8% of thecancer patients, whose cancers were detected by thescreening test, avoid death from colorectal cancer dueto the early detection. This estimation procedure isproblematic, since mortality reductions demonstratedwithin a relatively short observation period may consti-tute a postponement of death rather than the saving ofa life. Hence, the excess survival rate estimated heremay be exaggerated. Another problem is that not allscreen detection will have had an impact on mortalitywithin the observation period, since not all screen-de-tected cancers would have developed to late stage can-cers (and potential deaths) within this period, had theynot been screen-detected. This causes the excess survivalestimate to be underestimated. Thirdly, the survivalestimates are based on a randomised trial and not onobservational studies. If procedures are to be handledby less experienced physicians in the case that screeningis offered to the general population, similar results maynot apply. A conservative estimate of 30% was appliedin the model framework.

The detection of adenomas is a complementary effectof screening for colorectal cancer, since especially largeadenomas are likely to bleed. The effect of polypectomy

and subsequent surveillance of adenomas is yet un-known, but there is a strong belief in, and evidence for,an adenoma-cancer sequence. The detection of ade-nomas will incur reductions in incidence and conse-quently mortality—the question is how large this effectwill be, and at what cost it will be obtained. Despitebeing a routine procedure polypectomy has not beenevaluated in a controlled trial and is clinically un-proven. However, in a retrospective review of MayoClinic records from a 6-year period Stryker et al. [11]identified 226 patients with colonic polyps over 10 mmin diameter. Actuarial analysis revealed that the cumu-lative risk of diagnosis of cancer at the polyp site at 5,10 and 20 years was 2.5, 8 and 24%, respectively. Thesetransition rates were used in the present analysis. Ac-cording to Jørgensen et al. [12], the risk of cancerdiagnosis is reduced by 43% when adenomas are de-tected and patients are included in a follow-up pro-gramme. This additional benefit of a colorectal cancerscreening programme was included in the analysis.

The cost of the unhydrated H-II test is low. The FOBtest is estimated to cost US$1.50 and the overall costper test performed including test analysis in the Danishstudy is estimated at US$5, whereas colonoscopy wasestimated to cost US$165 [5]. All costs are in 1993prices. These cost estimates were applied in the mod-elling effort presented here. Based on the data from theDanish randomised trial Bech and Kronborg [13] foundthat the number of hospital days for patients withcancers detected in the period 1985–1990 were similarfor the screening group and the control group. Inaddition, the average number of hospital days percancer patient tended to be only slightly lower for thescreening group (26.8 versus 29.9 days). This suggeststhat no significant treatment cost savings are to bemade from early detection of colorectal cancers. Treat-ment cost savings are, however, incurred when ade-nomas are detected and cancers avoided.

2.2. Breast cancer screening

Whereas the cost-effectiveness model on colorectalcancer screening relies largely on Danish data, suchevidence is not yet available for breast cancer screening.Hence, the analysis relies on clinical effectiveness data

Table 1Sojourn time and sensitivity estimates based on screening data fromthe Swedish two-county trial

Sensitivity (%)Age Mean sojourn time

86.01.7 (1.4–2.1)40–4991.83.3 (2.9–3.7)50–59

60–69 3.8 (2.6–4.2) 93.870–74 2.6 (2.5–2.7) 100


from the Swedish two-county trial [14], whereas detailedcost data was taken from a Dutch study [15].

Tabar et al. [16] recently estimated the mean sojourntimes (latency periods) of different age groups based onscreening data collected from the Swedish two-countytrial. A Markov chain model was used and the sojourntime was assumed exponential. The method of estima-tion is developed by Duffy et al. [17], but is similar tothe model developed by Walter and Day [8]. Sensitivityrates were estimated simultaneously. The estimates,which have been applied in the present analysis, aregiven in Table 1.

The relationship between incidence rates, sensitivity,sojourn time and specificity is important in the evalua-tion of screening programmes. If incidence rates arehigh, sensitivity is high and sojourn time is long, lowspecifity levels may be acceptable since the ratio betweentrue positives and false positives will be low. In the caseof mammography screening the specificity seems to bemoderate. In the Swedish two-county trial [14] a specifityrate of 95.6% was observed in the first screening roundand 96.1% was observed at subsequent rounds; theseestimates were used in the analysis.

Since any mortality reduction attained by introduc-tion of a screening programme can be contributed toearly detected cancers, information on participationrates and interval cancer rates in the Swedish two-countytrial were used to estimate the mortality reduction perscreen-detected cancer for each age group. The informa-tion was taken from Tabar et al. [14] where 58.2% ofcancers observed in the test group amongst 40–49 yearolds were screen-detected. Corresponding proportionsfor age groups 50–69 and 70–74 were 69.1 and 59.1%.For these age groups breast cancer mortality ratios of0.87, 0.63 and 0.79 were observed amongst those womenwho were invited to participate in the screening pro-gramme (average follow-up period was 10.8 years). Inorder to estimate the expected excess survival due toscreen detection, Swedish screening data and mortalitystatistics for an unscreened Danish population werecombined. The mortality decrease per screen-detectedcancer for the age group 40–49 year olds was calculatedin the following manner: The relative 10-year survivalfor 40–49 year olds following a breast cancer diagnosisis 70% [18,19]. If a 13% decrease in mortality is to beobserved in this population this would entail a reducedmortality rate of 26.1%, which means that 73.9% ofbreast cancer patients have not died from their cancerafter a follow-up period of 10 years. Assuming that thissurvival probability is to be obtained in the Danishpopulation given the same participation rates and inci-dence interval rates as those observed in the Swedishtrial, the reduction in mortality is to be achieved throughthe detection of screen-detected cancers which constituteonly 58.2% of all observed cancers. Hence, the followingequation will produce an estimate of the excess survival

rate of screen-detected cancers: 0.582×x+ (1–0.582)×70.0=73.9 [ x=76.7. Thus, the excess survival rate is76.7–70.0=6.7. This means that 6.7% of patients withscreen-detected breast cancers will survive the diseasedue to the early detection. Similarly, excess survival ratesfor screen-detected cancers amongst 50–69 and 70–74year olds were calculated at 24.05 and 17.77, respec-tively. Again, these estimates suffer from the sameproblems as the excess survival estimate used in theevaluation of colorectal cancer screening.

The high incidence rates complemented by an effectivescreening test as well as significant increases in survivalfor screen-detected cancers creates a good case formammography screening. Nevertheless, performing amammography is far costlier than performing a Hemoc-cult II test. In a recent Danish report [20] the cost ofmammography was set at US$30 per mammographytest. In a more detailed analysis Van der Maas et al. [15]calculate the costs of mammography (1988 currency) inHolland including cost of screening units and centralunits, regional joint management boards and nationalorganisation. The cost per screen after initial set up isestimated at US$35.50, whereas the cost per test at thefirst and second screening round is US$86.00 andUS$53.50, respectively. These estimates were applied inthe cost-effectiveness analysis presented here. The fol-low-up procedure following a positive mammography iseither magnification-view mammography and/or fine-needle aspiration cytology or open biopsy. While theformer procedures are relatively inexpensive the openbiopsy is costly since it requires anaesthetics. We haveassumed that only 5% of false positive cases would resultin open biopsy, in accordance with the Swedish experi-ence [14]1. The Dutch cost analysis [15] calculates thecost of an open biopsy, and reaches an estimate ofUS$1500 (1988 currency). Cost estimates of the magnifi-cation-view mammography/needle cytology are lacking,however. In a Danish evaluation [20] both interventionsare estimated at US$62. Assuming that open biopsy isperfomed in 5% of false positive cases, the average costof performing a diagnostic test is US$78.

Whether mammography screening incurs savings intreatment costs is uncertain [21,22]. In our analysis weassumed a cost saving from early treatment. In ananalysis by Van der Maas et al. [15] the average costs oftreating cancers at different stages are calculated basedon data from medical files in the Netherlands. Costsavings are estimated using the Miscan model to simu-

1 This is an optimistic estimate, and can only be attained if stan-dard diagnostic procedures are of a high quality. Preliminary resultsfrom Funen County, Denmark, suggest that Danish screening pro-grammes can be as effective at minimising the number of falsepositives referred to open biopsy.


Table 2Parameter values used in the economic evaluations of mammography screening, colorectal cancer screening and cervical cancer screening

Colorectal cancer Breast cancer Cervical cancer

Unhydrated Hemocult II test One-view mammography Papanicolau-smear test(23–59 year olds)(50–69 year olds)(50–74 year olds)

Pre-symptomatic incidence (Danish) 0.00027–0.001530.00203–0.002450.0005–0.003182.1[9]Latency period (years) 3.3–3.8 [14] 16 [23]

Sensitivity of screening test (%) 62.1 [9] 91.8–93.8 [14] 85 [23]Excess survival rate 0.30 0.24 0.40 [23]

99.0 [2]Specificity (%) 96.0 [12] 99.4 [26]37 [6]5 [5]Cost of screening test (incl. 35 (86, 53) [13]

Analysis, US$)165 [5] 165 [6]Cost of diagnostic test (incl. 62, 1500 [13,18]

Analysis, US$)80Participation rate (%) 67 [1] 80

late the stage distribution for alternative screeningprogrammes and applying unit costs to these pre-dictions. The model predicts a saving in treatment costsdue to early detection corresponding to US$700 perlife-year saved (1988 prices) when costs and life-yearsare discounted by 5%. This cost estimate was applied inthe present analysis.

2.3. Cer6ical cancer screening

In interpreting any evaluation based on Danish inci-dence data, it is important to realise that Denmark hasa unique high rate of cervical cancer compared with thatof other developed countries. In the period 1978–1982the crude incidence rate was 24.0 (a cumulative incidenceof 1.9% before the age of 75), whereas in Sweden,Finland and Iceland it was much lower, in the range of8.0–19.0 [4]. In the US the crude incidence rate in thelate seventies was as low as 9.4 in Washington, Seattle(14.6 in New York City) and in Holland 8.9. Thesenumbers may be confounded by the level of screeningintensity in the respective countries. However, even inthe beginning of the 1960s when screening intensity waslow, the incidence in Denmark was double that of manyother countries.

The aim of screening for cervical cancer is largely todetect precursors to the disease such as dysplasia andcarcinoma in situ. These stages are, however, character-ised by significant regression rates, which entails thatwomen in some cases will be treated unnecessarily dueto screening programmes. In the present analysis it isassumed that 80% of all screen-detected cases of dys-plasia, and 60% of cases of carcinoma would haveregressed spontaneously [23,24]. The disease is thoughtto pass through a series of stages before developing tosymptomatic cancer. These stages are dysplasia, car-cinoma in situ (CIS), microinvasive and unsymptomaticcarcinoma. In order to evaluate screening programmes

it is necessary to have knowledge about the duration ofthese phases. Several studies have estimated these pro-gression rates [24–28]. In the present analysis estimatesbased on Danish screening data were applied [27]. Thesojourn time of dysplasia was estimated at 3 years, CISand microinvasive cancer had a duration of 10 years, andinvasive carcinoma had an estimated latency period of3 years. The total sojourn time was hence estimated at16 years, while the derived sensitivity estimate was 85%.

The value of screening was examined by Soost et al.[29], whose extrapolations showed a specificity of 99.4%for cytologic screening for cervical cancer, which is theestimate applied in the model.

There has been performed no randomised controlledtrial of screening for cervical cancer using the Pap-smeartest. Hence, the evidence of effectiveness is based on theeffect screening interventions have had on incidence andmortality of cervical cancer. In the Nordic countries thiseffect is large [30,31]. Naturally, such historic compari-sons are problematic since the underlying incidencetrends are unknown. Hence, in modelling applicationsassumptions are made on the efficacy of early detection.In the present analysis 99% of those persons who aretreated for dysplasia or CIS are assumed to survive,based on the opinion of an expert panel of physicians.In contrast, only about 58% of those who are treated forinvasive cervical cancer will survive according to diseasespecific 10-year relative survival data [19].

The cost of performing a Pap-smear test was estimatedat US$37, including pathological evaluation [6]. The costof a coloscopy is assumed to cost US$165. The costswere estimated based on Danish tariffs charged in 1992.

Since cervical cancer screening most often detectsearly precancerous stages and treatments of these stagesis considerably less costly than treating invasive can-cers, screening will entail savings in treatment costs.The costs of treating precancerous stages lie in the


range US$105–1130 while cancerous stages on averagecost between US$1130 and US$13 500 depending onthe necessary treatment [6]. The Danish estimates arebased on tariff charges and estimated average bed daycosts (1992 currency). Saving in treatment costs werecalculated on the basis of expected stage distributionsin a screening scenario.

2.4. A comparison

In the previous sections the core parameter valueswere presented for the three screening modes. Thesevalues are listed in a more compact form in Table 2.We now turn to the question: what effect does each ofthe attributes listed herein have on cost-effectiveness?

A higher incidence in the target population will lowerthe cost-effectiveness ratio (cost per life-year gained),since the effect of screening will be correspondinglyhigher. The latency period as well as the sensitivity rateis in reality a two-dimensional measure of the effective-ness of the screening test. Both figures have very impor-tant implications for cost-effectiveness. A long latencyperiod will entail a high pick-up rate at each screeninground and hence a lower CE ratio, since a high numberof prevalent cancers will exist at any time. Thus, a longlatency period may call for less frequent screening andcompensate for a low incidence, if accompanied by ahigh sensitivity rate. When the sojourn time is long andthe sensitivity is high, the incremental cost per life-yearof reducing the screening interval is likely to be consid-erable, since only few additional cancers will be de-tected when screening is intensified. If, however,sensitivity is low, it may be cost-effective to screen morefrequently, thereby detecting the cancers that were pre-viously overlooked. If the latency period is short andthe sensitivity is low, cost-effectiveness will, all otherthings equal, worsen considerably. However, in such ascenario frequent screening will not produce fast-risingincremental costs per life-year, since additional screen-ing rounds are likely to provide a significant increase innumber of screen-detected cancers.

The excess survival rate of early detected cancers,represents the added probability of surviving due toearly detection, and is crucial for the effectiveness ofscreening programmes. Screen-detecting cancers is themeans to the goal of saving lives. Only if we canactually reduce mortality by early detection have wereached this goal. The cost-effectiveness ratio is con-versely proportional to the excess survival rate.

A high specificity is important in order to containcosts. If the specificity is low, this will entail a highnumber of unnecessary diagnostic tests incurring highcosts, if the diagnostic test is costly. Hence, if specificityis low inexpensive diagnostic procedures are warrantedalong with infrequent screening. The combination of a

low specificity and a very comprehensive diagnostic testmay warrant a screening programme inoperational dueto the magnitude of the tangible costs as well as theintangible costs (anxiety, inconvenience etc) involved.

Finally, the cost of the screening test is very impor-tant, since this is the cost that is incurred by allparticipants. It is important to note that, in contrast, allother costs of a screening programme are only incurredby the small proportion of the target population whohave a positive screening test. Hence, small increases inthe cost of the screening test will have a significantinfluence on the CE ratio.

Looking again at Table 2, we can see that no screen-ing programme is obviously superior. Each type ofscreening programme has its own merits and disadvan-tages. Colorectal cancer has a short latency period anda short sojourn time, a combination which calls forfrequent screening if there is to be a reasonable effect ofintroducing such a screening programme. Although thetest is not impressive at detecting colorectal neoplasms,patients whose cancers are detected by the screeningtest have significantly improved prospects of survival.Moreover, frequent screening will not incur unsur-mountable costs, since the cost of the screening test isvery low and the specificity is high.

Breast cancer screening has other characteristics.Mammography is not an inexpensive test and the spe-cificity is only moderately high. Hence, mammographyscreening is likely to be a costly affair. However, thehigh incidence rate of mammae cancer is accompaniedby an effective screening test which may render thistype of screening cost-effective.

Cervical cancer screening clearly has its merits in theperformance of the Pap-smear test which provides goodprotection for participants. The very long sojourn timecombined with a reasonable sensitivity does howeversignal the importance of infrequent screening. An addi-tional advantage is the great improvement in survival ifthe cancer is detected prior to the invasive stage. Cervi-cal cancer screening is however characterised by nothaving a narrow high risk group, and the overall inci-dence for this type of cancer is considerably lower thanfor mammae cancer and colorectal cancer.

Having introduced the parameter values of the modeland hopefully given the reader a good understanding ofthe relative merits of the programmes, we now turn tothe modelling results and focus on the relative cost-ef-fectiveness of the three types of programmes.

3. Modelling the cost-effectiveness of screening

In previous works we modelled the effect of screeningfor colorectal cancer, cervical cancer and mammaecancer [5–7]. The model used for all three evaluations isa statistical model originally developed by Day and


Table 3Screening the 50–69 year olds every 2 years by mammographya

Life-years (5% p.a.)Cost (US$) (undiscounted)Life-years (undiscounted) Cost (US$) (5% p.a.)

First round 1251 3.1×106 2.9×1066361.8×1063092.0×106Second round 6781.2×106Third round 658 1.5×106 2711.7×107Overall 12 457 2.9×107 3232

a The programme is simulated over a period of 36 years.

Walter [8]. Variables such as mean sojourn time, sensi-tivity rate and age dependent incidence rates, are inputsinto a simulation process, where the number of cancersdetected per age group at each screening round areestimated for hypothetical screening programmes withvarying screening intervals and target groups. Numberof cancers detected are converted to ‘lives saved’ bymultiplying the number of cancers detected by theestimated excess survival rate2. Life-years gained areestimated by identifying how many lives are saved ineach 5-year age group and multiplying these by theiraverage life expectancy (adjusted for mean lead time).Gained life-years are not quality adjusted since it hasbeen shown that for colorectal cancer and mammaecancer recovery entails close to perfect health [32,33].To this author’s knowledge no quality of life studieshave been made for cervical cancer patients post-treat-ment, but since early detection most commonly entailseasy treatment with no side-effects, perfect health sub-sequent to disease is the most frequent outcome ofcervical cancer screening.

Number of gained life-years were estimated assumingthat a population corresponding approximately in sizeand age-distribition to the population of FunenCounty, Denmark was invited to participate in thescreening programmes. Each invitation initiated mailingcosts, and for each participant the cost of the screeningtest was incurred. Included on the cost side were alsoother direct health care costs such as cost of diagnostictests and treatment as well as overhead costs such ascosts of equipment, personnel and facilities. Most costswere assumed variable under the assumption that re-sources are adjusted to the scale of the programme inthe long run. All costs and effects were discounted topresent time by 5% p.a. In the evaluations were notincluded intangible costs such as the anxiety experi-enced in connection with a false positive result. Time

and travel costs experienced by participants were alsoexcluded. The viewpoint of the cost-effectiveness analy-ses is that of the national health care sector. For a morethorough description of the respective evaluations see[5–7].

Tables 3–5 present estimated costs and effects of thefirst three screening rounds for each of three screeningprogrammes. The target groups and screening intervalschosen here are not incidental. The cervical cancerscreening programme corresponds to the Danish Na-tional Health Board’s recommendation of screening the23–59 year olds every 3 years. The other two pro-grammes represent programmes setups that are imple-mented, or are most likely to be implemented, inDenmark.

After the initial three screening rounds the rate ofdetection will stabilise, making the results of the thirdscreening round the most important for the overallcost-effectiveness ratio. Outcomes are listed undis-counted as well as discounted by 5%.

Tables 3 and 5 depict high rates of detection at thefirst screening round relative to subsequent screeningrounds. For cervical cancer screening this effect is mostpronounced due to the very long latency period. Com-paring the discounted costs and effect of the thirdscreening round for the three programmes, cervicalcancer screening attains the largest effect but at thehighest cost while colorectal cancer screening incurs thefewest life-years at the lowest cost. Cervical cancerscreening obtains a good effect due to the wide age-span of its target group, the long latency period and thehigh sensitivity. The effect is, however obtained at ahigh cost due to a low incidence of this cancer in thetarget population. Also, the effect of cervical cancerscreening is reduced most markedly by discountingbecause the long latency period implies that lives aresaved in the distant future. Focusing on the undis-counted costs and effects screening the 23–59 year oldsevery 3 years for cervical cancer is a more cost-effectiveoption than the mammography programme simulatedhere. Comparison of discounted results does howeverlead to a different conclusion. The average cost perlife-year of a programme screening the 50–69 year oldsbiennially for breast cancer is US$5155 which is similarto the average cost (US$5060) of screening the 23–59year olds every 3 years for cervical cancer, when costs

2 In this analysis it is assumed that the excess survival rate amongstindividuals whose cancers are detected by screening is constant andindependent of screening interval. This may be an unrealistic assump-tion, since it is probable that cancers will be detected at a later stagewhen the screening interval is long, and at earlier stages when thescreening interval is short. For this reason, only screening intervalsthat did not differ significantly from the screening intervals applied inthe trials, were included in the analyses.


Table 4Screening the 50–74 year olds every 2 years using the unhydrated H-II testa

Cost (US$) (undiscounted) Life-years (5% p.a.) Cost (5% p.a.)Life-years (undiscounted)

9.5×105First round 350620 8.8×105

Second round 460 7.1×105 235 5.8×105

6.6×105 195Third round 4.9×1054081.3×107 2154 7.1×1067608Overall

a Costs and effects simulated over a 36-year period.

and life-year are discounted by 5% p.a. The least expen-sive option is inviting the 50–74 year olds to have aHemoccult II test every 2 years at a cost of US$3250per life-year saved.

Extending the comparison of the three screeningtechnologies from focusing on only one programmeconstellation for each screening mode, we now turn tothe estimated efficiency curves of each of these pro-grammes and focus on the incremental cost profile ofeach of the programme types.

In Fig. 1 are depicted efficiency curves for mammog-raphy, colorectal cancer screening and cervical cancerscreening, respectively. For each screening mode a se-ries of alternative screening programmes with varyingtarget groups and screening intervals were simulated todetermine the programme specific costs and effects[5–7]). Within each set of mutually exclusive pro-gramme setups, programmes were identified which for agiven level of cost maximised life-years gained. Eachefficiency curve constitutes this subset of dominating(efficient) programmes. Programmes on each efficiencycurve are mutually exclusive, while programmes ondifferent curves are independent and could be intro-duced simultaneously.

Tables 6–8 list the average and incremental costs perlife-year for each subset of efficient programmes. Theincremental cost per life-year signifies the cost perlife-year of the extra life-years that are saved due tomore intensive screening., i.e. moving up the efficiencycurve.

Fig. 1 and Tables 6–8 illustrate the characteristics ofthe three types of screening programmes. The efficientcolorectal cancer screening programmes are all placedin the southwest corner of the figure. The efficiencycurve shows a moderate tendency to curve upwardswith incremental costs per life-year ranging fromUS$2625 to 6570. Decreasing the screening interval hasrelatively little effect on cost per additional life-yearbecause the number of cancers detected is increasedconsiderably when the screening programme is inten-sified.

The incremental cost range for efficient mammogra-phy screening programmes as well as cervical cancerprogrammes is much wider with maximum incrementalcosts of US$79 870 and 77 290, respectively. The steep

slope of the cervical cancer screening curve is explainedby the long sojourn time and the high sensitivity of thescreening test which renders it unnecessary to screenfrequently. Incremental costs rise markedly if thescreening interval is reduced beyond 4 years. For mam-mae cancer the slope is likewise steep which is alsoexplained by the high sensitivity of mammography andthe length of the average sojourn time. However, sincethe latency period for this type of cancer is considerablyshorter than for cervical cancer, it is reasonably cost-ef-fective to screen as often as every 2 years. More fre-quent screening does however increase incrementalcosts significantly.

4. Discussion

From the list of efficient programmes in Tables 6–8,it is evident that while biennial mammography screen-ing of 50–69 year olds is amongst the efficient subset ofprogrammes, offering Pap-smear screening to the 23–59 years olds every 3 years and screening the 50–74year olds biennially for colorectal cancer are not effi-cient options. For example, screening the 23–59 yearolds every 3 years for cervical cancer gains 4257 life-years at an average cost of US$5060. This programmeis dominated by an alternative cervical cancer pro-gramme, which invites the 20–69 year olds every 4years. This programme gains 4346 life-years at an aver-age cost of US$4760.

These cost-effectiveness analyses suggest that col-orectal cancer screening is a cost-effective health careintervention irrespective of screening interval. The olderage groups should have first priority when setting thetarget group, since the increasing risk by age clearlyoffsets the decreasing life-expectancy. Hence, it is opti-mal to reduce the screening interval to 1 year beforeinviting the 50–54 year olds.

The results presented here rely on the assumptionsmade on parameter values. It should, however, benoted that a cost-effectiveness analysis based on theevidence from the H-II trial in Nottingham, UK [34],produces very similar unit cost estimates and almostidentical cost-effectiveness results. Nevertheless, if thecost of FOBT were to rise to US$3 (rather than


Table 5Screening the 23–59 year olds every 3 years using the Pap-smear testa

Cost (US$) (undiscounted) Life-years (5% p.a.)Life-years (undiscounted) Cost (US$) (5% p.a.)

1.5×106First round 15755350 3.1×106

Second round 2200 3.1×106 535 3.1×106

Third round 1870 3.2×106 380 2.6×106

3.8×107 425726 250 2.2×107Overall

a Costs and effects are estimated over a 36-year period.

US$1.50), the incremental cost ratios would lie in therange US$3040–7810 across the list of efficient pro-grammes. If the cost of colonoscopy were as much asUS$460, incremental cost per life-year would rise toUS$9140 for a programme that invites the 50–74 yearolds annually. If no cancers are avoided by adenomadetection and follow-up the incremental cost per life-year will lie in the range US$2970–7605.

The results of the evaluation of mammography indi-cate that it is reasonably cost-effective to implementbreast cancer screening programmes if the screeningprogrammes are not extended beyond screening the50–74 years olds every 2 years. Screening this agegroup more frequently will increase incremental costsconsiderably. Moreover, it is not cost-effective to screenthe 40–49 year olds. Screening the 50–69 year oldsbiennially was estimated to incur incremental costs ofUS$9060 per life-year or an average cost of US$5155per life-year. If the cost per mammography for the thirdand subsequent screening rounds were to differ fromthe present estimate (US$35.50) by 9US$8.00, thiswould alter the incremental cost ratio for this pro-gramme by 9US$1586 per life-year.

The incremental cost per life-year did however varydepending on frequency of open biopsy. If 25% of falsepositives were to undergo open biopsy, the incrementalcost ratio would increase by US$1035 for the leastintensive programme, and by as much as US$20 000 forthe most intensive programme, i.e. screening the 40–74years olds annually. Hence, in planning a breast cancerscreening programme it is not only important to decideon screening interval and target group. It is also impor-tant to decide on a policy regarding assessment proce-dures following a positive mammography.

In the cost-effectiveness analysis of cervical cancerscreening the incremental cost per life-year gained wasestimated to lie in the area of US$3255–17 440 if thescreening interval was not shorter than every 3 years[6]. The conclusions are that it is not cost-effective toscreen women under the age of 20 or above the age of69. Moreover, cost ratios rise markedly if screeningprogrammes are intensified beyond screening the 25–59year olds every 4 years.

Participation rates have very little effect on cost-ef-fectiveness in the above evaluations, the reason being

that most overhead costs are assumed variable in thelong run. Moreover, for colorectal cancer screeningwhere an invitation entails cost of H-II test in additionto the costs of a standard invitation, the model assumesthat persons who have denied previous invitations arenot re-invited3. This corresponds to the protocol of theFunen trial, and entails that the likelihood of sendingthe H-II test to people who decline to participate isminimised. This is not to say that resources should notbe spent on enhancing participation. The reason beingthat an increase in participation rates will incur addi-tional life-years at a lower cost than if programmeswere to be intensified by expanding the target groupand/or decreasing the screening interval.

Early detection of colorectal cancers is unlikely toproduce any significant savings in treatment costs [13].Detection of adenomas produces savings, since cancertreatment is avoided, but analysis has shown that themagnitude of such savings in present values is negligi-ble, since these savings will be incurred 10–20 yearsfrom the present time [5]. Although evidence is not

Fig. 1. Efficiency curves for colorectal cancer screening, breast cancerscreening and cervical cancer screening.

3 It is common practice in Denmark not to re-invite individualswho deny previous invitations. At present this system is practised inseveral population screening programmes.


Table 6Incremental costs for efficient colorectal cancer screening programmes

Life-yearsProgramme Cost (US$) Average cost per life-year Incremental cost per life-year

2.6×10665–74a,b 2625974 262560–74a,b 1425 3.9×106 2700 2870

5.3×106 29001831 358055–74a,b

6.6×106 310055–74a,c 437021299.2×106 35502607 550055–74a,d

1.2×107 4000 657050–74a,d 3081

a Units=years.b I=2 years.c I=1.5 years.d I=1 year.

Table 7Incremental costs for efficient cervical cancer screening programmes

Cost (US$)Life-years Incremental cost per life-yearProgramme Average cost per life-year

211830–50a,b 6.9×106 3255 3255314032209.4×106291030–59a,b

325125–59a,b 1.1×107 3415 506030–59a,c 3532 1.3×107 3610 585025–59a,c 3903 1.5×107 3880 6455

4161 1.8×10725–69a,c 4400 12 20047602.1×107434720–69a,c 12 900

4769 2.8×10720–69a,d 5880 17 440518020–69a,e 4.5×107 40 5308630

58 640943015–69a,e 5265 5.0×107

5.9×107 10 9005381 77 29015–99a,e

a Units=years.b I=5 years.c I=4 years.d I=3 years.e I=2 years.

based on randomised trials, cervical cancer screening islikely to produce substantial savings since most screen-detected neoplasms are precancerous and easily treated.However, the present value of these savings is signifi-cantly reduced due to the long latency period of thiscancer disease. For mammae cancer the situation is lessclear. There seems to be no published evidence basedon randomised trials, and those studies that are pub-lished do not agree on the importance of these potentialsavings [21,22]. In the present evaluation we have as-sumed that for every life saved a saving of approxi-mately US$7550 will incur. If it should turn out thatbreast cancer screening, like colorectal cancer screening,does not produce savings, the conclusions of this paperstill hold. If treatment costs remain constant after intro-duction of a breast cancer screening programme, costper life-year would decrease by as little as US$440–1150 and would not influence the list of efficient breastcancer programmes. Overall, one can conclude thattreatment cost saving has no significant impact on thecost-effectiveness ratio of the three screening pro-

grammes analysed here.Let us assume that risk reduction is valued similarly

whether it is derived from a reduction in deaths fromcolorectal cancer, mammae cancer or cervical cancer.Let us moreover assume that inclusion of time andtravel costs as well as intangibles involved in participat-ing in each of these programmes would not substan-tially alter the relative economics of these screeningmodes. Under these assumptions we can now compareincremental cost values and suggest that independentprogrammes be implemented such that incrementalcosts are kept approximately equal across all threescreening programmes. Any large discrepancy in incre-mental costs across programmes would entail an inopti-mal distribution of resources and redistribution couldpotentially improve effectiveness.

Implementing the following three programmes inDanish counties: biennial mammography screeningtargeted at the 50–69 year olds, cervical cancer screen-ing every 4 years for the 25–59 year olds and annualH-II testing of the 50–74 year olds would entail a


Table 8Incremental costs for efficient breast cancer screening programmes

Programme Life-years Cost (US$) Average cost per life-year Incremental cost per life-year

224050–64a,b 9.3×106 4170 41705505270850–69a,b 44001.2×107

3232 1.7×10750–69a,c 5155 90603522 2.0×10750–74a,c 5605 10 5903845 2.5×10750–74a,d 6590 17 350

30 77586803.7×107420950–74a,e

4533+40–49a,c 32 95010 4154.7×107

5.0×107 51 9504586+40–49a,d 10 895+40–49a,e 79 87011 9105.5×1074654

maximum cost per life-year of US$9060. The totallife-year gain based on a Funen population would be10 216 and the total cost US$44 million in present values.Such a programme constellation would represent anoptimal distribution of resources. Alternatively, offeringthe 50–69 year olds mammography at 3-year intervals orpossibly screening the 50–74 year olds biennially forbreast cancer would likewise represent good use ofresources. The former alternative would lower theoverall maximum cost per life-year to an estimate ofUS$6570, whereas screening the 50–74 year olds forbreast cancer every 2 years would increase the maximumcost per life-year across all programmes to US$10 590.This can be verified from conferring with Tables 6–8.

Various efficient programme constellations exist. Acombination of programmes should be chosen such thatincremental costs are near-equivalent subject to thebudget constraint. If a budget is not predetermined, thepolicy maker should consider how much he at maximumis prepared to pay per life-year and let this be a guideto planning future programmes setups.

To illustrate the importance of an appropriateresource allocation, let us assume that Funen countywere to introduce annual mammography screening ofthe 50–74 year olds while simultaneously offeringcervical cancer screening to the 23–59 year olds every 3years. Let us also assume that Funen county decided notto introduce colorectal cancer screening. The total costwould be US$59 million and the programmes wouldproduce a gain in life-years of only 8466. This exampleshows how vital it is to distribute resourcesappropriately so that a maximum effect is obtaineddown to the last dollar invested.

5. Conclusion

This paper seeks to compare the cost-effectiveness ofmammography screening, colorectal cancer screeningby FOBT and cervical cancer screening (Pap-smear).This comparative evaluation has shown that althoughbreast cancer screening and cervical cancer screening

programmes are more effective in detecting cancers,colorectal cancer screening, using the unhydrated H-IItest, is overall more cost-effective overall. This papersuggests that in a Danish setting, it would be optimal tointroduce annual colorectal cancer screening of the50–74 year olds along with biennial mammographytargeted at the 50–69 year olds and cervical cancerscreening every 4 years for the 25–59 year olds. Otheroptimal programme constellations can be identified de-pending on the relevant budget level and the implicitthreshold for marginal cost-effectiveness, but any largediscrepancy in incremental costs across programmeswould entail an inoptimal distribution of resources andredistribution could potentially improve effectiveness.

6. Reviewers

This paper was reviewed by Dr Rob Boer and DrWillem-Jan Meerding, Department of Public HealthiMGZ, Erasmus University of Rotterdam, P.O. Box1738, NL–3000 DR Rotterdam, The Netherlands.

References

[1] Kronborg O, Fenger C, Olsen J, Jøgensen OD, Søndergaard O.A randomised study of screening for colorectal cancer with fecaloccult blood test at Funen in Denmark. Lancet 1996;348:1467–71.

[2] Hardcastle JD, Chamberlain OJ, Robinson MHE, et al. Ran-domised controlled trial of faecal-occult blood screening forcolorectal cancer. Lancet 1996;348:1472–7.

[3] Kerlikowski K, Grady D, Rubin SM, Sandrock C, Ernster VL.Efficacy of screening mammography. A meta-analysis. J Am MedAssoc 1995;273:149–54.

[4] IARC. Cancer Incidence in five continents. Vol. V. Oxford Press,1987.

[5] Gyrd-Hansen D, Søgaard J, Kronborg O. Colorectal cancerscreening: efficiency and cost effectiveness. Health Econ 1998;7:9–20.

[6] Gyrd-Hansen D, Hølund B, Andersen P. A cost effectivenessanalysis of screening of cervical cancer screening.: health policyimplications. Health Policy 1995;34:35–51.

[7] Gyrd-Hansen D. Breast cancer screening. A sensitivity analysis.CHS Working Paper 1997, Odense University.


[8] Day NE, Walter SD. Simplified models for screening for chronicdisease: Estimation procedures for mass screening programmes.Biometrics 1984;40:1–14.

[9] Gyrd-Hansen D. Fecal Occult Blood Tests. A cost effectivenessanalysis. Int J Technol Assess Health Care 1998;14(2):290–301.

[10] Gyrd-Hansen D, Søgaard J, Kronborg O. Analysis of screeningdata: colorectal cancer. Int J Epidemiol 1997;26:1172–81.

[11] Stryker SJ, Wolff BG, Culp CE, Libbe SD, Ilstrup DM, Mac-Carthy RL. Natural history of untreated colonic polyps. Gas-troenterology 1987;93:1009–13.

[12] Jørgensen OD, et al. The Funen follow-up study. Incidence anddeath from colorectal carcinoma in an adenoma surveillanceprogram. Scand J Gastroenterol 1993;28:869–74.

[13] Bech K, Kronborg O. Sengedagsforbrug i forbindelse med screen-ing for tarmkræft. De første frem ar af en randomiseret befolkn-ingsundersøgelse. Ugeskrift for Læger 1992;154:696–9.

[14] Tabar L, Fagerberg G, Duffy SW, Day NE, Gad A, Grøntoft O.Update of the Swedish two-county program of mammographicscreening for breast cancer. Radiol Clinics North Am1992;30(1):187–210.

[15] Van der Maas PJ, de Koning HJ, van Ineveld BM, et al. Thecost-effectiveness of breast cancer screening. Int J Cancer1989;43:1055–60.

[16] Tabar L, Fagerberg G, Chen H-H, Duffy SW, Smart CR, GadA, Smith RA. Efficacy of breast cancer screening by age. Newresults from the Swedish two-county trial. Cancer1995;75(10):2507–17.

[17] Duffy SW, Chen HH, Tabar L, Day NE. Estimation of meansojourn time in breast cancer using a Markov chain model of bothentry and exit from the preclinical detectable phase. Stat Med1995;14(4):1531–43.

[18] Clemmensen IH and Storm HH. Kræft i Danmark. KræftensBekæmpelse, 1993.

[19] Carstensen B. et al., editors. Survival of Danish cancer patients1943–1987. Danish Cancer Society Division for Cancer Epidemi-ology, Kræftens Bekæmpelse, Munkgaard, Copenhagen 1993.

[20] Sundhedsstyrelsen. Brystkræft. Tidlig opsporing og undersøgelse.Redegørelse. Sundhedsstyrelsens udvalg vedrørende tidlig op-sporing og undersøgelse af lidelser i brystet, 1994.

[21] Butler JR, Furnival CM, Hart RF. The cost of treating breastcancer in Australia and the implications for breast cancer screen-ing. Aust New Zealand J Surg 1995;65(7):485–91.

[22] Salkeld G, Gerard K. Will early detection of breast cancer reducethe costs of treatment? Aust J Public Health 1994;18(4):388–93.

[23] van Ballegooijen M, et al. Preventive pap-smears: balancing costs,risks and benefits. Br J Cancer 1992;65:930–3.

[24] Parkin DM. A computer simulation model for the practicalplanning of cervical cancer screening programmes. Br J Cancer1985;51:551–68.

[25] Habbema JDf, van Oortmarssen GJ, Lubbe JThN, van der MaasPJ. The Miscan simulation program for the evaluation of screen-ing for disease. Comput Methods Programs Biomed 1984;20:79–93.

[26] Habbema JDF, van Oormarsse GJ, Lubbe JTN, van der Maas PJ.Model building on the basis of Dutch cervical cancer screeningdata. Maturitas 1985;7:11–20.

[27] Gyrd-Hansen D. A cost effectiveness analysis of screening againstcervical cancer on the basis of predictions of a mathematicalmodel. (En cost effectiveness analyse af screening for livmoderhal-skræft pa baggrund af en matematisk models forudsigelser). CHSWorking paper 1993:5, Odense University.

[28] Gustaffson L, Adami H-O. Optimization of cervical cancerscreening. Cancer Causes Control 1992;3:125–36.

[29] Soost H-J, Lange H-J, Lehmacher W, Ruffing-Kullmann B. Thevalidation of cervical cytology. Sensitivity, specifity and predictivevalues. Acta Cytol 1991;35:8–14.

[30] Day NE. The effect of cervical cancer screening in Scandinavia.Obstet Gynecol 1984;63:714–8.

[31] Hakkama M, Magnus K, Petterson F, et al. Effect of organizedscreening on the risk of cervical cancer in the Nordic countries.In: Miller AB, Chamberlain J, Day NE, et al., editors. CancerScreening. International Union Against Cancer. Cambridge Uni-versity Press, 1991 Chapter 16.

[32] Whynes DK, et al. Colorectal cancer screening and quality of life.Qual Life Res 1994;3:191–8.

[33] De Koning HJ, van Ineveld BM, van Oortmarrsen GJ, de HaesJCJM, Collette HJA, Hendriks JHCL, van der Maas PJ. Breastcancer screening and cost effectiveness; policy alternatives, qualityof life considerations and the possible impact of uncertain factors.Int J Cancer 1991;49:531–7.

Biography

Dorte Gyrd-Hansen (Msc, Phd) is a health economistpresently employed as an assistant professor at themultidisciplinary Institute of Public Health, OdenseUniversity, Odense, Denmark. Major interests: applica-tion of economic evaluations and discussion of relatedmethodological issues.

Documents

The relative economic of screening for colorectal cancer, breast cancer and cervical cancer