1029

Screening for Cervical Cancer inYoung Women

THE LANCET

ALTHOUGH the issues have changed, controversystill surrounds cervical-cancer screening pro-grammes. The debate is no longer about whetherthe programmes save lives: they almost certainlydo.1-3 It has turned instead to the age at which

screening should begin. The "Walton report",1 themost thorough discussion of cervical screening sofar, recommended that facilities for screening shouldbe offered to all women over the age of 18 yearswho have had sexual intercourse. It also recom-mended that cervical smears be repeated initiallywithin a year, then every 3 years until the age of35 and every 5 years thereafter until the age of 60.This might not, however, be the best way of usinglimited resources. Incorporating what is knownabout the natural history of cervical cancer into asimulation model, KNOX4 concluded that the effi-ciency of a screening programme could be im-proved by concentrating on screening at older ages,and that screening under the age of 35 was particu-larly unrewarding in terms of its potential for sav-ing lives. For these and other reasons, the BritishSociety of Cytologistss has continued to support theDepartment of Health and Social Security’s recom-mendation that routine screening should begin atage 35 and should be repeated every 5 years.Nevertheless, they do stress that women under 35should not be refused a smear and they encouragethe taking of routine smears during pregnancy.Lately, however, there have been calls to reducethe age at which routine screening should begin inthe U.K.6-8Of concern in England and Wales is the increas-

ing number of deaths from cervical cancer inwomen under 35, mortality-rates at age 25 to 34

1. Cervical Cancer Screening Programs Can. med. Ass. J. 1976, 114, 1003.2. Cramer, D. W. Cancer, 1974, 34, 2018.3. Miller, A. B., Lindsay, J., Hill, G. B. Int. J. Cancer, 1976, 17, 602.4. Knox, E. G. Br. J. Cancer, 1976, 34, 444.5. Spriggs, A. I., Husain, O. A. N. Br. med. J. 1977, i, 1516.6. Macgregor, E., Teper, S. Lancet, 1978, ii, 774.7. Andrews, F. J., Linehan, J. J., Melcher, D. H. ibid. p. 776.8. Miller, A. B. ibid. 1978, p. 469.

having doubled between 1966 and 1976.9,10Women born in the 1940s or later seem to be more

prone to cervical cancer than women born beforethat time. This difference is probably related to theincreasing use of the pill, the decreasing use of bar-rier methods of contraception, and the increasingexposure to sexually transmitted infections-all ofwhich may increase the risk of cervical cancer.1I,12Tragic though they are, deaths under the age of 35are few in number: 29 in England and Wales in1966, increasing to 69 in 1976.13 Even in 1976 theyrepresented only 3% of the 2206 cervical-cancerdeaths at all ages. Their importance lies in theirimplications for the future, since they foreshadowlarger increases in the numbers of deaths at olderages. Judging from the experience of earlier gener-ations of women, those born after 1940 will prob-ably maintain their high risk of cervical cancer asthey age.9,I4 There is therefore some reason to

expect an increase in cervical-cancer mortality in35 to 39 year-olds during the next 5 years, and in40 to 44 year-olds in the next 10 years. That is, un-less the impending epidemic of deaths is forestalledby the early detection and effective treatment ofwomen with cervical cancer or its precursors.

In Scotland, the numbers of deaths are too smallto show whether mortality has increased in thesame manner as in England and Wales. Sugges-tions6 that the cervical screening programmecentred in Aberdeen may have reduced mortalityunder 35 years in the surrounding Grampian andTayside regions compared with the rest of Scot-land, are intriguing; but they are based on suchsmall numbers-an annual average of less than 1death in the two regions combinedls-that thetrends may well represent chance fluctuations. Inthe U.S.A. and Canada, mortality from cervicalcancer in the generations born after 1940 has con-tinued to decline.8,16 This is despite major changesin lifestyle, and some indication that the incidenceof cervical cancer has increased there.2 While theevidence is circumstantial, the continuing decline inmortality in North America may reflect the benefitsof intensive screening under the age of 3 5 years.

So should the Department of Health alter its

recommendations concerning the age at which

screening should begin? There are disadvantages toscreening at young ages. The first is economic: thenumber of lives potentially saved per smear takenis low under the age of 35.4 The second relates to

9. Beral, V. ibid. 1974, i, 1037.10. Yule, R. ibid. 1978, i, 1031.11. Wright, N. H., Vessey, M. P., Kenward, B., McPherson, K., Doll, R. Br. J.

Cancer, 1978, 38, 273.12. Tech. Rep. Ser. Wld Hlth Org. 1978, no. 619, p. 26.13. Registrar General’s Statistical Review of England and Wales for 1966; and

O.P.C.S. Mortality Statistics: Cause; series DH2, vol. 3. H.M. StationeryOffice, 1976.

14. Hill, G. B., Adelstein, A. M. Lancet, 1967, ii, 605.15. Annual Report of the Registrar General for Scotland, 1976. H.M. Stationery

Office, 1977.16. Gardner, J. W., Lyon, J. L. Lancet, 1974, ii, 470.

1030

the danger of performing unnecessary uterine sur-gery and causing unnecessary anxiety to women,many of whom may not have completed their child-bearing. Screening aims to detect and treat precur-sors of malignant disease; but diagnostic errors arenot uncommon and there is doubt also about the

frequency with which the various premalignantconditions recognised cytologically progress to in-vasive cancer. Existing evidence suggests that

regression to normal is particularly common atyoung ages, whereas rapid progression to invasivecarcinoma is rare.17,I8 Moreover, if progressiondoes occur, carcinoma-in-situ probably takes morethan 10 years, and dysplasia longer still, to becomeinvasive. Is it therefore necessary to detect andtreat these apparently premalignant lesions as earlyas possible? Or might it not be better to wait untilolder ages where misdiagnoses seem to be less com-mon ?

Although screening at young ages seems to makelittle sense where resources are limited, it does havepractical advantages. Younger women are more ac-cessible for a mass screening programme than areolder women. Most sexually active women willeither have been pregnant or have sought contra-ceptive advice from medical personnel before theyare 35 years old. These consultations are ideal

opportunities for taking routine smears. That thisis so is illustrated by the large numbers of cervicalcytological investigations already performed inantenatal and family-planning clinics in womenunder 35 years of age.19,20 But the main advantageis that, at the same time as a smear is taken, eachwoman can be recruited into a long-term pro-gramme for regular cytological examination. More-over, "high-risk" women (those of low social classor those with many sexual partners) could be iden-tified at an early age, and special attention be givento their follow-up. This is very important. Themajor weakness of cervical-cancer screening pro-grammes is that these high-risk women rarelyattend for routine cytology. 21 Any means of encour-aging their regular examination is therefore desir-able. Of course this would not be achieved bysimply lowering the age recommended for routinescreening. It must be accompanied by a mechanismfor regularly recalling women for repeat smearsand for tracing those who do not return.Not enough is known for firm conclusions to be

drawn about the best age for screening to beginand the best time for subsequent smears to betaken. Any comparison of the merits of differentschemes must take into account the natural history

17. Kinlen, L. J., Spriggs, A. I. ibid. 1978, ii, 463.18. MacGregor, J. E., Teper, S. ibid. 1978, i, 1029.19. Health and Personal Social Services Statistics for England, 1976; p. 159.

H.M. Stationery Office, 1977.20. Department of Health and Social Security. Annual Report of the Chief Medi-

cal Officer for the Year 1972; p. 182. H.M. Stationery Office, 1973.21. Wakefield, J. (editor) Seek Wisely to Prevent. H.M. Stationery Office, 1972.

of the disease and errors in diagnosis, as well aseconomic and practical considerations. An efficientprogramme should certainly aim to maximise thenumbers of lives saved per smear taken; but itshould also ensure that it reaches the high-riskwomen who rarely volunteer for screening, and thatfollow-up is maintained. While screening at agesunder 35 seems to have little immediate potentialfor saving lives, it may offer an effective means ofrecruiting and identifying high-risk women. Manylives may be saved as a result. The recent increasein cervical-cancer mortality in young womenshould not cloud these issues. This increased mor-tality is probably a consequence of behavioural

changes in the community, and the numbers ofdeaths are small. Nevertheless, with the threat offuture increases in cervical-cancer mortality at

older ages, there is an urgent need to review the

validity of existing screening policy in the UnitedKingdom and elsewhere.

Poliovaccine for ParentsTHE control of infectious disease by immunisa-

tion has been one of the triumphs of medicine.Most notable has been the virtual eradication ofsmallpox from the world. Smallpox, indeed, illus-trated one of the problems of successful immunisa-tion : the time came when the dangers of vaccina-tion exceeded those of getting the disease. Thegeneral policy of Western countries was then tocontinue vaccination, at least for special groups, incase smallpox should be reintroduced from anendemic area. Much the same situation has nowarisen with poliomyelitis, and in countries wherevaccination has brought the disease under controlthe vaccine dangers are under fresh scrutiny. 2

In England and Wales, immunisation with livingpoliovaccine has reduced to single figures the inci-dence of paralytic cases in most years: in the sevenyears from 1969 to 1975 there were 31 paralyticcases3-an average of under 5 a year. But in 1976there were 13 cases, and in 1977, 26; doubtless thisdisturbing increase was connected with the adversepublicity about pertussis vaccine, which reducedacceptance of other vaccines. Of the 31 cases 11were acquired abroad, and 10 were associated withvaccination, either of recipients or of contacts. Ofthe 7 cases in contacts, 5 were in parents (3mothers, 2 fathers). At least 1 of the contact caseswas due to a wild type-I virus, but the other 4 weredue to viruses of types II and III, vaccine-like by thereproductive-capacity temperature marker. There istherefore a risk, though very small, to unvaccinatedadults in contact with vaccinated people. This risk

1. Dick, G. Progr. med. Virol. 1966, 8, 1.2. Melnick, J. L. Bull. Wld Hlth Org. 1976, 56, 21.3. Smith, J. W. G., Wherry, P. J. J. Hyg., Camb. 1978, 80, 155.