CORRESPONDENCE

The Effect of Changes in Tumor Size on BreastCarcinoma Survival in the U.S.: 1975-1999

The article by Elkin et al.1 provides interesting insights into the de-crease in breast cancer deaths that has occurred in the United States,

for the first time in 50 years, beginning in 1990. It would be interesting tolearn whether they could refine their analysis to take into account theonset of mammography screening in the United States that occurredduring 1983 to 1984 in sufficient numbers to affect National Statistics(Surveillance, Epidemiology, and End Results).2 At that time, not onlywas there a sudden increase in the detection of invasive cancers, butthere was also an abrupt increase in the detection of ductal carcinoma insitu, which is detected virtually only by mammography, indicating that1983 to 1984 was the beginning of widespread mammography screening.In fact, their graphs suggest that there was little size shifting within stagesuntil 1985, when the sizes began to shift consistent with the onset ofmammography screening.

Unfortunately, the authors have made the mistake that has beenmade repeatedly by others3 by combining the data for women ages 49and younger. I presume they did this thinking that these were the“premenopausal” women and that they may be grouped legitimately.This is not the case with regard to screening,4 and it causes the resultsto be biased5 by the very young women. I would encourage theauthors, at the least, to evaluate women ages 40 to 49 years separatelyfrom the younger women, because these are the women who havebeen encouraged to be screened in the United States. Although break-ing the data into even smaller age groups increases statistical fluctu-ation, it may provide greater insight into the benefits of screening thatdo not change suddenly at the age of 50 years, or at any other age.

REFERENCES1. Elkin FB, Hudis C, Begg CB, Schrag D. The effect of changes in tumor size on

breast carcinoma survival in the U.S.: 1975-1999. Cancer. 2005;104:1149-1157.2. Kopans DB. Beyond randomized controlled trials: organized mammographic screen-

ing substantially reduces breast carcinoma mortality. Cancer. 2002;94:580-581.3. Kopans DB. The breast cancer screening controversy: lessons to be learned.

J Surg Oncol. 1998;67:143-150.4. Kopans DB, Moore RH, McCarthy KA, et al. Biasing the interpretation of

mammography screening data by age grouping: nothing changes abruptly atage 50. Breast J. 1998;4:139-145.

5. Kopans DB. Informed decision making: age of 50 is arbitrary and has nodemonstrated influence on breast cancer screening in women. Am J Roentge-nol. 2005;185:177-182.

Daniel B. Kopans, MD

Avon Foundation Comprehensive Breast Evaluation CenterWang Ambulatory Care Center

Massachusetts General HospitalBoston, Massachusetts

10.1002/cncr.21805Published online 16 March 2006 in Wiley InterScience

(www.interscience.wiley.com).

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© 2006 American Cancer Society

Author Reply

We appreciate Dr. Kopans’s comments regardingour analysis of shifts over time in the size dis-

tribution of newly diagnosed breast tumors and theimpact of these shifts on within-stage breast cancersurvival.1 To address Dr. Kopans’s concern that weinappropriately grouped women ages 25 to 39 yearswith those ages 40 to 49 years in our susbet analysisby age at diagnosis, we repeated the analysis exclud-ing patients under age 40 years. In women ages 40 to49 years with localized breast cancer, standardiza-tion of relative survival on the basis of tumor sizeexplained 43% of the increase in relative survivalbetween the cohort of women who were diagnosedfrom 1975 to 1979 and the cohort of women whowere diagnosed from 1995 to 1999; this is slightlygreater than the 38% of survival improvement ex-plained by tumor size standardization in the entiregroup of women ages 25 to 49 years. In women ages40 to 49 years with regional breast cancer, tumorsize standardization explained 21% of the survivalimprovement over time, slightly less than the 23%of survival improvement explained by tumor sizestandardization in all women ages 25 to 49 years. Inboth localized and regional breast cancer, in allyears studied, women ages 40 to 49 years accountedfor at least two-thirds of all patients ages 25 to 49years.

We do not suggest that the benefits of screeningor of any other breast cancer intervention changeabruptly at age 50 years. Rather, we chose our agecategories (25-49 years, 50-64 years, and 65 yearsand older) so that our findings could be interpreted

in the context of the many screening, treatment,epidemiologic, health services, and other studiesthat use similar or identical age categories. In addi-tion, as we stated in our article, within-stage shift inthe tumor size distribution likely reflects the effectsof increased use of screening mammography in theUnited States, but its association with improvementin breast cancer survival is not definitive evidence ofthe effectiveness of screening. This applies to Dr.Kopans’s observation that most of the change incrude relative survival for localized disease appearsto occur in the mid-1980s. We believe that tumorsize standardization is a methodologic refinementthat improves our ability to interpret secular trendsin breast cancer survival.

REFERENCES1. Elkin FB, Hudis C, Begg CB, Schrag D. The effect of changes

in tumor size on breast carcinoma survival in the U.S.:1975-1999. Cancer. 2005;104:1149-1157.

Elena B. Elkin, Ph.D.

Clifford Hudis, M.D.

Department of Epidemiology and Biostatistics

Colin B. Begg, Ph.D.

Department of Medicine

Deborah Schrag, M.D., M.P.H.

Departments of Medicine andEpidemiology and Biostatistics

Memorial Sloan-Kettering Cancer CenterNew York, New York

10.1002/cncr.21806Published online 16 March 2006 in Wiley InterScience

(www.interscience.wiley.com).

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