© 2001 by Oxford University Press
Journal of the National Cancer Institute, Vol. 93, No. 1, 64-65,
January 3, 2001
© 2001 Oxford University Press
CORRESPONDENCE |
Re: Tumor Characteristics and Clinical Outcome of Elderly Women With Breast Cancer
Affiliations of authors: University of Colorado Health Sciences Center, Denver, CO.
Correspondence to: Michele Basche, M.D., Department of Geriatrics, 111D, VAMC, 1055 Clermont St., Denver, CO 80220 (e-mail: Michele.Basche{at}med.va.gov).
The conclusion reached by Diab et al. (1) that "screening mammography might have limited value in older patients" is flawed because of the misinterpretation of two observations. First, Diab et al. observed a pattern of increasing survival with advancing age among women with early-stage breast cancer and inferred that older women have more indolent disease. In fact, this pattern likely is due to the selection of healthier women for screening and surgical staging. Second, they misinterpreted the importance of the observation that breast cancer accounts for a decreasing proportion of total mortality as women age.
Screening bias best explains the authors' observation that relative survival increases with age among women with small tumors (<2 cm). Women older than 65 years who obtain screening mammograms are healthier than their peers who are not screened (2). Relative survival improves with age because older women with screen-detected tumors are less likely to have serious, comorbid disease than their age-matched peers in the general population. This pattern is not due to a more indolent type of breast cancer in older women. When we specifically examined cause-specific mortality in the Surveillance, Epidemiology, and End Results (SEER)1 population, we found no decrease in breast cancer mortality with advancing age (Table 1
) (3).
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Staging bias accounts for the authors' observation that the relative survival of women with pathologically negative lymph nodes increases with age (1). Women older than age 70 years who undergo lymphadenectomy for pathologic lymph node evaluation have less comorbid disease than those who do not (4). The proportion of women who are pathologically staged in the SEER population decreases with advancing age (Table 1
). When we reanalyzed the data and included women clinically staged, the age difference in relative survival was much reduced. Moreover, when we examined breast cancer mortality for women with lymph node-negative disease, we found no decrease in breast cancer mortality with advancing age (Table 1). Thus, the clinical outcome for women with lymph node-negative disease or tumors less than 2 cm does not improve with advancing age. Diab et al. (1) correctly observed that the proportion of total mortality due to breast cancer decreases with advancing age. This is true only because other causes of death become more common. The critical observation for screening policy is that breast cancer incidence and mortality rates both increase with advancing age (5). The appropriate application of the observation by Diab et al. lies instead at the level of the individual patient, where competing mortality risks should play a role in predicting mammography benefits for each individual regardless of age.
Does screening mammography reduce breast cancer mortality among women older than age 70 years? Observational data (6) suggest that mammography already has contributed to decreased breast cancer mortality rates for women aged 70–79 years. In addition, screening mammography detects early-stage disease as effectively among women aged 70 years and older as among women aged 50–69 years (7). Correctly interpreted, observational data suggest that screening mammography decreases breast cancer mortality among women aged 70 years and older as it does among women aged 50–69 years.
NOTES
1 Editor's note: SEER is a set of geographically defined, population-based, central cancer registries in the United States, operated by local nonprofit organizations under contract to the National Cancer Institute (NCI). Registry data are submitted electronically without personal identifiers to the NCI on a biannual basis, and the NCI makes the data available to the public for scientific research. 
REFERENCES
1
Diab SG, Elledge RM, Clark GM. Tumor characteristics and clinical outcome of elderly women with breast cancer. J Natl Cancer Inst 2000;92:550–6.
2 Use of cervical and breast cancer screening among women with and without functional limitations—United States, 1994–1995. MMWR Morb Mortal Wkly Rep 1998;47:853–6.[Medline]cancerlit;99005321
3 Surveillance, Epidemiology, and End Results (SEER) Program Public-Use CD-ROM (1973– 1996), National Cancer Institute, DCCPS, Cancer Surveillance Research Program, Cancer Statistics Branch, released April 1999, based on August 1998 submission.
4 Hebert-Croteau N, Brisson J, Latreille J, Blanchette C, Deschenes L. Compliance with consensus recommendations for the treatment of early stage breast carcinoma in elderly women. Cancer 1999;85:1104–13.[CrossRef][ISI][Medline]cancerlit;99190216
5 Ries LA, Miller BA, Hankey BF, Kosary CL, Harras A, Edwards BK, editors. SEER cancer statistics review, 1973–1991: tables and graphs. NIH Publ No. 94–2789. Bethesda (MD): National Cancer Institute; 1994.
6
Chu KC, Tarone RE, Kessler LG, Ries LA, Hankey BF, Miller BA, et al. Recent trends in U.S. breast cancer incidence, survival, and mortality rates. J Natl Cancer Inst 1996;88:1571–9.
7
May DS, Lee NC, Nadel MR, Henson RM, Miller DS. The National Breast and Cervical Cancer Early Detection Program: report on the first 4 years of mammography provided to medically underserved women. AJR Am J Roentgenol 1998;170:97–104.
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