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Journal of Clinical Oncology, Vol 23, No 7 (March 1), 2005: pp. 1585 © 2005 American Society of Clinical Oncology. DOI: 10.1200/JCO.2005.05.127
Long-Term Survival and Cure of Patients Diagnosed With Breast Cancer Before Age 50 YearsDepartment of Epidemiology, German Centre for Research on Ageing, Heidelberg, Germany
Finnish Cancer Registry, and the Department of Public Health, University of Helsinki, Helsinki, Finland To the Editor: In a recent Editorial,1 Dr Green commented on our recent work,2 in which we presented estimates of long-term survival of patients younger than 50 years who are diagnosed with breast cancer, obtained by period analysis.3 Her arguments are strongly misleading for several reasons. First, Dr Green has misinterpreted the goal of our analysis, which was not to predict the 40-year survival of patients diagnosed with breast cancer at younger than 50 years today. Rather, we aimed to provide current estimates of long-term survival expectations of breast cancer patients, making use of the most up-to-date available data. These data indicate that there was persistent excess mortality of breast cancer patients diagnosed before age 50 years, even if diagnosis was more than 30 years ago. Secondly, it is self-evident and has been repeatedly pointed out3-5 that the period estimates of long-term survival may turn out to be somewhat too pessimistic (albeit much less so than the traditional cohort-based estimates) if used as predictors of future survival rates (as done by Dr Green), in case of further ongoing improvement in survival. Dr Green used an entirely hypothetical scenario (scenario 2) to illustrate the potential magnitude of this underestimation, ignoring the extensive empirical work that has assessed this type of underestimation under "real life" conditions.4,5 That work had clearly demonstrated the possibilities of such underestimation, but it also showed that this underestimation was generally quite small, and in particular, much lower with period analysis than with traditional cohort analysis (which is not addressed at all in the scenarios given by Dr Green) under real-life conditions. By analogy with Dr Green’s way of reasoning, one might question whether current period life-tables, which are commonly applied in demography to estimate current life expectancy, tell us whether humans have a finite life span. With an assumption that at some point a "cure" that prevents mankind from dying will be invented (an assumption analogous to that made by Dr Green in her scenario 2), estimates of life expectancy from period life-tables would likewise be excessively far from the future average length of life of contemporary newborns. We agree with Dr Green and had stated in our article that reasons for persisting excess mortality are yet to be identified by further research. One of the potential reasons, secondary breast cancer, was quantitatively evaluated in our study and turned out to be of minor relevance. Other potential reasons, such as late effects of cancer therapy, could not be evaluated in our data. However, such effects might also be considered as failure of cure in a somewhat wider sense. Finally, we did not argue (and nobody would seriously claim) that none of the breast cancer patients were cured. Therefore, the scenarios given by Dr Green assessing various proportions of cured patients do not make a relevant contribution. The relevant question is whether patients who have survived breast cancer for some minimum time, such as 10 or 20 years, can generally (all) be considered cured (in a wider sense), and this question clearly had to be denied for a time interval up to 40 years following diagnosis, on the basis of the latest data available at the time of our analysis. Finally while one might try to include all of the details addressed above in the title of a journal article, we continue to prefer short titles that address the key questions on one hand (at the price of omitting some details) and attract the interest of the researchers and clinicians, for whom the results might be of interest, on the other. Authors’ Disclosures of Potential Conflicts of Interest The authors indicated no potential conflicts of interest. REFERENCES
1. Green S: Do estimates of long-term survival tell us whether patients diagnosed with breast cancer before age 50 are ever cured? J Clin Oncol 22:392-394, 2004
2. Brenner H, Hakulinen T: Are patients diagnosed with breast cancer below age 50 ever cured? J Clin Oncol 22:432-438, 2004 3. Brenner H, Gefeller O: An alternative approach to monitoring cancer patient survival. Cancer 78:2004-2010, 1996[CrossRef][Medline]
4. Brenner H, Hakulinen T: Up-to-date long-term survival curves of patients with cancer by period analysis. J Clin Oncol 20:826-832, 2002
5. Brenner H, Hakulinen T: Very long-term survival rates of patients with cancer. J Clin Oncol 20:4405-4409, 2002
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Copyright © 2005 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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