© 2002 by Oxford University Press
Journal of the National Cancer Institute, Vol. 94, No. 2, 143,
January 16, 2002
© 2002 Oxford University Press
CORRESPONDENCE |
Re: Risk-Reduction Mastectomy: Clinical Issues and Research Needs
Correspondence to: Gregory P. Swanson, M.D., Cancer Care Northwest, 601 S. Sherman, Spokane, WA 99202 (e-mail: greg.swanson{at}usoncology.com).
I read with interest the review by Stefanek et al. (1) on risk-reduction mastectomy. They conclude that the data present "a fairly strong argument for the risk-reduction potential of the surgical approach" (i.e., prophylactic mastectomy). Their recommendation for future research is presented later, with that statement as the central theme. The roles of screening and chemoprevention are also presented, but with a somewhat negative tenor.
The core of their argument for the effectiveness of risk-reduction mastectomy is an article published in 1999 (2). That study consisted of 639 women with a family history of breast cancer who had prophylactic radical mastectomies at some point during the 33 years from 1960 through 1993. On the basis of the number of other family members with breast cancer and/or ovarian cancer, they were then, retrospectively, classified as high risk (n = 214) or moderate risk (n = 425). There does not appear to have been a low-risk category. Of the 425 moderate-risk patients who had mastectomies, four patients developed breast cancer. Using the Gail model, Stefanek et al. retrospectively predicted 37. They then cited a risk reduction of 89.5%. Most patients and many physicians don't understand the concept of risk reduction; this makes its use misleading at best. When one looks at these data in a more concrete manner and assumes that the Gail model is valid in this patient population, mastectomy prevented cancer in 33 patients. What that means is that the mastectomies on the other 392 women (784 mastectomies) were performed unnecessarily. In absolute percentages, 1% of those women with mastectomy developed breast cancer versus 9% of those women without mastectomy who were predicted to develop the disease, for an absolute reduction of 8%. This number sounds dramatically different from 89.5%! This risk is actually less than the lifetime risk of breast cancer in the United States (12.5%) (3). Think of how many breast cancers we could prevent if all women underwent mastectomies at age 40 years (up to 183 000 per year!).
The average estimate of the development of cancer in the 214 patients at high risk is about 40 (18.7%), as opposed to the three (1.4%) who actually did develop this disease, for a risk reduction of about 92%. In absolute numbers, the risk difference is 17.3%, and 174 women (348 mastectomies) had surgery unnecessarily.
The ultimate goal is the prevention of cancer mortality. As shown in Table 2 of the review by Stefanek et al. (1), removing the breasts of 425 women at moderate risk (850 mastectomies) prevented 10 deaths, and removing the breasts of the 214 women at high risk (428 mastectomies) prevented 17 deaths. Although we don't want anyone to die of cancer, there has to be a serious discussion as to how many people have to be disfigured needlessly to achieve this goal. If all of the women in the United States received a mastectomy, we could prevent 40 000 deaths each year.
In their review of the acceptability of risk-reduction mastectomy to the patients, Stefanek et al. make it appear that patients on follow-up are satisfied with their decision to have a mastectomy. I maintain that, if these patients truly understood how few of them were actually reducing their risks, their satisfaction level would be much lower.
The preliminary analysis of BRCA1 and BCRA2 gene status of the Breast Cancer Prevention Trial in the National Surgical Adjuvant Breast and Bowel Project was presented at the meeting of the American Society of Clinical Oncologists (without abstract) in May 2001 (before the final submission of the current article). The analysis appears to show that tamoxifen reduces the incidence of breast cancer, at least in BRCA2 carriers. It is much too early to dismiss chemoprevention and screening as viable options in high-risk patients.
The focus of future research should not be on trying to justify the past use of mastectomy in breast cancer prevention but, rather, on how to avoid it.
REFERENCES
1
Stefanek M, Hartmann L, Nelson W. Risk-reduction mastectomy: clinical issues and research needs. J Natl Cancer Inst 2001;93:1297–306.
2
Hartmann LC, Schaid DJ, Woods JE, Crotty TP, Myers JL, Arnold PG, et al. Efficacy of bilateral prophylactic mastectomy in women with a family history of breast cancer. N Engl J Med 1999;340:77–84.
3 Greenlee RT, Murray T, Bolden S, Wingo, PA. Cancer statistics, 2000. CA Cancer J Clin 2000;50:7–33.[Abstract]
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