WHICH BENEFITS AND RISKS ARE IMPORTANT IN BREAST CANCER PREVENTION? Powles notes that the trials of tamoxifen and raloxifene reported to date have been concerned with breast cancer incidence data; and for NSABP P-1, the follow-up of cases has not continued after observation of a difference in this end point. These circumstances are important; subsequent reports of the NSABP P-1 trial have noted absence of cardiovascular benefits [7], but these data must be interpreted in light of the likely healthy volunteer population studied and the short-term treatment given and stopped when the breast cancer benefit was observed and communicated to the trial participants. By far the most critical global issue here is the question of mortality benefit. Since the NSABP P-1 trial was stopped based on an incidence finding, we may never know if a mortality benefit would follow. In fact, the numbers and circumstances suggest that a mortality benefit is unlikely in the studied population. This is true for two reasons. First, the cancers suppressed by tamoxifen treatment were hormone receptor-positive lesions, which, had they not been suppressed, would have likely appeared and been diagnosed clinically as T1 or T2 at most, stage 1 (usually) cancers. Such clinical cancers are associated with an excellent prognosis [8]. Thus, mortality associated with the cancers likely to have been prevented would be small. Second, there are quantifiable incidence risk-"costs" of tamoxifen treatment. These incident "events" can be associated with projections about lethality; pulmonary embolism, uterine malignancy, and stroke are each associated with some finite mortality rates. The rates of mortality here must be low but emphasize that mortality benefit from tamoxifen treatment of healthy women is far from certain (despite the dramatic breast cancer incidence benefit), particularly for postmenopausal women with a uterus. A comprehensive analysis of the risks and benefits of tamoxifen in different patient groups in the NSABP P-1 trial [9] should be mandatory reading for clinicians considering use of tamoxifen in healthy women. This analysis essentially confirms in premenopausal women given low risks of major side effects, long-term benefit is more likely, while in postmenopausal women, the opposite is true. Finally, with respect to benefits and risks, it must be emphasized that the data Powles reviews are of short-term treatment. The long-term consequences of a hormonal intervention, like tamoxifen, remain unknown and must be a concern. Over recent years we have seen clear evidence of the long-term consequences of oral contraceptive use; these observations should make us attentive to the possible multisystem consequences of tamoxifen or other breast cancer prevention interventions. THE SYMPTOMATIC SIDE EFFECTS OF HORMONAL INTERVENTIONS IN BREAST CANCER PREVENTION For women with life-threatening disease, symptomatic side effects that impair quality of life may be acceptable . For healthy women, the tolerance of such side effects must be predictably less. Tamoxifen is clearly associated with major increases in vasomotor symptoms [10]. These symptoms are likely the reason that perhaps one-quarter of women in prevention trials stop treatment. The analysis of risks and benefits of a prevention intervention for individual patients must consider those side effects also (Table 1). The Oncologist, Vol. 7, No. 2, 100-102, April 2002 © 2002 AlphaMed Press Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.