Re: Five Versus More Than Five Years of Tamoxifen Therapy for Breast Cancer Patients With Negative Lymph Nodes and Estrogen Receptor-Positive Tumors

Extract

In 1996, Fisher et al. ( 1 ) reported the 10-year follow-up results on the excellent double-blind placebo control trial (B-14) to determine the effectiveness of adjuvant tamoxifen therapy in patients with primary operable breast cancer who had estrogen receptor-positive tumors and no axillary lymph node involvement. The conclusions were that the benefit from 5 years of tamoxifen therapy persists through 10 years of follow-up, and no additional advantage is obtained from continuing tamoxifen therapy for more than 5 years. This is a critical trial because it contains a sufficient number of patients to answer the question of the use of tamoxifen therapy in this group of patients. The survival advantage is approximately 4% at 10 years, but less than 50% of the patients are at risk at 10 years at the time of this article. It appears that at 8 years there is no survival advantage. Thus, it is conceivable that with further follow-up the survival advantage that is seen at 10 years may change. Furthermore, the subanalysis of women who are 50 years of age or older, and who represent the majority of the patients in the study, demonstrates that there is no survival advantage over the 10-year follow-up [Fig. 3 survival curve P = .13 ( 1 )]. Are we to conclude that the use of tamoxifen in women greater than or equal to 50 years of age with node-negative estrogen receptor-positive operable breast cancer is not useful in prolonging survival or is it necessary that further follow-up be obtained to see the survival advantage? Although tamoxifen is a relatively benign form of treatment, there are side effects associated with it, including hot flashes and an increased incidence of thrombosis. Furthermore, many gynecologists, because of the increased risk of endometrial cancer, are performing routine endometrial biopsies that are quite painful for the patient. Thus, it is critical to know whether the use of this drug is truly improving the survival of such patients as reported in this study.