A recent study shows that a 50-year-old postmenopausal woman with localized breast cancer who receives radiation therapy (RT) along with tamoxifen following breast conserving therapy is 54 percent less likely to die from breast cancer than if she receives tamoxifen alone. An 80-year-old women reduces her risk by 42 percent. The absolute benefits of tamoxifen plus RT also vary with respect to the outcome studied, that is, recurrence-free survival time, time with an intact breast, and overall survival time. Therefore, doctors should consider the relative benefits of adding RT to tamoxifen and individual patient preferences when helping women select among treatment options, suggests Rinaa S. Punglia, M.D., M.P.H., of Brigham and Women's Hospital and Harvard University. The study was supported in part by the Agency for Healthcare Research and Quality (National Research Service Award training grant T32 HS00020).
The researchers used a model to compare outcomes for hypothetical groups of postmenopausal women with estrogen receptor-positive tumors (2 cm or less in size) with uninvolved axillary lymph nodes who were treated with tamoxifen plus RT versus tamoxifen alone after breast-conserving surgery. The model used data from randomized trials and retrospective studies to simulate patients' clinical course and estimate various outcomes.
Based on the model, recurrence-free survival was greater in the RT plus tamoxifen group, but the absolute difference between the groups decreased with increasing age at diagnosis. For example, expected recurrence-free survival was 30.38 years for women aged 50 at diagnosis who were treated with RT plus tamoxifen. This decreased to 27.03 years without RT (net benefit 3.35 years). However, for women who were aged 80 at diagnosis, expected recurrence-free survival increased by only .61 year with the addition of RT. Both groups of women (age 50 and age 80) who received tamoxifen plus RT were less likely to die from breast cancer than if they received tamoxifen alone (2.43 vs. 5.29 percent, and 1.17 vs. 2.02 percent, respectively), but the difference was greater for the younger women.
See "Radiation therapy plus tamoxifen versus tamoxifen alone after breast-conserving surgery in postmenopausal women with stage 1 breast cancer: A decision analysis," by Dr. Punglia, Karen M. Kuntz, Jason H. Lee, and Abram Recht, in the June 15, 2003, Journal of Clinical Oncology 21(12), pp. 2260-2267.