Purpose: To identify predictors of adjuvant tamoxifen use, side effects, and discontinuation in older women. Patients and Methods: We followed a cohort of 303 women greater than or equal to 55 years of age diagnosed with stage I or stage II breast cancer for nearly 3 years. Data were collected from women's surgical records and from computer-assisted telephone interviews at 5, 21, and 33 months after primary tumor therapy. Results: Two hundred ninety-two (96%) of 303 patients in the study provided information about tamoxifen use. Tamoxifen use was reported by 189 patients (65%); 26 (15%) discontinued use during the follow-vp period. Patients who were 65 to 74 years of age (relative to those 55 to 64 years of age), held stage II disease, were estrogen receptor-positive, saw a greater number of breast cancer physicians, and had better perceptions of their abilities to discuss treatment options with physicians had greater odds of tamoxifen use. Those who had better physical function, had received standard primary tumor therapy, and had obtained helpful breast cancer information from books or magazines had lesser odds of tamoxifen use. patients greater than or equal to 75 years of age (relative to those 55 to 64 years of age) and patients with better emotional health had significantly lesser odds of reporting side effects, Patients who were estrogen receptor-positive were less likely to stop taking tamoxifen; patients who experienced side effects were more likely to stop taking tamoxifen. Conclusion: Deviations from a prescribed course of adjuvant tamoxifen occur relatively frequently, The clinical consequences of this deviation need to be identified. J Clin Oncol 19:322-328. (C) 2001 by American Society of Clinical Oncology.
