Prognostic factors in elderly women with metastatic breast cancer treated with tamoxifen: An analysis of patients entered on four prospective clinical trials

BACKGROUND Information regarding prognostic factors and survival in elderly women with metastatic breast cancer treated with tamoxifen is limited. METHODS The data from 4 prospective clinical trials were analyzed, including information on 396 postmenopausal women with advanced breast cancer who received tamoxifen as initial therapy for metastatic disease. Emphasis was placed on 184 elderly patients (age greater than 65 years) to characterize the response to therapy, time to progression (TTP), overall survival (OS), prognostic factors, and treatment-related toxicity. RESULTS Among 363 patients with measurable or evaluable disease, the objective response rates were higher in the elderly patients (46% versus 33%, P = 0.06); but age did not achieve significance in a logistic regression analysis (P = 0.1). The median TTP (10.5 months versus 6.2 months, log rank P = 0.002) and OS (35.7 months versus 28.8 months, log rank P = 0.02) were superior in the elderly cohort. In multivariate analysis, age at diagnosis approached statistical significance (P = 0.055) for TTP but was not significant for OS (P = 0.17). Among elderly patients, disease free interval (DFI) (greater than 5 years), dominant disease site (soft tissue), prior adjuvant chemotherapy, positive estrogen/progesterone receptor (ER/PgR) and performance status (PS) were independent prognostic factors. Hot flashes were common in both younger and older cohorts (25% versus 33%, P = 0.14), while anorexia (14% versus 22%, P = 0.04) and mood changes (2% versus 6%, P = 0.03) were more common in the elderly patients. CONCLUSIONS There was no indication that elderly women with metastatic breast cancer treated with tamoxifen have a poorer outcome with regard to response rate, TTP or OS; in fact, they appeared to have a slightly better prognosis although this was not significant after adjustment for other prognostic factors. In elderly patients, DFI, PS, positive ER or PGR, and dominant disease site are independent prognostic factors. Cancer 1996; 77:683-90.