Adjuvant radiation after modified radial mastectomy for breast cancer fails to prolong survival

Recent literature has reported improved local disease control and overall s urvival in premenopausal node-positive (stage II, and III) breast cancer pa tients undergoing modified radical mastectomy (MRM) using radiation therapy (RT) combined with chemotherapy. To assess the efficacy of postoperative R T in our own community, we analyzed all patients undergoing MRM for carcino ma utilizing an extensive database from the three major teaching hospitals in Tulsa, OK, between 1965 and 1993. A total of 5257 patients underwent MRM during this time period. One hundred thirty-seven patients were excluded f or insufficient data or because they were found to be at stage TV, leaving a total study population of 5125. Overall survival (OS), overall mean survi val (MS), disease-free survival (DFS), and locoregional DFS (LRDFS) were an alyzed for all patients and were further analyzed according to stage, lymph node involvement, and menopausal status. Median follow-up was 103 months. Statistical analysis was performed using Kaplan-Meier and t-tests. The DFS at 10 years was 65 per cent in the RT group and 80 per cent in the patients who did not receive RT (P = 0.00). No improved DFS was obtained in the rad iation-treated patients, regardless of stage, lymph node involvement, or me nopausal status. Similarly the LRDFS at 10 years was 91 per cent in the RT group and 96 per cent in the patients who did not receive RT (P = 0.00). No improved LRDFS was obtained in the radiation-treated patients, regardless of stage, lymph node involvement, or menopausal status. The overall MS was 97 months in the RT group and 104 months in the patients who did not receiv e RT (P = 0.00). Comparisons of overall MS rates revealed apparent survival benefits from RT in the premenopausal nodenegative group, postmenopausal o ne to four-positive-node group, and all stage I patients. This apparent sur vival advantage was not confirmed by Kaplan-Meier curves of OS. No other ov erall MS differences were detected according to stage, lymph node, or menop ausal status. Using Kaplan-Meier survival curves, the OS in the RT group at 10 years was 46 per cent; and 63 per cent in the patients who did not rece ive RT (P = 0.00). No improved OS was obtained in the radiation-treated pat ients, regardless of stage, lymph node involvement, or menopausal status. T hese findings from a large breast cancer database failed to demonstrate any meaningful benefit from RT after MRM and serve to further question the eff icacy of this treatment modality in postmastectomy breast cancer patients.