The role of radiotherapy in the management of operable locally advanced breast carcinoma: results of a randomized trial by the Eastern Cooperative Oncology Group

Abstract

Background: The purpose of this study was to test the role of radiotherapy following total mastectomy, axillary dissection, and adjuvant systemic therapy in the management of operable locally advanced breast carcinoma.

Methods: After undergoing mastectomy and axillary dissection, 426 patients with locally advanced breast carcinoma were registered on study and stratified by patient characteristics and risk factors. All patients were then treated with six courses of chemohormonotherapy. After being restaged, the 332 patients remaining without recurrence were randomized to receive prophylactic radiotherapy or to undergo observation and receive radiotherapy only if and when there was locoregional recurrence.

Results: Three hundred twelve of 332 randomized patients were deemed eligible and analyzed for both time to relapse and survival. The median follow-up period was 9.1 years. There were no significant differences in time to relapse and overall survival between the two treatment arms. Of those assigned to radiation, 60% relapsed, with a median time to relapse of 4.7 years, and 46% were alive at last follow-up, with a median survival of 8.3 years. Of those assigned to observation, 56% relapsed, with a median time to relapse of 5.2 years, and 47% were alive at last follow-up, with a median survival of 8.1 years. The two treatment arms had significantly different patterns of sites of first recurrence. There were 9% fewer locoregional first recurrences among those assigned to radiation than among those assigned to observation (15% vs. 24%), whereas there were 15% more first relapses at distant sites (50% vs. 35%) among those assigned to radiation (P = 0.003).

Conclusions: Radiotherapy for locally advanced breast carcinoma, following mastectomy, axillary dissection, and adjuvant systemic therapy, results in fewer locoregional but more distant recurrences at first relapse. No significant advantage was seen for consolidation radiotherapy over observation in terms of either time to relapse or survival, both of which were virtually identical in the two treatment arms. [See editorial counterpoint on pages 1061-6 and reply to counterpoint on pages 1067-8, this issue.]