The use of electron beams in treating local recurrence of breast cancer in previously irradiated fields

Abstract

A retrospective study was performed to assess the efficacy of using electron beam therapy to treat locally recurrent breast cancer in previously-irradiated fields. In a group of patients who received postmastectomy nodal and chest wall megavoltage photon therapy to doses of 4000-5000 rads, an additional 4000-5000 rads were delivered to chest wall recurrences with 7-10 MeV electrons. Good tumor responses were obtained without unacceptable concomitant normal tissue damage. With a follow-up time of 9 mo. to 5 yr, 62% (8 of 13) are alive and clinically free of disease in the irradiated volume. Two patients died at respective times of 5 and 6 mo. after retreatment, with only 1 showing evidence of chest wall recurrence. One patient showed no response to therapy and the remaining 2 patients recurred in the treated volume at 10 and 59 mo. Morbidity was limited to dry and/or moist desquamation with no evidence of soft tissue necrosis. The 1st course of irradiation did not select for a subset of radioresistant tumor cells. A 2nd course of radiation therapy may have much to offer in controlling locally recurrent breast cancer.