Treatment-related toxicity from a randomized trial of the sequencing of doxorubicin and radiation therapy in patients treated for early stage breast cancer

Purpose: There is concern that breast cancer patients treated with left-sid ed radiation therapy (XRT) and doxorubicin (DOX) may have an increased risk of cardiac toxicity. In addition, the effect of different sequencing of XR T and chemotherapy (CT) on the likelihood of cardiotoxicity, as well as cel lulitis, arm edema, or brachial plexopathy, is not well understood. We revi ewed the records of patients treated on a randomized trial testing the sequ encing of CT and XRT to determine if there was an increase in cardiac event s or other complications in patients treated with a total dose of DOS of 18 0 mg/m(2) and XRT, comparing patients with treatment to the left breast and the right breast, and comparing patients treated with initial CT and initi al RT, Materials and Methods: From June 1984 to December 1992, 244 patients with c linical stage I or II breast cancer were randomized following conservative surgery to receive CT (4 cycles of CAMFP at 3 week intervals) either before or after XRT (45 Gy to the entire breast, followed by a boost of 16 Gy; no dal radiation therapy was optional). Two hundred thirty-one patients were e valuable for the development of cardiac toxicity. The median age at diagnos is was 45 years (range, 20-68), CT doses were: doxorubicin, 45 mg/m(2) IV b olus, d 3; methotrexate, 200 mg/m(2) IV, d I and 15; 5-fluorouracil, 500 mg /m(2) IV, d 1; cyclophosphamide, 500 mg/m2 IV, d 1; prednisone 40 mg p.o., d 1-5, A cardiac event was defined as a myocardial infarction or clinical e vidence of congestive heart failure. Median follow-up time was 53 months. Results: No cardiac events were observed for patients with either left- or right-sided breast cancer. The sequencing of CT and XRT had no significant effect on the risk of cardiac toxicity, cellulitis, arm edema or brachial p lexopathy. Conclusions: We observed no evidence of an increased risk of cardiac toxici ty from the addition of left breast tangential irradiation to DOX at a tota l dose of 180 mg/m(2). Additional follow-up is needed to exclude possible l ate events. In addition, the sequencing of CT and XRT does not appear to af fect the risk of cellulitis, arm edema, or brachial plexopathy. (C) 1999 El sevier Science Inc.