Impact of radiation therapy on acute toxicity in breast conservation therapy for early breast cancer

Abstract

Aims: To document the acute toxicity experienced by women receiving radiation therapy as part of breast-conservation therapy (BCT) for early breast cancer. Materials and methods: A retrospective review was undertaken of the medical records of 234 consecutive women managed with radiation therapy for BCT over a 2-year period. A policy of formal acute toxicity documentation was present during this period with descriptive measures as well as the Radiation Therapy Oncology Group (RTOG) acute toxicity scoring system. Cutaneous moist desquamation, peak RTOG score, breast oedema and chemotherapy dose intensity were end points assessed. Patient and treatment characteristics were investigated for their association with study end points using Chi-squared and logistic regression analyses. Results: A total of 223 (95%) of women had data available for analysis. All women were treated with tangential fields on megavoltage linear accelerators. Eighty-three (37.2%) women had systemic chemotherapy either delivered simultaneously in 58 and sequentially in 25. Moist desquamation occurred in 70 (31.4%) women; principally in the inframammary fold only in 43 (19.3%). Only 12 (5.4%) had a confluent moist reaction. Two hundred and ten (94%) women had a peak RTOG skin grade of 2 or less. Breast oedema was evident at treatment end in 46 (20.5%). On univariate analysis, physical factors, such as patient weight (P<0.001) and breast size (P<0.001), were significantly associated with moist desquamation, as were the volume of breast resected (P=0.02) and the use of chemotherapy (P=0.03). Only the physical factors remained significant on multivariate analysis. The presence of breast oedema was associated with surgical factors such as post-operative oedema (P<0.001) and infective complications (P<0.001). The use of concurrent chemoradiotherapy did not affect chemotherapy dose intensity, nor did the presence of moist desquamation increase the risk of febrile complications in chemotherapy-related neutropenia. Conclusion: This study confirms the relatively low incidence of significant acute toxicity experienced by women during radiation therapy as part of BCT. These study data should assist surgeons and women in the decision-making process for BCT.