Response to radiation therapy and prognosis in breast cancer patients with BRCA1 and BRCA2 mutations

Background and purpose: The purpose of this study is to evaluate overall survival in BRCA1 or BRCA2 breast cancer patients, describe presenting stage, review histologic findings and evaluate response to radiotherapy. Materials and methods: A retrospective study was performed evaluating breast cancer patients with known mutations of BRCA1 or BRCA2. Patients from 12 different pedigrees were cross-referenced with the Utah Cancer Registry (UCR), histologic findings were verified and radiotherapy records were reviewed for acute response to treatment. Actuarial survival calculations were performed and patients were matched for age, date of diagnosis and tumor size. Results: Thirty breast cancer patients with BRCA1 mutations were found to have 34 breast cancers (four had bilateral metachronous lesions) and 20 breast cancer patients with BRCA2 mutations were: found to have 22 boast cancers (two had bilateral metachronous disease). The median age at diagnosis was 49 years (range 21-77 years) and 42 years (range 23-83 years), respectively, for BRCA1 and BRCA2 patients. Unusual histologic types of breast cancers were represented with 7% (4/56) medullary and 5% (3/56) lobular carcinomas. Complete staging was possible for 63% (35/56) of cancers. Stages I, II, III and IV represented 26, 63, 6 and 6% of cancers, respectively. The most severe radiation reaction was moist desquamation which was self-limiting and developed in 29% (6/21) of irradiated patients. The mean follow-up was 9.8 and 7.5 years for BRCA1 and BRCA2 cancers, respectively. Kaplan-Meier survival analysis demonstrated 5-year survival values of 75%, for BRCA1 patients, 73% for BRCA2 patients, 70% for matched controls and 69% for UCR controls. No statistically significant differences were evident between the groups at 5 or 10 years. Conclusions: Despite their younger age at presentation, breast cancer patients harboring BRCA1 or BRCA2 mutations present at a similar stage, display a normal acute reaction to radiotherapy and have a similar prognosis when compared with sporadic breast cancer patients. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.