External beam irradiation plus (192)Ir implant after breast-preserving surgery in women with early breast cancer.

PURPOSE: To provide more information for the clinician and to analyze the impact of the boost with brachytherapy on the local disease-free survival (LDFS), disease-free survival (DFS), specific overall survival (OS), and cosmesis, a retrospective study of external radiation therapy and (192)Ir implantation in early breast cancer at Institut Català d'Oncologia has been undertaken.

PATIENTS AND METHODS: From 1986 to 1996, 530 patients were selected for this study with a median follow-up period of 39.5 months (range, 10-115 months). External radiation therapy (combined with brachytherapy) was administered postoperatively to the breast in all patients. Mean given dose was 48.7 Gy (range, 42-52 Gy) with external radiation therapy to the breast, and 16.8 Gy (range, 10-27 Gy) was the mean dose with brachytherapy. Variables have been tested for cosmesis. Univariate and multivariate analysis have also been carried out.

RESULTS: Mean age of the patients was 54 years (range, 28-81 years). Stages were distributed as follows: 350 patients (66%) in Stage I, 173 in Stage II (32.8%), and 7 in Stage III (1.1%). Pathologic distribution was 445 patients with infiltrating ductal carcinoma (84%), 20 patients with infiltrating lobular carcinoma (4%), and 65 patients (12%) of a miscellaneous group. OS for the entire group was 89.4% and 85.9% at 5 and 7 years respectively. Probability of DFS was 81.7% and 70.1% at 5 and 7 years. The LDFS was 94.9% and 91.7% at 5 and 7 years. The MFS probability was 85.5% and 76.9% at 5 and 7 years, respectively. Univariate analysis demonstrated that age (older than 52 years), premenopausal status, moderate and high histologic grades (Grades II-III), and presence of intraductal comedocarcinoma were prognostic factors for local relapse. Multivariate analysis for local disease-free survival demonstrated that only perineural or muscular infiltration remain as prognostic factors. Tumor dose bed of 70 Gy or higher had a negative impact in breast subcutaneous fibrosis, whereas dose rate lower than 65 cGy/h was better for skin color at 2 years.

CONCLUSION: We conclude that patients with early-stage breast cancer undergoing external radiotherapy and LDR brachytherapy can be effectively managed. Overall survival, long-term local control, and cosmetic control are excellent.