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.