Purpose: In the breast conserving management of mammary cancer a high-dose-rate (HDR)-Iridium-192 source is used for interstitial boosting of the primary tumor site after external radiotherapy. We want to show the clinical results and side effects and to demonstrate the safe use of a HDR source.
Patients and method: From December 1984 until November 1988, 154 patients with breast cancer stage T1-2, N0-1 were treated by conservative surgery and radiation. A dose of 45 to 50 Gy was given to the whole breast by external radiotherapy, and the previous tumor area was boosted by an interstitial implant with Iridium-192 HDR. We applied 10 Gy in one or two fractions.
Results: The mean follow-up period of survivors is 76 months (range 57 to 107 months). In 36 patients failures occurred: eight patients (5%) developed local recurrences, 31 patients (20%) had distant metastases, and 19 (12%) died with cancer. The Kaplan-Meier estimation for five year overall survival is 86.9%, for disease-specific survival 89.3%, for local control 95.8%, and for disease free survival 80.1%. The most frequent late effects were telangiectasia (11%), fibrotic masses in the previous tumor area (6.5%), and lymphedema of the arm (6.5%). No serious complications could be observed.
Conclusion: With the HDR-Boost of 10 Gy in addition to external beam radiotherapy in the treatment of breast cancer we obtained good clinical results without serious side effects.