Background and purpose: Evaluation of the efficacy of combined hyperthermia and radiotherapy (TRT) in high-risk breast cancer patients with microscopic involved margins (R1) after mastectomy or with resected locoregional, early recurrence with close margins or R1-resection. Main endpoint was local tumour control (LC); secondary endpoints were overall survival (OS), disease free survival (DFS) and acute toxicity.
Material and methods: Between 1997-2001, 50 patients were treated with TRT. Thirteen patients (group 1) received a post-operative TRT in a high-risk situation (free margin <1 cm or R1, N+), 37 patients (group 2) received TRT after close/R1 resection of a locoregional recurrence. Thirteen out of 37 patients in group 2 already had had two-to-seven recurrences prior to TRT. Median radiation dose was 60 Gy (range: 44-66.4 Gy), the additional local hyperthermia (>41 degrees C, 60 min) was given twice a week. Median follow-up for patients at risk was 28 months. All statistical tests were done using Statistica software.
Results: Actuarial OS for all patients at 3 years accounted for 89%, DFS for 68% and LC for 80%. Actuarial OS was 90% for group 1 and 89% for group 2, with four patients having died so far. DFS at 3 years was 64% in group 1 and 69% in group 2, actuarial 3 year LC was 75% and 81%, respectively. For patients with recurrent chest wall disease, there was no difference concerning local control between patients who underwent TRT with or without prior radiation. No prognostic factors could be detected due to the small number of patients investigated. The combined modality treatment was well tolerated. Grade IV toxicity, according to the Common Toxicity Criteria, did not occur.
Conclusion: The results concerning local tumour control and overall survival in these high-risk patients are promising, especially for TRT for the treatment of local recurrences. A longer follow-up is needed to estimate late toxicity.