Partial breast irradiation with interstitial high-dose-rate brachytherapy in early breast cancer: results of a phase II prospective study.

AIM: To investigate, in a phase II prospective study, the efficacy of partial breast irradiation administered with high-dose-rate brachytherapy. METHODS: After conservative surgery 80 patients with low-risk early-stage breast cancer received 4 Gy twice a day for 4 days (total dose 32 Gy). Catheter implantation was performed during surgery in 15 cases and postoperatively, at a median of 8 weeks from surgery, in 65 patients. Adjuvant therapy was chemotherapy (8) and/or hormone therapy (61). RESULTS: Cosmetic results were good/excellent in 79 patients. Perioperative toxicity was very low. Acute skin toxicity developed in seven cases (six G1; one G2); late G3 cutaneous toxicity in one patient and late subcutaneous toxicity in five (three G1; two G2). Grade 1 teleangiectasia occurred in eight patients and grade 2 in one. Fat necrosis was symptomatic in one patient and asymptomatic in five. Only one patient presented pain after brachytherapy. A significantly (p=0.001) higher frequency of late toxicity was observed in patients implanted during surgery, the group, which included the only patient with a fair cosmetic result. No local or regional relapses have occurred to date. The median follow-up was 30 months (range 3-52). CONCLUSION: This strategy is a viable option in selected patients with early-stage breast cancer as it is feasible, reproducible and associated with very low perioperative and acute toxicity. The low incidence of late side effects will probably change as follow-up lengthens.