Full-dose intraoperative radiotherapy with electrons in breast cancer. First report on late toxicity and cosmetic results from a single-institution experience

Abstract

Purpose: To investigate the feasibility of applying exclusive intraoperative radiation therapy (IORT) after conservative surgery in limited-stage breast carcinoma and to evaluate late effects and cosmetic results after this new conservative treatment.

Patients and methods: From October 2000 to November 2002, 47 consecutive patients with unifocal breast carcinoma up to a diameter of 2 cm received conservative surgery followed by IORT with electrons as the sole adjuvant local therapy. Three different dose levels were used: 20 Gy (seven patients), 22 Gy (20 patients), and 24 Gy (20 patients). Patients were evaluated using RTOG/EORTC scale to assess the incidence of late complications. During follow-up, a radiologic assessment with mammography and sonography was periodically performed and any breast-imaging alterations were reported.

Results: After a follow-up ranging from 36 to 63 months (median, 48 months), 15 patients developed breast fibrosis (grade 2 in 14 patients, grade 3 in one patient), two patients presented with grade 3 skin changes, one patient developed a clinically relevant fat necrosis, and one patient showed breast edema and pain. Two patients developed contralateral breast cancer and one distant metastases; no local relapses occurred. Asymptomatic findings of fat necrosis were observed at mammography in twelve patients (25.5%), while an hypoechoic area was revealed by sonography in ten patients (21.5%). In four patients (8%), mammographic and sonographic findings suggested malignant lesions and required a rebiopsy to confirm the benign nature of the lesion.

Conclusion: IORT in breast carcinoma is still an experimental treatment option for select patients with breast cancer and its application should be restricted to prospective trials. Although preliminary data on local control are encouraging, a longer follow-up is needed to confirm the efficacy of IORT in breast cancer and to exclude that severe late complications compromise the cosmetic results or modify the radiologic breast appearance during follow-up increasing the need for additional investigations.