Cosmetic Outcome and Chronic Breast Toxicity After Intraoperative Radiation Therapy (IORT) as a Single Modality or as a Boost Using the Intrabeam ® Device: A Prospective Study.

PURPOSE: We aim to report our results in terms of chronic toxicities and cosmetic outcomes after intraoperative radiotherapy (IORT) using kV X-rays in women treated for early breast cancer at our institution.

METHODS: Patients with early breast carcinoma were recruited between April 2011 and November 2014. After breast-conserving surgery, patients were treated with IORT using the Intrabeam® device. IORT was completed by whole-breast radiotherapy (WBRT) at a dose of 46-50.4 Gy in 23-28 fractions in case of adverse pathologic criteria on the final specimen examination. Skin toxicity was graded using the Late Effects in Normal Tissues-Subjective, Objective, Management and Analytic (LENT-SOMA) scale every 6 months, and cosmetic outcomes were evaluated at 36 months by patient self-evaluation and by two radiation oncologists, on a 1-10 scale.

RESULTS: Forty-one women received IORT only and 30 patients received IORT followed by WBRT (IORT + WBRT group). After a median follow-up of 38.9 months, no locoregional or distant recurrence occurred. After IORT only, 2.4% of grade 2 or higher breast fibrosis, and no other grade 2 or higher disease, was observed. In the IORT + WBRT group, grade 2 or higher fibrosis and grade 2 or higher breast retraction were observed in 43.3 and 23.3% of patients, respectively. Objective cosmetic outcomes were very good and significantly better in the IORT-only group compared with the IORT + WBRT group (8.87 vs. 6.96) (p < 0.001).

CONCLUSION: IORT using the Intrabeam® is well-tolerated, with very little chronic toxicity and good cosmetic outcome. However, a high rate of grade 2 or higher chronic breast toxicity was observed when IORT had to be completed by WBRT.