Leonardi MC, Fodor AD, Frassoni S, Rojas DP, Fozza A, Blandino G, Ciabattoni A, Alessandro M, Catalano G, Ivaldi GB, Martini S, De Rose F, Fodor C, Veronesi P, Galimberti VE, Intra M, Cornacchia L, Braga F, Durante S, Dicuonzo S, Morra A, Zaffaroni M, Cattani F, Belgioia L, Palumbo I, Massaccesi M, Bagnardi V, Orecchia R, and Jereczek-Fossa BA
Aim: Intraoperative radiotherapy with electrons (IOERT) may represent a viable choice for partial breast re-irradiation (rePBI) after repeat quadrantectomy for local recurrence (LR) for primary breast cancer (BC) in lieu of mastectomy., Materials and Methods: A database collecting data on rePBI with IOERT from 8 Italian centres was set up in 2016- 2018, providing data on cumulative incidence (CumI) of 2 nd LR nd survival with a long follow-up (FU) RESULTS: From 2002 to 2015, 109 patients underwent the conservative retreatment. The median primary BC -1stLR interval was 11.1 years (range: 2.4-27.7). The median 1stLR size was 0.9 cm (range: 0.3-3.0) and 43.6% were Luminal A. Median IOERT dose was 18 Gy (range: 12-21) and median collimator was 4 cm (range: 3-6). Median FU was 11.7 years (interquartile range: 7.7-14.6). The 2ndLR CumI was 12.2% (95% CI: 6.8-19.2) at 5 years and 32.3% at 10 years (95% CI: 22.8-42.2), occurring in the same site as the 1stLR in about half of the cases. HER2 status and collimator size were independent LR predictors. The 5- and 10-year overall survival were 95.2% and 88.3%, respectively, while 5- and 10-year BC specific survival were 98% and 94.5%. The development of a 2ndLR significantly reduced BCSS (HR=9.40, P<0.001). Grade ≥3 fibrosis was 18.9%. Patient-reported cosmesis was good/excellent in 59.7% of the cases., Conclusion: 2ndLR CumI was within the range of the literature, but higher than expected, opening questions on radiation field extension and fractionation schedule. Since a 2ndLR worsened the outcome, salvage modality must be carefully planned., (Copyright © 2024. Published by Elsevier Inc.)