ESTRO 2024 - Abstract Book

S579

Clinical - Breast

ESTRO 2024

1890

Digital Poster

Salvage breast conserving surgery and IOERT re-irradation for recurrent BC: a multicentric study

Francesca Braga 1,2 , Alexandru David Fodor 2 , Samuele Frassoni 3 , Damaris Patricia Rojas 1 , Alessandra Fozza 4 , Gladys Blandino 4 , Antonella Ciabattoni 5 , Marina Alessandro 6 , Gianpiero Catalano 7 , Giovanni Battista Ivaldi 8 , Stefania Martini 9 , Fiorenza De Rose 10 , Cristiana Fodor 1 , Luigi Cornacchia 1,2 , Ekaterina Milovanova 1,2 , Stefano Durante 11 , Samantha Dicuonzo 1 , Anna Morra 1 , Liliana Belgioia 12,4 , Isabella Palumbo 13 , Mariangela Massaccesi 14 , Vincenzo Bagnardi 3 , Roberto Orecchia 15 , Barbara Alicja Jereczek-Fossa 1,2 , Maria Cristina Leonardi 1 1 IEO, Division of Radiation Oncology, Milan, Italy. 2 University of Milan, University, Milan, Italy. 3 University of Milan Bicocca, Department of Statistics and Quantitative Methods, Milan, Italy. 4 IRCCS Policlinico San Martino, Division of Radiation Oncology, Genoa, Italy. 5 San Filippo Neri Hospital, Division of Radiation Oncology, Rome, Italy. 6 Città di Castello Hospital, Division of Radiation Oncology, Città di Castello, Italy. 7 Multimedica, Division of Radiation Oncology, Milan, Italy. 8 ICS Maugeri, Division of Radiation Oncology, Pavia, Italy. 9 Santa Croce e Carle Hospital, Division of Radiation Oncology, Cuneo, Italy. 10 Santa Chiara Hospital, Division of Radiation Oncology, Trento, Italy. 11 IEO, Division of Breast Surgery, Milan, Italy. 12 University of Genoa, University, Genoa, Italy. 13 University of Perugia, University, Perugia, Italy. 14 Policlinico Gemelli, Division of Radiation Oncology, Rome, Italy. 15 IEO, Scientific Directorate, Milan, Italy

Purpose/Objective:

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.

Material/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 2ndLR and 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 rate was 18.9%. Patient-reported cosmesis was good/excellent in 59.7% of the cases.