Intraoperative electron beam radiotherapy (IOERT) versus high-dose-rate intraoperative brachytherapy (HDR-IORT) in patients with an R1 resection for locally advanced or locally recurrent rectal cancer
Menée auprès de 373 patients atteints d'un cancer rectal localement avancé ou récidivant localement traité par résection R1 entre 2000 et 2016, cette étude compare l'efficacité, du point de vue de la survie globale et de la survie sans récidive locale, d'une radiothérapie intra-opératoire par faisceaux d'électrons et d'une curiethérapie peropératoire à haut débit de dose
Introduction: Intraoperative radiotherapy (IORT), delivered by intraoperative electron beam radiotherapy (IOERT) or high-dose-rate intraoperative brachytherapy (HDR-IORT), may reduce the local recurrence rate in patients with locally advanced and locally recurrent rectal cancer (LARC and LRRC, respectively). The aim of this study was to compare the oncological outcomes between both IORT modalities in patients with LARC or LRRC who underwent a microscopic irradical (R1) resection. Methods: All consecutive patients who received IORT because of an R1 resection of LARC or LRRC between 2000 and 2016 in two tertiary referral centers were included. In LARC, a resection margin ≤2 mm was considered R1. A resection margin of 0 mm was considered R1 in LRRC. Results: In total, 215 LARC patients were included, of whom 151 (70%) received IOERT and 64 (30%) received HDR-IORT; further, 158 LRRC patients were included, of whom 112 (71%) received IOERT and 46 (29%) received HDR-IORT. After multivariable analyses, the overall survival was not significantly different between the two IORT modalities. The local recurrence free survival was significantly longer in patients treated with HDR-IORT, both in LARC (p=0.041; HR 0.496; 95%CI 0.253-0.973) and LRRC (p=0.021; HR 0.567; 95%CI 0.349-0.920). In LARC patients, major postoperative complications were similar for both IORT modalities (IOERT:30%, HDR-IORT:27%), whereas in LRRC patients, the incidence of major postoperative complications was higher after HDR-IORT (IOERT:26%, HDR-IORT:46%). Conclusion: This study showed a significantly better LRFS in favor of HDR-IORT in patients with an R1 resection for LARC or LRRC. Optimization of the IOERT technique seems warranted.
International Journal of Radiation Oncology, Biology, Physics 2021