A phase II study investigating the acute toxicity of targeted intraoperative radiotherapy as tumor-bed boost plus whole breast irradiation after breast-conserving surgery in Korean patients
Menée en Corée du Sud sur 215 patientes atteintes d'un cancer du sein traité par chirurgie conservatrice, cet essai de phase II évalue la toxicité aiguë d'un traitement comportant une radiothérapie intra-opératoire ciblée de type "boost" utilisant des rayons X de faible énergie et une irradiation de l'ensemble du sein
Background : There are concerns regarding local toxicity when IORT is applied in Asian women with a smaller breast volume than that of Western women. Trials are required to develop safety profiles for this technique. The aim of this trial was to evaluate acute toxicity after intra-operative radiotherapy (IORT) with low-energy X-ray plus whole breast irradiation (WBI) in Asian patients with breast cancer. Methods : This single-arm, single-institute, phase II trial investigated acute toxicity after completion of radiotherapy (targeted IORT followed by WBI) in Korean patients treated with breast-conserving surgery (BCS). In the conventional WBI arm from the TARGIT-A trial, the incidence of acute toxicity within 6 months was 15%. To prove the non-inferiority of the acute toxicity rate, 215 patients were required. This trial is registered with ClinicalTrials.gov (NCT02213991). Results : Two-hundred and fifteen women were enrolled, and 198 underwent IORT. In 33 patients, clinically significant complications during the acute period were noted. The incidence of acute toxicity was 16.7% (95% CI 11.5–21.9%). There were 29 patients with seroma needing more than 3 aspirations, 4 with wound infection, and 2 with skin breakdown. There was no difference in the rate of complications according to the tumor volume or the tumor-breast volume ratio. Advanced age and high BMI were risk factors for acute complications. Conclusions : Targeted intra-operative radiotherapy using Intrabeam® is a safe procedure for Korean patients with breast cancer with an acceptable toxicity profile in the acute period.