Robotic stereotactic boost in early breast cancer, a phase II trial
Mené sur 28 patientes atteintes d'un cancer canalaire invasif ou d'un cancer lobulaire de stade pT1-2 traité par lumpectomie puis radiothérapie de l'ensemble du sein, cette étude française évalue la toxicité mammaire cutanée d'une radiothérapie stéréotaxique robotique de type "boost"
Purpose : to evaluate the feasibility and toxicity of a single 8Gy-fraction stereotactic boost after whole breast irradiation (WBI) in early breast cancer. The primary aim of this phase II study was to evaluate cutaneous breast toxicity utilizing CTC-AEv4 three months after the boost. Secondary objectives were local control, survival and patient-reported quality of life using the EORTC QLQ-C30 and breast specific EORTC QLQ-BR 23 questionnaires. Methods and materials : Patients with invasive ductal or lobular, pT1-2 breast cancer treated with lumpectomy with clear margins and pN0 were included. Patients requiring chemotherapy were excluded. Results : 28 eligible patients received the planned boost and 26 had hormonal therapy. The procedure was technically successful without procedural complications. A median of three fiducials were tracked and 115 beams were used. There were 22 acute grade-1 breast skin toxicities including fibrosis, pain, erythema or pigmentation. There were two acute grade 2 erythemas. Median skin boost dose was inversely correlated with acute skin toxicity (p=0.028). QLQ-C30 scores revealed acute dyspnea and arm symptoms without correlation to the boost dose. Breast symptom QLQ-BR23 scores did not deteriorate while upset by hair loss and systemic side-effects of hormonal therapy were observed. After a median follow-up of 38 months, one patient had in-boost field relapse and there were 5 late grade 1 and 1 grade 2 skin toxicities. Conclusion : Single-fraction stereotactic boost after conventional WBI in early breast cancer is feasible in minor toxicities. Quality of life and specific breast items showed excellent patient acceptance.