Background: The current standard of local treatment for patients with localized breast cancer (BC) includes whole breast irradiation (WBI) after breast-conserving surgery (BCS). Ultrahypofractionated WBI schemes (1-week treatment) were shown not to be inferior to the standard WBI. Tumor bed boost using photon intraoperative radiotherapy (IORT) is safe and feasible in combination with standard WBI. The aim of the present study is to assess, for the first time, the feasibility and safety of combining photon IORT with ultrahypofractionated WBI. Methods: Patients diagnosed with low-risk early BC candidates for BCS were included in this prospective study. IORT was administered at a dose of 20 Gy to the surface’s applicator, and WBI was administered 3–5 weeks after surgery at a total dose of 26 Gy in five consecutive days. Results: From July 2020 to December 2022, seventy-two patients diagnosed with low-risk early BC and treated in our institution were included in this prospective study. All patients completed the proposed treatment, and no severe acute or late grade 3 toxicity was observed 3 and 12 months after WBI, respectively. Conclusions: Our results confirm for the first time that the combination of ultrafractionation WBI and photon-IORT after BCS is a feasible and safe option in patients with early BC.
背景：目前局限性乳腺癌（BC）患者的局部治疗标准包括保乳手术（BCS）后的全乳照射（WBI）。超大分割WBI方案（1周疗程）已被证明不劣于标准WBI。光子术中放疗（IORT）用于瘤床加量联合标准WBI是安全可行的。本研究旨在首次评估光子IORT联合超大分割WBI的可行性与安全性。方法：本研究为前瞻性研究，纳入诊断为低风险早期BC且适合BCS的患者。IORT剂量为施源器表面20 Gy，术后3-5周进行WBI，总剂量26 Gy，连续5天完成。结果：2020年7月至2022年12月期间，72例在我院诊断并治疗的低风险早期BC患者纳入本研究。所有患者均完成既定治疗方案，分别在WBI后3个月和12个月未观察到严重急性或晚期3级毒性反应。结论：我们的结果首次证实，在早期BC患者中，BCS后采用超大分割WBI联合光子IORT是一种可行且安全的选择。
肿瘤(癌症)患者之家