放化疗 (CRT) 联合顺铂是局部晚期头颈鳞状细胞癌 (LA-SCCHN) 患者的非手术明确治疗的标准治疗方法。然而，CRT 与严重的晚期不良事件增加相关，包括吞咽功能障碍、口干症、耳毒性和甲状腺功能减退症。很少有旨在在不影响治疗结果的情况下实现微创 CRT 的策略取得成功。本研究的目的是确认临床 III-IVB 期 LA- 患者的治疗失败时间 (TTF) 方面，40 Gy 的减少剂量预防性放射与 56 Gy 标准剂量预防性放射相比具有非劣效性。 SCCHN。本研究是一项多中心、双组、开放标签、随机 III 期试验。排除 p16 阳性口咽癌的 LA-SCCHN 患者被随机分配至标准组或实验组。双臂给予肿瘤总剂量为 70 Gy，同时给予 100 mg/m2 顺铂。对于预防领域，标准组中的患者使用同步积分加强 (SIB56) 接受 35 次分次 56 Gy 的总剂量，持续 7 周，而实验组中的患者使用两步方法接受 40 Gy 20 次分次的总剂量，持续 4 周（ 2-步骤40)。 5年内将从52家日本机构总共招募400名患者。主要终点是 TTF，次要终点是总生存期、完全缓解率、无进展生存期、局部无复发生存期、急性和晚期不良事件、生活质量评分和吞咽功能评分。 2-step40 程序在 TTF 方面不低于标准组，在安全性终点方面优于标准组，对于确定性 CRT 来说，2-step40 程序是比 SIB56 更有用的治疗方法。该试验已在日本临床试验注册中心注册为 jRCTs031210100 ( https ://jrct.niph.go.jp/latest-detail/jRCTs031210100）。注册日期：2021 年 5 月。© 2023。作者。

Chemoradiotherapy (CRT) with concurrent cisplatin is the standard of care as a nonsurgical definitive treatment for patients with locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN). However, CRT is associated with increased severe late adverse events, including swallowing dysfunction, xerostomia, ototoxicity, and hypothyroidism. Few strategies aimed at less invasive CRT without compromising treatment outcomes have been successful. The purpose of this study is to confirm the non-inferiority of reduced dose prophylactic radiation with 40 Gy compared to standard dose prophylactic radiation with 56 Gy in terms of the time to treatment failure (TTF) among patients with clinical stage III-IVB LA-SCCHN.This study is a multicenter, two-arm, open-label, randomized phase III trial. Patients with LA-SCCHN excluding p16 positive oropharynx cancer are randomized to the standard arm or experimental arm. A total dose of 70 Gy for tumors with concurrent cisplatin at 100 mg/m2 are administered in both arms. For prophylactic field, patients in the standard arm receive a total dose of 56 Gy in 35 fractions for 7 weeks using simultaneous integrated boost (SIB56) and those in the experimental arm receive 40 Gy in 20 fractions using two-step methods for 4 weeks (2-step40). A total of 400 patients will be enrolled from 52 Japanese institutions within 5 years. The primary endpoint is TTF, and the secondary endpoints are overall survival, complete response rate, progression-free survival, locoregional relapse-free survival, acute and late adverse events, quality of life score, and swallowing function score.If the experimental arm is non-inferior to the standard arm in terms of TTF and superior on the safety endpoints, the 2-step40 procedure is the more useful treatment than SIB56 for definitive CRT.This trial has been registered in the Japan Registry of Clinical Trials as jRCTs031210100 ( https://jrct.niph.go.jp/latest-detail/jRCTs031210100 ). Date of Registration: May 2021.© 2023. The Author(s).