BACKGROUND AND PURPOSE A multicenter prospective randomized controlled trial was performed to investigate whether dose reduction to the elective nodal volume (PTVelect) in head and neck carcinoma reduces radiation-induced dysphagia, primary endpoint, without compromising tumor control, secondary endpoint. Here, we report on the long-term follow-up of the secondary endpoint (NCT01812486). MATERIALS AND METHODS Two hundred patients treated with primary (chemo)radiotherapy (RT) were randomized (1:1) between the standard arm, irradiation to PTVelect up to an equivalent dose (EQD2) of 50 Gy and the experimental arm, irradiation to PTVelect up to EQD2 of 40 Gy. The primary tumor and involved nodes were treated according to the standard of care, EQD2 70 Gy (PTVhigh). Regional recurrences (RR) were projected on the initial RT planning-CT to identify the recurrence localization. RESULTS The 5-year (5Y) RR was 14.0% (CI95% 7.9; 21.8) in the 40 Gy arm versus 7.5% (CI95% 3.3; 14.0) in the 50 Gy arm (p = 0.10). Majority of RR in the 40 Gy arm (9/13) were projected in PTVhigh and 2 RR were seen outside the treated RT volume. Only 2 RR occurred in PTVelect irradiated up to 40 Gy which was the same number as RR occurring in the 50 Gy PTVelect. The 5Y-overall survival (OS) was 56.5% (CI95% 45.7; 65.9) in the 40 Gy arm versus 49.6% (CI95% 39.0; 59.2) in the 50 Gy arm (p = 0.56). CONCLUSION At 5-years, no statistically significant differences regarding OS, local recurrence, RR nor distant metastases were observed between both treatment arms. This study is underpowered to undoubtedly demonstrate non-inferiority. However, since in both arms only two RR in the PTVelect were observed, reducing the dose to PTVelect appears safe and should be further investigated.

中文翻译：

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降低头颈部鳞状细胞癌择期颈部放疗剂量的随机临床试验；更新长期肿瘤结果

背景和目的进行了一项多中心前瞻性随机对照试验，以研究减少头颈癌选择性淋巴结体积 (PTVelect) 的剂量是否能减少放射引起的吞咽困难，主要终点，而不影响肿瘤控制，次要终点。在这里，我们报告了次要终点 (NCT01812486) 的长期随访。材料和方法 200 名接受初级（化学）放疗 (RT) 治疗的患者被随机 (1:1) 分为标准组、PTVelect 照射至 50 Gy 的等效剂量 (EQD2) 和实验组、PTVelect 照射高达 40 Gy 的 EQD2。根据护理标准 EQD2 70 Gy (PTVhigh) 治疗原发肿瘤和受累淋巴结。区域复发 (RR) 被投影到初始 RT 计划-CT 以确定复发定位。结果 40 Gy 组的 5 年 (5Y) RR 为 14.0%（CI95% 7.9；21.8），而 50 Gy 组为 7.5%（CI95% 3.3；14.0）（p = 0.10）。40 Gy 组中的大部分 RR (9/13) 投射在 PTVhigh 中，2 RR 出现在治疗的 RT 体积之外。在照射高达 40 Gy 的 PTVelect 中仅发生 2 RR，这与在 50 Gy PTVelect 中发生的 RR 数量相同。40 Gy 组的 5 年总生存率 (OS) 为 56.5%（CI95% 45.7；65.9），而 50 Gy 组为 49.6%（CI95% 39.0；59.2）（p = 0.56）。结论 在 5 年时，两个治疗组之间在 OS、局部复发、RR 或远处转移方面没有观察到统计学上的显着差异。这项研究毫无疑问地证明了非劣效性。然而，