Department of Radiation Oncology, KU Leuven - University of Leuven, University Hospitals Leuven, Belgium.
Department of Radiation Oncology, Iridium Kanker Netwerk, University of Antwerp, Faculty of Medicine and Health Sciences, Belgium.
Radiother Oncol. 2020 Feb;143:24-29. doi: 10.1016/j.radonc.2020.01.005. Epub 2020 Feb 7.
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).
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.
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).
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.
一项多中心前瞻性随机对照临床试验旨在研究头颈部癌选择性淋巴结照射野（PTVelect）剂量降低是否会降低放射性吞咽困难（主要终点），同时不影响肿瘤控制（次要终点）。在此，我们报告了次要终点的长期随访结果（NCT01812486）。
200 例接受根治性（放化疗）的患者随机分为标准组（照射至 PTVelect 达到等效剂量[EQD2] 50 Gy）和实验组（照射至 PTVelect 达到 EQD2 40 Gy）。根据标准治疗方案，对原发肿瘤和累及淋巴结进行照射，EQD2 70 Gy（PTVhigh）。将区域复发（RR）投影到初始放疗计划 CT 上，以确定复发部位。
40 Gy 组的 5 年局部区域无复发生存率（LRR）为 14.0%（95%CI95%：7.9; 21.8），50 Gy 组为 7.5%（95%CI95%：3.3; 14.0）（p=0.10）。40 Gy 组中大多数 RR（9/13）发生在 PTVhigh 中，2 个 RR 位于治疗 RT 体积之外。仅在照射至 40 Gy 的 PTVelect 中发生了 2 个 RR，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%（95%CI95%：45.7; 65.9），50 Gy 组为 49.6%（95%CI95%：39.0; 59.2）（p=0.56）。
在 5 年时，两组患者的 OS、局部复发、RR 或远处转移均无统计学差异。本研究的效力不足以明确证明非劣效性。然而，由于在两个治疗组中仅在 PTVelect 中观察到 2 个 RR，因此降低 PTVelect 的剂量似乎是安全的，应该进一步研究。
