鼻咽癌调强放疗中上颈部CTV剂量优化对主要中线结构的保护

目的 探讨调强放疗和多模态影像指导下,鼻咽癌中上颈临床靶区(CTV)剂量优化对保护喉咽、前环和后环的意义。方法 回顾性分析2016—2018年间江苏省肿瘤医院收治的 298例初治鼻咽癌患者资料。所有患者按以下方案进行个体化中上颈CTV剂量优化:A组:双侧完全优化,即双颈CTV剂量均50.4Gy;B组:单侧完全优化,即单侧CTV剂量50.4Gy、对侧60Gy;C组:双侧不完全优化,即双侧CTV剂量均50.4Gy,可疑阳性淋巴结选择性同步推量至60Gy;D组:单侧不完全优化,即单侧CTV剂量50.4Gy,其中可疑阳性淋巴结选择性同步推量至60Gy,对侧60Gy;E组:未优化,即双侧CTV剂量均60Gy。结果 298例患者中 215例行颈部CTV剂量优化,83例未行剂量优化。优化方案中A组 114例、B组 36例、C组 60例、D组 5例。随访时间 6.0~46.3个月,中位随访期28.5个月。全组总生存率为95.6%,无进展生存率为84.2%,颈部区域控制率为98.0%。6例颈部淋巴结复发,其中咽后外侧淋巴结复发 1例,Ⅱ区复发 4例,Ⅲ区复发 0例,Ⅳ区复发 1例。A、B、C、D与E组间喉咽平均剂量比较,P值分别为<0.001、0.016、0.001、0.572;前环平均剂量差异比较,P值分别为<0.001、0.011、<0.001、0.805;后环平均剂量差异比较,P值分别为<0.001、0.004、<0.001、0.252。结论 在多模态影像指导下,结合鼻咽癌颈部淋巴结转移规律进行中上颈CTV剂量优化是安全的,可明显降低喉咽、前环和后环的剂量,从而为中上颈部CTV降量提供依据。

Effect of CTV dose optimization in upper and middle neck on protecting the main midline structures in intensity-modulated radiotherapy for nasopharyngeal carcinoma

Objective To explore the significance of the clinical target volume (CTV) dose optimization in the upper and middle neck in protecting the laryngopharynx, anterior and posterior rings during intensity-modulated radiotherapy (IMRT) and multimodal imaging system for nasopharyngeal carcinoma. Methods Clinical data of 298 nasopharyngeal carcinoma patients admitted to Jiangsu Cancer Hospital from 2016 to 2018 were retrospectively analyzed. According to the following five strategies of CTV dose optimization in the upper and middle neck:group A, complete optimization of bilateral cervical lymph nodes (CLNs), that is, the CTV doses of bilateral CLNs were 50.4Gy;group B, complete optimization of unilateral CLNs, that is, the CTV dose of unilateral CLNs was 50.4Gy and the contralateral CLNs was 60Gy;group C, incomplete optimization of bilateral CLNs, that is, the CTV doses of bilateral CLNs were 50.4Gy, while the suspicious positive CLNs were selectively boosted to 60Gy;group D, incomplete optimization of unilateral CLNs, that is, the CTV dose of unilateral CLNs was 50.4Gy and the suspicious positive CLNs were selectively boosted to 60Gy, and the CTV dose of contralateral side was 60Gy;group E:no optimization, that is, the CTV doses of bilateral CLNs were 60Gy. Results Among 298 patients, 215 patients received dose optimization and 83 cases did not receive dose optimization. In the dose optimization schemes, 114 cases were assigned in group A, 36 cases in group B, 60 cases in group C and 5 cases in group D. The median (range) follow-up time was 28.5(6.0-46.3) months. The overall survival rate was 95.6%, the progression-free survival rate was 84.2% and the locoregional control rate of CLNs was 98.0%. Local relapse of CLNs occurred in six patients, including 1 case of retropharyngeal lymph node, 4 cases of Ⅱ area and 1 case of Ⅳ area. The P values of average dose of laryngopharynx in group A, group B, group C and group D compared with that in group E were<0.001, 0.016, 0.001 and 0.572, respectively. The P values of the average dose of the anterior ring in group A, group B, group C and group D compared with that in group E were<0.001, 0.011,<0.001 and 0.805, respectively. The P values of the average dose of the posterior ring in group A, group B, group C and group D compared with that in group E were<0.001, 0.004,<0.001 and 0.252, respectively. Conclusions Combined with the metastatic rules of CLNs and multimodal imaging system, it is safe to optimize the CTV dose of the upper and middle neck during IMRT in nasopharyngeal carcinoma patients, which can significantly reduce the doses of laryngopharynx, anterior and posterior rings, thereby providing evidence for reducing the CTV dose in the upper and middle neck.