基于调强放疗N0期鼻咽癌颈部预防照射的选择

目的 探讨基于调强放疗(IMRT) N₀期鼻咽癌患者颈部预防照射的方式。方法 回顾分析2003—2008年本中心IMRT的 270例N₀期(第6版AJCC/UICC分期)初治鼻咽癌患者的临床资料,其中 171例接受上半颈预防照射,99例接受全颈预防照射。所有患者均接受鼻咽原发灶、上颈部淋巴引流区(包括双颈Ⅱ、Ⅲ、Ⅴ_A区)6 MV X线IMRT,鼻咽原发灶剂量为68 Gy分30次,上颈剂量为54 Gy分30次,疗程6周。全颈预防照射者下颈部及锁骨上采用颈前半野常规技术,剂量为50 Gy分25次。结果 中位随访65.1个月,随访率为93%。上颈、全颈预防照射的 5年肿瘤相关生存率分别为95.3%、91.9%(χ²=0.76,P=0.384),颈部无复发生存率分别为99.4%、99.0%(χ²=1.18,P=0.278),无远处转移生存率分别为98.8%、94.9%(χ²=2.31,P=0.128)。咽后淋巴结阴、阳性患者 5年无远处转移生存率分别为99.4%、93.7%(χ²=8.96,P=0.003)。急性不良反应主要为1、2级黏膜炎和咽喉炎,无3+4级张口困难和口干等晚期不良反应。结论 N₀期鼻咽癌患者IMRT时行上半颈预防照射也许是可行的,第7版AJCC/UICC将颈淋巴结阴性而咽后淋巴结阳性鼻咽癌上调为N₁是合理的。

Volume of prophylactic irradiation to neck for stage N0 nasopharyngeal carcinoma patients treated with intensity-modulated radiotherapy

Objective To investigate the volume of prophylactic irradiation to the neck for stage N₀ nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT). MethodsRetrospective analysis was performed on the clinical records of 270 patients with stage N₀ NPC (based on the 6^th version of AJCC/UICC staging system), who underwent IMRT as the initial treatment in our center from 2003 to 2008. Among all the patients, 171 received prophylactic upper-neck irradiation, and 99 prophylactic whole-neck irradiation. All of them received 6-MV X-ray IMRT to the primary focus of NPC and the lymphatic drainage area in the upper neck (Levels Ⅱ, Ⅲ, and Ⅴ_A lymph nodes) at doses of 68 Gy/30 fractions and 54 Gy/30 fractions over 6 weeks. In addition, the patients receiving prophylactic whole-neck irradiation had the lower neck and supraclavicular fossae treated by anterior neck semi-field conventional technique at a dose of 50 Gy/25 fractions. Results The median follow-up was 65.1 months (range 4—106 months), and the follow-up rate was 93%. The patients undergoing prophylactic upper-neck irradiation and prophylactic whole-neck irradiation had 5-year disease specific survival rates of 95.3% and 91.9%(χ²=0.76,P=0.384), relapse-free survival rates of 99.4% and 99.0%(χ²=1.18,P=0.278), and distant metastasis-free survival rates of 98.8% and 94.9%(χ²=2.31,P=0.128). The 5-year distant metastasis-free survival rate was significantly higher in patients without retropharyngeal lymph node (RLN) metastasis than in those with RLN metastasis (99.4% vs. 93.7%, χ²=8.96,P=0.003). Grade 1—2 mucositis and pharyngitis were the most common acute adverse reactions in patients. At 24 months after IMRT, no grade 3 or 4 xerostomia and trismus were developed. Conclusions Prophylactic irradiation to the upper neck may be feasible for stage N₀ NPC patients treated with IMRT. It is reasonable in the 7^th version of AJCC/UICC staging system that NPC with negative cervical lymph nodes and positive RLNs is reclassified to stage N₁.