鼻咽癌放射治疗后颅神经损伤影响因素研究

Radiation-induced cranial nerve palsy and its causative factors in nasopharyngeal carcinoma

目的回顾性分析鼻咽癌放射治疗后放射性颅神经损伤的发生情况,并探讨其影响因素。方法512例鼻咽癌中Ⅰ、Ⅱ、Ⅲ、Ⅳ期分别为31、212、198、71例。60Coγ线或6MVX线为放射源,面颈野或耳前野为主野加鼻前野放射,部分病例根据鼻咽肿瘤情况辅以颅底野、耳后野及鼻咽腔内后装放射。鼻咽部放射中位剂量为7130cGy,颈部根治性放射的中位剂量为6410cGy,预防放射的中位剂量为5480cGy。合并化疗101例。结果中位随访时间6.7年。512例中81例发生颅神经损伤,中位潜伏期4.6年。5、10年累积发生率分别为10.3%、25.4%。以第Ⅻ颅神经损伤最为多见。多因素分析显示前组颅神经放射性损伤主要与放射治疗前颅神经侵犯、化疗、鼻咽外放射总剂量及年龄有关,而后组颅神经损伤与N分期、放射野分组有关。颅神经侵犯、合并化疗、鼻咽总剂量>7000cGy者前组颅神经放射性损伤增加。而颈淋巴结分期晚者后组颅神经损伤增加,放射野分组中以第1组后组颅神经损伤发生的危险性大,其次为第2组,第3组后组颅神经损伤的危险性较小。34例鼻咽腔内后装放射者仅1例发生前后组颅神经损伤。结论鼻咽癌放射治疗后颅神经损伤并不少见,随着生存期延长而呈上升趋势。前、后组颅神经放射性损伤的影响因素不同,可能与其解剖部位及走向有关。控制外放射总剂量?

Objective To analyze the incidence and causative factors of radiation-induced cranial nerve palsy in patients with nasopharyngeal carcinoma(NPC). Methods 512 NPC patients who underwent radiotherapy from January 1, 1989 to December 31, 1990 and from January 1 ,1994 to December 31, 1995 were retrospectively analyzed. According to Fuzhou '92 NPC Staging Classification, there are 31 patients in stage Ⅰ, 212 in stage Ⅱ, 198 in stage Ⅲ and 71 in stage Ⅳ. All patients were treated by ~~60 Co or 6?MV X-ray with faciocervical fields or pre-auricular fields to primary area. Some patients were boosted by post-auricular fields or cranial fields. The median dose to the nasopharyngeal region was 7130?cGy by external beam radiotherapy. Thirty-four patients were boosted by brachytherapy. The medial dose to cervical lymph nodes was 6410?cGy as definitive treatment and 5480?cGy as prophylactic treatment. 101 patients were treated with combined chemotherapy. Results The median follow-up was 6.7 years . Radiation-induced cranial nerve palsies occurred in 81 among the 512 patients. The 5-and 10-year cumulative incidences were 10.3%, 25.4 %, respectively. The most common affected nerve was XⅡ. On multivariates analysis, cranial nerve invasion before radiation, chemotherapy, dose to the nasopharyngeal region and age were the independent factors of radiation-induced cranial nerve palsy on nerve Ⅰ-Ⅶ, while the N stage and the radiation fields were independent factors on nerve Ⅸ-Ⅻ. The cumulative incidence of cranial nerve Ⅰ-Ⅶ palsies increased in patients with cranial nerve invasion, chemotherapy and the dose to the nasopharyngeal region (>7000?cGy). The cumulative incidence of cranial nerve Ⅸ-Ⅻ palsies increased in patients with advanced N stage. Patients in the first group of treatment field had the highest risk to progress cranial nerve Ⅸ-Ⅻ palsies, followed by the second group, and the third group had the lowest risk. Only 1 in 34 patients with brachytherapy developed cranial nerve palsy. Conclusions Our retrospective data show that the radiation-induced cranial nerve palsy is a common complication in NPC patients after radiotherapy and the incidence seems to increase with the duration of the follow-up. Factors that potentially affect the injury of cranial nerve Ⅰ-Ⅶ and Ⅸ-Ⅻ are different, because of the different anatomy. Controlling the doses to the nasopharyngeal region and using faciocervical fields may help to lower the incidence of cranial nerve palsy.