MRI诊断颅神经侵犯在鼻咽癌分期中意义

Value of cranial nerve involvement found on MRI in staging of nasopharyngeal carcinoma

目的探讨MRI发现的颅神经侵犯在鼻咽癌分期中意义。方法回顾分析2005—2007年间基于MRI诊断的816例初诊鼻咽癌患者资料。T4期颅神经组定义为MRI上伴有颅神经侵犯但体检无颅神经麻痹且无其他T4期解剖结构侵犯者，余T4期患者定义为T4期其他组。临床分期中Ⅳa期颅神经组定义为T4期颅神经组N0-2期，余M期患者定义为M期其他组。比较T分期、临床分期各亚组疗后生存情况。Kaplan-Meier法计算生存率并用Logrank法检验。结果随访率为94．1％。鼻咽癌颅神经侵犯率为38．5％。T分期中T2、L3、T4期颅神经组的无局部复发生存、无远处转移生存以及疾病相关生存曲线重合，但与T4期其他组能拉开。临床分期中Ⅳa期颅神经组5年疾病相关生存率与Ⅲ期的相似（X2=0．18，P=0．674），而与Ⅱ、Ⅳa期其他组不同（X2=5．86、7．23，P=0．015、0．007）。结论MRI诊断颅神经侵犯的T4期、Ⅳa期患者，若无合并其他T4期解剖结构受累则无局部复发、无远处转移生存率与T2、T3期相似，疾病相关生存率与Ⅲ期相似，预后较T4期其他组及Ⅳa期其他组好；若将这部分患者归为T4期、Ⅳa期将导致患者接受适合于Ⅳ期病例的治疗方案从而引起过度治疗的可能。

Objective To identify the value of cranial nerve involvement found on magnetic resonance imaging （ MRI ） in staging of nasopharyngeal carcinoma （ NPC ）. Methods A retrospective analysis was performed on the clinical data of 816 patients with NPC initially diagnosed by MRI during 2005 -2007. The patients with stage T4 NPC were divided into cranial nerve subgroup, which was defined as patients who had cranial nerve involvement on MRI, but without cranial nerve palsy or other T4-related anatomical structure involvement, and other subgroup, which was defined as other patients with stage T4 NPC ;the patients with stage Ⅳa NPC were divided into cranial nerve subgroup, which was defined as patients with T4N0-2 NPC who were classified into the cranial nerve subgroup of patients with stage T4 NPC, and other subgroup, which was defined as other patients with stage Ⅳa NPC. The survivals of the subgroups were compared. The Kaplan-Meier method was used for calculating survival rates, and the survival differences were analyzed by the log-rank test. Results The follow-up rate was 94. 1%. Cranial nerve involvement was seen in 38. 5% of all patients. Local recurrence-free survival, distant metastasis-free survival, and disease-related survival curves of patients with stage T2 and T3 NPC and the cranial nerve subgroup of patients with stage T4 NPC coincided, but they were separated from the curves of the other subgroup of patients with stage T4 NPC. There was no significant difference in 5-year disease-related survival rate between the cranial nerve subgroup of patients with stage Ⅳa NPC and the patients with stage Ⅲ NPC （X2 =0. 18, P = 0. 674）, but significant differences were found when this subgroup was compared with patients with stage Ⅱ NPC （X2 =5. 86, P=0. 015） and the other subgroup of patients with stage Ⅳa NPC （X2=7.23, P = 0. 007 ）. Conclusions The patients with stage T4/IVa NPC who have cranial nerve involvement on MRI, but without other T4-related anatomical structure involvement, have similar local recurrence-free survival rate and distant metastasis-free survival rate as those with stage T2 and T3 NPC andhave a similar disease-related survival rate as those with stage m NPC, and their prognosis is better than that of the other subgroup of patients with stage T4/Ⅳa NPC. It may lead to overtreatment for patients if they are classified as stage T4/Ⅳa and receive the treatment regimen for stage IV NPC.