鼻咽癌调强放疗后甲状腺功能减退的危险因素分析

Analysis on Risk Factors of Hypothyroidism After Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma

目的分析鼻咽癌调强放疗(IMRT)后甲状腺功能减退的相关危险因素,探讨相关因素在预测甲减中的应用价值。方法选择2013年2月至2016年12月96例在本院接受调强放疗的初治鼻咽癌患者纳入研究。定期随访,以发生甲减的患者为观察组,未发生甲减的患者为对照组,比较两组的性别、年龄、临床分期、 N分期、是否化疗以及甲状腺的体积、 V_(30)、 V_(40)、 V_(45)、V50、 D_(mean),单因素分析结果有差异的因素用Logistic回归模型进行多因素分析。结果中位随访38个月, 96例患者有14例发生亚临床甲减, 29例发生临床甲减,发生率为44.8%。1年、 2年、 3年、 4年甲减的累计发生率分别为25.0%、 31.2%、 37.5%、42.7%。单因素分析显示两组的N分期以及甲状腺的D_(mean)、 V_(40)、 V_(45)差异有统计学意义(P <0.05)。将N分期以及甲状腺的D_(mean)、V_(40)、 V_(45)纳入Logistic回归模型,结果显示N分期以及甲状腺的V_(40)、 D_(mean)是影响鼻咽癌放疗后甲减的危险因素。结论 N_2～N_3期患者甲减发生率高;甲状腺D_(mean)≥46.8 Gy,甲减发生率为60.0%; V_(40)≥80.6%,甲减发生率为60.4%。鼻咽癌IMRT优化中应尽量将甲状腺的D_(mean)控制在46.8 Gy以下, V_(40)控制在80.6%以下,以达到保护甲状腺的目的。

Objective To analyze the related risk factors of hypothyroidism after intensity modulated radiation therapy(IMRT)for nasopharyngeal carcinoma(NPC)and to evaluate the application value of related factors in predicting hypothyroidism.Methods 96 patients with de novo nasopharyngeal carcinoma(NPC)treated by intensity modulated radiation therapy(IMRT)in our hospital from February 2013 to December 2016 were selected in this study.Under regular follow-up,patients with hypothyroidism were taken as observation group and patients without hypothyroidism were taken as control group.The sex,age,clinical stage,N stage,chemotherapy or not,and volume,V30,V40,V45,V50 and Dmeanof thyroid gland were compared between the two groups.The factors with different results of univariate analysis were analyzed by Logistic regression model.Results During a median follow-up of 38 months,subclinical hypothyroidism was found in 14 cases and clinical hypothyroidism in 29 cases,with the incidence of 44.8%.The cumulative incidences of hypothyroidism at 1,2,3 and 4 years were 25.0%,31.2%,37.5%and 42.7%,respectively.Univariate analysis showed significant differences in N stage,and Dmean,V40 and V45 of thyroid gland between the two groups(P<0.05).The N stage,and Dmean,V40 and V45 of thyroid gland were enrolled in Logistic regression model,and the results showed that N stage,and V40 and Dmeanof thyroid gland were risk factors of hypothyroidism after radiotherapy for nasopharyngeal carcinoma.Conclusions The incidence of hypothyroidism is high in N2~N3 patients.Hypothyroidism rate is 60.0%when thyroid gland Dmean≥46.8 Gy;hypothyroidism rate is 60.4%when V40≥80.6%.In the optimization of IMRT of nasopharyngeal carcinoma,the Dmeanof thyroid gland should be controlled below 46.8 Gy and V40 should be controlled below 80.6%in order to protect the thyroid gland.