预防鼻咽癌根治性放疗后甲状腺功能减退的剂量-体积限制参数的外部验证

External validation of dose-volume limitation parameters for the prevention of hypothyroidism after radical radiotherapy for nasopharyngeal carcinoma

目的:验证既往研究报道的甲状腺剂量-体积限制参数是否影响患者放疗后原发性甲状腺功能减退(hypothyroidism,HT)的发生。方法:选取2018年3月至2019年12月福建省肿瘤医院就诊的符合纳入排除标准的92例鼻咽癌患者,末次随访时间为2022年9月,主要结局为原发性HT,单因素和多因素Cox回归分析既往研究报道的甲状腺剂量-体积限制参数与放疗后HT风险之间的关联。结果:中位随访时间为34个月。多因素Cox回归分析显示,调整了年龄、性别和放疗技术后,治疗前甲状腺体积越大(<16 cm^(3)vs.≥16 cm^(3)),45 Gy下甲状腺的绝对体积(the absolute volumes of thyroid spared from 45 Gy,VS45)越大(<5 cm^(3)vs.≥5 cm^(3))、VS50越大(<8 cm^(3)vs.≥8 cm^(3))以及VS60越大(<10 cm^(3)vs.≥10 cm^(3))能够降低放疗后HT的风险[HR(95%CI)分别为0.290(0.099~0.847)、0.320(0.132~0.772)、0.267(0.113~0.633)和0.376(0.163~0.869)]。结论:治疗前甲状腺体积<16 cm^(3)应谨慎放疗后HT的发生,甲状腺VS45≥5 cm^(3)、VS50≥8 cm^(3)和VS60≥10 cm^(3)可以作为甲状腺受照剂量限制推荐参数。

Objective:To validate whether the dose-volume restriction parameters of the thyroid gland in previous studies affect the development of primary hypothyroidism(HT)after radiotherapy.Methods:The study included patients with nasopharyngeal carcinoma(NPC)who were treated at Fujian Cancer Hospital between March 2018 and December 2019.The last follow-up was conducted in September 2022,and the main outcome was primary HT.Univariate and multivariate Cox regressions were performed to analyze the association between thyroid dose-volume limitation parameters reported in previous studies and the risk of HT after radiotherapy.Results:In this study,92 NPC patients were included,with a median follow-up time of 34 months.Multivariate Cox regression analysis showed,after adjustment for age,sex,and radiation technology,higher thyroid volume before treatment(<16 cm^(3)vs.≥16 cm^(3)),higher absolute volume of thyroid spared from 45 Gy(VS45)(<5 cm^(3)vs.≥5 cm^(3)),higher VS50(<8 cm^(3)vs.≥8 cm^(3)),and higher VS60(<10 cm^(3)vs.≥10 cm^(3))could decreased the risk of HT after radiotherapy[HR(95%CI)were 0.290(0.099−0.847),0.320(0.132−0.772),0.267(0.113−0.633),and 0.376(0.163−0.869),respectively)].Conclusions:We should be more cautious about the occurrence of HT after radiotherapy for thyroid volume<16 cm^(3)before treatment.Thyroid VS45≥5 cm^(3),VS50≥8 cm^(3),and VS60≥10 cm^(3)can be recommended for treatment planning.