背景与目的：鼻咽癌患者放射过程中，照射野包含部分或全部甲状腺,易造成甲状腺功能损伤。该研究旨在探讨调强放疗对鼻咽癌患者甲状腺血流动力学及功能变化。方法：收集2012年07月—2013年10月接受根治性放化疗初治鼻咽癌患者68例，按UICC 2010年分期为Ⅱ~Ⅳc期。采用2个周期TPF(多西他赛+顺铂+氟尿嘧啶)诱导+2个周期顺铂同期放化疗+2个周期TPF辅助治疗模式。放疗采用调强适型放疗(intensity- modulated radiation therapy，IMRT)技术。在放疗前、放疗结束即刻及结束后3和6个月通过电化学发光法检测血清中血清游离三碘甲腺原氨酸(free triiodothyronine，FT3)、血清游离甲状腺素(free thyroxin， FT4)和促甲状腺激素(thyroid-stimulating hormone，TSH)的浓度；采用甲状腺B超测量收缩期流速、舒张期流速、阻力指数、甲状腺各径线值。结果：68例鼻咽癌患者随访均满6个月。甲状腺功能减退情况：放疗结束即刻甲状腺功能减退发生率为5.9%，放疗结束后3个月甲状腺功能减退发生率为13.2%，放疗结束后6个月甲状腺功能减退发生率为26.5%。放疗结束即刻甲状腺体积变化较放疗前比较差异无统计学意义(P>0.05)；在放疗结束后3、6个月甲状腺体积较放疗前比较差异有统计学意义(P<0.05)。放疗结束即刻FT3、FT4和TSH较放疗前比较差异无统计学意义(P>0.05)；在放疗结束后3个月FT3、FT4、TSH较放疗前比较差异有统计学意义(P<0.05)。单因素相关分析结果显示，放疗结束即刻、结束后3、6个月甲状腺体积与甲状腺平均照射剂量均有相关性(P<0.05)。单因素相关分析结果显示，放疗结束即刻甲状腺功能减退发生率与甲状腺剂量-体积参数V40有相关性(P<0.05)；独立t检验结果显示，放疗结束后6个月发现临床甲状腺功能减退病例与放疗时甲状腺接受的平均照射剂量有相关性(P<0.05)。单因素相关分析结果显示，在放疗结束即刻及结束后3、6个月甲状腺功能减退与甲状腺动脉收缩期最高流速及阻力指数无相关性(P>0.05)。结论：随着放疗结束后时间的延长，甲状腺功能减退发生率可能升高。甲状腺受照射剂量的增大、随访时间的延长，甲状腺体积可能缩小。鼻咽癌放疗后应常规复查。甲状腺剂量-体积参数V40可能是急性放射性甲状腺损伤的预测因素。该研究目前暂未发现甲状腺功能减退与甲状腺B超血流速度相关。%Background and purpose:When the patients with nasopharyngeal carcinoma (NPC) receive radiotherapy, their thyroids are inevitably involved. As a result, thyroid damage occurs. This study aimed to explore the effects of intensity modulated radiation therapy (IMRT) on dynamics of thyroid blood flow in patients with NPC.Methods:A total number of 68 patients with NPC were enrolled in the study who received primary treatment of radical radiation and chemotherapy from Jul. 2012 to Oct. 2013. And the TMN stage was fromⅡ toⅣc according to UICC 2010. The treatment method consisted of 2 cycles of TPF induction treatment, concurrent radiation therapy (IMRT) with 2 cycles of DDP and 2 cycles of adjuvant therapy sequentially. Before radiotherapy, at the end of radiotherapy, 3 and 6 months after radiotherapy, serum free triiodothyronine (FT3), free thyroxin (FT4) and thyroid-stimulating hormone (TSH) concentrations of all cases were detected by electrochemiluminescence. The highest systolic velocity, mean velocity, minimum diastolic velocity, resistance index, and the value of all thyroid diameter lines were measured by type-B ultrasound.Results:All the patients were followed up for 6 months. Hypothyroidism: the incidence of immediate clinical hypothyroidism after radiotherapy was 5.9%; 3 months later, the incidence was 13.2%; and 6 months later, the incidence was 26.5%. The difference in volume change between before radiotherapy and at the end of radiotherapy had no statistical signiifcance (P>0.05). The difference in volume change between 3 and 6 months after radiotherapy had statistical signiifcance (P<0.05). The difference in FT3, FT4 and FSH between the end of radiotherapy and before radiotherapy had no statistical signiifcance, while there was statistically signiifcant difference between at the end of radiotherapy and 3 months after radiotherapy. The thyroid volume correlated with the average dose at the end of radiotherapy, 3 and 6 months after radiotherapy as shown by the single factor correlation analysis (P<0.05). The results of sinlge factor correlation analysis also showed that the occurrence of hypothyroidism correlated with thyroid dose-volume parameter V40 at the end of radiotherapy (P<0.05). The correlation between hypothyroidism and the average dose on thyroid 6 months after radiotherapy was demonstrated by independentt test (P<0.05). Hypothyroidism had no correlation with thyroid artery systolic maximum velocity and resistance index at the end of radiotherapy, 3 and 6 months after radiotherapy (P>0.05).Conclusion:The incidence of hypothyroidism may increase with time after radiotherapy. The volume may decrease with the increased dose of radiotherapy and the follow-up time. The patients with NPC after radiotherapy should be tested for thyroid lesions routinely. The thyroid dose-volume parameter V40 may be a predictor for acute radioactive thyroid lesions. The study did not reveal temporarily that hypothyroidism was associated with thyroid ultrasound blood lfow velocity.
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