Department of Radiation Oncology, Nara Hospital Kindai University, Ikoma, Nara, Japan.
Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Osaka, Japan.
Acta Otolaryngol. 2021 Nov;141(11):1022-1026. doi: 10.1080/00016489.2021.1998615. Epub 2021 Nov 5.
Hypothyroidism is a common adverse event after radiotherapy for head and neck tumors and the incidence need to be re-evaluated because of using intensity-modulated radiotherapy (IMRT).
AIMS/OBJECTIVES: Confirm the dose-volume effect of IMRT for pharyngeal cancer on hypothyroidism.
This was a retrospective analysis of patients underwent IMRT for pharyngeal cancer from June 2011 to May 2018. Patients were classified into group A (thyroid stimulating hormone (TSH) <5μU/ml), group B (5< =TSH < 10), and group C (10< =TSH) based on TSH over 36 months post-radiation. Radiation dose, thyroid volume, and the proportion of the thyroid that received X Gy or greater (Vx) were measured.
Fifty-two patients were included in this work. Hypothyroidism developed in 33/52 (63%) patients, 13 in group B and 20 in group C. The mean radiation dose to the thyroid was 49.4 Gy and the median time until hypothyroidism was 39 months after irradiation. Hypothyroidism was significantly related to neck dissection (ND) and radiation dose to the thyroid. Patients whose thyroid received 45 Gy or more (V45) >67% had a significantly higher incidence of hypothyroidism.
Patients with pharyngeal cancer who had ND and V45 to the thyroid >67% are at risk of hypothyroidism.
甲状腺功能减退症是头颈部肿瘤放疗后的常见不良反应，由于采用调强放疗（IMRT），需要重新评估其发病率。
证实 IMRT 治疗咽癌后甲状腺功能减退的剂量-体积效应。
这是一项回顾性分析，纳入了 2011 年 6 月至 2018 年 5 月期间接受 IMRT 治疗的咽癌患者。根据放疗后 36 个月 TSH 水平，患者被分为 A 组（TSH＜5μU/ml）、B 组（5≤TSH＜10）和 C 组（TSH≥10）。测量甲状腺刺激激素（TSH）、甲状腺体积和甲状腺接受 X Gy 或更高剂量的比例（Vx）。
共纳入 52 例患者，其中 33 例（63%）发生甲状腺功能减退，B 组 13 例，C 组 20 例。甲状腺的平均照射剂量为 49.4Gy，发生甲状腺功能减退的中位时间为放疗后 39 个月。甲状腺功能减退与颈清扫术（ND）和甲状腺照射剂量显著相关。甲状腺接受 45Gy 或更高剂量（V45）>67%的患者发生甲状腺功能减退的风险显著增加。
行颈清扫术和甲状腺接受>67%V45 的咽癌患者有发生甲状腺功能减退的风险。
