Thyroid V40 Predicts Primary Hypothyroidism After Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma
Thyroid V40 Predicts Primary Hypothyroidism After Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma
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DOI：
10.1016/j.ijrobp.2017.03.007
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发表时间：
2017-07-01
影响因子：
7
通讯作者：
Fong, Kam Weng
中科院分区：
文献类型：
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作者：
Sommat, Kiattisa;Ong, Whee Sze;Fong, Kam Weng
目的：调查可预测鼻咽癌（NPC）调强放射治疗（IMRT）后发生原发性甲状腺功能减退症（HT）风险的各种临床和甲状腺剂量学参数，并确定有用的甲状腺剂量限制以指导放射治疗计划。方法和材料：从2009年9月至2012年8月，本研究纳入了102名临床甲状腺功能正常的NPC患者。所有患者均接受 IMRT 治疗，并随机接受诱导化疗，然后进行同步化疗-IMRT 或单独同步化疗-IMRT。通过在每年随访时测量促甲状腺激素和游离甲状腺素来评估甲状腺功能。获得了各种临床和剂量测定参数（例如，V40 [接受 >40 Gy 的甲状腺体积百分比]）。进行单变量和多变量逻辑回归分析以确定 HT 的预测因子。结果：中位随访时间为 48.8 个月。在 102 名患者中，44 名（43.1%）在放射治疗后 2 年内出现了 HT。 HT 的中位时间为 36.7 个月（范围：24.9-49.0 个月）。 HT的1年和2年累计发病率分别为33%和44.5%。单变量分析显示，年龄较小、T 分期早期、甲状腺最小剂量、V40 和 V45 与 HT 相关。多变量分析显示，年龄较小 (P=.017)、早期 T 分期 (P=.005) 和 V40 (P=.009) 仍具有统计学意义。 V40>85%的患者HT累积发生率显着高于V40患者
Purpose: To investigate the various clinical and thyroid dosimetric parameters that could predict the risk of primary hypothyroidism (HT) after intensity modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC) and to determine useful thyroid dose constraints to guide radiation therapy planning.Methods and Materials: From September 2009 to August 2012, 102 clinically euthyroid NPC patients were included in this study. All patients were treated with IMRT and randomized to induction chemotherapy followed by concurrent chemo-IMRT or concurrent chemo-IMRT alone. Thyroid function was evaluated by measuring thyroid-stimulating hormone and free thyroxine at each annual follow-up visit. Various clinical and dosimetric parameters (eg, V40 [percentage of thyroid volume receiving >40 Gy]) were obtained. Univariate and multivariate logistic regression analyses were performed to identify predictors of HT.Results: Median follow-up was 48.8 months. Among the 102 patients, 44 (43.1%) developed HT within 2 years after radiation therapy. The median time to HT was 36.7 months (range, 24.9-49.0 months). The 1-year and 2-year cumulative incidence rates of HT were 33% and 44.5%, respectively. Univariate analysis revealed that younger age, early T stage, minimum dose to the thyroid gland, V40, and V45 were associated with HT. On multivariate analysis, younger age (P=.017), early T stage (P=.005), and V40 (P=.009) remained statistically significant. Patients with V40 >85% had significantly higher cumulative incidence rates of HT than patients with V40