Gade V K V, Bahl A, Rastogi A, Oinam A S, Panda N K, Ghoshal S
Department of Radiotherapy and Oncology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Department of Endocrinology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Acta Endocrinol (Buchar). 2024 Jan-Mar;20(1):59-64. doi: 10.4183/aeb.2024.59. Epub 2024 Oct 3.
Radiation-induced hypothyroidism is a well-recognized entity that occurs after an interval of 15-21 months. However, in the treatment of locally advanced Head and neck Squamous cell carcinoma (HNSCC), thyroid-sparing techniques are infrequently employed.
To evaluate the dosimetric and early clinical outcomes of thyroid-sparing SIB-VMAT technique (Simultaneous Integrated Boost - Volumetric Modulated Arc Radiotherapy) in patients of locally advanced HNSCC.
In this two-arm prospective pilot study, patients in the study group received radiotherapy by SIB-VMAT technique with a thyroid constraint to a dose of 70 Gy to the gross disease and 59.4 Gy to nodal and subclinical disease in 33 fractions over 6 ½ weeks with concurrent cisplatin. V50Gy<75% was the thyroid constraint used. The control group was treated with the same dose and technique but without using a thyroid gland constraint. The dose-volume parameters of the thyroid gland, PTV (Planning Target Volume) along with thyroid profile were analyzed.
Twenty-six patients were recruited. Thyroid V50Gy of the study group (65.33 ±6.63 %) was significantly lower than that of control group (80.35 ±13.40 %) (p=0.003). Tumor dose parameters of both groups were compared and revealed no significant difference. At 18 months follow-up, the incidence of any degree of hypothyroidism was 46.15% in the study group and 23.07% in the control group (p=0.216).
In locally advanced HNSCC, it is feasible to spare the thyroid gland without compromising the tumour coverage. This has the potential to reduce the frequency of radiation-induced hypothyroidism.
放射性甲状腺功能减退是一种在15 - 21个月的间隔后出现的公认病症。然而，在局部晚期头颈部鳞状细胞癌（HNSCC）的治疗中，很少采用甲状腺保护技术。
评估局部晚期HNSCC患者采用甲状腺保护的同步整合加量容积调强弧形放疗（SIB - VMAT）技术的剂量学和早期临床结果。
在这项双臂前瞻性试验研究中，研究组患者通过SIB - VMAT技术接受放疗，对甲状腺进行限制，给予大体肿瘤70 Gy的剂量，淋巴结和亚临床病灶59.4 Gy的剂量，在6个半月内分33次给予，同时使用顺铂。采用V50Gy<75%作为甲状腺限制条件。对照组采用相同的剂量和技术，但不使用甲状腺限制。分析甲状腺的剂量 - 体积参数、计划靶体积（PTV）以及甲状腺状况。
招募了26名患者。研究组的甲状腺V50Gy（65.33±6.63%）显著低于对照组（80.35±13.40%）（p = 0.003）。比较两组的肿瘤剂量参数，未发现显著差异。在18个月的随访中，研究组任何程度甲状腺功能减退的发生率为46.15%，对照组为23.07%（p = 0.216）。
在局部晚期HNSCC中，在不影响肿瘤覆盖的情况下保护甲状腺是可行的。这有可能降低放射性甲状腺功能减退的发生率。
