Study of related factors of radiation-induced hypothyroidism in nasopharyngeal carcinoma / 中华放射肿瘤学杂志

ABSTRACT

Objective:To explore the main factors of hypothyroidism after radiotherapy and to identify the optimal thyroid dosimetric parameters by analyzing the dosimetric parameters of the thyroid.Methods:The general clinical characteristics and dosimetric parameters of 206 patients with nasopharyngeal carcinoma treated in Cancer Hospital of University of Chinese Academy of Sciences were collected, and the correlation between them and the incidence of hypothyroidism was analyzed.Results:The incidence of hypothyroidism in patients with nasopharyngeal carcinoma after radiotherapy was 50.49%(104/206). Univariate analysis showed that gender, N-stage, volume, mean dose, V 20Gy, V 25Gy, V 30Gy, V 35Gy, V 40Gy, V 45Gy of thyroid were associated with the incidence of hypothyroidism. Multivariate analysis demonstrated that volume (≤12.82 cm 3) and mean dose of thyroid were the independent risk factors of hypothyroidism. Mean dose of thyroid combined with volume could significantly predict the incidence of hypothyroidism after radiotherapy. Conclusion:Mean dose of thyroid ≤ 47.21 Gy is the optimal dosimetric parameter for radiation-induced hypothyroidism, especially the patients with thyroid volume ≤ 12.82 cm 3 should pay more attention to the protection of thyroid gland during radiotherapy.