A Prospective Cohort Study on Radiation-induced Hypothyroidism: Development of an NTCP Model

作者：Boomsma Marjolein J; Bijl Hendrik P; Christianen Miranda E M C; Beetz Ivo; Chouvalova Olga; Steenbakkers Roel J H M; van der Laan Bernard F A M; Wolffenbuttel Bruce H R; Oosting Sjoukje F; Schilstra Cornelis; Langendijk Johannes A^*

来源：International Journal of Radiation Oncology, Biology, Physics, 2012, 84(3): E351-E356.

DOI：10.1016/j.ijrobp.2012.05.020

Purpose: To establish a multivariate normal tissue complication probability (NTCP) model for radiation-induced hypothyroidism. %26lt;br%26gt;Methods and Materials: The thyroid-stimulating hormone (TSH) level of 105 patients treated with (chemo-) radiation therapy for head-and-neck cancer was prospectively measured during a median follow-up of 2.5 years. Hypothyroidism was defined as elevated serum TSH with decreased or normal free thyroxin (T4). A multivariate logistic regression model with bootstrapping was used to determine the most important prognostic variables for radiation-induced hypothyroidism. %26lt;br%26gt;Results: Thirty-five patients (33%) developed primary hypothyroidism within 2 years after radiation therapy. An NTCP model based on 2 variables, including the mean thyroid gland dose and the thyroid gland volume, was most predictive for radiation-induced hypothyroidism. NTCP values increased with higher mean thyroid gland dose (odds ratio [OR]: 1.064/Gy) and decreased with higher thyroid gland volume (OR: 0.826/cm(3)). Model performance was good with an area under the curve (AUC) of 0.85. %26lt;br%26gt;Conclusions: This is the first prospective study resulting in an NTCP model for radiation-induced hypothyroidism. The probability of hypothyroidism rises with increasing dose to the thyroid gland, whereas it reduces with increasing thyroid gland volume.

• 出版日期2012-11-1