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

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2012.05.020· OSTI ID:22149591

Boomsma, Marjolein J.; Bijl, Hendrik P.; Beetz, Ivo; Chouvalova, Olga; Wolffenbuttel, Bruce H.R. ^[1]; Oosting, Sjoukje F. ^[2]; Schilstra, Cornelis ^[3]

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1. Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)
2. Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)
3. Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)

Purpose: To establish a multivariate normal tissue complication probability (NTCP) model for radiation-induced hypothyroidism. 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. 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{sup 3}). Model performance was good with an area under the curve (AUC) of 0.85. 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.

• OSTI ID: 22149591
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 84; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
HEAD
HYPOTHYROIDISM
MULTIVARIATE ANALYSIS
NECK
NEOPLASMS
PATIENTS
PERFORMANCE
PROBABILITY
RADIATION DOSES
RADIOTHERAPY
THYROID
TSH