Radiation-Induced Hypothyroidism After Radical Intensity Modulated Radiation Therapy for Oropharyngeal Carcinoma

Mona Kamal, MD, PhD; Christopher Ryan Peeler, PhD; Pablo Yepes, PhD; Abdallah S.R. Mohamed, MD, MSc; Pierre Blanchard, MD; Steven Frank, MD; Lei Chen, PhD; Amit Jethanandani, MPH; Rohit Kuruvilla, MD; Benjamin Greiner, MD; Jared Harp, MD; Robin Granberry, BA; Vivek Mehta, MD; Crosby Rock, MD; Katherine Hutcheson, PhD; Carlos Cardenas, PhD; G.Brandon Gunn, MD; Clifton Fuller, MD, PhD; Dragan Mirkovic, PhD

Advances in Radiation Oncology (Jan 2020)

Radiation-Induced Hypothyroidism After Radical Intensity Modulated Radiation Therapy for Oropharyngeal Carcinoma

Mona Kamal, MD, PhD,
Christopher Ryan Peeler, PhD,
Pablo Yepes, PhD,
Abdallah S.R. Mohamed, MD, MSc,
Pierre Blanchard, MD,
Steven Frank, MD,
Lei Chen, PhD,
Amit Jethanandani, MPH,
Rohit Kuruvilla, MD,
Benjamin Greiner, MD,
Jared Harp, MD,
Robin Granberry, BA,
Vivek Mehta, MD,
Crosby Rock, MD,
Katherine Hutcheson, PhD,
Carlos Cardenas, PhD,
G.Brandon Gunn, MD,
Clifton Fuller, MD, PhD,
Dragan Mirkovic, PhD

Affiliations

Mona Kamal, MD, PhD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Clinical Oncology and Nuclear Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt
Christopher Ryan Peeler, PhD: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
Pablo Yepes, PhD: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Physics and Astronomy, Rice University, Houston, Texas
Abdallah S.R. Mohamed, MD, MSc: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Clinical Oncology and Nuclear Medicine, Faculty of Medicine, University of Alexandria, Alexandria, Egypt; MD Anderson Cancer Center/UTHealth Graduate School of Biomedical Sciences, Houston, Texas
Pierre Blanchard, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Steven Frank, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Lei Chen, PhD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Amit Jethanandani, MPH: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Rohit Kuruvilla, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Benjamin Greiner, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Jared Harp, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Robin Granberry, BA: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Vivek Mehta, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Crosby Rock, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Katherine Hutcheson, PhD: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas
Carlos Cardenas, PhD: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
G.Brandon Gunn, MD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
Clifton Fuller, MD, PhD: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; MD Anderson Cancer Center/UTHealth Graduate School of Biomedical Sciences, Houston, Texas
Dragan Mirkovic, PhD: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; Corresponding author: Dragan Mirkovic, PhD

Journal volume & issue: Vol. 5, no. 1
pp. 111 – 119

Abstract

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Purpose: To evaluate 2 published normal tissue complication probability models for radiation-induced hypothyroidism (RHT) on a large cohort of oropharyngeal carcinoma (OPC) patients who were treated with intensity-modulated radiation therapy (IMRT). Methods and Materials: OPC patients treated with retrievable IMRT Digital Imaging and Communications in Medicine (DICOMs) data and available baseline and follow-up thyroid function tests were included. Mean dose (Dmean) to the thyroid gland (TG) and its volume were calculated. The study outcome was clinical HT at least 6 months after radiation therapy, which was defined as grade ≥2 HT per Common Terminology Criteria for Adverse Events grading system (symptomatic hypothyroidism that required thyroid replacement therapy). Regression analyses and Wilcoxon rank-sum test were used. Receiver operating characteristic curves and area under the curve for the fitted model were calculated. Results: In the study, 360 OPC patients were included. The median age was 58 years. Most tumors (51%) originated from the base of tongue. IMRT-split field was used in 95%, and median radiation therapy dose was 69.96 Gy. In the study, 233 patients (65%) developed clinical RHT that required thyroid replacement therapy. On multivariate analysis higher Dmean and smaller TG volume maintained the statistically significant association with the risk of clinical RHT (P < .0001). Dmean was significantly higher in patients with clinical RHT versus those without (50 vs 42 Gy, P < .0001). Patients with RHT had smaller TG volume compared with those without (11.8 compared with 12.8 mL, P < .0001). AUC of 0.72 and 0.66 were identified for fitted model versus for the applied Boomsma et al and Cella et al models, respectively. Conclusions: Volume and Dmean of the TG are important predictors of clinical RHT and shall be integrated into normal tissue complication probability models for RHT. Dmean and thyroid volume should be considered during the IMRT plan optimization in OPC patients.

Published in Advances in Radiation Oncology

ISSN: 2452-1094 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Medicine: Medicine (General): Medical physics. Medical radiology. Nuclear medicine; Medicine: Internal medicine: Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Website: http://www.journals.elsevier.com/advances-in-radiation-oncology/

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