Thyroid Cancer Coverage from Every Angle

ASTRO 2020: Does a Reduced Radiation Field Decrease Toxicity in Advanced Thyroid Cancer?

By: Julia Fiederlein
Posted: Thursday, November 5, 2020

According to Ana P. Kiess, MD, PhD, of Johns Hopkins University School of Medicine, Baltimore, and colleagues, reduced fields of external-beam radiation therapy may be associated with less toxicity while maintaining locoregional disease control in patients with differentiated thyroid cancer. The results of this study were recently presented during the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 3913).

“With validation in a larger cohort, these findings may inform future guidelines to ultimately improve quality of life for patients with advanced thyroid cancer who receive external-beam radiation therapy,” the investigators concluded.

The researchers focused on data from the Oncospace database on 42 patients with differentiated thyroid cancer who underwent either unilateral (n = 10) or bilateral (n = 32) external-beam radiation therapy between 2009 and 2019. Follow-up data were provided for a median of 16 months after treatment.

Locoregional failure was observed in one patient; however, the unilateral radiation field had been significantly reduced due to prior treatment of a childhood malignancy. The locoregional control rates at 2 years were 100% and 90% in patients who underwent bilateral and unilateral radiation therapy, respectively. Patients who underwent unilateral radiation therapy appeared to have significantly lower mean doses of radiation to the contralateral parotid gland than those who underwent bilateral radiation therapy (P = .04).

According to the investigators, patients who underwent unilateral radiation therapy seemed to experience less severe acute toxicities. Grade 2 or 3 xerostomia (28%), dysphagia (12%), and mucositis (9%) were reported in patients who underwent bilateral radiation therapy; however, these adverse events were not observed in those who underwent unilateral radiation therapy.

Disclosure: For full disclosures of the study authors, visit


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