External beam radiotherapy for thyroid cancer: Patients, complications, and survival.

BACKGROUND

Patterns of utilization of external beam radiation therapy (EBRT) in thyroid cancer are incompletely described. We characterize therapeutic intent, complications, and survival in thyroid cancer treated with EBRT.

METHODS

In this retrospective study of 105 thyroid cancer patients treated with EBRT at one institution (2008-2018), the primary outcome was overall survival. Secondary outcomes included incomplete treatment, emergency department (ED) visits, weight change, and gastrostomy placement.

RESULTS

Dominant histopathology was differentiated (44%), anaplastic (45%) and poorly-differentiated (11%) disease. EBRT was mainly utilized for locoregional control (differentiated 87%, poorly-differentiated 75%, anaplastic 92%). Palliative EBRT was more common in poorly-differentiated disease (42%). Weight loss was greater in aggressive/advanced disease (differentiated 10 lb, poorly-differentiated 27 lb, anaplastic 18 lb). Anaplastic cancer had higher rates of gastrostomy (34%) and lowest rates of treatment completion (83%). ED encounters were common (differentiated 44%, poorly-differentiated 50%, anaplastic 45%). Gastrostomy was associated with mortality on multivariable analysis in non-anaplastic malignancy.

CONCLUSIONS

EBRT was most frequently administered for locoregional control in thyroid cancer. Despite complications, the majority of patients completed EBRT therapy.