Abstract
INTRODUCTION: The relationship between treatment for differentiated thyroid cancer and patient-report of decreased energy and fatigue remains unclear. METHODS: Patients diagnosed with differentiated thyroid cancer from 2014 to 2015 included in the Georgia and Los Angeles, California cancer registries of the Surveillance, Epidemiology, and End Results program were surveyed 2 to 4 years after diagnosis, and responses were linked to data from the Surveillance, Epidemiology, and End Results registry. Multivariable logistic regression analysis determined characteristics associated with the report of worse energy level at 2 to 4 years compared to before treatment and current fatigue severity using adjusted odds ratios with 95% confidence intervals. RESULTS: Of the 2,584 respondents, 988 (38.2%) reported much worse or somewhat worse energy and 1,310 (50.7%) reported moderate to very severe fatigue. The majority of patients were treated with total thyroidectomy with or without nodal dissection (total thyroidectomy with lymph node removal [49.3%] or total thyroidectomy [38.3%]). Only 12.3% had a thyroid lobectomy. Just over half were treated with radioactive iodine therapy (56.7%) and thyroid hormone suppression (50.2%) after the thyroidectomy. Younger age, history of depression, thyroid hormone suppression (odds ratio 1.48 [confidence interval 1.21-1.82]), and receipt of radioiodine (odds ratio 1.31 [confidence interval 1.10-1.56]) correlated with worse energy. Similarly, correlates of substantial fatigue included younger age, more comorbidities, history of depression, and thyroid hormone suppression (odds ratio 1.63 [confidence interval 1.34-1.99]). The presence of low serum calcium levels for >3 months after thyroidectomy was associated with worse energy (odds ratio 1.26 [confidence interval 1.02-1.54]) and substantial fatigue (odds ratio 1.49 [confidence interval 1.21-1.84]). CONCLUSION: In addition to accepted risk factors such as depression and comorbidities, receiving radioactive iodine and reporting low calcium after thyroidectomy for differentiated thyroid cancer were associated with reports of worse energy compared to preoperative levels; thyroid hormone suppression was associated with reports of both worse energy and substantial post-treatment fatigue.