(0412) Survival Differences of Anaplastic Thyroid Cancer by Different Extent of Surgical Resection: A Surveillance, Epidemiology, and End Results Database Analysis

Introduction: Anaplastic thyroid cancer (ATC) is an aggressive endocrine malignancy. Many patients present with advanced cancers and are inoperable at the time of presentation. However few studies have compared outcomes in those patients that do undergo surgery. The aim of this study is to investigate survival differences by extent of surgery in ATC.

Methods: Patients from the Surveillance, Epidemiology, and End Results (SEER) diagnosed with ATC between 2000-2020 were selected. Extent of surgical resection was divided into sub-lobectomy/lobectomy or subtotal/total thyroidectomy groups. Additional variables included age, gender, race, stage, tumor size and morphology, chemotherapy and radiation status, median household income and population size of the patient’s home area. Log-rank and Cox regression analyses were completed to compare survival.

Results: A total of 1,632 patients were included. The median survival of the cohort was 4 months and the one- and five-year survival rates were 24.9% and 16.7%, respectively. On log-rank tests, patients who received total thyroidectomy survived longer than both lobectomy and nonsurgical patients (p’s < 0.001). Cox regression showed worse survival for nonsurgical and sub-lobectomy/lobectomy patients (p’s < 0.001). Asian race (p=0.040), regional (p=0.008) and distant stage of diagnosis, age over 65 years, and tumor size >4.0 cm also had worse survival (p’s < 0.001). Chemotherapy and radiation therapy recipients had improved survival (p’s < 0.001).

Conclusions: Outcomes for ATC remain poor however these findings indicate improved survival with thyroidectomy compared to lobectomy. Treatment with radiation and chemotherapy also improved survival. Patient age, race, stage at diagnosis, and tumor size, may also impact ATC survival outcomes. When considering management for ATC, these demographic and clinical variables should be considered in the decision-making process.