SUN-367 - Trends in Surgical Management of Differentiated Thyroid Cancer in Hawaii Following the 2015 American Thyroid Association Guidelines

Background: The 2015 American Thyroid Association (ATA) Guidelines support initial hemithyroidectomy to treat small, low-risk differentiated thyroid cancer (DTC). The authors aim to compare the rate of hemithyroidectomy for appropriately selected DTCs in Hawaii before and after the guidelines’ release.

Methods: Statewide data from the Hawaii Tumor Registry were retrospectively reviewed to identify patients diagnosed with papillary or follicular thyroid cancer by cytology or histopathology between 2008 and 2021. Inclusion criteria were age ≥18 at the time of diagnosis, tumor size ≤4 cm, lack of extrathyroidal extension, and lack of nodal or metastatic disease. Demographic, tumor, and treatment characteristics were recorded. Patients were then split into two groups based on date of diagnosis: 2008-2014 and 2015-2021. T-tests and Chi-square tests were used to characterize intergroup differences. Additional comparisons were made between patients in the 2015-2021 group who did and did not receive hemithyroidectomy.

Results: A total of 1470 patients were eligible. Papillary thyroid cancer comprised a majority of included cases (n = 1418, 96.5%). Primary tumor staging was T1 in 78.6% (n = 1155) of patients. Preoperative characteristics were similar between the study groups. Patients diagnosed after 2015 were more likely to receive hemithyroidectomy (33.3% vs. 22.7%, p < 0.0001) and less likely to undergo postoperative radiation (23.6% vs. 48.7%, p < 0.0001). Subgroup analysis of patients in the 2015-2021 group revealed a positive association between T1 staging and hemithyroidectomy (p = 0.0023).

Conclusion: Hawaii patients with small, low-risk DTCs were more likely to undergo hemithyroidectomy following the release of the 2015 ATA guidelines. Treatment protocols after 2015 less frequently included postoperative radiation. Tumor size may continue to influence the extent of surgery in patients considered eligible for hemithyroidectomy.