The survival after thyroidectomy versus lobectomy in multifocal papillary thyroid microcarcinoma patients

The extent of thyroid surgery for multifocal papillary thyroid microcarcinoma (PTMC) remains controversial. Studies on the optimal surgical approach for a multifocal PTMC are scarce. This study aimed to compare the effectiveness of thyroidectomy and lobectomy for the treatment of multifocal PTMC.

A population-based retrospective cohort of patients with multifocal PTMC was analyzed using the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2017, and divided into two groups (thyroidectomy, lobectomy) based on the surgical approach. The clinicopathologic features and survival outcomes were compared between the two groups. Cox proportional hazards regression analysis to explore prognostic factors of survival. Propensity score matching (PSM) was used to balance covariates.

Overall, a total of 9387 multifocal PTMC patients were included in the study. Among them, 8,107 (86.36%) patients received thyroidectomy, and 1280 (13.64%) patients underwent lobectomy. Compared to patients in the thyroidectomy group, patients in the lobectomy group were diagnosed with older age (50.47 years vs. 49.32 years, p = 0.003), a higher proportion of males (20.47% vs. 14.99%, p < 0.001), larger tumors (6.22 mm vs. 4.97 mm, p < 0.001), and more frequently underwent radiotherapy (35.40% vs. 10.16%, p < 0.001). Multivariate Cox regression analysis revealed that age was the only independent prognostic factor for thyroid cancer-specific survival (TCSS), and the determinants of overall survival (OS) were age and gender. Unadjusted survival analysis revealed no difference between the two treatment groups in TCSS (p = 0.598) and OS (p = 0.126). After 1:1 Propensity Score Matching (PSM), there was still no difference in TCSS (p = 0.368) or OS (p = 0.388). The stratified analysis revealed that for patients aged under or above 55, thyroidectomy was not associated with superior BCSS or OS (p > 0.05).

Thyroidectomy was not associated with improved survival compared to thyroid lobectomy for patients with multifocal PTMC.