Comparison of Lobectomy vs Total Thyroidectomy for Medullary Thyroid Carcinoma: A SEER Analysis With Chinese Cohort Validation

This study aimed to clarify whether lobectomy provides survival benefits for patients with early-stage medullary thyroid carcinoma (MTC). Patients with tumor size less than 4 cm, excluding those with lateral neck involvement, bilateral foci, extrathyroidal extension or distant metastases, were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database and Zhejiang Cancer Hospital in China. Propensity score matching (PSM), Kaplan-Meier analysis, and Cox regression analyses were used to evaluate treatment outcomes and identify risk factors. Among 1,009 patients in the SEER database, total thyroidectomy (TT) was associated with multifocality (p < 0.001) and local nodal metastasis (p < 0.001). After PSM, 73 pairs were matched. In the Chinese cohort form Zhejiang Cancer Hospital, TT was correlated with larger tumor (p < 0.001), higher calcitonin peak-to-basal ratio (p = 0.002), and T2 stage (p = 0.025), with 38 matched pairs after PSM. Cox regression analyses showed that the extent of thyroid resection was not an independent prognostic factor for overall survival (SEER: OS p = 0.607) or progression-free survival (Chinese cohort: PFS p = 0.411). Kaplan-Meier analysis revealed no significant survival differences between the TT and lobectomy groups (SEER: OS p = 0.43; Chinese cohort: PFS p = 0.21). Additionally, the TT group had more frequent adverse events (transient hypocalcemia: p < 0.001, transient vocal cord paralysis: p < 0.025), longer hospital stays (p = 0.011), and higher costs (p = 0.001) than the lobectomy group. For patients with early-stage MTC, lobectomy may be an optimal alternative option that does not impair prognosis and confers a low risk of adverse events. Although the American Thyroid Association Guidelines (ATA) guidelines recommend TT for patients with MTC, there has been increasing voices to reduce the surgical extent in recent years. This study suggests that lobectomy provides a comparable prognosis to TT for early-stage MTC patients while avoiding additional complications, making it a viable treatment option.