Survival Outcome and Optimal Candidates of Primary Tumor Resection for Patients With Metastatic Medullary Thyroid Cancer.

Context: Medullary thyroid cancer (MTC) often exhibits aggressive growth with distant organ metastasis, leading to poor survival.

Objective: The question of whether primary tumor resection (PTR) is beneficial for patients with metastatic MTC remains a subject of debate. In this study, we evaluated the prognostic significance of organ-specific metastases and the number of metastatic organs in these patients, and we also conducted an analysis to determine the therapeutic value of PTR in managing this rare malignancy.

Materials And Methods: Patients initially diagnosed with metastatic MTC were identified within the Surveillance, Epidemiology, and End Results database. Univariable and multivariable Cox proportional hazards regression models were performed to identify survival predictors. Survival outcomes were calculated using the Kaplan-Meier method and compared using the log-rank tests.

Results: A total of 186 patients with metastatic MTC at initial diagnosis from 2010 to 2020 were included. Bone, lung, and liver were the most common metastatic organs. Patients with brain metastasis had significantly worse overall survival (P = .007) and cancer-specific survival (P = .0013). Among all patients, 105 (56.45%) underwent PTR, and this group showed reduced overall mortality and cancer-specific mortality (all P < .05). When analyzing different metastatic patterns, PTR significantly lowered the risk of overall mortality and cancer-specific mortality for patients with bone, lung, liver, or distant lymph node involvement (all P < .05). Additionally, among patients with 1 or 2 metastases, those undergoing surgical resection were significantly associated with favorable overall survival (P = .008) and cancer-specific survival (P = .0247).

Conclusion: PTR may confer therapeutic benefits for carefully selected individuals with metastatic MTCs. To integrate these insights into clinical decision-making settings, it is imperative to undertake multicenter prospective studies in the future.