Prognostic factors for progression free survival in patients with medullary thyroid cancer: a multicenter cohort study.

Many patients with medullary thyroid cancer (MTC) experience recurrent or persistent disease after surgery due to its aggressive nature. However, the prognostic factors for progression-free survival (PFS) have been poorly investigated. This study aimed to explore prognostic factors associated with PFS in patients with MTC. Patients with MTC were enrolled from 15 medical centers in Shandong Province, China, between January 2010 and December 2021. Univariate and multivariate Cox regression analyses were used to explore the prognostic factors for PFS in patients with MTC. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff value of the metastatic lymph node ratio (LNR) in predicting PFS. Patients with MTC from the Surveillance, Epidemiology, and End Results (SEER) database were used to test the predictive value of the LNR cutoff for overall survival (OS) and disease-specific survival (DSS). In the Shandong cohort, extrathyroidal extension (HR, 1.622; 95% CI 1.022-2.575, P = 0.040), LNR (HR, 2.806; 95% CI 1.121-7.025, P = 0.028), and T3 stage (HR, 2.060; 95% CI 1.074-3.952, P = 0.030) were independent risk factors for PFS in patients with MTC. The optimal cutoff value of the LNR for predicting PFS was 0.19. Compared to patients with LNR < 0.19, those with LNR ≥ 0.19 suffered worse PFS (Log-rank P < 0.0001) in the Shandong cohort, and worse OS (Log-rank P < 0.0001) and DSS (Log-rank P < 0.0001) in the SEER cohort. This study identified prognostic factors for PFS in patients with MTC. LNR ≥ 0.19 could be used as an adverse prognostic factor for patients with MTC.