Predicting Structural Progression-Free Survival After Surgery for Medullary Thyroid Carcinoma

Medullary thyroid cancer (MTC) is an aggressive tumor for which surgery is the only curative treatment. However, after surgery, some patients may experience persistence/recurrence. It is important to identify the prognostic factors that may affect structural disease-free survival (SDFS), which may influence the follow-up of our patients.

To assess SDFS in patients with MTC and related factors.

A retrospective observational study was conducted in a tertiary hospital including patients with MTC without distant metastases. The following variables were assessed: sex, age, heritability, type of surgery, calcitonin (Ct) and CEA, tumor size, stage, lymph nodes ratio (LNR), vascular invasion, high risk, structural disease, and SDFS. A descriptive and comparative univariate and multivariate analysis of SDFS was performed using SPSS version.29 and Cox regression, defining structural disease as the event. p < 0.05 was considered statistically significant.

A total of 140 patients with a median age of 34 years were evaluated. Forty-six percent (n = 65) were male. Twenty-two percent (n = 31) had sporadic MTC, 75% (n = 106) had MEN2a, and 2% (n = 3) had MEN2b. The median calcitonin level was 182.5pg/mL and median follow-up was 179.5 months. Structural disease occurred in 24% of patients (n = 33). The variables that influenced the SDFS were as follows: sporadic CMT, older age, preoperative CEA, size, lymph node involvement, higher LNR, vascular invasion and high risk, and Ct levels > 150pg/mL at 6-12 months. In the multivariate analysis, age, LNR, T category, and postoperative Ct remained independent predictors.

The SDFS in MTC is significantly influenced by LNR, T category, and postoperative Ct levels at 6-12 months.