Prognostic Impact of Further Treatments on Distant Metastasis in Patients With Minimally Invasive Follicular Thyroid Carcinoma: Verification Using Inverse Probability of Treatment Weighting.

Abstract

The aim of this study was to evaluate the prognostic impact of further treatments in minimally invasive follicular thyroid carcinoma (MIFTC) patients. The risk factors for distant metastases were analyzed, and the impact of surgical extent on distant metastasis was verified by using weighted logistic regression models with inverse-probability of treatment weighting (IPTW). 166 patients including 31 males (18.7%) and 135 females (81.3%), with the mean age of 41.5±13.5years, were enrolled for this study. The median follow-up period was 103.5months (range, 13-244months). Seven patients (4.2%) had distant metastases during follow-up period. The presence of vascular invasion (Hazard ratio [HR]=29.06; 95% Confidence Interval [CI]=3.06-209.08; p=0.015) and extensive vascular invasion≥4 foci (HR=40.57; 95% CI=2.09-789.13; p=0.014) were the independent risk factors for distant metastasis by multivariate analysis. Surgical extent did not influence distant metastasis. Logistic regression with IPTW also demonstrated that there were no statistically significant differences in the development of distant metastasis based on surgical extent (HR=1.28; 95% CI=0.15-10.87; p=0.823). The presence of extensive vascular invasion is the most powerful predictor of distant metastasis. However, it is noteworthy that further treatments do not demonstrate an advantageous effect on preventing distant metastasis during the follow-up period.