Prognostic Factors and Competing Risk Analysis in Early-Stage Follicular Thyroid Carcinoma: A Population-Based Study.

Area of Science:

• Endocrinology
• Oncology
• Epidemiology

Background:

• Follicular thyroid carcinoma (FTC) exhibits distinct behavior compared to papillary thyroid carcinoma.
• While early-stage FTC generally has favorable outcomes, risk stratification within AJCC stages I-II requires further investigation due to limited specific evidence.

Purpose of the Study:

• To analyze disease-specific survival (DSS) and mortality causes in patients with AJCC stage I-II follicular thyroid carcinoma.
• To identify prognostic factors for mortality in early-stage FTC using competing-risk methods.

Main Methods:

• Utilized the SEER database to identify 4220 patients diagnosed with AJCC stage I-II FTC between 2010 and 2022.
• Employed cumulative incidence functions (CIFs) to estimate thyroid cancer-specific and other-cause mortality.
• Applied Fine-Gray competing-risk regression to evaluate prognostic factors.

Main Results:

• Over the follow-up period, other-cause mortality surpassed thyroid cancer-specific mortality.
• At approximately 10 years, other-cause death rates were around 6%, while thyroid cancer-specific death rates remained below 1.5%.
• AJCC stage II was identified as the only significant predictor of thyroid cancer-specific mortality compared to stage I (SHR 7.76; P=0.002).

Conclusions:

• Early-stage FTC demonstrates overall low cancer-specific mortality, but a concentrated risk exists within stage II.
• This highlights clinically significant heterogeneity within the "early stage" classification.
• Findings support tailored patient counseling and follow-up strategies, emphasizing the utility of competing-risk methodologies in FTC outcome assessment.