Scoring system for predicting recurrences in patients with papillary thyroid microcarcinoma

Area of Science:

• Endocrinology
• Oncology
• Surgical Pathology

Background:

• Papillary thyroid microcarcinomas (PMC) are small thyroid tumors (≤10 mm) with generally good prognosis.
• Recurrence is possible in PMC, necessitating prognostic tools for risk stratification.
• Current clinical interest focuses on developing predictive scoring systems for PMC recurrence.

Purpose of the Study:

• Identify prognostic factors associated with recurrence in patients diagnosed with PMC.
• Develop a predictive scoring system for PMC recurrence risk, incorporating lymph node status, multifocality, and sex.
• Evaluate the impact of extrathyroidal invasion (ETI) and define multifocality thresholds for recurrence prediction.

Main Methods:

• Retrospective analysis of a large cohort (n=1669) of PMC patients treated at a single center from 1960 to 2007.
• Kaplan-Meier survival analysis and Cox proportional hazards models were employed to identify prognostic factors.
• A novel scoring system was developed and validated based on identified recurrence predictors.

Main Results:

• Lymph node metastasis, tumor multifocality, and male sex were significant predictors of recurrence in PMC patients.
• Tumor size was not a significant factor for recurrence.
• The developed scoring system effectively stratified patients into distinct risk groups for recurrence-free survival. For node-negative (Nx) PMC, multifocal tumor size >20 mm significantly increased recurrence risk. Radioiodine (RAI) ablation improved outcomes in PMC with ETI.

Conclusions:

• A validated scoring system can accurately classify recurrence risk in patients with papillary thyroid microcarcinoma.
• Multifocality is a critical factor for therapeutic strategy planning in node-negative PMC.
• Radioiodine ablation may reduce recurrence probability in pT3 PMC, particularly those with extrathyroidal invasion.