Prospective Validation of ATA Risk Score for Papillary Thyroid Microcarcinoma: An ITCO Real-World Study

Area of Science:

• Endocrinology
• Oncology
• Surgical Oncology

Background:

• Papillary thyroid carcinoma (PTC) smaller than 1 cm (microPTC) has a low recurrence risk.
• Predictors of disease persistence in microPTC remain unclear.
• Understanding microPTC characteristics is crucial for tailored management.

Purpose of the Study:

• Compare clinical and pathological features of microPTCs and larger PTCs (>1 cm).
• Identify predictors of biochemical and structural incomplete response one year post-treatment in microPTC.
• Evaluate the reliability of risk stratification systems for microPTC outcomes.

Main Methods:

• Analysis of a large cohort from the Italian Thyroid Cancer Observatory (NCT04031339).
• Inclusion of patients with complete pathological, clinical, treatment, and 1-year follow-up data.
• Comparison of microPTC characteristics and outcomes against larger PTCs.

Main Results:

• MicroPTCs exhibit more indolent pathological features, with low rates of high-risk classification (3%) and distant metastases (1%).
• MicroPTCs show favorable outcomes: 5% biochemical incomplete response (BIR) and 2.3% structural incomplete response (SIR).
• Distant metastases at diagnosis (OR 5.13) and ATA high-risk classification (OR 5.47) are significant predictors of SIR in microPTC.

Conclusions:

• This study confirms the favorable initial outcomes for microPTC in a large patient series.
• The ATA risk classification is a reliable tool for predicting biochemical and structural persistence in microPTC.
• Tailored management strategies based on comprehensive risk stratification, not just tumor size, are essential for microPTC patients.