What Features Predict Poorer Outcomes in Micropapillary Thyroid Carcinoma? A Retrospective Cohort Study

Abstract

OBJECTIVE: Micropapillary thyroid carcinoma (MPTC), a variant of papillary thyroid carcinoma sized </=10 mm, is increasingly detected due to advanced ultrasound. This study aimed to describe characteristics and risk assessment of patients with MPTC to predict outcomes and guide initial management. METHODS: This retrospective cohort study (June 1980 to September 2023) assessed patients with MPTC using 2015 American Thyroid Association guidelines for risk stratification and determination of response to treatment. Outcomes ranged from excellent to structural incomplete responses. RESULTS: Among 208 patients with papillary thyroid carcinoma with a primary tumor focus </=10 mm, 68.8 were low risk, 29.3 intermediate risk, and 1.9 high risk. Higher risk was linked to larger tumor size (>/=7 mm) (odds ratio OR, 3.196; P value = .001) and multifocality (OR, 2.431; P value = .004). Age (OR, 0.973; P value = .048) and background Hashimoto thyroiditis (OR, 0.439; P value = .014) were found as protective factors. Excellent response to therapy was observed in 48.4% of patients, whereas structural and biochemical incomplete responses were found to be 11.2% and 7.5%. Recurrence was detected in 14 (8.18%) patients. CONCLUSION: MPTC generally has a good prognosis and responds well to the treatment. Larger tumors (>/=7 mm), younger age (<40 years), multifocality, and absence of Hashimoto thyroiditis correlate with a higher American Thyroid Association risk and poorer outcomes.