SUN-364 - Active Surveillance vs Immediate Surgery for Low-Risk Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis of Real-World Outcomes

Background: Active surveillance (AS) is increasingly used for low-risk papillary thyroid microcarcinoma (PTMC) because it may preserve quality of life and reduce healthcare costs. However, concerns remain regarding disease progression, delayed intervention, patient-reported outcomes, and the comparative value with immediate surgery (IS). For clinicians, payers, and patients, it is essential to understand both the economic impact and clinical outcomes to inform value-based decisions.

Methods: We conducted a systematic review and meta-analysis of observational studies comparing AS and IS in adults with low-risk PTMC (≤1 cm, intrathyroidal, cN0). No randomized trials were identified. Studies used propensity score matching to balance baseline characteristics, though some confounding may persist due to patient preferences and care access. Primary outcomes were tumor progression (≥3 mm growth) and new lymph node metastasis; secondary outcomes included conversion to surgery, complications, patient-reported outcomes (PROs), and cost. We calculated pooled event proportions and synthesized hazard ratios (HRs) where available.

Results: In AS cohorts, tumor enlargement ≥3 mm occurred in 3.4% and new lymph node metastasis in 0.8%, with low heterogeneity, supporting consistent oncologic safety. Comparative analyses showed IS was associated with fewer nodal events than AS (HR 0.42), but absolute risk differences were small ( < 1% over 10–20 years), requiring approximately 200 patients to undergo IS instead of AS to prevent one nodal event. Younger age correlated with tumor growth (HR per year: 0.92). Detection bias from surveillance intensity is possible.

Compared directly, AS resulted in less cumulative surgical burden than IS, with IS patients requiring more interventions per person. Only a minority of AS patients converted to surgery. IS had higher rates of transient vocal cord paralysis, hypoparathyroidism, and long-term levothyroxine dependence. AS avoided about 10 cases of permanent hypoparathyroidism per 100 patients, reducing lifelong morbidity.

Economic analyses showed much lower 10-year costs for AS compared to IS, primarily due to fewer operations, complications, and less hormone replacement. Patient-reported outcomes at 1–2 years were generally better with AS: less neck discomfort, fewer activity limitations, and similar or lower cancer-related anxiety compared to IS.

Conclusion: Real-world evidence supports AS as a safe, surgery-sparing, and cost-effective strategy for selected patients with low-risk PTMC. Clinicians should present AS as the default option, explain modest reductions in nodal events with IS, and address the higher surgical burden and complications of IS. This supports shared decision-making aligned with patient values and healthcare sustainability.

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