Microwave ablation for T1N1M0 papillary thyroid cancer with lymph node oligometastasis (≤3) - a preliminary study with median follow-up beyond 3 years.

Objectives: To evaluate the efficacy and safety of microwave ablation (MWA) for T1N1M0 PTC with LN oligometastasis (≤3).

Materials and methods: In this retrospective study, 41 patients who underwent MWA for T1N1M0 PTC with LN oligometastasis between June 2018 and June 2023 were included. Progression-free survival (PFS), risk factors for tumor progression and complications were assessed.

Results: MWA was successfully performed in all the enrolled patients. The median age was 37 years (IQR: 30.5-46.0), with 13 males and 28 females. After a median follow-up of 43 months (IQR: 37.0-51.5; range: 20-70 months), the 1-, 3-, and 5-year PFS rates were 90.2%, 75.3%, and 62.0%, respectively. The maximum diameter of the PTC was the only significant risk factor for tumor progression (hazard ratio: 7.60; p = 0.010). Major complications included only transient hoarseness, occurring in 7.3% (3/41) of the patients, with full recovery within 2-3 months without treatment.

Conclusion: MWA is a feasible treatment option for selected patients with T1N1M0 PTC with LN oligometastasis (≤3), providing favorable therapeutic outcomes and low complication rate.