Chronological Age and Outcomes after Ultrasound-guided Thermal Ablation for Thyroid Nodules: A Single-center Retrospective Cohort Study

Abstract Background Chronological age is often used to select candidates for minimally invasive treatment, but whether age itself affects outcomes after ultrasound-guided thermal ablation of thyroid nodules is unclear. We examined whether age was associated with postablation ablation-zone volume reduction and treatment-related complications, using both a clinically relevant age threshold and continuous age. Methods This single-center retrospective cohort study included patients who underwent thyroid radiofrequency or microwave ablation and completed at least one ultrasound follow-up. Age at first treatment was categorized as older than 55 years or 55 years or younger, based on the thyroid cancer staging threshold, and also analyzed as a continuous variable and using conventional geriatric thresholds (> 60 and > 65 years). The primary effectiveness outcome was patient-level postablation ablation-zone volume reduction ratio (VRR) at 9–15 months, estimated using multivariable linear regression with robust standard errors; IPTW and IPCW sensitivity analyses were also performed. The primary safety outcome was any recorded treatment-related complication, summarized as risk differences with 95% CIs. Results Among 799 patients (669 aged ≤ 55 years, 130 aged > 55 years), 272 contributed to the primary 9-15-month effectiveness analysis. Raw median VRR was 93.3% (younger) and 93.8% (older); adjusted VRR was 86.5% and 86.3%, respectively, with an older-minus-younger difference of -0.3 percentage points (95% CI: -8.0, 7.5; P = .94). Supportive estimates from last-imaging, IPCW-weighted, and IPTW-weighted analyses ranged from 2.9 to 3.6 percentage points, all in the same direction. Any recorded complication occurred in 67 of 669 (10.0%) younger and 11 of 130 (8.5%) older patients (risk difference, -1.6 percentage points; 95% CI: -6.0, 4.8; P = .75); no serious complications occurred. Modeling age continuously or using 60- and 65-year thresholds gave directionally consistent, though imprecise, results. Conclusions Chronological age, on its own, did not distinguish short-term effectiveness or recorded safety in this single-center cohort of patients selected for ultrasound-guided thyroid thermal ablation. Across the age definitions and sensitivity analyses used here, older patients had similar adjusted postablation ablation-zone volume reduction and no higher rate of recorded complications than younger patients. Ablation candidacy for older adults should rest on lesion characteristics, technical feasibility, comorbidity, functional status, and patient goals rather than an age cutoff. Frailty and comorbidity were incompletely captured, so these results should not be extended to unselected or functionally dependent older populations.