Efficacy and Safety of Microwave and Radiofrequency Ablation in the Treatment of Hyperparathyroidism in Older Individuals: A Multicenter Prospective Study

Background Hyperparathyroidism impacts older individuals' quality of life and increases mortality risk. Thermal ablation has gained attention as an alternative to parathyroidectomy due to its minimal invasiveness and repeatability. Purpose To compare the efficacy and safety of microwave ablation (MWA) and radiofrequency ablation (RFA) in older individuals with primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT). Materials and Methods This prospective, multicenter study included individuals aged 55 years or older with PHPT or SHPT who underwent MWA or RFA (September 2017-March 2022). Treatment outcome (cure rate in participants with PHPT and parathyroid hormone [PTH] achievement rate in participants with SHPT [ie, the proportion maintaining target PTH levels for ≥6 months]), biochemical parameters (PTH, calcium, phosphorus, and alkaline phosphatase [ALP]), and treatment-related complications were evaluated over a 24-month follow-up period. Longitudinal changes in biochemical parameters were analyzed using a generalized linear mixed model. Selection bias was minimized using inverse probability weighting. Predictors of treatment failure were identified through univariable and multivariable analyses. Results A total of 153 participants (mean age, 63.3 years ± 6.9 [SD]; 98 female participants) were included. The overall cure rate for PHPT was 80% (61 of 76; 78% [42 of 54] for MWA vs 86% [19 of 22] for RFA; <i>P</i> = .59). The PTH achievement rate for SHPT was 90% (69 of 77; 92% [36 of 39] for MWA vs 87% [33 of 38] for RFA; <i>P</i> = .48). Both techniques reduced serum PTH, calcium, and ALP between baseline and 24 months in PHPT and SHPT, whereas phosphorus increased in PHPT and decreased in SHPT. Preoperative PTH level was the only independent predictor of treatment failure (PHPT: univariable analysis odds ratio, 1.01, <i>P</i> = .007; multivariable analysis odds ratio, 1.01, <i>P</i> = .02; SHPT: univariable analysis odds ratio, 1.001, <i>P</i> = .01; multivariable analysis odds ratio, 1.001, <i>P</i> = .02). The most common complication was transient hypocalcemia (13% [10 of 76] in PHPT; 51% [39 of 77] in SHPT). There was no evidence of a difference in complication rate for MWA versus RFA in participants with PHPT (15% [eight of 54] vs 27% [six of 22]; <i>P</i> = .21) or SHPT (92% [36 of 39] vs 87% [33 of 38]; <i>P</i> = .48). Conclusion In older participants with hyperparathyroidism, MWA and RFA were safe and effective alternatives, and preoperative PTH level was found to be an independent predictor of treatment failure. © RSNA, 2025 <i>Supplemental material is available for this article.</i>