Parathyroid Carcinoma and Primary Hyperparathyroidism: Trends and Outcomes

Parathyroid carcinoma is rare, and its epidemiological relationship to non-cancer primary hyperparathyroidism, along with the comparative long-term cardiometabolic burden of both conditions, remains poorly characterized at the population level. Using the Korea National Health Insurance Service database (2005-2020), we identified 296 patients with incident parathyroid carcinoma and 6,837 patients with non-cancer primary hyperparathyroidism, compared against 71,330 age- and sex-matched controls from the general population. Over the study period, the annual incidence of non-cancer primary hyperparathyroidism increased 7.7-fold, while that of parathyroid carcinoma rose 5.0-fold; because benign disease expanded more rapidly, the proportional contribution of carcinoma among all primary hyperparathyroidism cases declined from 6.67% (2006-2010) to 4.06% (2016-2020). Survival analysis demonstrated that both parathyroid carcinoma (adjusted hazard ratio 2.29; 95% confidence interval 1.53-3.43) and non-cancer primary hyperparathyroidism (adjusted hazard ratio 1.22; 95% confidence interval 1.09-1.35) were associated with significantly higher 10-year all-cause mortality than matched controls, with mortality risk markedly greater in the carcinoma group. Both parathyroid conditions also conferred modestly elevated risks for subsequent incident cardiometabolic complications, including atherosclerotic cardiovascular disease and new-onset type 2 diabetes mellitus. These findings document a rising burden of parathyroid disease in Korea and underscore the need for cardiometabolic risk surveillance in patients with both malignant and benign parathyroid disorders.