Primary hyperparathyroidism in patients with thyroid cancer: prevalence and prognosis in a retrospective monocentric study

Purpose: Primary hyperparathyroidism (PHPT) is associated with long-term implications on many aspects of general health and has been linked to various tumor types. This retrospective monocentric study aimed to evaluate the prevalence of primary hyperparathyroidism in a cohort of thyroid cancer patients and its impact on their general prognosis. Methods: The prevalence of primary hyperparathyroidism (concomitant or subsequent) was retrospectively evaluated in a cohort of 450 patients with a diagnosis of differentiated thyroid cancer. Its association with oncological outcomes and overall survival was analysed. Results: Among the study population, 30 patients (6,7%) were diagnosed with primary hyperparathyroidism. This subgroup displayed older age at diagnosis and a higher prevalence of prior cardiovascular disease, other primary tumors and multinodular goiter (p < 0.001). PHPT was associated with increased mortality; however, no significant difference in thyroid cancer-specific mortality was found. Conclusion: A significant proportion of thyroid cancer patients may present concomitant primary hyperparathyroidism, which appears to negatively affect long-term prognosis, independently from their oncological outcomes.