Papillary thyroid carcinoma prevalence and its predictors in patients with primary hyperparathyroidism

Abstract

Aim: Papillary thyroid carcinoma (PTC) and primary hyperparathyroidism (PHPT) are among the most common endocrine diseases. Although it has been shown that hyperparathyroidism may be associated with various cancers, the question of whether there is an association between hyperparathyroidism and PTC remains controversial. To evaluate the incidence of concomitant PTC among patients with PHPT and to identify possible risk factors for the development of PTC in these patients. Material and Method: The data of 543 patients who had been operated on due to PHPT in our institution were reviewed retrospectively. Patients who underwent thyroid surgery in conjunction with parathyroidectomy and patients whose diagnosis of PTC was confirmed histopathologically were compared in terms of their clinical, biochemical, and histopathological features. The prevalence of PTC found in patients with PHPT was compared with national rates to estimate standardized incidence ratios (SIRs). Results: Of the 456 PHPT patients enrolled in the study, 281 (61.6%) had concomitant thyroid nodules on thyroid ultrasonography, and PTC was detected in 53 (11.6%) patients during their thyroid surgeries. Compared to the general population, the incidence of papillary thyroid cancer was increased in both women and men with PHPT (SIR: 272.2, 95% CI: 201.6-360.0, p<0.001 and SIR: 736.5, 95% CI: 322.1-1457.0, p<0.001, respectively). Patients who were found to have PTC were older than non-PTC patients and had higher serum calcium levels (p=0.026 and p= 0.012, respectively). In multivariate analysis, a high serum calcium level and advanced age were independent predictors of PTC in patients with PHPT (OR: 1.402, 95% CI: 1.046-1.878, p=0.024 and OR: 1.024, 95% CI: 1.001-1.047, p=0.043, respectively). Conclusion: Our study showed a significant increase in the prevalence of PTC in patients with PHPT compared to the general population in association with both older age and higher levels of serum calcium. Due to their higher levels of risk, such patients should particularly be comprehensively screened for PTC preoperatively, and the indications for thyroid surgery entailing parathyroidectomy should be updated in the current guidelines.