Long-term therapeutic outcomes of papillary thyroid carcinoma with concomitant hyperparathyroidism: A single center case-control study

Background: Papillary thyroid carcinoma occasionally presents with concomitant hyperparathyroidism; however, the clinical significance has not been well established. This study aimed to evaluate the long-term cancer prognosis following a multimodality therapy. Methods: We conducted a case-control study using prospectively maintained data from a medical center thyroid cancer database between 1980 and 2013. The study cohort comprised patients with concomitant papillary thyroid carcinoma and hyperparathyroidism. Patients with papillary thyroid carcinoma only were matched using the propensity score method. Therapeutic outcomes, including the non-remission rate of papillary thyroid carcinoma and patient mortality, were compared. Results: We identified 27 study participants from 2537 patients with papillary thyroid carcinoma, with 10 patients having primary hyperparathyroidism and 17 having renal hyperparathyroidism. Eighty-five percent of the cohort was found to have tumor-node -metastasis stage I disease. During a mean follow-up of 7.7 years, we identified 3 disease non-remission and 4 mortality events. The non-remission risk did not increase (hazard ratio [HR], 1.66; 95% confidence interval [CI], 0.43-6.40; p = 0.47); however, the overall mortality risk significantly increased (HR, 4.43; 95% CI, 1.11-17.75; p = 0.04). All mortality events were not thyroid cancer related, including two identified cardiovascular diseases. Conclusions: Patients with papillary thyroid carcinoma who present with concomitant hyperparathyroidism are usually diagnosed at an early cancer stage with compatible therapeutic outcomes. However, hyperparathyroidism-related comorbidity may decrease long-term survival.