Background: Parathyroid carcinoma is a rare cause of hyperparathyroidism. Surgery is the only effective therapy, and en bloc resection has previously been recommended.
Methods: A retrospective cohort study of patients with parathyroid carcinoma in the California Cancer Registry and California Office of Statewide Health Planning and Development database from 1999 to 2012 was performed. Patients were stratified by surgical procedure: parathyroidectomy alone, thyroid resection with en bloc parathyroidectomy, and parathyroidectomy with delayed thyroid resection within 6 months. The primary outcome was overall survival stratified by surgical procedure. Secondary outcomes included perioperative complications within 30 days of initial surgery and disease-related complications.
Results: Among our study cohort (n = 136), 60 patients underwent parathyroidectomy alone, 58 patients had en bloc resection, and 18 patients had parathyroidectomy followed by delayed thyroid resection. For the entire cohort, the 5-year and 10-year overall survival rates were 86.9 and 72.0 %. The overall survival rates did not differ between the surgical procedures. Factors that were independently associated with decreased survival included age (hazard ratio 1.05, P = 0.017) and distant metastases (hazard ratio 4.73, P = 0.017), while en bloc resection and delayed thyroid resection were not associated with improved survival over parathyroidectomy alone. There were no differences in perioperative or disease-related complications across procedures.
Conclusions: The addition of thyroid resection to parathyroidectomy may not improve survival for patients with parathyroid carcinoma over complete parathyroid resection alone. A larger prospective study is necessary to determine the optimal treatment to achieve long-term survival with minimal complications.