Long-term recurrence after parathyroidectomy in primary hyperparathyroidism-do predictors exist?

Background: Primary hyperparathyroidism (pHPT) is the third most common endocrine disease, affecting predominantly postmenopausal women. About 85% of cases are caused by a solitary parathyroid adenoma which leads to a hypersecretion of the parathyroid hormone (PTH) and consequently to elevated serum calcium concentrations. Parathyroidectomy is the only curative treatment. While a very low recurrence rate of 0.4-1.3% was previously thought, recent long-term studies have shown significantly higher recurrence rates at longer follow-up intervals of more than 6 months to several years, posing new challenges for surgeons. In addition, laboratory dynamics may occur in the early postoperative period that cannot yet be adequately explained in terms of long-term outcomes. Therefore, the aim of this study was to evaluate the long-term outcome after parathyroidectomy for pHPT at the Department of General Surgery at the University Medical Center Rostock with regard to late recurrences. Methods: This retrospective long-term follow-up evaluated the postoperative course after parathyroidectomy for pHPT. Based on 111 patients who underwent surgery at the Department of General Surgery at the University Medical Center Rostock between 2007 and 2017, 65 patients were followed for a median postoperative period of 41 months. Results: In addition to normocalcemic PTH fluctuations in the early postoperative period, which is a wellknown phenomenon, the result shows an elevated calcium or PTH concentration during a follow-up of more than 10 years. These results may predict late recurrence. Furthermore, it is not the preoperative PTH and calcium, but rather the preoperative serum creatinine that plays a role in late follow-up, contrary to expectations. Conclusions: The results emphasise the importance of long-term follow-up of patients who have undergone parathyroidectomy and may help to guide the development of institutional postoperative surveillance.