How long should we follow patients after apparently curative parathyroidectomy?

Little is known about the long-term recurrence risk for primary hyperparathyroidism after immediately "curative" parathyroidectomy. This study aimed to evaluate the risk of recurrent hyperparathyroidism in the 10 years after operation.

We retrospectively identified patients with sporadic primary hyperparathyroidism undergoing initial parathyroidectomy between November 1, 2000 and June 30, 2005. Recurrence was defined as serum calcium >10.2 mg/dL after 6 months from operation. Kaplan-Meier estimates and Cox proportional hazards were used to evaluate disease-free survival and predictors of recurrence.

We evaluated 196 patients with a 14.8% 10-year recurrence rate. Median time to recurrence was 6.3 years (interquartile range 3.4-10.8 years), and 34.5% of all recurrences were identified >10 years after operation. There was no difference in recurrence between open and minimally invasive operation (P = .448). Double adenomas (P = .006), intraoperative parathyroid hormone drop <70% (P = .015), and young age (P = .032) were predictive of disease recurrence. Multivariable analysis demonstrated that older age was protective against recurrence (hazard ratio 0.97, 95% confidence interval 0.94-0.99, P = .034), while double adenomas (hazard ratio 3.52, 95% confidence interval 1.23-10.08, P = .019) were an independent predictor for recurrence.

The long-term recurrence rate for sporadic primary hyperparathyroidism after "curative" parathyroidectomy is likely greater than reported. With over one-third of our institutional recurrences at >10 years after the initial operation, long-term follow-up is essential.