How long should we follow patients after apparently curative parathyroidectomy?

BACKGROUND: 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.

METHOD: 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.

RESULTS: 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.

CONCLUSION: 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.