Long-Term Surveillance of Treated Hyperparathyroidism for Multiple Endocrine Neoplasia Type 1: Recurrence or Hypoparathyroidism?

BACKGROUND: Primary hyperparathyroidism (HPT) in multiple endocrine neoplasia type 1 (MEN1) is surgically treated with either a subtotal parathyroidectomy removing 3 or 3,5 glands (SPX), less than 3 glands (LSPX), or a total parathyroidectomy with autotransplantation (TPX). Previous studies with shorter follow-up have shown that LSPX and SPX are associated with recurrent HPT, and TPX with hypocalcemia and substitution therapy. We examined the situation after long-term follow-up (median 20,6 years).
METHODS: Sixty-nine patients with MEN1 HPT underwent 110 operations, the first operation being 31 LSPX, 30 SPX, and 8 TPX. Thirty patients underwent reoperative surgery in median 120 months later, as completion to TPX (n = 12), completion of LSPX to SPX (n = 9), extirpation of single glands (n = 3) still resulting in LSPX, and resection of forearm grafts (n = 3). Nine patients underwent a second, and 2 a third reoperation. In 24 patients genetic testing confirmed MEN1, and in the remaining heredity and phenotype led to the diagnosis.
RESULTS: TPX had higher risk for hypoparathyroidism necessitating substitution therapy, at latest follow-up 50%, compared to SPX (16% after 3-6 months; none at latest follow-up). Recurrent HPT was common after LSPX, leading to 24 reoperations in 17 patients. No need for substitution therapy after SPX indicated forthcoming recurrent disease. Not having hypocalcemia in the postoperative period and less radical surgery than TPX were significantly associated to risk for recurrence. Further, mutation in exon 3 in the MEN1 gene may eventually be linked to risk of recurrence.
CONCLUSION: LSPX is highly associated with recurrence and TPX with continuous hypoparathyroidism, also after long-term follow-up. SPX should be the chosen method in the majority of patients with MEN1 HPT.