Endocrine Abstracts

Background: Primary hyperparathyroidism (pHPT) is the most prevalent manifestation of multiple endocrine neoplasia type 1 (MEN1). Surgery is the preferred treatment but which type of surgery offers the best chance of cure combined with the lowest risk of postoperative hypoparathyroidism is still uncertain.

Aims: Identifying the optimal surgical technique for MEN1 related pHPT. Describing the course of postoperative hypoparathyroidism. To see if a genotype–phenotype correlation exists with regard to recurrent pHPT.

Methods: A retrospective longitudinal cohort study performed at the departments of endocrinology of the University Medical Centers (UMCs) of Utrecht and Nijmegen in The Netherlands. Patients were selected from the Dutch MEN1 database which includes all Dutch patients aged ≥16 years who are treated for MEN1 in one of the Dutch UMCs between 1990 and 2009. Data were collected by medical record review.

Results: Seventy-three patients who underwent parathyroidectomy for MEN1-related pHPT were included. The studied surgical procedure was the primary surgery for 42 (57.5%) patients. Persistent or recurrent pHPT was seen in 19 (26%) patients:.after less than three parathyroids resected (<SPTX) in 53%, after subtotal resection (SPTX) in 17% and after total resection (TPTX) in 19% of patients. Persistent (≥6 months) postoperative hypoparathyroidism was seen in 34 (46.6%) patients: after <SPTX in 23.5%, after SPTX in 39.1% and after TPTX in 65.6% of patients. The median duration of postoperative hypoparathyroidism was 1.5 years. In 65% of the patients successful cessation of substitution therapy (calcium supplements and vitamin D) was possible, even after >10 years. Patients with nonsense or frameshift mutations in exons 2, 9 and 10 had a significantly lower risk of persistent or recurrent pHPT than patients with other mutations.

Conclusions: SPTX is the procedure of choice in MEN1-related pHPT. Patients with nonsense or frameshift mutations in exons 2, 9 or 10 have less risk of persistent or recurrent pHPT. Postoperative hypoparathyroidism lasting ≥6 months should not be considered permanent and it is advisable to try to taper off the substitution therapy even several years after surgery.