Response to “Preoperative matching studies in the diagnosis of parathyroid adenoma for primary hyperparathyroidism: Can we avoid intraoperative PTH monitoring?”

Dear Editor:

We have read with interest the article by Laxague et al.¹ on their results in the surgical treatment of primary hyperparathyroidism (PTH). We would like to add the experience in our centre and compare it with their results.

Our series consists of 273 patients, operated on for PTH caused by single gland involvement from January 2006 to May 2021. The mean age of the patients was 59.3 years, 72% of whom were female. Mean serum calcium was 11 mg/dL (range 8.8–15.7 mg/dL) and mean parathyroid hormone (PTH) was 158.9 pg/mL. Intraoperative measurement of PTH (PTHio) showed a decrease in 94.5% of cases after excision of the gland considered pathological.

In the cases in which there was no decrease (5.5%), 7 were considered persistent PTH. In these cases, we observed that, in addition to not achieving a decrease in PTHio, there was a 62.5% discordance between scintigraphy and ultrasound at the preoperative site. Persistent PTH was due to adenomas in ectopic glands in 3 cases, in 3 cases due to multiglandular disease and in one case no other pathological gland was found and medical treatment with cinacalcet was chosen. On the other hand, in the remaining cases in which there was no decrease in PTHio, a decrease in calcium and PTH was observed during follow-up, without requiring a second surgery.

Although our rate of non-lowering of iPTH was 5.5%, we found a cure rate of 97.5%. In the work of Laxague et al., this percentage is 4.2%, with a cure rate of 99%. The results of both series support the idea that, in cases where a single adenoma is suspected, PTHio measurement could be discontinued systematically, as recommended by the European Society of Endocrine Surgeons.² In these cases, in which there is concordance in imaging tests, the prevalence of multiglandular disease ranges between 1% and 3.5%³, so we consider the benefit of iPTH to be very small.

In conclusion, according to our data, routine PTHio measurement is not necessary in patients with localised PTH. We encourage other groups to publish their experience both with the results of PTHio measurement and if they have discontinued it systematically.

Conflict of interest

The authors have no conflict of interests to declare.