Utility of Postoperative Thyroid Hormone Levels in Predicting the Diagnosis of Adult Growth Hormone Deficiency in Patients Undergoing Surgery for Nonfunctioning Pituitary Neuroendocrine Tumor: A Pilot Study.

Background: Adult growth hormone deficiency (AGHD) is often diagnosed after surgery for nonfunctioning pituitary neuroendocrine tumor (NF-PitNET). While a growth hormone stimulation test (GHST) is required to establish its diagnosis, it is associated with a large burden on patients and healthcare providers alike. Currently, the recommended indicators for the diagnosis of AGHD include the IGF-1 standard deviation score (IGF-1SDS) from a random blood sample and the number of deficiencies in pituitary hormones other than GH; however, there are also some challenges associated with these indicators. Therefore, to predict the need for GHST, this study focused on the interrelationship between GH and pituitary hormones to investigate whether postoperative thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels measured before GHST could represent novel predictors of AGHD. Methods: Among 166 patients who underwent GHST following surgical treatment for NF-PitNET, 60 patients who were diagnosed with NF-PitNET based on clinical and pathological criteria were included in this analysis. Exclusion criteria were as follows: missing data ( Results: Patients with AGHD showed significantly lower postoperative levels of FT3 and FT4 prior to GHST, with median values of 2.10 pg/mL (1.97-2.34) and 0.98 ng/dL (0.77-1.19), respectively, than those without postoperative AGHD, who showed median levels of 2.45 pg/mL (2.28-2.67) and 1.18 ng/dL (1.03-1.26) ( Conclusion: These findings suggest the potential utility of FT3 and FT4 as novel predictors for the diagnosis of postoperative AGHD.