Endocrine Abstracts

Introduction: Persistent or intermittent postoperative discordance between growth hormone (GH) after OGTT and insulin-like growth factor-1 adjusted for age and gender (IGF-1) is up to 39% according to different studies. The aim of this study was to evaluate the impact of this discrepancy (normal GH and elevated IGF1 or vice versa) over the risk of biochemical and tumour recurrence after initial successful surgery for acromegaly.

Methods: In this retrospective study, we examined 180 patients who have been treated or were under follow-up for acromegaly in our department between 2014–2018. We excluded patients who have undergone gamma-knife or had a tumour remnant at 3 months after initial surgery or with any medical treatment for acromegaly before/at the time of objectified discrepancy. Patients with factors that could possibly influence IGF1/GH levels, such as poorly controlled diabetes, hypothyroidism, renal or hepatic failure, glucocorticoid, estrogens or testosterone therapy, were also excluded. We included 16 patients with persistent or intermittent GH-IFG1 discordance.

Results: Study group included 5M/11F, with mean age at diagnosis of 42.6±11.2 years, and a mean tumor size 13.7±8.3 mm (CT scan) or 20±12.8 mm (MRI scan). The mean duration of follow-up was 4.2±1.9 years. Preoperative, the mean IGF1 level was 878±266 ng/ml and mean nadir GH during OGTT 11.5±13.7 ng/ml. At 3 months after surgery, the mean IGF1 level was 297.5 ng/ml and mean GH after OGTT 0.76 ng/ml. During follow-up of 16 patients, 9 normalized IGF1 and GH without any further treatment, with a mean period until normalization of 23 month; 5/16 had persistence of discordant values and no tumor recurrence on imagistic scans during follow-up and 2 patients presented biochemical and tumor recurrence at 15 months; 2 patients had GH and PRL co-secretion before surgery, both with discordant IGF1 and GH at 3 months after surgery and normal imagery. In one PRL secretion persisted, but responded at dopamine analogues and the other one normalized during follow-up.

Conclusions: Out of 10 patients with discordant IGF1-GH levels and no imagistic tumour evidence at 3 months, the majority had IGF 1 and GH normalization at 12 months postoperative without recurrence disease during follow-up. Therapeutic approach should be individualized between additional medical treatment and close follow-up in biochemically discordant patient. Further studies are needed to clarify the influence of discordant values on mortality and morbidity of the disease.