Endocrine Abstracts

Objective: Growth hormone treatment (GHT) is a widely accepted treatment in growth hormone deficient (GHD) adults with nonfunctioning pituitary adenoma (NFPAs). However, concerns remain about the safety of GHT, because of its potentially stimulating effect on tumour (re)growth. The aim of this study was to evaluate tumour progression in NFPA patients using GHT.

Patients and methods: From the Dutch National Registry of growth hormone treatment in adults, a nationwide surveillance study in severe GHD adults (1998–2009), all NFPA patients with >30 days of GHT were selected (n=783). Anonymized data of all patients were thoroughly and retrospectively collected from the start of GHT in adulthood (baseline). Recurrent tumour after apparent complete remission at baseline and regrowth of residual tumour were both defined as tumour progression.

Results: Tumour progression developed in 12.5% of the patients after a median time of 2.2 (0.14–14.9) years. Median follow-up time for patients with and without tumour progression was 5.1 (0.2–20.2) and 6.0 (0.71–5.2) years respectively (P=0.10). After adjustment for age and gender, initial radiotherapy decreased the risk of developing tumour progression compared to no initial radiotherapy (Hazard ratio (HR)=0.16, 95% confidence interval (CI)=0.09–0.26). Analysis in 577 patients with available baseline imaging data showed that, after adjustment for age and gender, residual tumour at baseline increased the risk of tumour progression compared to no residual tumour (HR=3.7, 95% CI 2.0–6.8).

Conclusions: In this large cohort of adult NFPA patients using GHT tumour progression was observed in 12.5% of the patients. Pituitary radiotherapy decreased the risk of developing tumour progression, while the presence of residual tumour at baseline increased this risk. More large studies, ideally long-term randomized studies, are needed to provide conclusive evidence with regard to the safety of GHT in GHD patients with a (treated) NFPA.