Tumor Recurrence or Regrowth in Adults With Nonfunctioning Pituitary Adenomas Using GH Replacement Therapy

Context: GH replacement therapy (GH-RT) is a widely accepted treatment in GH-deficient adults with nonfunctioning pituitary adenoma (NFPAs). However, some concerns have been raised about the safety of GH-RT because of its potentially stimulating effect on tumor growth. Objective: The aim of this study was to evaluate tumor progression in NFPA patients using GH-RT. Design, Setting, and Patients: From the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide surveillance study in severely GH-deficient adults (1998-2009), all NFPA patients with >= 30 days of GH-RT were selected (n = 783). Data were retrospectively collected from the start of GH-RT in adulthood (baseline). Main Outcome Measure: Tumor progression, including tumor recurrence after complete remission at baseline and regrowth of residual tumor. Results: Tumor progression developed in 12.1% of the patients after a median (range) time of 2.2 (0.1-14.9) years. Prior radiotherapy decreased tumor progression risk compared tonoradiotherapy (hazard ratio = 0.16; 95% confidence interval, 0.09-0.26). Analysis in 577 patients with available baseline imaging data showed that residual tumor at baseline increased tumor progression risk compared to no residual tumor (hazard ratio = 4.5; 95% confidence interval, 2.4-8.2). Conclusions: The findings in this large study were in line with those reported in literature and provide further evidence that GH-RT does not appear to increase tumor progression risk in NFPA patients. Although only long-term randomized controlled trials will be able to draw firm conclusions, our data support the current view that GH-RT is safe in NFPA patients.