Younger age is a risk factor for regrowth and recurrence of nonfunctioning pituitary macroadenomas: Results from a single Australian centre

Objective The natural history of non-functioning pituitary macroadenomas (NFPMA) after surgical resection is variable, with guidelines unable to define the duration of radiological follow up. In this first Australian series, we identify risk factors for regrowth/recurrence of NFPMA to assist with guiding recommendations for long-term follow-up. Design Retrospective analysis of all radiotherapy naive cases with NFPMA resected between 1995 – 2013. Patients One hundred and twenty-three cases had both ≥ 2 post-operative scans and ≥ 12 months follow up. Measurements Regrowth was defined as any sustained increase in diameter of residual adenoma or recurrence as any new adenoma occurring post complete resection on serial pituitary MRI. Results Median follow up time was 48 months (IQR 31-86). Overall regrowth/recurrence occurred in 29% (36/123). Regrowth occurred in 40% (30/76) at a median time of 44.5 months (IQR 22-80) compared to recurrence of 12.5% (6/48) (p=0.003), occurring at a median time of 48 months (IQR 12-96) (p=0.7). Further treatment was required in 66.7% and 56.7% respectively (p=1.0). Risk factors for regrowth/recurrence by multivariate analysis were presence of residual disease and younger age at presentation. The longest time for regrowth was 168 months (14 years), and recurrence 156 months (13 years). Conclusions Presence of post-operative residual adenoma and younger age at presentation are the main predictors of regrowth/recurrence in NFPMA. Long-term serial imaging is required to detect regrowth and recurrence in younger patients and those with residual disease. Most regrowth/recurrences will occur within 10 years of follow up. This article is protected by copyright. All rights reserved.