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 nonfunctioning 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-naïve cases with NFPMA resected between 1995 and 2013. Patients: One hundred and twenty-three cases had both ≥2 postoperative scans and ≥12-month 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\ua0months (interquartile range [IQR]: 31-86). Overall regrowth/recurrence occurred in 29% (36/123). Regrowth occurred in 40% (30/76) at a median time of 44.5\ua0months (IQR 22-80) compared to recurrence of 12.5% (6/48; P=.003), occurring at a median time of 48\ua0months (IQR 12-96; P=.7). Further treatment was required in 66.7% and 56.7%, respectively (=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\ua0months (14\ua0years) and recurrence 156\ua0months (13\ua0years). Conclusions: Presence of postoperative 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\ua0years of follow-up