Predictors for secondary therapy after surgical resection of nonfunctioning pituitary adenomas.

ObjectiveFactors determining recurrence of nonfunctioning pituitary adenomas (NFAs) that require further therapy are unclear as are postoperative follow-up imaging guidelines. We aimed to identify predictors for secondary therapy after surgical resection of NFAs and use this knowledge to inform postoperative management. Design and patientsA single-centre retrospective study of surgically resected NFAs in 108 patients followed for up to 15years. Serial tumour images were analysed for size, location and growth rate (GR) and tissue analysed for hormone cell type and proliferation indices with secondary treatment as outcome measure. ResultsTwenty-four of 66 (36%) patients harbouring a postoperative remnant required secondary treatment, all occurring within 10years. No secondary treatment was required in any of 42 patients with complete tumour resection. Age, gender, remnant volume and tumour histology were not different between patients requiring and not requiring secondary therapy. Remnant GRs in those requiring secondary therapy were more than 10-fold higher (P<.01). Tumours with a GR 80mm(3)/y (Hazard Ratio[HR]: 8.1, Confidence Interval [CI]: 2.4-27.3,P<.01) and those located in the suprasellar region (HR: 6.1, CI: 1.1-32, P=.03) had a higher risk for secondary therapy. Tumour GR in the first three postoperative years correlated significantly (r(2)=.6, P<.01) with GR during the period of follow-up. ConclusionIn surgically resected NFAs further treatment is dependent on the presence of residual tumour, growth rate and location but not tumour histology. Postoperative growth rate of NFAs in the first 3years of imaging can be used to tailor long-term follow-up to optimize use of health resources.