Presentation and surgical results of incidentally discovered nonfunctioning pituitary adenomas: evidence for a better outcome independently of other patients' characteristics

Objective: Few data are available on the surgical results in patients with incidentally discovered nonfunctioning pituitary adenoma (NFPA). We investigated the efficacy and safety of surgery in patients with incidentally discovered NFPA. Design: Retrospective analysis of prospectively recorded outcomes. Methods: From 1990 to 2011, of 804 consecutive patients undergoing surgery for NFPA, 212 cases had an incidentally discovered tumor (26.4%). Among them, 117 patients were asymptomatic, while 95 had some visual and/or hormonal deficit. The main outcome of the study was to evaluate the frequency of radical resection as judged on the first postoperative neuroimaging study and detection of recurring disease during long-term follow-up. Results: Postoperative residual tumor was detected in 8.9% of patients with asymptomatic incidentalomas as compared with 31.2% of patients with symptomatic incidentalomas (P<0.001) and 41.2% of patients in the control group (P<0.001). Multivariate analysis confirmed that having an asymptomatic incidentaloma was independently associated with a better outcome. The 5-year recurrence-free survival in patients with incidentaloma was 86.8% (95% CI 80.2-92.4%) as compared with 77.9% (95% CI 73.6-82.2%; P<0.01) in the control group. This difference was almost completely due to a lower frequency of relapse in asymptomatic patients. Multivariate analysis confirmed the independent lower risk of tumor recurrence in asymptomatic NFPA. Conclusion: Our study shows for the first time that surgically treated patients with asymptomatic NFPA have a better early and long-term outcome that is independent from all the other demographic, clinical, and morphologic characteristics of the patients.