Non-functioning pituitary adenoma underwent surgery: A multicenter retrospective study over the last four decades (1977-2015).

Objective: To assess clinical features, diagnostic procedures, therapies and outcomes in patients with clinically non-functioning pituitary adenomas (NFPAs) surgically treated over the last four decades.

Design And Methods: A multicenter retrospective study in NFPA patients periodically followed up in specialized neuroendocrinology units who underwent surgery in the period 1977-2015 was performed.

Results: A total of 131 patients were studied [66 women (50.4%); mean age 52.6±14.8years (range, 15-82)]. Median diameter of the adenoma was 2.6cm (interquartile range, 2.0-3.1). The most frequently type of surgery used was endoscopic endonasal surgery (58.5%) followed by microscopic transsphenoidal surgery (37.4%). Radiation therapy was used in 19 patients (14.5%). Ki-67 labeling index performed in 54 patients was ≤2% in 70% samples. After a median follow-up time of 57months (25 to 128months), tumor diameter significantly decreased to 0.9cm (0-1.8cm), p<0.001. Multivariant analysis showed that endoscopic endonasal surgery (HR 2.74, 1.06-6.87, p=0.036) and radiotherapy (HR 0.04, 0.02-0.65, p=0.024) behaved as positive and negative predictors, respectively, of tumor absence in the follow-up. Endoscopic endonasal surgery (HR 6.71, 1.45-31.05, p=0.015) was the only positive predictor for complete cure in the follow-up.

Conclusion: NFPAs surgically treated in Spain are usually macroadenomas diagnosed around the sixth decade of life with no sex predilection. Type of surgery is associated with clinical outcome. Endoscopic endonasal surgery behaves as a positive predictor for the absence of tumor imaging and complete cure in the follow up.