Epidemiology of pituitary tumors treated by gamma knife radiosurgery in Mexico: a single-center study

Objective: Pituitary adenomas (PAs) represent the second most common intracranial tumors usually treated with surgery.Total resection is rare, so adjuvant radiosurgery is often indicated to control tumor growth.This study aims to describe a cohort of Mexican patients treated with Gamma Knife Radiosurgery (GKR) for PA over 17 years in a single center.Methods: The records of adult patients treated with GKR for PA at San Javier Hospital in Guadalajara, Mexico, from 1998 to 2015 were retrospectively reviewed.The analyzed factors included tumor imaging characteristics, visual field abnormalities, prior treatment, and radiographical improvement after radiosurgery.Results: This study included 111 patients (70 females, median age 39.5 years, [IQR: 33-51]).The median tumor volume was 3.55 cm 3 (2.14-6.82),and the median diameter was 0.95 mm (0.5-1.4).We found an abnormal visual field pre-GKR in 33 (29%) patients.The most common type of tumor was prolactinoma (43%).The median dose of radiation was 21 Grays (16-25).Forty-five (39.5%) patients had radiographic improvement.The variables associated with significant radiographic improvement were having a normal pre-treatment visual field campimetry (p = 0.03; odds ratio [OR] = 2.4 [95% confidence interval (CI), 1. 05-5.48]) and the absence of chiasmatic extension (p = 0.03; OR = 2.66 [95% CI, 1.06-6.99])which are essential to anticipate and improve outcomes in patients with pituitary tumors.Conclusions: GKR was safe and valuable for the volumetric control of PA.Nearly half the patients had radiographic improvement without reported adverse effects (different from hormonal deficiencies) within a median follow-up of 12 months.