Treatment of Nonfunctional Pituitary Adenoma Postoperative Remnants: Adjuvant or Delayed Gamma Knife Radiosurgery?

Objective It is still not clear whether Gamma Knife radiosurgery (GKRS) for nonfunctional pituitary adenomas should be used as a standard adjuvant postoperative therapy or applied when there is documented progression of the remnant on follow-up magnetic resonance imaging. Methods We performed a retrospective study of patients with nonfunctional pituitary adenomas who underwent primary surgery and GKRS between 2002 and 2015. Patients were divided into 2 groups on the basis of the GKRS indication: adjuvant treatment (GKRS ≤6 months postoperatively) or delayed treatment (GKRS if documented progression occurred on the follow-up magnetic resonance imaging). Results Fifty patients were included and grouped based on adjuvant ( n  = 13) or delayed ( n  = 37) GKRS following primary surgery. The adjuvant and delayed groups had 10-year actuarial tumor control rates of 92% and 96% ( P  = 0.408), respectively. The 10-year actuarial endocrinologic control rate was 82% for the adjuvant group and 49% for the delayed group ( P  = 0.597). None of the patients developed any new neurologic deficit post-GKRS. GKRS-induced complications (intratumoral bleeding and tumoral tissue inflammation) occurred in 6% of the patients, of whom 4% were in the delayed group and 2% in the adjuvant group. Conclusion Adjuvant treatment with GKRS yields the same high long-term tumor control as delayed GKRS. Neither adjuvant nor delayed GKRS induced additional neurologic complications. There is a trend that adjuvant GKRS induces less additional endocrinologic deficits compared with delayed GKRS.