Comparing primary gamma knife radiosurgery and postoperative gamma knife radiosurgery for acromegaly: A monocenter retrospective study.

Objective: To compare the efficacy and safety between primary GKS and postoperative GKS for acromegaly, and to elucidate predictors associated with endocrine remission, we performed a monocenter, retrospective study.
Method: Seventy-five patients with acromegaly who had received GKS in West China Hospital between March 2010 and December 2018 were included in this study. Endocrine remission was defined as age-sex matched IGF-I normalization and either nadir level of GH <1 ng/mL after OGTT or the random GH < 2.0 ng/mL.
Results: We didn't find significant differences in endocrine remission, biochemical recurrence, imaging regression, imaging progression, radiation-induced complications between the primary GKS group and the postoperative GKS group(P > 0.05). Actuarial rates of durable endocrine remission at 3, 5, 8 year were 10.60 %, 33.80 % and 70.60 % in the primary GKS group and 6.70 %, 43.40 % and 78.80 % in the postoperative GKS group(P = 0.800). Only base nadir GH after OGTT (HR = 0.637,95 % CI:0.416-0.977; P = 0.039) was found to be a predictor of duration endocrine remission.
Conclusion: We find comparable efficacy and safety between primary GKS and postoperative GKS. Lower base nadir GH after OGTT was a positive predictor associated with endocrine remission. GKS should be considered for residual or recurrent tumor after surgery. For those who couldn't sustain surgery, GKS is an alternative treatment. Further studies are required to elucidate the efficacy and safety of GKS in acromegaly.
(Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)