High-Precision Conformal Fractionated Radiotherapy Is Effective In Achieving Remission In Patients With Acromegaly After Failed Transsphenoidal Surgery

Abstract

Variable efficacy of pituitary radiotherapy in acromegaly is reported. Here we sought to assess the efficacy of high-precision conformal fractionated radiotherapy (CRT) in patients with acromegaly after failed TSS. A retrospective analysis was conducted a in tertiary care referral center between 1999 to 2013 on 36 acromegaly patients (M: 16, F: 20; median age: 36.0 years) with macroadenoma and mean growth hormone (GH) and insulin-like growth factor-1 (IGF1) upper limits of normal (ULN) of 15.9 ± 14.3 ng/mL and 1.74 ± 0.43, respectively. The cohort was divided into 2 groups: 30 patients (M: 13, F: 17) who were medical treatment naïve, and 6 patients (M: 3, F: 3) who received medical treatment after CRT. Normalization of GH (fasting GH <1 ng/mL), normalization of IGF1 (ULN <1), and remission (normalization of GH and IGF1) were achieved in 20 (55%), 23 (63%) and 20 (55%) patients, respectively. The mean time required to achieve remission was 63 ± 33.4 months. Follow-up duration was the only predictor of achieving remission. GH level declined exponentially by 65% and 89% at 2 and 5 years, respectively. New onset hypopituitarism was noted in 33% of patients. Tumor control was achieved in 100% of patients. In groups 1 and 2, 18 (60%) and 2 (33.3%) achieved remission post-CRT, and the mean times required to achieve remission were 58.6 ± 30.7 months and 102 ± 42.4 months, respectively. High-precision CRT is an effective modality to achieve remission in patients with acromegaly after failed TSS.