Long-term results of hypofractionated stereotactic radiotherapy with CyberKnife for growth hormone-secreting pituitary adenoma: evaluation by the Cortina consensus.

Abstract

The aim of the present study was to evaluate the safety and feasibility of hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for growth hormone-secreting pituitary adenoma (GH-PA). Fifty-two patients with GH-PA were treated with hypofractionated SRT between September 2001 and October 2012. Eight patients had clinically silent GH-PA and 44 were symptomatic. Only 1 patient was inoperable. The other patients had recurrent or postoperative residual tumors on MRI. All patients had received pharmacotherapy prior to SRT with a somatostatin analog, dopamine agonist, and/or GH receptor antagonist. The marginal doses were 17.4-26.8 Gy for the 3-fraction schedule and 20.0-32.0 Gy for the 5-fraction schedule. Endocrinological remission was assessed by the Cortina consensus criteria 2010 (random GH <1 ng/ml or nadir GH after an oral glucose tolerance test <0.4 ng/ml and normalization of age- and sex-adjusted insulin-like growth factor-1). The median follow-up period was 60 months (range 27-137). The 5-year overall survival, local control, and disease-free survival rates were 100, 100, and 96 %, respectively. Nine patients (5 clinically silent and 4 symptomatic patients) satisfied the Cortina criteria without receiving further pharmacotherapy, whereas the remaining 43 patients did not. No post-SRT grade 2 or higher visual disorder occurred. Symptomatic post-SRT hypopituitarism was observed in 1 patient. CyberKnife hypofractionated SRT is safe and effective when judged by imaging findings for GH-PA. However, it may be difficult to satisfy the Cortina consensus criteria in most symptomatic patients with SRT alone. Further investigations of optimal treatments are warranted.

• Authors: Hiromitsu Iwata, Kengo Sato, Ryutaro Nomura, Yusuke Tabei, Ichiro Suzuki, Naoki Yokota, Mitsuhiro Inoue, Seiji Ohta, Shozo Yamada, Yuta Shibamoto
• Journal: Journal of neuro-oncology (J Neurooncol) Vol. 128 Issue 2 Pg. 267-75 (06 2016) ISSN: 1573-7373 [Electronic] United States
• PMID: 26961771 (Publication Type: Journal Article)

Topics

• Adenoma (metabolism, radiotherapy)
• Adolescent
• Adult
• Aged
• Female
• Follow-Up Studies
• Growth Hormone-Secreting Pituitary Adenoma (metabolism, radiotherapy)
• Humans
• Male
• Middle Aged
• Prospective Studies
• Radiosurgery (methods)
• Radiotherapy Dosage
• Survival Analysis
• Treatment Outcome
• Young Adult