CyberKnife treatment for parasellar tumors

: Microscopic and endoscopic techniques requiring superior skills are required for the examination of parasellar tumors. However, the parasellar region is surgically inaccessible, and complete excision of parasellar tumors remains a challenge. CyberKnife (CK) enables frameless radiosurgery and provides chronological and spatial freedom. We have previously treated parasellar tumors with stereotactic radiotherapy (SRT). Here, we evaluated the feasibility of CK surgery for parasellar tumors. Between June 2000 and August 2010, we conducted CK surgery for 4,500 patients. This study included 246 patients with pituitary adenoma (PA); 78, craniopharyngioma (CP); 38, parasellar meningioma (PM); and 6, metastatic pituitary tumor (M). The tumor volume ranged from 0.3 to 107 mL (median: 4.8 mL), and the patients were treated with 1-5 sessions of SRT. The treatment results were analyzed with a follow-up period of more than a year (range, 12-120 months; median: 35 months). The control rate of PA, CP, PM, and M was 96.6%, 79.0%, 100%, and 100%, respectively. Treatment failure in the case of CP was related to tumor volume. One PA patient had visual deterioration, and another had new hypopituitarism. One M patient showed visual loss 12 months after the CK treatment, which was related to the treatment dose. Thus, CK was found to be feasible for parasellar tumors, although its safety and efficacy must be observed in long-term follow up.