Multisession Cyberknife Surgery for parasellar Tumors Adjacent to Optic Apparatus; Safety for Optic Apparatus, preliminary study

초록

PURPOSE : Multissesion Cyberknife surgery has been known as a good alternative in the parasellar tumors adjacent to optic apparatus. In order to use it more broadly and safely, exact optic apparatus tolerance dose should be obtained. We performed this study to get safe multisession schedule for these lesions. MATERIALS AND METHODS : Eight patients with Pituitary adenoma (n=2), Metastatic brain tumors (n=2), Menigioma (n=2), and Nasal cavity cancer (n=1), which had been situated within 3 mm of optic apparatus, underwent multissession Cyberknife surgery. CyberKnife radiosurgery was delivered in four to six sessions and cumulative average marginal dose was 2400 cGy to 2800 cGy. Contouring and measuring volume of optic apparatus had been based on the MRI. We measured cumulative dose on the optic apparatus. Formal visual testing or clinical examinations were performed before treatment and at follow-up intervals beginning at 6 months. RESULTS : Cummulative maximal dose on the optic apparatus were under 2500cGy in all patients. Single maximal dose had been kept below 500 cGy, Six months after treatment, Visual function was unchanged in five cases and has been impoved in three cases. Tumor volume has been decreased in three cases or stabilized in other cases. There were no acute complications. CONCLUSION : If cumulative maximal dose could be kept below 2500 cGy and single session dose below 500 cGy, we can do safely Multisession Cyberknife Surgery for perisellar tumors adjacent to optic apparatus.