Cyberknife Radiosurgery for Patients With Neurinomas

Most vestibular schwannomas are benign and slow-growing. Based on that fact, conservative management with serial imaging is a viable alternative. For patients who undergo treatment because of tumor growth, progressive symptoms, or personal preference, options include serial observation, microsurgical resection, fractionated stereotactic radiotherapy, and stereotactic single-session radiosurgery. Despite improved radiosurgical techniques and lower marginal doses, a recent report has shown a somewhat disappointing 10-year actuarial hearing preservation rate of 44.5%, with hearing loss developing as much as 6 years after. Fractionation of the prescribed dose may takes some advantages from radiobiologic principles to reduce toxicity and maintain tumor control. Staged frame-based radiotherapy using a 12-hour interfraction interval was successfully used at Stanford university and has shown a hearing preservation rate of 77% at 2 years of follow-up. The aim of the present protocol is to evaluate the hearing preservation, the local control and toxicity after single-session (sSRS) or multi-session (3 fractions) radiosurgery (mSRS) by using the frameless robotic CyberKnife® system (Accuray Incorporated, Sunnyvale, CA, USA). In order to investigate about this a randomised controlled double harm (sSRS vs mSRS) trial was designed.