Radiosurgery of Intracranial Schwannomas: Comparative Study of Follow-Up Evaluation

Background: In addition to tumor control, it is important to evaluate functional outcomes following radiosurgery for intracranial schwannomas. Methods: We reviewed 432 cases of various intracranial schwannomas treated with radiosurgery, including vestibular (317), trigeminal (40), lower cranial nerve (25), facial (15), and bilateral schwannomas associated with neurofibromatosis type II (NFII) (35). The tumors had a mean volume of 5.6-11.1 cc and were treated with a marginal dose of 12.9-14.2 Gy. Results were evaluated with respect to tumor control as well as functional control and adverse effects, with mean follow-up ranging from 29 to >60 months. Results: The tumor control rates were generally excellent, ranging from 85 to 100%. Tumor response rates were 80% in the facial nerve group, 70% in the lower cranial nerve group, and at least 50% in the other groups. Functionally, the best neurological recovery was seen in facial and lower cranial schwannomas, followed by trigeminal and vestibular schwannomas. NFII tumors demonstrated a poorer functional recovery, in spite of excellent tumor control. Conclusion: Excellent tumor control of all intracranial schwannomas is obtained with radiosurgery. Our results suggest that the functional response is better for motor nerve schwannomas than sensory nerve schwannomas. Jugular foramen tumors and facial schwannomas, which are difficult to totally extirpate by surgery, are the best indication for radiosurgery. For large tumors, a combined approach with surgical resection and radiosurgery is recommended, especially for tumors in eloquent areas such as the jugular foramen. Copyright (C) 2010 S. Karger AG, Basel