Stereotactic brain radiosurgery in the treatment of skull base tumors

Stereotactic radiosurgery has shown effectiveness in the multimodal treatment of skull base tumors, however it is suggested that in radiobiologically sensitive areas (eg. optic nerves and brainstem) the radiation dose should be reduced due to radiotoxic effects. To avoid the consequent therapeutic ineffectiveness, a recently implemented alternative is multisession radiosurgery (RCH). We retrospectively analyzed a series of patients with skull base tumors, in order to evaluate the treatment with RCH through tumor control in the post-treatment images. Age, sex, tumor histology, tumor volume, radiation protocol, pre-treatment Karnofsky performance status (KPS) previous neurosurgery and radiant treatment were also evaluated. Eighty-four patients were treated between January 2009 and January 2017. The median age was 51.5 years; females: 53.6%. There was a 92.7% non-progression after treatment. with a median follow-up time of 36 months. Treated tumors were mainly pituitary adenomas, acoustic schwannomas, and skull base meningiomas. Most of the patients received a 5-day fractionated treatment scheme, with a total dose of 25 Gy. No clinically manifest late radiotoxicity was observed. In the multivariate analysis, a high pre-treatment KPS was significantly associated with tumor non-progression. In our series, the high incidence of tumor non-progression would indicate that treatment with RCH could be a therapeutic option in some cases of skull-base tumors, mainly recurrences or tumor residuals of pituitary adenomas, neurinomas and meningiomas.