Hypofractionated stereotactic radiotherapy for benign intracranial tumours of the cavernous sinus

Abstract

We present our experience with hypofractionated stereotactic radiotherapy (HSRT) using 15 fractions to treat benign conditions of the cavernous sinus (CS) and emphasise the outcome in terms of cranial nerve (CN) function and toxicity for long term safety and efficacy. We performed a retrospective review of prospectively collected data on 112 patients with benign tumours of the CS treated with HSRT between 1 January 1998 and 31 December 2009. While all tumours involved the CS, a separate analysis was undertaken for meningiomas and pituitary adenomas. The median follow-up was 77months (range: 2.3–177). Fifty-seven patients (51%) had a diagnosis of meningioma and 55 (49%) had pituitary adenomas. Prior to HSRT, 82 patients (73%) underwent microsurgery. The median tumour volume was 6.6cm3 for meningiomas and 3.4cm3 for pituitary adenomas (interquartile range: 2.8–7.9), and the mean prescribed dose was 38Gy (range: 37.5–40.0) to the tumour margin, delivered in 15 fractions. After HSRT, 57% of all preexisting cranial neuropathies either resolved or improved and 38% remained stable, whereas 5% deteriorated. The diagnosis of meningioma was the only variable associated with recovery of cranial neuropathy (p<0.001). Permanent CN complications occurred in three patients (3%). The 5 and 10year actuarial freedom from progression for patients with meningiomas was 98% and 93%, respectively, and for patients with pituitary adenomas this was 96% and 96%, respectively. We demonstrate low rates of CN morbidity after HSRT and the possibility of resolution or improvement in CN function for common histologies involving the CS.