Stereotactic radiosurgery in the treatment of parasellar meningiomas: long-term volumetric evaluation

Abstract

OBJECTIVE Parasellar meningiomas tend to invade the suprasellar, cavernous sinus, and petroclival regions, encroaching on adjacent neurovascular structures. As such, they prove difficult to safely and completely resect. Stereotactic radiosurgery (SRS) has played a central role in the treatment of parasellar meningiomas. Evaluation of tumor control rates at this location using simplified single-dimension measurements may prove misleading. The authors report the influence of SRS treatment parameters and the timing and volumetric changes of benign WHO Grade I parasellar meningiomas after SRS on long-term outcome. METHODS Patients with WHO Grade I parasellar meningiomas treated with single-session SRS and a minimum of 6 months of follow-up were selected. A total of 189 patients (22.2% males, n = 42) form the cohort. The median patient age was 54 years (range 19-88 years). SRS was performed as a primary upfront treatment for 44.4% (n = 84) of patients. Most (41.8%, n = 79) patients had undergone 1 resection prior to SRS. The median tumor volume at the time of SRS was 5.6 cm (0.2-54.8 cm). The median margin dose was 14 Gy (range 5-35 Gy). The volumes of the parasellar meningioma were determined on follow-up scans, computed by segmenting the meningioma on a slice-by-slice basis with numerical integration using the trapezoidal rule. RESULTS The median follow-up was 71 months (range 6-298 months). Tumor volume control was achieved in 91.5% (n = 173). Tumor progression was documented in 8.5% (n = 16), equally divided among infield recurrences (4.2%, n = 8) and out-of-field recurrences (4.2%, n = 8). Post-SRS, new or worsening CN deficits were observed in 54 instances, of which 19 involved trigeminal nerve dysfunction and were 18 related to optic nerve dysfunction. Of these, 90.7% (n = 49) were due to tumor progression and only 9.3% (n = 5) were attributable to SRS. Overall, this translates to a 2.64% (n = 5/189) incidence of direct SRS-related complications. These patients were treated with repeat SRS (6.3%, n = 12), repeat resection (2.1%, n = 4), or both (3.2%, n = 6). For patients treated with a margin dose ≥ 16 Gy, the 2-, 4-, 6-, 8-, 10-, 12-, and 15-year actuarial progression-free survival rates are 100%, 100%, 95.7%, 95.7%, 95.7%, 95.7%, and 95.7%, respectively. Patients treated with a margin dose < 16 Gy, had 2-, 4-, 6-, 8-, 10-, 12-, and 15-year actuarial progression-free survival rates of 99.4%, 97.7%, 95.1%, 88.1%, 82.1%, 79.4%, and 79.4%, respectively. This difference was deemed statistically significant (p = 0.043). Reviewing the volumetric patient-specific measurements, the early follow-up volumetric measurements (at the 3-year follow-up) reliably predicted long-term volume changes and tumor volume control (at the 10-year follow-up) (p = 0.029). CONCLUSIONS SRS is a durable and minimally invasive treatment modality for benign parasellar meningiomas. SRS offers high rates of growth control with a low incidence of neurological deficits compared with other treatment modalities for meningiomas in this region. Vol...

Radiotherapy of Parasellar Tumours

“…The reported tumour control after proton beam RT is ranged from 90 to 96% at 5 years, similar to that observed with fractionated photon techniques (Table 2) [43,44]. The reported actuarial control rates after SRS is in the range of 90-95% at 5 years and 80-90% at 10 and 15 years using a median margin dose to the tumour of 13-15 Gy, with a variable improvement of neurological functions in up to 60% of patients [45][46][47][48][49][50][51][52][53][54][55][56]. The rate of significant complications at doses of 13-15 Gy is < 10%, being represented by either transient or permanent complications [45,51].…”

Stereotactic Radiosurgery of Cavernous Sinus Meningiomas

“…For evaluation of radiological tumor control, the pretreatment MRI data were compared with the MRI images at last FU. Radiological tumor control was classified according to 8 such that the tumor regression was assumed in cases of more than 10% volume loss, tumor progression was diagnosed when the volume increased by > 10%, and the tumor was presumed to be stable when its volume changes did not exceed 10%. Postradiosurgery tumor volumes were calculated using OsiriX software (Pixmeo SARL, Switzerland).…”

Evaluation of Radiosurgery Target Volume Determination for Meningiomas Based on Computed Tomography (CT) And Magnetic Resonance Imaging (MRI)

“…Multimodality imaging may be utilized for determining radiosurgery treatment volumes [28]. For radiotherapeutic management of meningiomas, Magnetic Resonance Imaging (MRI) has been utilized for several purposes including detection, localization and target definition, lesion characterization, differentiation of meningioma grades based on imaging features, prediction of clinical agressiveness, assessment of treatment response and prognosis [29][30][31][32][33][34][35][36]. In this context, we evaluated the incorporation of Magnetic Resonance Imaging (MRI) into target volume definition for radiosurgery of meningiomas in this study.…”