J.C.T. Chen

COMPARISON OF EARLY COMPLICATIONS FOR PATIENTS WITH CONVEXITY AND PARASAGITTAL MENINGIOMAS TREATED WITH EITHER STEREOTACTIC RADIOSURGERY OR FRACTIONATED STEREOTACTIC RADIOTHERAPY

OBJECTIVEPatients with convexity and parasagittal (CPS) meningiomas treated with stereotactic radiosurgery (SRS) have been shown to be at risk for posttreatment symptomatic peritumoral edema (SPTE). We sought to analyze the pattern of this complication and compare it with the SPTE experienced in our patients treated with fractionated stereotactic radiotherapy. METHODSFrom January 2003 to October 2005, 32 patients with CPS meningiomas were treated. Thirty patients with a total of 38 lesions had sufficient follow-up for analysis. Group A (n = 14) patients were treated with single fraction SRS, and Group B (n = 16) patients were treated with fractionated stereotactic radiotherapy. The lesion volume was different between the two groups with the Group B median volume (7.46 cm3) being larger than that for Group A (2.84 cm3) (P = 0.0008). Conversely age, follow-up, sex, prior surgical events, number of lesions, tumor location, and atypical histology did not differ between these groups. The median marginal dose for patients in Group A was 14 Gy (range, 12.5–18 Gy). For Group B, six patients received a median marginal dose of 50.4 Gy in 28 fractions, and 10 patients received a marginal dose of 25 Gy in five fractions. RESULTSSeven of the 30 patients treated in this series developed posttreatment SPTE. The incidence of SPTE in Group A (six of 14 patients) was significantly higher than that in Group B (one of 16 patients) (P = 0.031). The median time to onset of SPTE in the six patients in Group A was 4 months. In Group B, one patient had onset of SPTE in 3 months. On univariate analysis, larger tumor volume (P = 0.0014) and tumor margin dose >14 Gy in patients undergoing SRS (P = 0.031) was associated with onset of SPTE. Age, previous surgery, and tumor location were not associated with onset of SPTE. CONCLUSIONDespite larger lesion volumes, fractionated stereotactic radiotherapy is associated with less risk of posttreatment SPTE than SRS for patients with CPS meningiomas in our series. For patients treated with SRS, smaller volume and dose <14 Gy seems to be safe. Longer follow-up will be required to compare late complications and tumor control rates in these patients.

Occlusion of a clival dural arteriovenous fistula using a novel approach through the foramen ovale

Dural arteriovenous fistulas (DAVFs) are abnormal connections between arteries and veins that are classified by location, morphology or direction of venous drainage. Treatment of DAVFs is undertaken in patients with severe symptoms or those with retrograde cortical venous drainage and/or venous ectasia. Much is written regarding the treatment of DAVFs involving the transverse sigmoid sinuses, cavernous sinus and tentorium, but little is written concerning the treatment of clival DAVFs. We demonstrate a novel transforaminal percutaneous approach through the foramen ovale as a viable method to occlude a clival vein. Specialised software was used to create a safe trajectory to the DAVF via the foramen ovale. The patient then underwent successful occlusion of the clival DAVF, thus further increasing the neurointerventionalists armamentarium when attempting to treat difficult to reach clival DAVFs.

Frameless Stereotactic Radiosurgery of Arteriovenous Malformations Using High-Resolution 3-Dimensional Rotational Angiography.

Purpose/Objective(s): Previous studies have shown similar clinical outcome between single or multi-fraction (Fr) radiation therapy for MSCC patients with poor prognosis whereas patients with expected longer survival may require long course radiation therapy to prevent local failure. However, such poor risk group has not yet been clearly identified for daily clinical practice. We examined if the known predictive Tokuhashi scoring system could be adapted in MSCC patients treated with palliative radiation therapy. Materials/Methods: A retrospective review of the treatment outcome of the MSCC patients who received palliative radiation therapy from January 2014 to May 2015 was conducted. The patients were stratified by the Tokuhashi scoring system into group 1(score < 9): expected survival < 6 months, and group 2(score > or equal 9): expected survival > 6 months. Their survival was tested against subsequent systemic therapy (chemotherapy, targeted or hormonal therapy) and other risk factors including age, primary site, visceral metastasis, baseline motor function, prior radiation therapy, radiation therapy fraction (single or multiple). Results: The outcome of 119 patients was studied, 100 (84%) patients have already succumbed. The overall median survival was 55 days (range 4 to 576 days). 93 patients (78.2%) belonged to group 1. The median dose delivered was 25 Gy in 5 Frs (range: 7 Gy in 2 Frs to 40 Gy in 10 Frs). Only 9 patients (7.6%) received singlefraction radiation therapy, all belonging to group 1. Patients belonging to Tokuhashi group 1 had shorter median survival than group 2; 49 and 108 days respectively (P Z 0.02).Among all the patients, subsequent systemic treatment (Hazard ratio [HR] Z 0.354, 95% CI 0.194-0.647, P Z 0.01) and non-visceral metastasis (HR Z 0.593, 95% CI 0.363-0.968, P Z 0.037) were associated with better survival in multivariate analysis. For patients in group 1, primary breast or prostate cancer (HR Z 0.260, 95% CI 0.109-0.620, P Z 0.002) or lung cancer (HR Z 0.425, 95% CI 0.246-0.734, P Z 0.002), non-visceral metastasis (HR Z 0.426, 95% CI 0.236-0.771, P Z 0.0048), multi-fraction (HR Z 0.462, 95% CI 0.2180.982, P Z 0.0447) and subsequent systemic therapy (HR Z 0.424, 95% CI 0.217-0.828, P Z 0.012) were associated with better survival. The survival of a subset of patients in group 1 without subsequent systemic therapy was dismal (median survival only 40 days) and not altered by radiation therapy schedule (P Z 0.198). Conclusion: MSCC comprises of a very heterogeneous group of patients, even under the Tokuhashi grouping, systemic therapy or visceral metastasis may be more important prognostic factors. Further studies are necessary to better select the poor risk group. In clinical practice, singlefraction radiation therapy could be considered in Tokuhashi group 1 patients due to expected short survival, especially those without reasonable systemic treatment options. Author Disclosure: W. Mui: None. T. Lam: None. F. Wong: None. W. Sze: None. S. Tung: None.