Clinical Validation of a Multiplex Kit for RAS Mutations in Colorectal Cancer: Results of the RASKET (RAS KEy Testing) Prospective, Multicenter Study

AbstractBackgroundRAS (KRAS and NRAS) testing is required to predict anti-epidermal growth factor receptor (EGFR) treatment efficacy in metastatic colorectal cancer (CRC). Although direct sequencing (DS) with manual microdissection (MMD) is widely used, a diagnostic kit providing rapid detections of RAS mutations would be clinically beneficial. We evaluated the MEBGENTM RASKET KIT (RASKET KIT), a multiplex assay using PCR-reverse sequence specific oligonucleotide and xMAP® technology to concurrently detect exon 2, 3, and 4 RAS mutations in a short turnaround time (4.5h/96-specimens).MethodsFormalin-fixed paraffin-embedded (FFPE) tissues were obtained from 308 consenting patients with histologically-confirmed CRC at six hospitals in Japan. For the RASKET KIT, we used only 50–100ng DNA from each FFPE specimen not processed by MMD. The primary endpoint was the concordance rate between RAS mutations identified with the RASKET KIT and two reference assays (DS with MMD and TheraScreen® K-RAS Mutation Kit). As the secondary endpoints, we evaluated the concordance rate between DS and the RASKET KIT for RAS mutations in the wild-type KRAS exon 2 population and the genotyping performance of the RASKET KIT compared with DS.FindingsAmong 307 analyzable specimens, the reference assays detected 140 (45.6%, 140/307) RAS mutations: 111 KRAS exon 2 and 29 other (minor) RAS mutations. The RASKET KIT detected 143 (46.6%, 143/307) mutations: 114 KRAS exon 2 and 29 minor RAS mutations. The between-method concordance rate was 96.7% (297/307) (95% CI: 94.1–98.4%). Minor RAS mutations were detected in 15.7% (30/191) of the wild-type KRAS exon 2 population (n=191); the concordance rate was 98.4% (188/191) (95% CI: 95.5–99.7%). The concordance rate of RAS genotyping was 100% (139/139) (95% CI: 97–100%).InterpretationThe RASKET KIT provides rapid and precise detections of RAS mutations and consequently, quicker and more effective anti-EGFR therapy for CRC (Study ID: UMIN000011784).FundingMedical & Biological Laboratories Co., Ltd. (MBL). MBL had roles in study design, data collection, data analysis, and writing of the report for the study

Proposed predictors of the need for retreatment after coil embolization of unruptured cerebral aneurysms with major or minor recanalization: Analysis of a single center’s experience

Objective: Various risk factors for recanalization after coil embolization have been reported, but the indications for retreatment of recanalized aneurysms have not been determined.The aim of this study was to identify risk factors indicating the need for retreating recanalization during long-term follow-up (approximately 1 year). Methods: A total of 172 unruptured saccular aneurysms in 155 patients treated by initial coil embolization between February 2012 and July 2019 were retrospectively analyzed. Intraluminal thrombosed aneurysms, aneurysms treated with stent assistance, and aneurysms followed without digital subtraction angiography (DSA) were excluded. Recanalization was identified in 31 aneurysms. Recanalized aneurysms (Meyer grade ≥2) were defined as major recanalization (MA); those that worsened to Meyer grade 1 were defined as minor recanalization (MI). Age, sex, aneurysm location, shape, five morphological variables (neck, height, width, dome-to-neck ratio, aspect ratio), aneurysm volume, endovascular technique, immediate Meyer grade, and volume embolization ratio (VER) were compared between MI (n = 18) and MA (n = 13). Predictors of MA were determined using logistic regression and receiver operating characteristic (ROC) curve analyses. Results: On multivariate logistic regression analysis, spherical shape (odds ratio (OR) 11.9; 95% confidence interval (CI) 1.28–111) and VER (OR 1.92; 95% CI 1.13–3.28) were independent predictors of MA. On ROC curve analysis, the optimal cut-off value for the VER was 20.8% (sensitivity, 76.9%; specificity, 77.8%). Conclusions: Lower VER and non-spherical shape appear to be independent risk factors for progression to MA in recanalized aneurysms, and packing with a VER >20.8% is expected to prevent progression to MA