Comparison of a large NGS panel to hot-spot testing and small panels for the ability to accurately stratify advanced colorectal cancer patients to appropriate treatment pathways.

510 Background: It is well established that KRAS mutations confer resistance to anti-EGFR therapy for colorectal cancer patients. More recently, other RAS mutations (NRAS and BRAF) have been determined to cause similar resistance and treatment guidelines are changing to incorporate testing of these genes as well. In addition, evidence suggests that mutations outside of hot-spot regions (Codons 12 & 13 of KRAS and NRAS; BRAF V600E) can also mediate therapeutic response. Recent data also suggest that other genes are relevant for treatment planning. We evaluated the ability of a 415 gene panel, CancerPlex, to accurately stratify colorectal cancer patients to appropriate treatment pathways compared to single gene “hot-spot” testing and small gene panels ( ≤ 50 genes). Methods: 70 colorectal cancer samples were analyzed by a large NGS panel of 415 genes that includes full-gene sequencing for SNPs, short insertions and deletions, and CNVs. All actionable mutations for each patient were recorded. We calculated r...