Clinical Features and Outcomes of Patients with Colorectal Cancers Harboring NRAS Mutations.

mutations are now routinely included in RAS testing prior to EGFR inhibitor therapy for metastatic colorectal cancer (mCRC). The clinical implications of mutation beyond lack of response to anti-EGFR therapy, however, are not known. We undertook this study to determine the clinical features and treatment outcomes of patients with -mutant mCRC. We reviewed clinical characteristics, concurrent mutations, and outcomes for all mCRC cases with mutations undergoing standard genotyping at our institution from 2008 to 2015. Comparison groups consisted of wild-type and -mutant mCRC consecutive cases genotyped from 2008 to 2012. Three percent (87/2764) of mCRC patients had -mutant tumors (45% exon 2 and 55% exon 3), including three cases with concurrent and mutations. Left-sided primary site and African American self-reported race were associated with mutation ( < 0.01). Resection rate at 12 months was lower for -mutant mCRC than for wild-type or -mutant mCRC. Median survival from time of first known metastasis was 33 months for -mutant, 47 months for -mutant, and 78 months for wild-type cases ( < 0.001). Multivariate analysis assigned an HR for overall survival of 2.0 for mutation and 1.5 for mutation ( < 0.01). defines a molecular subset with distinct clinical characteristics from -mutant and wild-type mCRC. mutations are enriched in left-sided primary tumors and among African Americans. Mutations in are associated with poor survival and worse outcomes than either -mutant or wild-type mCRC. .