An evaluation of RAS testing and survival among mCRC patients in the United States.

Abstract

e15144 Background: The status of mutations in the rat sarcoma viral oncogene homolog ( RAS) family of genes, which includes Kirsten RAS ( KRAS) and Neuroblastoma RAS ( NRAS) predicts response to anti-EGFR therapies in metastatic colorectal cancer (mCRC) patients. Current treatment guidelines recommend all mCRC patients to receive RAS testing prior to initiating treatment with an anti-EGFR agent. This study sought to establish estimates of RAS testing among mCRC patients in the US prior to initiation of first and third lines of treatment, and to describe median survival by treatment groups. Methods: Data from the Oncology Services Comprehensive Electronic Records (OSCER) 2.0 dataset were utilized. Patients diagnosed with mCRC between January 1, 2011 and July 31, 2017 were eligible. Patients were followed for up to 1 year, or until death, following their mCRC diagnosis. Results: A total of 17,387 mCRC patients were included in the analysis, among which 69% were RAS tested and 31% were never tested. Among the RAS tested patients, 23% were tested prior to their mCRC diagnosis 60% received RAS testing following mCRC diagnosis but prior to first line of treatment, 3% were tested following first line treatment but prior to third line, and the remaining 14% were tested following third line. Demographic variables did not differ between tested and untested groups, overall and by line of treatment. The overall median survival of RAS WT patients was 31.1 months (95% CI: 30.0, 32.4). MCRC patients who were not RAS tested had a lower median survival of 20.7 months (95% CI: 19.1, 22.5). Conclusions: The timing of when patients are being tested varies greatly. While nearly 70% of patients had a RAS test, approximately 30% failed to be tested, identifying a large gap in testing practices. Universal RAS testing provides patients and their physicians with knowledge of their anti-EGFR treatment options and may result in improved survival.