An evaluation of RAS testing among metastatic colorectal cancer patients in the USA.

Background: Data on RAS testing practices prior to metastatic colorectal cancer (mCRC) treatment initiation are lacking in the USA. Materials & methods: Flatiron data were utilized for patients diagnosed with mCRC between 2011 and 2017. Flatiron is a longitudinal, demographically and geographically diverse database representing data from over 1.5 million active US patients treated at 255 community and hospital-affiliated oncology clinics. Results: Among 17,387 mCRC patients 69% were RAS tested and 31% were never tested. Timing of RAS testing was as follows: 23% were tested at the time of their initial CRC diagnosis, 60% following mCRC diagnosis but prior to first line of treatment, 3% prior to third line, the remaining 14% were tested following third line. Conclusion: A third (31%) of patients failed to receive RAS testing, therefore all treatment options were unavailable to them. These data highlight how universal testing has not been achieved.