Characterization of KRAS, NRAS, and BRAF testing and timing among mCRC patients treated at community cancer centers in the United States.

Abstract

695 Background: The requirement to establish RAS status prior to administration of an EGFR inhibitor has increased the need to understand which patients are tested for RAS and the length of time it takes for the treating oncologist to receive the RAS test result. Our objective was to evaluate factors that may influence RAS testing among patients with metastatic colorectal cancer (mCRC) and the turn-around time for RAS testing among patients who are treated at community cancer centers in the United States (U.S.). Methods: The sample includes 1550 patients in the Oncology Services Comprehensive Electronic Records (OSCER) database who were diagnosed with mCRC between 1/1/2011 and 8/31/2015. Patient demographics and clinical characteristics were evaluated at the time of mCRC diagnosis. The median number of days and interquartile range (IQR) between the following dates was summarized: diagnosis for mCRC, tissue collection for biomarker testing, tissue was received by the lab for biomarker testing, and biomarker results returned to the oncologist. Results: The frequency of RAS testing was as follows: KRAS (n = 964; 62%), NRAS (n = 116; 7%), BRAF (n = 231; 15%), all three simultaneously (n = 94, 6%). There were significant differences in KRAS testing by age and type of insurance, with young (p < 0.001) and commercially-insured (p = 0.01) patients more likely to receive testing. The median number of days and IQR between specimen collection and diagnosis of mCRC was as follows: KRAS (0; 0 to 443), NRAS (0; -18.5 to 362), and BRAF (-3; -474 to 0). The median number of calendar days between the date the specimen was collected and the date it was received by the lab was as follows: KRAS (19; 1 to 303), NRAS (34.5, 8 to 518), and BRAF (29; 2 to 428). The median number of days between the date the specimen was received by the lab and the date the result was returned to the oncologist was as follows: KRAS (7; 5 to 13), NRAS (10; 7 to 15), and BRAF (8; 6 to 14). Conclusions: Many patients had a specimen collected for biomarker testing at the time of mCRC diagnosis and the results were generally returned to the treating oncologist within one week of it arriving at the lab.