How is KRAS testing associated with treatment and supportive care for patients with metastatic colorectal cancer? VA national assist project.

Abstract

64 Background: EGFR monoclonal antibody (mAb) therapies improve quality of life and outcomes for metastatic colorectal cancer (mCRC), but only wild-type KRAS benefit from treatment. We evaluated KRAS testing and pharmacogenetic-guided treatment and supportive and end of life (EOL) care. Methods: Among a national random sample of 265 veterans diagnosed with mCRC in 2008 we evaluated KRAS testing, EGFR mAb therapy, supportive care using the Cancer Quality ASSIST indicators, and healthcare use. Three oncology nurses abstracted charts for care received 2008-2011. We linked chart to VA and Medicare administrative data and compared care received by KRAS testing and results. Results: 227/265 (85%) veterans died within 3 years and received an average of 48% of recommended supportive care processes. 96 / 265 (36%) underwent KRAS testing, of whom 41, 42, and 13 had wild-type, mutant, and indeterminant/unknown KRAS. 27/41 (66%) wild-type KRAS patients received an EGFR mAb; 18/45 (40%) patients receiving an EGFR mAb had mutant, indeterminant/unknown, or untested KRAS. KRAS testing was associated with increased systemic therapy but not differences in supportive care or intensity of care at the EOL. KRAS tested vs. not tested received hospice or palliative care (67 vs. 73%, p=0.55); any systemic therapy (96 vs. 40%, p<0.001) including new regimen in last month (0 vs. 6%); any chemotherapy in last 14 days of life (9 vs. 7%); and any acute care in last month of life (28 vs. 32%, p=0.78). Conclusions: KRAS testing was not performed for most veterans with mCRC in 2008, and EGFR mAb therapy was administered to many without wild-type KRAS. KRAS-tested patients were more likely to receive systemic treatments, and testing was not associated with greater intensity or inappropriate EOL care, and rates of such care were low among veterans.