Abstract
PURPOSE: To examine associations of KRAS mutation with tumor deposit status and overall survival in colorectal cancer (CRC) patients. METHODS: This retrospective cohort study included patients with incidental CRC diagnosed during 2010-2014 and recorded statuses of KRAS and tumor deposit in the National Cancer Database of the USA. Multivariable logistic regression and time-varying Cox regression analyses were used. RESULTS: We included 45,761 CRC patients with KRAS status (24,027 [52.5%] men, 24,240 [53.0%] < 65 years old, 17,338 [37.9%] with KRAS mutation). Adjusted for microsatellite instability, age, pathologic stage and tumor grade, KRAS mutation (versus wild type) was associated with tumor deposit presence (odds ratio = 1.11, 95% CI 1.02-1.20). KRAS mutation was also linked to worse overall survival of CRC patients regardless of tumor deposit status (adjusted Hazard ratio [HR] = 1.20, 95% CI 1.07-1.33 for CRC with tumor deposits, and adjusted HR = 1.24, 95% CI 1.14-1.35 or CRC without) or tumor stage (adjusted HR = 1.32, 95% CI 1.14-1.54 for early-stage and adjusted HR = 1.18, 95% CI 1.10-1.27 for late-stage). Microsatellite instability was associated with better overall survival in CRC without tumor deposit (adjusted HR = 0.89, 95% CI 0.79-0.99), but not in CRC with tumor deposit (adjusted HR = 1.12, 95% CI 0.97-1.30). CONCLUSION: KRAS mutation is independently associated with tumor deposit presence and a worse overall survival in CRC patients.