Table 3.

Colorectal cancer patient mortality according to KRAS mutation status in 1075 BRAF wild type cases

Colorectal cancer–specific mortalityOverall mortality
KRASBRAFTotal NNo. of eventsUnivariate HR (95% CI)Multivariate HR (95% CI)No. of eventsUnivariate HR (95% CI)Multivariate HR (95% CI)
Wild typeWild type6351491 (referent)1 (referent)2751 (referent)1 (referent)
All codon 12 mutantsWild type3321191.68 (1.32–2.14)1.30 (1.02–1.67)1831.46 (1.21–1.77)1.24 (1.02–1.51)
P < 0.0001P = 0.037P < 0.0001P = 0.029
All codon 13 mutantsWild type108311.25 (0.85–1.84)0.86 (0.58–1.27)541.17 (0.87–1.57)0.96 (0.71–1.30)
NSNSNSNS

NOTE: We tested the specific study hypothesis on the prognostic role of KRAS codon 12 mutations, among BRAF wild type cases. Thus, a P value for significance was set at P = 0.05.

The multivariate, stage-stratified Cox regression model initially included age, sex, year of diagnosis, tumor location, tumor differentiation, family history of colorectal cancer, MSI, CpG island methylator phenotype, PIK3CA, and LINE-1 methylation. A backward stepwise elimination with a threshold of P = 0.20 was used to select variables in the final model.

Abbreviation: NS, not significant.