Table 5.

PIK3CA mutation in colorectal cancer and patient mortality according to KRAS and BRAF mutation status

Colorectal cancer–specific mortalityOverall mortality
Total No.No. of eventsUnivariate HR (95% CI)Stage-stratified HR (95% CI)Multivariate stage-stratified HR (95% CI)No. of eventsUnivariate HR (95% CI)Stage-stratified HR (95% CI)Multivariate stage-stratified HR (95% CI)
BRAF wild type and KRAS wild type
PIK3CA (–)5161241 (referent)1 (referent)1 (referent)2241 (referent)1 (referent)1 (referent)
PIK3CA (+)62130.88 (0.49–1.55)0.91 (0.51–1.62)0.97 (0.54–1.74)230.83 (0.54–1.28)0.88 (0.57–1.36)0.83 (0.54–1.28)
BRAF mutant and KRAS wild type
PIK3CA (–)140411 (referent)1 (referent)1 (referent)681 (referent)1 (referent)1 (referent)
PIK3CA (+)2681.08 (0.51–2.32)1.04 (0.48–2.24)1.67 (0.76–3.69)120.90 (0.49–1.67)0.88 (0.47–1.64)1.09 (0.59–2.04)
BRAF wild type and KRAS mutant
PIK3CA (−)3111091 (referent)1 (referent)1 (referent)1651 (referent)1 (referent)1 (referent)
PIK3CA (+)100300.81 (0.54–1.21)0.72 (0.48–1.08)0.69 (0.46–1.04)500.87 (0.64–1.20)0.82 (0.59–1.13)0.75 (0.54–1.04)

NOTE: The multivariate, stage-stratified Cox regression model initially included age, sex, year of diagnosis, tumor location, tumor grade, MSI, CpG island methylator phenotype and LINE-1 methylation. A backward elimination with a threshold of P = 0.05 was used to select variables in the final models.