Table 4.

PIK3CA mutation in colorectal cancer and patient mortality

Colorectal cancer–specific mortalityOverall mortality
PIK3CA statusTotal 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)
Wildtype9812771 (referent)1 (referent)1 (referent)4671 (referent)1 (referent)1 (referent)
Mutant (exon 9 or 20)189510.95 (0.70–1.28)1.03 (0.77–1.40)1.07 (0.79–1.45)850.92 (0.73–1.16)0.97 (0.76–1.22)0.91 (0.72–1.15)
Mutation in only exon 9109290.94 (0.64–1.38)1.05 (0.72–1.55)1.05 (0.71–1.56)480.93 (0.69–1.25)0.99 (0.73–1.33)0.90 (0.67–1.22)
Mutation in only exon 2073180.83 (0.52–1.34)0.87 (0.4–1.40)0.96 (0.59–1.55)300.77 (0.53–1.12)0.80 (0.55–1.15)0.80 (0.55–1.16)
Mutations in both exon 9 and exon 20742.84 (1.05–7.69)3.61 (1.32–9.87)3.51 (1.28–9.62)73.37 (1.58–7.15)3.91 (1.83–8.36)2.68 (1.24–5.77)

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