In the CAPOX-C arm , carriers of both 131R and 158F alleles had a statistically significant improvement in PFS ( 5 years : 78.4 % ; HR , 0.22 ; P = 0.002 ) and overall survival ( OS ; 5 years : 86.4 % ; HR , 0.24 ; P = 0.018 ) when compared with patients homozygous for 131H and/or 158V ( 5-year PFS : 35.7 % ; 5-year OS : 57.1 % ) .