Table 1.

Aspirin chemoprevention for colorectal tumor recurrence in a male nonsmoker subset of the Japanese J-CAPP cohort genotyped for CYP2A6*1, *4, *7, and *9

	No change	Recurrence of polyps	Total	Odds ratio (95% CI)	P value
CYP2A6*1/*1,*7,*9 (normal genotypes)
Placebo	2	3	5	2.2 (0.24–24)	P = 0.58 with Fisher’s exact test
Aspirin	3	10	13
CYP2A6*1/*4 and *4,*7,*9/*4,*7,*9 (impaired genotypes)
Placebo	1	8	9	0.06 (0.005–0.76)	P < 0.05 with Fisher’s exact test
Aspirin	6	3	9

Odds ratios are shown with respect to the reference (placebo) group. P for interaction was 0.043 (adjusted for age)