Concept of chemoprevention in colorectal cancer

Table 2 Role of aspirin in colorectal neoplasia risk among patients with past tumour

Trials	n	Aspirin dose	Duration (yr)	Relative risk (95% CI)
Baron et al[28]	1121	81/325 mg	1	0.96 (0.81-1.13)
Benamouzig et al[29]	272	160/300 mg	1	0.82 (0.7-0.95)
Greenberg et al[30]	864		4	0.52 (0.31-0.89)
PPSG[31]	1905	< 325 mg	4	0.82 (0.65-1.02)
		> 325 mg		0.54 (0.3-0.96)
Sandler et al[32]	492	> 15 tab/month	5	0.84 (0.5-1.43)
Breuer-Katschinski et al[33]	442	> 4 tab/week	< 5	0.91 (0.32-2.64)
			> 5	0.09 (0.01-0.82)

CI: Confidence interval; PPSG: Polyp prevention study group.