Table 2.

Aspirin adjuvant studies in patients with established colorectal cancer

Efficacy of aspirin in patients with surgically resected colorectal cancer
Name of Study group	Type	Study population (N)	Aspirin dose used	Result from aspirin use post-diagnosis [Multivariate HR (95% CI)]
CALGB 89803(28)	Subgroup analysis in a randomized controlled trial	Stage III CRC (N=830)	325 mg	HR 0.48 (95% CI, 0.24–0.99) for disease free-survival HR 0.52 (95% CI, 0.19–1.46) for death (OS)
Nurses’ Health and Health professional Follow-up study(27)	Prospective cohort study	Stage I, II & III CRC (N=1279)	325 mg	HR 0.71 (95% CI, 0.53–0.95) for CRC−specific mortality HR 0.79 (95% CI, 0.65–0.97) for overall mortality In aspirin non-users before diagnosis: HR 0.53 (95% CI, 0.33–0.86) for CRC−specific mortality In aspirin users before diagnosis: HR 0.89 (95% CI, 0.59–1.35) for CRC−specific survival
Eindhoven Cancer Registry and PHARMO prescription registry(30)	Retrospective cohort study	Stage I-IV CRC (N=4481)	80 mg	RR 0.77 (95% CI, 0.63–0.95) for CRC-specific mortality RR 0.65 (95% CI, 0.50–0.84) for colon cancer mortality RR 1.03 (95% CI, 0.75–1.40) for rectal cancer mortality
Health Informatics Centre Registry, Scotland(29)	Retrospective cohort study	Stage I-IV CRC (N= 2916)	75 mg	HR 0.67 (95% CI, 0.57–0.79) for CRC-specific mortality HR 0.72 (95% CI, 0.57–0.91) for colon cancer mortality HR 0.80 (95% CI, 0.58–1.11) for rectal cancer mortality

Abbreviations: CRC, colorectal cancer; HR, Hazard ratio; OS, overall survival; RR, relative risk.