Ronald Koretz, MD
Does aspirin reduce risk for colorectal cancer and related mortality in the long term?
Included trials were done in the UK or Sweden in the 1980s and early 1990s and compared aspirin with control, had ≥ 1000 participants, and had a median scheduled treatment period ≥ 2.5 years. Outcomes were colorectal cancer incidence and mortality.
5 randomized controlled trials (RCTs) met the selection criteria: 4 compared aspirin with control for primary (Thrombosis Prevention Trial, British Doctors Aspirin Trial) or secondary (Swedish Aspirin Low Dose Trial, UK-TIA Aspirin Trial) prevention of vascular events, and 1 (Dutch TIA Aspirin Trial) assessed different doses of aspirin. Follow-up for colorectal cancer incidence and mortality was extended in each trial through searches of national cancer and death registries. Individual patient data were pooled from the 4 trials comparing aspirin with control (n = 14 033, mean age 61 y at randomization, 88% men).
Over a median follow-up of 18.3 years, aspirin, 75 to 1200 mg/d, reduced risk for colorectal cancer and colon cancer and related mortality but not rectal cancer or related mortality (Table). Aspirin reduced risk for proximal colon cancer and related mortality but not distal colon cancer and related mortality (Table). Benefit of aspirin increased with duration of treatment; aspirin for ≥ 5 years also reduced risk for rectal cancer and related mortality (Table).
Aspirin reduces risk for colon cancer and related mortality, particularly proximal colon cancer at 20 years. Effects are more pronounced when aspirin is taken for ≥ 5 years.
Aspirin, 75 to 1200 mg/d, vs control for prevention of colorectal cancer*
*CI defined in Glossary. Based on pooled individual patient data.
Koretz R. Meta-analysis: Aspirin reduces risk for colon cancer and related mortality at 20 years, particularly when taken for ≥ 5 years. Ann Intern Med. 2011;154:JC3–3. doi: 10.7326/0003-4819-154-6-201103150-02003
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Published: Ann Intern Med. 2011;154(6):JC3-3.
Colorectal Cancer, Gastroenterology/Hepatology, Gastrointestinal Cancer, Hematology/Oncology.
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