| アブストラクト | BACKGROUND: Evidence from clinical trial populations suggests low-dose aspirin reduces the risk of colorectal cancer (CRC). Part of this reduction in risk might be due to protection against metastatic disease. METHODS: We investigated the risk of CRC among new-users of low-dose aspirin (75-300 mg), including risk by stage at diagnosis. Using The Health Improvement Network, we conducted a cohort study with nested case-control analysis. Two cohorts (N = 170,336 each) aged 40-89 years from 2000 to 2009 and free of cancer were identified: i) new-users of low-dose aspirin, ii) non-users of low-dose aspirin, at start of follow-up, matched by age, sex and previous primary care practitioner visits. Patients were followed for up to 12 years to identify incident CRC. 10,000 frequency-matched controls were selected by incidence density sampling where the odds ratio is an unbiased estimator of the incidence rate ratio (RR). RRs with 95% confidence intervals were calculated. Low-dose aspirin use was classified 'as-treated' independent from baseline exposure status to account for changes in exposure during follow-up. RESULTS: Current users of low-dose aspirin (use on the index date or in the previous 90 days) had a significantly reduced risk of CRC, RR 0.66 (95% CI 0.60-0.74). The reduction in risk was apparent across all age groups, and was unrelated to dose, indication, gender, CRC location or case-fatality status. Reduced risks occurred throughout treatment duration and with all low-dose aspirin doses. RRs by aspirin indication were 0.71 (0.63-0.79) and 0.60 (0.53-0.68) for primary and secondary cardiovascular protection, respectively. Among cases with staging information (n = 1421), RRs for current use of low-dose aspirin were 0.94 (0.66-1.33) for Dukes Stage A CRC, 0.54 (0.42-0.68) for Dukes B, 0.71 (0.56-0.91) for Dukes C, and 0.60 (0.48-0.74) for Dukes D. After 5 years' therapy, the RR for Dukes Stage A CRC was 0.53 (0.24-1.19). CONCLUSIONS: Patients starting low-dose aspirin therapy have a reduced risk of Stages B-D CRC, suggesting a role for low-dose aspirin in the progression of established CRC; a substantial reduction in the risk of Dukes A CRC may occur after 5 years' therapy. |
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| 組織名 | Spanish Centre for Pharmacoepidemiologic Research, c/ Almirante 28, 2 degrees ,;28004, Madrid, Spain.;Epidemiology, Bayer AG, Mullerstr. 178, 13353, Berlin, Germany.;montse.soriano-gabarro@bayer.com.;EpiMed Communications Ltd, Abingdon, Oxford, OX14 1QS, UK.;London School of Hygiene and Tropical Medicine, Keppel St, London, WC1E 7HT, UK.;Servicio de Aparato Digestivo, Hospital Clinico, University of Zaragoza, IIS;Aragon, Zaragoza, Spain.;CIBERehd, Av. Monforte de Lemos, 3-5. Pabellon 11. Planta 0, 28029, Madrid,;Spain.;Department of Preventive Medicine and Public Health, Faculty of Medicine,;Complutense University of Madrid, Av. Seneca, 2, 28040, Madrid, Spain. |
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