Acute myocardial infarction and stroke were associated with an increased first-year risk of colorectal cancer (SIR 1.85 and 1.42, respectively), likely reflecting detection of occult cancer.
Cohort (n=544,521)
Yes
Does acute myocardial infarction or stroke increase the risk of developing colorectal cancer?
The increased risk of colorectal cancer in the first year after AMI or stroke likely reflects detection of occult cancer at the time of the vascular event rather than a shared pathophysiological association.
Effect estimate: SIR 1.08 (95% CI 1.05-1.11)
p-value: p=<0.001
BACKGROUND: An association between colorectal cancer and acute myocardial infarction (AMI) and stroke has been suggested, but evidence is conflicting. METHOD: We conducted a population-based cohort study (1978-2010) of the association between AMI/stroke and colorectal cancer by linking nationwide Danish registries. We calculated standardized incidence ratios (SIR) of colorectal cancer after AMI/stroke as the ratios of observed to expected incidence. RESULTS: A total of 297,523 patients with AMI (median age, 69.4 years; 64% men) were followed for a median of 3.1 years (range, 0-33 years) and 4,387 developed colorectal cancer SIR, 1.08; 95% confidence interval (CI), 1.05-1.11; P < 0.001. In the first year of follow-up, the SIR was 1.85 (95% CI, 1.73-1.98; P < 0.001), whereas it was 0.98 (95% CI, 0.95-1.02; P = 0.318) in the second and subsequent years. We followed 246,998 patients with stroke (median age, 72.4 years; 52% men) for a median of 2.9 years (range, 0-33 years) and 3,035 developed colorectal cancer (SIR, 1.04; 95% CI, 1.00-1.07; P = 0.053). In the first year of follow-up, the SIR was 1.42 (95% CI, 1.31-1.53; P < 0.001), whereas it was 0.96 (95% CI, 0.93-1.00; P = 0.072) thereafter. We found no difference between the SIRs for ischemic and hemorrhagic stroke. The increased one-year relative risks for AMI and stroke corresponded to a 0.3% absolute risk. CONCLUSIONS: Our findings reflect detection of occult cancer at the time of the vascular event. The lack of increased risk after one year suggests that an association based on shared risk factors or chronic inflammation is unlikely. IMPACT: In patients with AMI/stroke, the diagnostic workup including screening for colorectal cancer should follow that of the general population.
Erichsen et al. (Wed,) conducted a cohort in Acute Myocardial Infarction and Stroke (n=544,521). Acute myocardial infarction and stroke vs. Expected incidence in the general population was evaluated on Colorectal cancer incidence (SIR 1.08, 95% CI 1.05-1.11, p=<0.001). Acute myocardial infarction and stroke were associated with an increased first-year risk of colorectal cancer (SIR 1.85 and 1.42, respectively), likely reflecting detection of occult cancer.