Venous thromboembolism may be a harbinger of cancer. Patients with diverticular disease are suggested to have an increased risk of developing venous thromboembolism compared with the general population, but it remains unclear whether venous thromboembolism is also a marker of occult cancer in these patients. We investigated the risk of cancer after venous thromboembolism among patients with diverticular disease.

We used Danish health registries to conduct a nationwide, population-based cohort study during 1996–2017. We identified all venous thromboembolism patients with a diagnosis of diverticular disease and calculated absolute risks of cancer and standardized incidence ratios (SIRs) by comparing observed and expected cancer incidence based on national cancer incidence in the Danish population.

We followed 3406 patients with venous thromboembolism and diverticular disease for a median of 3.0 years (interquartile range: 1.0–6.0). During the first year of follow-up, we observed 212 cancer cases. The corresponding one-year risk of cancer was 6.2% (95% confidence interval [CI]: 5.5–7.1) with a SIR of 2.9 (95% CI: 2.5–3.3). The SIRs were particularly elevated for cancers of the stomach, pancreas, ovary, and kidney. During the second and subsequent years of follow-up, 337 cancers were diagnosed with a SIR of 1.1 (95% CI: 1.0–1.3).

Venous thromboembolism is a harbinger of occult cancer in patients with diverticular disease.