Diverticular disease and the risk of colon cancer - a population-based case-control study

Background Colon cancer and diverticular disease are most common in the Western world and their incidences tend to increase with advancing age. The association between the diseases remains unclear. Aim To analyse the risk of colon cancer after hospitalisation for diverticular disease. Methods Nationwide case-control study. A total of 41 037 patients with colon cancer during 1992-2006, identified from the Swedish Cancer Register were included. Each case was matched with two control subjects. From the Swedish Inpatient Register, cases and control subjects hospitalised for diverticular disease were identified. Odds ratios (OR) and confidence intervals for receiving a diagnosis of colon cancer after hospital discharge for diverticular disease were calculated. Colon cancer mortality was compared between patients with or without diverticular disease. Results Within 6 months after an admission due to diverticular disease, OR of having a colon cancer diagnosis were up to 31.49 (19.00-52.21). After 12 months, there was no increased risk. The number of discharges for diverticular disease did not affect the risk. Colon cancer mortality did not differ between patients with and without diverticular disease. Conclusions Diverticular disease does not increase the risk of colon cancer in the long term, and a history of diverticular disease does not affect colon cancer mortality. The increased risk of colon cancer within the first 12 months after diagnosing diverticular disease is most likely due to surveillance and mis-classification. Examination of the colon should be recommended after a primary episode of symptomatic diverticular disease.