There is no increased risk for colorectal cancer and adenomas in patients with diverticulitis: a retrospective longitudinal study

Aim This study was designed to assess the relationship between diverticulitis and the development of colorectal cancer (CRC) and colonic adenomas. Method A retrospective study was longitudinally conducted. Patients who had been admitted to the hospital between 1990 and 2000 with diverticulitis were retrieved and the incidence of CRC and prevalence of colonic adenomas in these patients was determined. Data were collected from the electronic clinical and pathology records. The incidence of CRC and prevalence of adenomas in this patient cohort was compared with the general population. The patients were followed until 2008. Results A total of 288 patients with diverticulitis were included (167 of whom were female patients [58%]). The mean age of patients at admittance for diverticulitis was 66 years (range: 27-92). CRC was detected in five patients (1.7%) (95% CI 0.8-3.5) with a mean age of 77 years; colonic adenomas were found in 18 patients (6.3%) (95% CI 4.3-9.0) with a mean age of 62 years. The lifetime risks of developing CRC and adenomas were presumed to be 4% and 20% respectively. Expected rates for CRC and adenomas in our patients were calculated as 17(95% CI 4.0-8.6) and 69 patients (95% CI 20.1-28.3) respectively. Conclusion This study showed a lower prevalence of CRC and colonic adenomas in patients with diverticulitis compared with the lifetime risk which means that diverticulitis is not a risk factor for development of CRC and adenomas. Long-term colonic screening after a negative colonoscopy for diverticulitis (generally performed several weeks after recovery) does not seem to be justified.