Diverticular Disease and Colorectal Neoplasms: Association between Left Sided Diverticular Disease with Colorectal Cancers and Right Sided with Colonic Polyps.

BACKGROUND Both colorectal cancer (CRC) and diverticular disease (DD) are common in the affluent West, and their prevalence is also increasing in the rest of the world with economic development. Both diseases have common epidemiologic characteristics; increasing incidence, more common with advancing age and related to specific dietary changes. However, studies of associations between the two have generated mixed results with some showing positive correlations, whilst others have shown no or negative links. Most of these studies have been from the West with study populations that were predominantly Caucasians. Here the focus was on DD and colorectal neoplasms, including CRC, in Brunei. MATERIALS AND METHODS All patients who had undergone complete colonoscopy between 2011 and 2014 were identified and retrospectively reviewed. Patients under the age of 18 years old or had previous colonic surgeries (including previous CRC resection) were excluded. RESULTS The total number of colonoscopies included in the study was 2,766 (mean age 53.2±14.8 years old, male 51.8%), of which DD, CRC and colonic polyps were detected in 17.3%, 4.7% and 28.2% respectively. The proportions of DD, polyps and CRC increased proportionally with age (<30 years, 30-49, 50-69 and ≥70). Overall, there was no association between the presence of DD and CRC (3.6% vs. 5.0%, p=0.179) but there was a significant association between CRC and left sided DD (p=0.034 by trend). There were also a significant association between presence of DD and polyps (36.1% vs. 28.2%, p=0.001), in particular with right-sided and pan-DD (p=0.001 for trend). CONCLUSIONS Our study showed that the prevalence of DD, CRC and polyps increases with age. There were significant associations between presence of left-sided DD with CRC and right-sided or pan-DD with colonic polyps. This suggests shared risk factors. Further studies are required to assess links in other countries of the Asian Pacific region.