In the study, 2.10% of patients with Crohn’s disease and 1.90% of patients with ulcerative colitis were diagnosed with colorectal cancer.
While the majority of research of colorectal cancer in patients with inflammatory bowel disease (IBD) has focused on a younger population, new research is looking at elderly-onset IBD and whether or not it is related to an increased incidence and mortality rate of colorectal cancer.
A team, led by Asa H. Everhov, Department of Clinical Science and Education Södersjukhuset, Karolinska Institutet, estimatated the risk of incident colorectal cancer and mortality in elderly onset IBD.
There is previous research showing an increased relative risk of colorectal cancer in IBD, but this is limited to young-onset IBD.
“The risk of [colorectal cancer] is higher in IBD patients with extensive disease, a family history of [colorectal cancer], primary sclerosing cholangitis (PSC), and long disease duration,” the authors wrote.
Currently, endoscopic surveillance programs recommend varied colonoscopy intervals according to the presence of risk factors.
In addition, approximately 4-21% of patients with Crohn’s disease and 11-25% of patients with ulcerative colitis are diagnosed after the age of 60 years. And the highest risk of colorectal cancer is reported for patients diagnosed with IBD aged younger than 30 years.
The study included patients diagnosed with IBD aged 60 years and older between 1969-2017 identified using Danish and Swedish National Patient Registers and histopathology data.
The investigators linked data to the Cancer and Causes of Death Registers. They also estimated hazard ratios for colorectal cancer diagnosis and mortality compared to a control group matched by sex, age, and region of IBD-free individuals using Cox regression.
Overall, the team identified 7869 patients with Crohn’s disease that were followed for 54,220 person-years and 21,224 patients with ulcerative colitis followed for 142,635 person-years.
Of this group, 2.10% of patients with Crohn’s disease and 1.90% of patients with ulcerative colitis were diagnosed with colorectal cancer, compared to 2.26% and 2.34% of reference individuals (median follow-up 6 and 7 years).
In addition, the cancer incidence was elevated during the first year following an IBD diagnosis. The data show an incidence rate of 4.36 (95% CI, 3.33-5.71) in Crohn’s disease and 2.48 (95% CI, 2.03-3.02) in ulcerative colitis. However, this decreased after the first year of follow-up to 0.69 (95% CI, 0.56-0.86) for Crohn’s disease and 0.78 (95% CI, 0.69-0.88) for ulcerative colitis.
Following a colorectal cancer diagnosis, mortality was similar between patients with IBD and the general population.
“The excess risk of [colorectal cancer] in elderly-onset IBD was probably due to bias and not observed beyond the first year,” the authors wrote. “From 2010, the HR for [colorectal cancer] diagnosis more than 1 year after initial IBD diagnosis was lower than in the largely unscreened reference population, supporting the benefit of endoscopic screening and surveillance in patients with IBD.”
The study, “Colorectal cancer in elderly-onset inflammatory bowel disease: A 1969–2017 Scandinavian register-based cohort study,” was published online in Alimentary Pharmacology & Therapeutics.