Patients with Crohn Disease Have Increased Risk of Diagnosis, Death from Colorectal Cancer

Patients diagnosed with Crohn disease and colorectal cancer (CRC) have a higher rate of mortality than patients without Crohn disease who are also diagnosed with CRC.

Patients with Crohn disease are at increased risk of diagnosis and death from colorectal cancer (CRC), and those diagnosed with both diseases have a higher mortality rate than patients without Crohn disease who are also diagnosed with CRC, according to a study published in The Lancet Gastroenterology & Hepatology.

Previous studies reflect older treatment and surveillance strategies, and most have assessed risks for incident CRC without acknowledging surveillance and lead-time bias. Investigators wanted to assess rates of incident CRC and CRC mortality among patients with Crohn disease compared with the general population.

The nationwide register-based cohort study used International Classification of Diseases codes in national patient registers and pathology reports to identify incident cases of Crohn disease. In Demark, they searched for incident cases between January 1977 and December 2011, and in Sweden between January 1969 and December 2017.

For each patient with Crohn disease, the researchers identified up to 10 reference individuals in national population registers and matched them by sex, age, calendar year, and place of residence.

The main outcome was death from CRC as main or contributory cause of death detailed in the cause-of-death registers. The secondary outcome was incident CRC, as defined by cancer registers. The investigators used a series of Cox models to estimate cause-specific hazard ratios (HRs) of the different competing outcomes, CRC diagnosis, CRC death, and other causes of death, and adjusted for tumor stage at CRC diagnosis.

Within the study period, the research team identified 47,035 patients with incident Crohn disease, of whom 13,056 were located in Denmark and 33,979 were located in Sweden, as well as 463,187 matched reference individuals.

During follow-up, 296 CRC deaths occurred among individuals with Crohn disease compared with 1968 in reference individuals, corresponding to an overall adjusted HR of 1.40. Patients with Crohn disease who were diagnosed with CRC were at increased risk of CRC mortality compared with reference individuals also diagnosed with CRC and tumor stage at CRC diagnosis did not differ between groups.

Patients with Crohn disease who had follow-up of 8 years or longer or who were diagnosed with primary sclerosing cholangitis (PSC) and were potentially eligible for CRC surveillance had an increased overall risk of CRC death or CRC diagnosis. However, in patients potentially eligible for CRC surveillance, the study team only found significantly increased risks in patients diagnosed with Crohn disease before the age of 40 years, patients with disease activity in the colon only, or patients with PSC.

The authors noted that CRC surveillance should likely be focused on patients diagnosed with Crohn disease before 40 years of age, on patients with colon inflammation, and on those who have PSC.

Reference

  • Colorectal Cancer in Ulcerative Colitis and Crohn Disease [news release]. ESMO website. Published February 17, 2020. https://www.esmo.org/oncology-news/colorectal-cancer-in-ulcerative-colitis-and-crohn-s-disease. Accessed February 20, 2020.