Chronic liver disease appears to double the risk of colorectal cancer (CRC), even after patients undergo liver transplantation, according to a report published in Gastrointestinal Endoscopy.

“Strict surveillance for colorectal cancer is warranted in this patient population,” said Yuga Komaki, MD, of the section of gastroenterology, hepatology, and nutrition, University of Chicago, and associates.

One prominent chronic liver disease, primary sclerosing cholangitis, is known to raise the risk of CRC, which “is mainly attributed to the concurrence of inflammatory bowel disease.” In addition, whether liver transplantation mitigates that risk remains “controversial,” the investigators noted.

To assess whether chronic liver disease impacts CRC risk, they performed a systematic review and meta-analysis of the literature, examining data from 55 observational studies involving 55,991 participants. Case patients had a variety of chronic liver diseases, including primary sclerosing cholangitis, viral hepatitis, autoimmune hepatitis, primary biliary cirrhosis, and alcoholic liver damage.

Overall, the pooled standardized incidence ratio of CRC was 2.06 among patients with liver disease, compared with control subjects. It was highest in the subgroup of patients with primary sclerosing cholangitis at 6.70, the investigators said ( Gastrointest. Endosc. 2017;86:93-104 ).

CRC risk appeared to be slightly higher among patients who had cirrhosis than among those who had hepatitis, “suggesting that advanced liver damage may lead to higher risks of CRC. This is not surprising because advanced liver damage can cause systemic alterations in immunity that may precipitate malignant transformation,” Dr. Komaki and associates noted.

The pooled standardized incidence ratio of CRC remained elevated at 2.16 among patients who underwent liver transplantation for a variety of causes. It is possible that their exposure to immunosuppressive therapy plays a role in elevating this risk, the researchers added.

“We propose that patients with chronic hepatitis and cirrhosis require a screening colonoscopy every 5 years, as opposed to the 10-year interval in the general population. Patients undergoing liver transplant should have a colonoscopy before the transplant and, subsequently, should undergo colonoscopy at 5-year intervals,” Dr. Komaki and associates said.

They added that the sixfold increase in CRC risk among patients with PSC “justifies the present recommendation of annual surveillance colonoscopy that should be continued after transplant.”