Chronic liver disease may boost risk of colorectal cancer

Last Updated: 2017-01-18

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Patients with chronic liver disease may have an elevated risk for colorectal cancer (CRC), even after a liver transplant, according to a systematic review and meta-analysis.

"Patients with chronic liver disease, regardless of the cause, had an increased risk of colorectal cancer that persisted after liver transplant," senior author Dr. Atsushi Sakuraba of the University of Chicago Medicine in Illinois told Reuters Health.

"A more intensive screening/surveillance colonoscopy program to reduce mortality from colorectal cancer should be applied to patients with chronic liver disease," he advised in an email.

Dr. Sakuraba and his colleagues assessed the risk of CRC in patients with chronic liver diseases before and after liver transplantation. They searched electronic databases for studies assessing the risk of CRC in patients with chronic liver diseases and identified 55,991 patients in 50 studies.

In a paper online December 21 in Gastrointestinal Endoscopy, they report that among studies that included patients with hepatitis and cirrhosis, the pooled standardized incidence rate (SIR) was 2.06 (P<0.0001; 95% confidence interval 1.46 to 2.90) with moderate heterogeneity (I-squared statistic=49.2%), likely due to the difference between the disease subgroup and the power of the studies.

Three studies showed an increased risk of CRC in primary sclerosing cholangitis (PSC) (pooled SIR 6.70; P<0.0001; 95% CI, 3.48 to 12.91) with moderate heterogeneity (I2=36.3%), apparently due to the difference between the power of the studies.

Of the studies that included post-transplant patients, the pooled SIR was 2.16 (P<0.0001; 95% CI, 1.59 to 2.94) with moderate heterogeneity (I2=56.4%).

On meta-regression, a correlation was found between the proportion of autoimmune-related liver diseases and the risk of CRC.

"It was previously thought that only patients with PSC had an increased risk of colorectal cancer, but our study showed that patients with other liver diseases also have an increased risk," Dr. Sakuraba said.

"It would be important to study" whether patients with other chronic liver diseases "are equally at increased risk," Dr. Sakuraba explained.

Dr. Patrick Boland of the Roswell Park Cancer Institute in Buffalo, New York, who was not involved in the study, noted in an email that "most patients here had cirrhosis, PSC or a prior liver transplant. The most convincing increased risk was seen in patients who had PSC, which is associated with inflammatory bowel disease, a known risk factor for colon cancer."

"However," he said, "the post-transplant patients, and specifically those patients with underlying autoimmune diseases, also had increased risk of colon cancer."

"Organ transplantation requires the use of immune suppressive drugs, with a long-term risk of secondary malignancies," he noted. "We already have evidence that patients with a prior kidney transplant have an increased risk of colon cancer. These data would suggest that patients who are being evaluated for and/or who have undergone a liver transplantation are at approximately a two-fold greater risk for developing colon cancer."

Dr. Boland said the findings are not entirely surprising because links to inflammation, immune suppression, and the risk of colon cancer are known.

"One might consider colonoscopy as part of the liver transplant workup, particularly in patients with primary sclerosing cholangitis (PSC)," he suggested.

"It would be very interesting to know if this risk is predominantly linked to an increase in right-sided vs left-sided colon cancers, knowing that there are important biologic differences between cancers arising in different portions of the large bowel," Dr. Boland said.

The Pediatric Oncology Research Fellowship of the Children's Cancer Association of Japan helped fund the study.

SOURCE: http://bit.ly/2iRQeR9

Gastrointestinal Endosc 2016.