Photo Credit: Mohammed Haneefa Nizamudeen

Sanjay K. Murthy, MD, MSc (Epid), talked with Physician’s Weekly about changes in digestive cancer types among patients with IBD as IBD treatment has evolved.

“Cancer risk is always top of mind for patients and clinicians,” Sanjay K. Murthy, MD, MSc (Epid), notes. “Cancer risk in IBD is of special interest because studies have reported higher risks for several cancers in individuals with IBD.”

There have been “major changes to the treatment of IBD over the past two decades,” Dr. Murthy notes, from the introduction and widespread use of new therapies to the adoption of newer strategies, including treating to a target of complete bowel healing as opposed to symptoms alone.

“All of these changes have led to improved IBD control, which should have reduced the risks of intestinal cancers in this population, including colorectal and small bowel cancers,” Dr. Murthy says. “However, the rising use of certain therapies could have simultaneously increased the risks for some cancers outside of the intestines, among organs that are otherwise less impacted by IBD itself. There is a need to study, and continuously update, cancer risks faced by the IBD population, to promote the development of targeted research initiatives and preventative strategies aimed at curtailing cancer risks in this population.”

For a study published in The American Journal of Gastroenterology, Dr. Murthy and colleagues used population-level administrative and cancer registry data to examine the risk for different digestive system cancers in patients with IBD. Physician’s Weekly (PW) spoke with Dr. Murthy to learn more about the findings.

PW: Can you provide a brief overview of the findings?

Sanjay K. Murthy, MD, MSc (Epid): In our population-based study of more than 110,000 individuals with IBD and more than 1.1 million age- and sex-matched individuals without IBD, we observed a comparable steady decline in colorectal cancer rates over 25 years in both populations, but observed marked rises in rates of small bowel, liver, and bile duct cancers and numerical trends toward rising rates of esophageal and stomach cancers among those with IBD, which significantly outpaced trends for these cancers among matched controls over the same period. Overall, while the higher risks for intestinal cancers among those with IBD have been persistent since the early 1990s, the risks for extra-intestinal digestive cancers, collectively, have shifted from being lower among those with IBD in the 1990s to being higher among those with IBD in the 2010s.

How significantly have the patterns changed?

Among those with IBD, between 1994 and 2019, the relative rate of colorectal cancers has been falling by 1.0% to 2.5% per year, while the relative rates of small bowel, liver, bile duct, and pancreatic cancers have been rising by roughly 1.5% to 7.7%, 4.1% to 13.1%, 3.7% to 10.8%, and 1.1% to 4.5% per year, respectively. Compared with matched controls, the collective rates of extra-intestinal digestive system cancer diagnoses among those with IBD has gone from being about half as large in 1994-1999 to 1.3 times higher in 2010-2019.

What is the significance of these findings for clinicians?

Gastroenterologists who treat IBD will need to exercise increased vigilance in screening and preventing small bowel, liver, bile duct, and pancreatic cancers.  How such strategies should be conducted remains uncertain, as it would be neither practical nor cost-effective to universally screen all patients at regular intervals. A risk-based strategy will need to be developed to target screening and prevention to those at higher risk, such as those with long-standing active small bowel inflammation, underlying hepatobiliary or pancreatic diseases, or family history of cancers in these organs, using the most cost-effective approaches. Ancillary preventive strategies, such as reducing modifiable factors that may further promote some of these cancers, should also be part of routine cancer prevention in patients with IBD. The development of such strategies should be the focus of future research and guidelines.

What additional research is needed in this area?

Exploration of the risks of extra-digestive cancers in IBD and preventable or modifiable factors impacting cancer risk is critical to further guide shared decision-making about IBD treatment and cancer prevention in these patients. Such studies should be conducted across multiple jurisdictions globally and updated frequently to understand the risks and risk factors. In particular, the specific contributions of the underlying disease and specific IBD treatments toward cancer risk need to be explored to develop clinically and financially effective strategies for cancer prevention. Furthermore, future research will need to distinguish an actual rise in cancer risks from an apparent rise due to greater detection of existing cancers. Ultimately, developing individualized cancer risk prediction tools, incorporating demographic, clinical, genetic, serologic, and/or microbial factors, would be of major value in offering “smart” strategies that target specific measures to people most likely to benefit from them.