Neeraj Narula, MD, on How Periodic Colonscopies Improve CRC Survival in Patients With UC

In this podcast, Dr Narula, from McMaster University in Toronto, discusses how 2 patients with ulcerative colitis (UC) who developed advanced colorectal cancer led him to conduct research into the prognostic value of regular colonoscopy among patients with UC.

Neeraj Narula, MD, is director of the Inflammatory Bowel Disease Center at McMaster University in Hamilton, Ontario.

TRANSCRIPT

GASTROENTEROLOGY LEARNING NETWORK:  Hello and welcome to another podcast in the Gastroenterology Learning Network. I'm your moderator, Angelique Platas, and today, I'll be speaking with Dr. Narula. Hello, Dr. Narula. Thank you so much for joining us today.

Dr. Neeraj Narula:  Thanks for the invitation, Angelique. My name is Neeraj Narula. I'm a gastroenterologist based out of McMaster University in Hamilton, Ontario, Canada. My main clinical and research interests are in inflammatory bowel disease.

GLN:  How much greater is the risk of colorectal cancer among patients with ulcerative colitis (UC) than among the general population?

Dr. Narula:  At one point, it was felt to be approximately 50 percent higher than the baseline general population, although studies in the last decade have not demonstrated similarly elevated risk. I suspect that this is probably due to more frequent surveillance in these patients over the past decade, which has lowered their chance of development of colorectal cancer.

GLN:  Could you give us a brief overview of your objectives, the data you retrieved and how you measured low risk versus high risk and colonoscopy intervals?

Dr. Narula:  Absolutely. First, I'll tell you about what inspired me to do this. This was inspired by two patients I saw within one week who basically had the exact same story. Long-standing ulcerative colitis, they had not had a colonoscopy in more than 10 years, even though they were eligible for surveillance.

Both presented with advanced colorectal cancer at an advanced stage. I thought to myself, "If only someone would have scoped this patient 5 years ago, then we likely could have prevented this poor outcome."

In this study, we looked at patients with ulcerative colitis who did develop colorectal cancer and I wanted to compare the outcomes of those who had more frequent colonoscopies prior to their diagnosis of colorectal cancer compared to those who had less frequent colonoscopy or no colonoscopy surveillance at all.

We did this using administrative data from Ontario billing claims, which is part of the provincial health insurance plan in Ontario. Colorectal cancer stages were divided into low and high risk based on the 5-year survival data provided by the American Joint Committee on Cancer.

For the purposes of our analysis, we defined low-risk colorectal cancer as any stage of cancer with a 5-year survival rate of at least 80% and high-risk being that had a five-year survival rate of less than 80%.

With regards to colonoscopy interval, the real main objective of this study from a power standpoint was to compare those who had colonoscopies prior to catch a diagnosis versus not.

We did do subanalysis looking at follow-up scopes every three years or less compared to less frequent than that, as most guidelines in North America do suggest surveillance colonoscopy should be conducted every one to three years in these patients.

GLN:  It's well known that patients with UC are at increased risk for colorectal cancer, what factors would contribute to these patients not receiving any follow-up colonoscopies or having them at more frequent intervals?

Dr. Narula:  We cannot definitively say this based on our study, as that was not the purpose of our study. I suspect it's factors such as patients not being aware of this risk and, as a result, not seeking care, or it could be having less access to health care due to socio-economic reasons or rural location.

GLN:  What did your results tell you about the outcomes among patients with UC who developed colorectal cancer?

Dr. Narula:  In short, we found that those who had follow-up colonoscopies prior to their diagnosis were more likely to be discovered at an earlier stage of colorectal cancer than those who did not. Further, there was mortality benefit demonstrated in those who had more frequent colonoscopies prior to colorectal cancer diagnosis compared to those who did not.

GLN:  Did you draw any conclusions about how often patients with UC should receive screening colonoscopies?

Dr. Narula:  In our study, we showed that the 15-year mortality rate was 17% in those who had colonoscopy at average intervals of less than or equal to every 3 years, which was lower than the 22.1% observed in patients with less frequent colonoscopy or 27% in those who had no follow-up colonoscopies prior to their diagnosis.

Based on this, I will support the current practice in North America to offer surveillance colonoscopies to ulcerative colitis patients at an interval of at least every 3 years, if not more frequent once they've had their disease for at least 8 years.

GLN:  What advice do you have for gastroenterologists whose patients may resist regular screening? How can they help overcome the hesitation?

Dr. Narula:  The data from our study can help support these discussions. Certainly, we all come across these types of patients. From my experience, the patients I come across who resist screening, they tend to focus on things like the inconvenience of taking a bowel preparation or taking a day off work, for example.

When you educate these patients about the risk of cancer and that there does appear to be benefit associated with periodic colonoscopy from a monitoring standpoint, and that might even confer some mortality benefit, it will help patients realize that it's a worthwhile endeavor to engage in colonoscopy surveillance once they're eligible.

GLN:  Thank you. As we wrap up here, do you have any final words you'd like to share with our audience about your study?

Dr. Narula:  This is mainly observational data. Certainly, there can be other factors that can confound the results we find. The person who has more frequent colonoscopy, that might be someone who's otherwise taking in other health-promoting or healthier behaviors, like more conscious of their diet and more cautious with other screening, for example.

That could be a reason why you see improved mortality benefit in these types of patients. You have to always take these with a grain of salt. We won't be ultimately 100% convinced unless you have a high-quality randomized control trial that basically probably needs thousands of patients in order to clearly demonstrate their mortality benefit when it comes to this indication.

GLN:  Thank you, Dr. Narula, so much for sitting down with us and taking the time to answer a few questions today.

Dr. Narula:  OK. My pleasure. Thanks for inviting me.

Reference

Narula N, Hu A, Nguyen GC et al. Periodic colonoscopies are associated with improved survival and prognosis of colorectal cancer in ulcerative colitis. Dig Dis Sci (2021). https://doi.org/10.1007/s10620-021-07151-7