Dr. Darren Brenner is a cancer epidemiologist with the University of Calgary’s Cumming School of Medicine. He breaks down how big data and precision screening initiatives are leading to dramatic drops in colorectal cancer diagnoses and deaths.
By: Sean P. Young
As a cancer epidemiologist, Dr. Darren Brenner describes his work as “using data analysis to understand the who, what, when, why and how of cancer risks and trends in screening.” While colorectal cancer is the third most common cancer diagnosis in Canada, it’s also had the fastest decline in the rate of new diagnoses in the country. Much of this improvement, Brenner says, can be attributed to targeted, population-based screening; high-risk screening (where a screening test is offered to targeted groups of high-risk individuals); and advancements in testing technology.
Q: Can you discuss the importance of population-based screening for colorectal cancer?
“I co-chair the Canadian Cancer Statistics Advisory Committee and we estimate that, this year, about 24,100 people in Canada will be diagnosed with colorectal cancer. But the good news is this is a massive improvement from where we used to be. Since the late ’80s, when the first rudimentary endoscopy-based screening became available, we’ve seen a 25 per cent reduction in the rates of people being diagnosed with colorectal cancer and about a 35 per cent reduction in the rates of people dying from colorectal cancer in Canada. These dramatic reductions are the direct consequence of population-based cancer screening, like we have here in Alberta.”
Q: How does more screening lead to a reduction of diagnoses?
“Screening for colorectal cancer is interesting because you catch the cancers early, offering better treatments and better outcomes. These tests can also detect polyps [small growths which can sometimes become cancerous]. These can be removed at the time of colonoscopy and that removal basically stops that pathway to cancer, as those polyps may have eventually become cancerous.”
Q: How has the screening technology improved to help keep those numbers dropping?
“It used to be that a colonoscopy was the primary screening test. But they’re invasive, they’re costly and they have potential consequences. So, for the average-risk person — meaning you don’t have regular symptoms and you don’t have a family history of colon cancer — you’re able to get a fecal immunochemical test (FIT) kit sent to you, which makes it easier to get more people screened quickly. It’s a test that looks for blood in your stool that’s so minor you can’t see it. It’s an amazing test because you can do it at home and send it away. If the test identifies blood in your stool, then you’ll have a follow-up colonoscopy to make sure that blood isn’t caused by cancer.”
Q: You mentioned regular symptoms. What are potential signs of colorectal cancer to look out for?
“Large amounts of rectal bleeding. A change in your bowel habits that would be continual over time, such as narrow or ribbon-like stools, which could mean that there’s a potential blockage. Also, frequent diarrhoea or constipation, consistent pain in your abdomen and losing weight. If you experience any of those, you should follow up with your health-care professional right away.”
Q: What is your hope for the future of population-based screening?
“The impact of artificial intelligence [AI] and machine learning is being seen across all different areas of research in colorectal cancer screening. It’s using big population-level data sets to understand what increases people’s risk of cancer, who to screen, how best to screen them and who had the best treatment outcomes after treatment. There is also exciting research underway that uses biological markers to improve screening and treatment. These new tests and measures generate enormous amounts of data that would be impossible to process with traditional approaches. The application of AI is making these improvements possible.
“The data suggest that we can get more people across all segments of the population to go for screening. The data also suggest that we can further drop those rates of incidence and mortality from colorectal cancer. Tools and resources like ScreeningForLife.ca can help make getting screened an easy option. Most importantly, you can also actually begin the process of ordering a FIT kit to your house if you don’t have a family physician.”