Colon cancer: Improving polyp detection to prevent cancer and save lives

Dr. Ian Epstein and Dr. Donald MacIntosh use colonoscopy to detect and remove polyps (clumps of pre-cancerous cells).
Dr. Ian Epstein and Dr. Donald MacIntosh use colonoscopy to detect and remove polyps (clumps of pre-cancerous cells).

Although colon cancer is not in the spotlight like breast and prostate cancer, it is the second-most common cancer in Nova Scotia in both women and men. And, rates are higher in Atlantic Canada than the rest of the country.

“The key to reducing the risk of colon cancer is to find and completely remove all polyps, which are clumps of precancerous cells,” said Dr. Donald MacIntosh, gastroenterologist with Nova Scotia Health Authorty (NSHA) and head of the Nova Scotia Colon Cancer Screening Program. “If you don’t find the polyps, or if any part of a polyp is left behind in a colonoscopy, the patient is at risk of developing cancer. That’s why we are rigourously collecting and analyzing data about how well our specialists are performing colonoscopies in the province.”

Results of these quality assurance studies — conducted in part by gastroenterology resident Dr. Matt Miles — are used to identify where clinicians need further training to perfect their skills.

Nova Scotia launched province-wide colon cancer screening in 2009, collecting stool samples from citizens aged 50 to 74. If any traces of blood are found in the sample, the person is called in for a colonoscopy.

“About 10 per cent of people screened will require a scope and polyps will be found and removed in about 60 per cent,” noted Dr. MacIntosh. “About one per cent of people with a positive test will have bowel (or colon) cancer.”

When cancer is found, the cure rate is 85 to 95 per cent if it’s removed before it has spread. Once metastasized, cure rates for colon cancer plummet to 10 or 15 per cent.

“The quality of the procedure is of paramount importance,” said Dr. MacIntosh. “That includes how patients are advised to prepare for their colonoscopy.”

There is currently no national standard for bowel preparation for colonoscopy. NSHA gastroenterologist Dr. Ian Epstein is leading the Nova Scotia arm of the national B-Clean study, comparing different regimens to see which lead to the highest polyp-detection rates.

“We really need to be able to advise our patients as to how much fluid to consume, whether or not to fast, and what laxative formula they should use,” said Dr. Epstein. “We enrolled 300 patients in this study and will work with our colleagues across Canada to translate our findings into clinical practice guidelines.”

Nova Scotia is poised to expand its research in the realm of colon cancer screening, detection, and early intervention.

“We’re building a comprehensive database,” said Dr. MacIntosh. “There are a lot of questions to be asked and answered and we can lead the country in this.”