Canadian researchers are putting the finishing touches on new optical technology that will allow better images of the colon and much more precise screening for colorectal cancer.
"It will provide a 360-degree view of the colon – a bit like Google Street View," Dr. Qiyin Fang, Canada Research Chair in Biophotonics at McMaster University in Hamilton, said in an interview. (Biophotonics is the application of physical, chemical and engineering advances to biological and medical challenges.)
Colonoscopy is a test that allows examination of the interior lining of the large intestine to detect polyps and cancerous tumours. The colonoscope is a flexible instrument that is inserted in the rectum and snaked up into the colon; it is equipped with a light and a tiny camera.
The plan is to take that instrument and modify it to provide better images using a rotating camera and a computer program that will create a 3-D map of the colon.
"Colonoscopy is the best method we have of detecting cancer but the problem is that, because the colon folds and stretches, you don't always know where you are and you can miss things," said Dr. David Armstrong, a gastroenterologist and associate professor of medicine at McMaster.
The new colonoscope, which is being developed with an innovation grant from the Canadian Cancer Society, will be equipped with infrared in addition to traditional white light. That will allow precise mapping of the colon, including a view of the surface, and the vessels just below the surface of the intestine.
"We should be able to detect lesions that are otherwise hidden," Armstrong said. But he stressed this still needs to be demonstrated in the real world.
The new camera is now being tested in animals, and researchers are seeking approval for human trials, where they will compare results with those of traditional colonoscopes.
"We hope this will be available to patients in two to three years" said Fang, who is also an associate professor of engineering physics at McMaster.
Fang and his team received a $194,000 grant from the Cancer Society to develop and test the new imaging technology, part of $7-million in new funding awarded to Canadian researchers on Monday.
Armstrong said the new technology would not result in any change in the procedure for patients, but more precise images could reduce the need for repeat colonoscopies.
"The better we can see the image, the better we can distinguish between benign and cancerous polyps," he said.
Colorectal cancer is the second most deadly form of cancer after lung cancer. Last year, an estimated 23,300 Canadians were diagnosed with colorectal cancer and 9,200 died of it.
The Canadian Cancer Society recommends that men and women age 50 and over be screened every two years. This is a two-step procedure. The first step is a simple stool test (fecal occult blood test or fecal immunochemical test). If blood or certain immune markers are detected in the stool, then a follow-up test is recommended, which can consist of a colonoscopy, a double contrast barium enema (an X-ray of the large intestine), or flexible sigmoidoscopy. However, some physicans recommended being screened directly with a colonoscopy, especially if there is a family history of colorectal cancer.
André Picard