Colorectal cancer should be screened at all costs for early detection. What are polyps?

A colonoscopy makes it possible to detect the possible presence of polyps in the colon and rectum and remove them before they turn into cancer. Because in more than 80% of cases, colorectal cancer comes from a benign tumor – a polyp – which slowly develops and eventually becomes cancer.

Most polyps develop insidiously within the colon and rectum, without any noticeable symptoms to anyone. For this reason, a screening test has been developed: the faecal immunological test (FIT) is able to detect the smallest trace of blood in the stool, which is the most common indicator of the presence of polyps.

If the immunological test is positive, in 4% of cases, a person should undergo a colonoscopy. Some people who have a very high risk of colorectal cancer are sent straight to a colonoscopy without going through the “FIT” box.

Colonoscopy, the “2 in 1” exam

“If polyps are identified during colonoscopy, further operations depend on their size, appearance and number

Dr Bertrand Breau, Head of the “Cancer Screening and Prevention” Commission of the French Society of Digestive Endoscopy (SFED) clarifies. Because in addition to examining the walls of the colon and rectum, colonoscopy allows the removal of polyps or cancer.“The removed polyps are then sent to a laboratory for tissue analysis (histological analysis), to assess the level of risk of developing new polyps and to adapt monitoring.

3 types of colorectal polyps

Polyps are benign growths, comparable to warts, that occur on the inner lining of the colon and rectum. These lesions grow slowly, taking about a decade before becoming cancerous. Three main types of polyps can be distinguished. First, “hyperplastic polyps”, which are benign and never degenerate. Then, “adenomas,” which are the most common polyps, can develop into colon cancer. Finally, there is a new intermediate class known as “scalloped polyp”, and which is also associated with colon cancer. “This latter category of polyps are flat lesions that are more difficult to detectBertrand Breau notes, But recent advances in the use of high definition endoscopes have improved their detection. “

New techniques to remove polyps

In recent years, endoscopic resection techniques for precancerous or early cancerous lesions have replaced the surgical approach to remove large polyps and superficial colorectal cancer. Surgery (we remove the part of the colon where the polyp or cancer is located) is necessary for polyps that have progressed to invasive cancer, meaning cancer that has penetrated deep into the colon wall.

Mucosectomy (removal of part of the lining of the colon wall on which the polyp grows) makes it possible to remove polyps between 10 and 20-25 mm. Beyond this size, or when a polyp is suspected to be cancerous, new techniques such as submucosal dissection are becoming increasingly necessary, which make it possible to remove polyps without size limitations. To understand this new technology, an image is telling: we can compare the wall of the digestive tract to the wall of a house with wallpaper (mucosa), coating (submucosa) and bricks (muscle). In submucosal dissection, fluid is injected into the “plaster” (through the “wallpaper”) to increase the working surface and move away from the bricks to inflate and protect the wallpaper. We can then cut into the submucosal layer to remove the polyp, without perforating the colonic wall.

AI-assisted endoscopy is already tomorrow

“Augmented colonoscopy” using artificial intelligence (AI) is coming to operating theatres. When the gastroenterologist passes his endoscope into the intestine a visual signal (a colored square), with or without an audible signal, appears around the detected polyp. “AI increases the detection rate of adenomas by 10 to 15%Dr. Breau believes. This technology helps the practitioner, potential lesions that may escape the human eye, due to fatigue, difficulty seeing them or for those who are just starting out.“

In addition to identifying polyps, AI is now able to display in real-time the types of polyps detected (so that the gastroenterologist can make an informed decision at that time whether to remove them), to identify other anomalies (ulcerations, vascular lesions). , etc.) and also to verify the quality criteria of endoscopic examinations.