“It’s every 2 years!” : Blue Mars starts today, we explain how colorectal cancer screening works

Dépistage du cancer colorectal, c’est en mars mais aussi toute l’année

Mars bleu est là pour nous le rappeler chaque année : entre 50 et 74 ans, pour la majorité de la population, un test immunologique rapide, simple et gratuit est à réaliser à son domicile, tous les deux ans. Il permet de prévenir 90 % des cancers du côlon et du rectum.

Details from Dr Bertrand Brieau, head of the "Cancer screening and prevention" of the French Society of Digestive Endoscopy (SFED).

Each year, health authorities mark the occasion with Blue Mars, reminding on this occasion that from the age of 50, colorectal cancer screening concerns us all.

"Screening for colorectal cancer, from the age of 50, is every 2 years!"

This teaser of the new mobilization campaign of the National Cancer Institute (INCa) is accompanied by a TV spot where we see the protagonist leaving his own birthday party for his 50th birthday. It’s for a good cause: he slips away to take his colorectal cancer test, leaving his guests first taken aback then understanding. A light way to approach a serious subject.

"Screening for colon cancer is important for two reasons, underlines Dr. Bertrand Brieau. On the one hand because it is the second cause of death by cancer in France (47,000 people affected and 17,100 deaths) and, on the other hand, because unlike other types of cancer such as breast cancer, colon cancer is preventable, mainly due to the presence of precancerous lesions in the form of polyps, at a stage where there is still time to intervene. In more than 80% of cases, it comes from a benign tumor (the polyp) which evolves slowly and eventually becomes cancerous."

Prevention and early detection means cure

When it comes to colorectal cancer, prevention and early detection means cure: 90% of these cancers are cured when detected at an early stage . This is why, from the age of 50 and up to 74, people classified as “medium risk”, i.e. the majority of the population, are invited every two years by Health Insurance to carry out a free fecal immunological test (FIT).

In addition to being simple (2 minutes) and accessible, this immunological test which detects the slightest trace of blood in the stools is "reliable, insists Bertrand Brieau, that is to say, it returns very few ‘false negatives’. We speak of a false negative when a cancer is not detected even though it is indeed present."

For the "high risk" population, a colonoscopy rather than an FIT

The population classified as "at high risk" colorectal cancer requires special monitoring and the systematic provision of a preventive colonoscopy at regular intervals. The risk is high when the person has a first-degree relative with colorectal cancer or an adenomatous polyp regardless of age, or when there are several 2nd or 3rd degree relatives who have had colorectal cancer. "Around 20% of colorectal cancers occur in people at high risk, specifies the gastroenterologist, and 5 to 10% in those whose risk is very high. People at high risk have about a one in ten risk of developing colorectal cancer."

Less than 35% of the population concerned take the test

Of the 17.7 million people eligible for the immunological test, 6.1 million completed a FIT in 2021-2022, i.e. a participation rate of 34.4% (34.6% in 2020-2021). We are still a long way from the 65% participation rate set by the ten-year strategy to combat cancer, which would prevent 5,700 colorectal cancers and 6,600 deaths each year. "It is necessary to reach at least 45% participation to observe a significant impact on mortality linked to colon cancer, adds Bertrand Brieau. With an efficient strategy and widespread participation in colon cancer screening, we could almost eradicate it in France."

‍FIT in practice

"You should know that only 4% of these FIT tests come back positive, reassures Bertrand Brieau, of which 6-7% are cancers and more than 45% of polyps can degenerate into cancer." Within 15 days, the result is communicated to the interested party as well as to their attending physician. If the test is positive, the latter will contact their patient and refer them to a gastroenterologist for a colonoscopy. The making of a colonoscopy makes it possible to detect the possible presence of polyps and to remove them during the same procedure before they transform into cancer.

Women and men aged 50 to 74 affected by organized colorectal cancer screening are invited by Health Insurance. Since January 2024, the first reminder and the second reminder (when it does not include a collection kit) have been dematerialized and deposited in the Ameli account of eligible people. The methods for receiving results by patients are also changing: a link is sent to them by SMS, provided that they have entered their telephone number on the identification form. Otherwise, they will receive their results by mail.

It is also possible to order a kit for free, online at monkit.depistage-colorectal.fr, in a pharmacy, or during a consultation with your doctor (general practitioner, gastroenterologist, gynecologist and doctor at a health examination center).

To find out more:

The tutorial from the National Cancer Institute for carrying out the test can be viewed here.

The Colon Tour® 2024, by the League against cancer

Information on colorectal cancer, from the National Cancer Institute