Colon cancer: symptoms, diagnosis, treatment

SUMMARY :

Colon cancer: what symptoms?
Colon cancer: how to do the screening test?
Colon cancer: how is the diagnosis made?
Colon cancer: what risk factors?
Colon cancer: what are the treatments?
Colon cancer: what life expectancy?

THE colon cancer or colorectal cancer is is a malignant tumor of the mucosa, colon and rectum. It is one of the cancers with the best prognosis: it is cured in 90% of cases when caught in time. It is moreover to ensure that it is detected early enough that people aged 50 to 74 are invited every two years to participate in organized screeningeven if they have no symptoms or associated risk factors. Because, in 95% of cases, colorectal cancer affects people over 50 years old. Besides age, being overweight and being sedentary are two other risk factors for colon cancer.

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Colon cancer: what symptoms?

Colon cancer grows over many years, mostly from benign tumors (called polyps) that grow on the inside lining of the colon and rectum. We talk about cancer in situ. Over time, if left undetected, the tumor spreads deeper inside the wall. This is called invasive cancer.

The symptoms that should alert are the following:

Blood in the stool (hematochezia) or dark red stools.
A change in abdominal transit that persists (unusual constipation or diarrhea)
Mucus in the stool
Unusual abdominal pain
Difficulty having a bowel movement
Unexplained anemia.

>> If in doubt, consult a gastroenterologist.

Colon cancer: how to do the screening test?

Every two years, people aged 50 to 74 receive a letter inviting them to take part in organized screening for colon cancer. Until now, this invitation had to be given to the general practitioner who checked that the patient was not at particular risk before giving him immunological test for screening. But since March 2022, eligible people who have received this invitation can also go to the website monkit.depistagecolorectal.fr with the number appearing on the invitation letter. A questionnaire determines whether the test is appropriate based on the person’s personal and family history. If so, the test is sent to him. This stool-hidden blood test is quick and effective. The test is to be done at home, then sent free of charge to the laboratory for analysis.

This screening is particularly important: the earlier it is detected, the lighter the treatments and the greater the chances of recovery. Detected early, colorectal cancer is cured in 9 out of 10 cases.

Colon cancer: how is the diagnosis made?

After performing the immunological test, the results are available on another website: result-depistage.fr.

>> The test is negative (which happens in 96% of cases): no abnormal presence of pre-cancerous lesion or tumor was detected. You will be asked to take the test again in two years.

>> The test is positive : blood was detected in the stool. This does not necessarily mean that you have cancer, but it should be do a colonoscopy. It makes it possible to diagnose colorectal cancer at an early stage, or even to avoid cancer by highlighting polyps or adenomas, before they degenerate into cancerous lesions. They will then be removed during the colonoscopy.

Colon cancer: what risk factors?

Who is affected by colorectal cancer? There are three risk factors: medium, high and very high.

A medium risk that’s a 4% risk of developing colon cancer. These are people with no symptoms or personal or family history of colorectal cancer or advanced colonic adenoma (polyp > 1 cm) or inflammatory colon disease. Overall, 75-80% of colon cancers occur in people at “average” risk.
The risk is high in case of family history before the age of 65 and/or personal polyp or colorectal. The individual risk increases and becomes very high with the number of cases and their proximity (first degree relatives). About 15-20% of colorectal cancers occur in people at high risk and 5% in those at very high risk
“Some people are even classified as ‘very high risk’ : they have up to 100% risk in familial adenomatous polyposis (a hereditary condition caused by a genetic mutation in the APC and MYH genes) and 80% in Lynch syndrome (hereditary non polyposis colorectal cancer or HNPCC)” adds the French National Society of Gastroenterology.

>> The risk factors on which we can intervene : overweight and a fortiori obesity promote colon cancer through systemic inflammation generated by adipose tissue (fat) via pro-inflammatory substances, growth factors and estrogens. Physical inactivity is also a risk factor for colorectal cancer. Finally, the deleterious role of red meat and cold meats is consolidated according to the INCa, with a quarter of the population exposed to the risk of colorectal cancer described as “convincing” when they consume more than 500g of red meat/week and/or more 50g of charcuterie/day.

Colon cancer: what are the treatments?

In general, this cancer is cured well, if detected early. A CT scan (computed tomography) of the chest, abdomen and pelvic region is used to assess its extent in order to develop an appropriate treatment plan. When the tumor is located in the rectum, an MRI can determine if the tumor has spread to nearby organs (bladder, prostate, uterus) and if the lymph nodes located in the fat that surrounds the colon or rectum are affected by cancer cells, which would promote their dissemination.

If the tumors are small (diameter less than 2-3 cm) and that they are superficial (at the level of the colon and rectum mucosa) the treatment consists in removing the tumors by means of the endoscope. If the polyp is too largethe part of the colon where the tumor is located is surgically removed. If lymph nodes are affectedadjuvant (postoperative) chemotherapy is proposed.

Colon cancer: what life expectancy?

When detected at an early stage (stage 0 and I), this cancer has a good prognosis and achieves a 90% overall survival rate at 5 years. But this rate is only 13% when detected at a metastatic stage (stage IV).

The stages of colorectal cancer:

Stage 0 : Iance cells are found only in the inner lining (mucosa) of the colon or rectum.
Stage 1 : Ihe tumor has grown into the layer of connective tissue that surrounds the lining or thick outer muscle layer of the colon or rectum.
Stage 2 : the tumor has invaded the layer of tissue between the muscularis and the serosa or the tissues beyond the muscularis (stage 2A); it has crossed the membrane that covers and supports the colon and rectum (stage 2B); it has traveled through the wall of the colon or rectum to other organs or areas of the body, such as the bladder, prostate, or uterus (stage 2C).
Stage 3 😮n see cancer cells in the lymph nodes near the colon or rectum.
Stage 4 : IThe cancer has spread to other parts of the body (distant metastases), such as the liver or lungs. He can too may have reached the peritoneum (stage 4C).