Your cancer

Living with the disease

Colon Cancers

What is it ?

Each year colon cancer, also referred to as colorectal cancer, affects more than 45,000 people in France. (This according to INCA data from 2020.) A common form of cancer, it is the second most likely to occur with women and third most likely with men. Colon cancer occurs overwhelmingly in people aged 50 with an average age of diagnosis in the early 70s. And most importantly, it is a very serious and complex disease, resulting in an estimated 17,000 deaths nationwide in 2018. (9,000 men and 8,000 women).

Colon cancers

Colorectal cancer is an adenocarcinoma (malignant tumor) that develops when the cells that line the colon or the rectum become abnormal and grow out of control. Treatment varies depending on the exact location of the tumor and its molecular status.

Patient Testimonial

André, retired from the SNCF, shares his story about his colon cancer.

Discover his testimony and his impressions in this fight against cancer.

A complex disease with multiple potential interventions

Unlike many other cancers, colon cancer generally responds well to treatment and can often be cured at a metastatic stage. It is vital that the medical team determines the appropriate multi-modal treatment at the onset. This may include drug therapies, surgery, radiotherapy, and/or interventional radiology.

Treatments can be adapted per molecular profile

Colon cancer is a disease that lends itself to molecular profiling. Various molecular and clinical factors influence the prognosis and prescribed treatment. The overall treatment plan will depend on the tumors’ location, histological type and specific molecular characteristics (e.g. status of microsatellites, mutation of the RAS, BRAF, PI3K genes, HER2 expression, etc.) as well the location of any metastases and other factors.

The symptoms

The most common symptoms of colon cancer are changes to digestive and bowel habits and/or an unexplained deterioration of the patient’s general health.

Symptoms can include :

Abdominal pain

Gastrointestinal obstruction

discomfort, cramps, build-up of gas/wind

Bowel issues

such as diarrhea and constipation

The presence of blood in the stool

Unusual and persistent fatigue

Unexplained weight loss

Loss of appetite

A blood test revealing anemia


Colorectal cancer screening can be performed by colonoscopy, which is recommended for patients with a past history of colonic polyposis and/or with a familial history of colorectal cancer.

Diagnostic Process

Computerized Tomography scan (CT or CAT scan) of the chest, abdomen and pelvis.

Computerized Tomography scan (CT or CAT scan) of the chest, abdomen and pelvis.

Magnetic Resonance Imaging (MRI) scan and/or Positron Emission Tomography (PET) scan may be required.

A pathologist may conduct a histological diagnosis,
(analysis of the sample tissues to define the type and histological subtype of the cancer)
and the presence of markers.
Molecular analysis to look for potential predictive mutations.

Molecular analysis to look for potential predictive mutations.

Risk factors

Colon cancer has a multi-factorial origin :
heredity, lifestyle, and exposure to carcinogens are amongst the key considerations.
When considering risk factors, we typically place the patient into one of three groups:

Premièrement, les personnes à risque moyen :
those aged 50 and older who have tested positive
for blood
for blood in the stool

Deuxièmement, les personnes à risque élevé de cancer colorectal : antécédent de polype, de cancer du côlon, ou de parent atteint d’un cancer colorectal avant 65 ans,
de maladie inflammatoire chronique de l’intestin.

People at very high risk of colorectal cancer
e.g those who are carriers of a genetic disease.

High and very high-risk groups should be monitored by a gastroenterologist.

Your physician and/or oncologist will be particularly attentive to the following molecular abnormalities:

  • The instability of microsatellites, which help identify patients who are likely to benefit from immunotherapy treatment
  • Mutations in the RAS gene that would be unlikely to benefit from (contra-indicated) targeted anti-EGFR-type therapies ces maladies)
  • Mutations in the BRAF gene to propose treatment with targeted anti-BRAF therapies

Sometimes an MRI of the rectum or PET / CT scan may be requested.


The specific course of treatment of colorectal cancer is primarily determined by the tumors’ stage and molecular characteristics, specifically:

Localized colon tumors are typically removed surgically. In some cases, the surgery will be accompanied by postoperative chemotherapy.

Localized rectal cancers will more often be treated with radiotherapy alone
Localized rectal cancers will more often be treated with radiotherapy alone or in combination with chemotherapy that is initiated prior to any surgical procedure. Localized colon tumors are typically removed surgically. In some cases, the surgery will be accompanied by postoperative chemotherapy..

Therapeutic alternatives are more complex for metastatic cancers, or tumors that are active and spreading. In such cases, the treatment plan will may consist of surgery on the primary tumor and metastases combined with a chemotherapy regimen. More frequently, treatment will rely heavily on medical treatments such as intravenous chemotherapy, oral chemotherapy, or other more targeted therapies whose administration depends on the genetic characteristics of the tumor. Finally, there exist a small subgroup of patients that can benefit from anti-PD-1 immunotherapy, oftentimes with remarkable results.