Your cancer

Living with the disease

Colon Cancers

What is it ?

Each year, colon cancers, also referred to as colorectal cancer,
affects more than 100,000 people in the United States.
A common form of cancer, it is the third most likely cancer :
the third 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 52,000 deaths nationwide in 2020. (28,000 men and 24,000 women).

Colon cancers

Colon cancer is an adenocarcinoma that develops to the detriment
of the cells in the colonic lining. 
This disease, defined by its location
modifies both the support (right colon, left colon, rectum)
and the molecular status of the tumor.

A complex disease with multiple potential interventions

Unlike many other cancers, colon cancer responds well and can often be cured at a metastatic stage when the right multi-modal treatment executed effectively: e.g. drug therapies, surgery and/or radiotherapy, interventional radiology. The correct initial treatment by an expert medical team can result in the ideal outcome for the patient and the care team.

A disease requiring molecular profiling to adapt treatment

Colon cancer is a disease that lends itself to molecular profiling to inform the treatment plan: The proper perspective is to think not of colon cancer but of colon cancers. The various molecular and clinical factors not only influence the prognosis but also the quality of the response to treatment. Thus, the complete therapeutic strategy will depend on location of the tumor (right colon or left colon), histological type, location of any metastases, the specific molecular characteristics of the tumor (e.g. status of microsatellites, mutation of the RAS, BRAF, PI3K genes, HER2 expression, etc.), and other factors only now being discovered and understood.


The most common symptoms of colon cancer to look for are changes in the digestive and bowel habits of the patient and an unexplained deterioration in the general condition of the patient. 

Symptoms can include :

Abdominal pain

Gastrointestinal obstruction

discomfort, cramps, build-up of gas

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


Today, in France, organized screening is available that tests for blood in the stool.
This simple screening option can be conducted every 2 years
from 50 to 70 years as a simple way to ensure early detection. Colorectal cancer screening can also be performed by colonoscopy, in patients with a familial history of colorectal cancers, or in patient with a past history of colonic polyposis.

Diagnostic Process

Diagnosis of colon cancer is primarily based on a colonoscopy, and usually performed under general anesthesia. 
The procedure, combined with sample testing, can confirm the presence
of a tumor, its location and the level of disease progression.
For a more intensive diagnosis, the characteristics of the cancer will be further confirmed through various other examinations and techniques :

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, analyzing
the sample tissues to define the type
and histological subtype of the cancer
and the presence of markers that will inform the treatment plan.
Molecular analysis to look for potential
predictive mutations.

Risk factors

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

People at medium risk :
age over 50 years for whom
a national screening by testing for blood
in the stool is presented.
People at higher risk of colorectal cancer: e.g. past history of polyps, colon cancer, or a parent with colorectal cancer before age 65,
chronic inflammatory bowel disease.
People at very high risk
of colorectal cancer :
e.g. carriers of a genetic disease making
them predisposed to colon cancer.

Notably, the second and third categories above warrant special monitoring by a gastroenterologist.

Molecular abnormalities that your physician or oncologist will be particularly attentive to include :

  • Investigation of the instability of microsatellites, which will help identify patients
    likely to benefit from treatment with immunotherapy
  • Search for mutations in the RAS gene that would be unlikely to benefit from
    (contra-indicated) targeted anti-EGFR-type therapies 
  • Search for 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 stage and molecular characteristics of tumors. Specifically :
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.

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.