Caring for you as we would for ourselves

Colon cancer and colorectal cancer

The colon, or large intestine, is the end portion of the digestive tract. Its function is to absorb water and certain vitamins while moving stools toward the anus. Colon cancer most often develops in the end part of the colon, the rectum, where stool is stored prior to being evacuated. That is why we generally talk about colon cancer or colorectal cancer and sometimes intestinal cancer.

The colon and the rectum are part of the large intestine, which, along with the small intestine, stomach, esophagus, and mouth, make up the digestive system.
The colon is the longest part of the large intestine. It is basically divided into four parts:

  • the ascending colon, on the right side of the abdomen;
  • the transverse colon, passing through the upper part of the abdomen;
  • the descending colon, on the left side of the abdomen;
  • and lastly, the sigmoid colon, connected to the rectum.

Symptoms of Colorectal Cancer

In the early stages, namely when the tumor is still very small, you might not notice any particular symptoms. The symptoms of colon cancer appear after a period that may be quite long and depends on the progression of the disease. These symptoms can include:

  • disturbances in the intestinal transit (diarrhea, constipation, or both in alternation),
  • feeling like you need to pass a bowel movement when in fact you don't,
  • persistent and unexplained abdominal pain, potentially accompanied by bloating,
  • sudden weight loss and stools that are bloody or black (indicating the presence of blood),
  • or traces of mucus in the stools.


Causes of Colon Cancer

Colon cancer is caused by a change in the behavior and method of growth of certain cells. This long process starts with a change to the DNA of these cells, which then become cancerous and proliferate in an anarchic manner within the organ. They can then spread to neighboring tissue and form secondary tumors (metastases*A tumor formed from cancerous cells that have become detached from the first tumor (primary tumor) and moved to a different part of the body where they have taken root.) in other areas of the body.

Not all cellular modifications that affect the colon develop into a cancerous tumor. They can cause benign tumors*A mass of non-cancerous cells that develops locally without producing metastases., known as polyps, or pre-cancerous tumors*A mass of abnormal cells that can transform into cancer if not properly treated. which require treatment to stop them becoming malignant*A mass of cancerous cells that can cause metastases if not properly treated..


Risk Factors for Colon Cancer

Certain hereditary intestinal conditions (for example polyps), a family history of colorectal cancer (one or several cases among close family members), and chronic inflammatory conditions of the intestine such as ulcerative colitis*A chronic inflammatory disease of the colon and rectum. or Crohn's disease*A chronic inflammatory disease that can affect all segments of the digestive tract, in particular the ileum, colon, and anus. constitute risk factors for colorectal cancer. A low-fiber diet, consuming large amounts of red and/or processed meats (cured meats for example), being overweight, a lack of physical activity, smoking, and alcohol can also be at fault.

People are normally over the age of 50 when they are diagnosed with colon cancer, and the risk increases with age. At the time of diagnosis, 37% of patients are aged between 50 and 69, and 55% are 70 or older. It is also more common in men than in women.

Treating Colorectal Cancer

Several factors determine the choice of treatment strategy. In addition to the location, type, size, spread, and stage of evolution of the tumor, the patient's opinions and personal preferences in terms of their care are at the heart of the decision-making process.
The main treatment options are surgery, medication, and radiotherapy*A medical treatment that uses radiation to destroy cancer cells and block their ability to multiply..

There are several different kinds of procedure for operating on a tumor by removing part of the intestine. Anti-cancer drugs, referred to as cytotoxic drugs, are used in chemotherapy*A drug treatment that targets cancer cells.. This is normally a systemic type of treatment, which means that the active substances in the medication destroy cancerous cells, including those that could have spread outside of the colon or rectum, by circulating in the blood. However, chemotherapy can also be limited to a specific area of the body. In addition, it can be combined with radiotherapy, a technique that uses rays or high-energy particles to destroy cancerous cells. This is known as chemoradiation.

Sometimes a targeted treatment is required, potentially combined with chemotherapy. This involves prescribing molecules that specifically target the cancerous cells by sending them signals to tell them to stop growing or dividing.

Progression and Possible Complications

Cancer of the colon or rectum can spread beyond the organ it first appeared in. We talk about different stages of cancer, depending on severity. Cancer is also referred to as localized, regional, or distant (when secondary tumors, or metastases, are formed elsewhere in the body).

When colorectal cancer spreads, it can affect the lymph nodes*Small glands involved in the immune defenses located in different parts of the body. The nodes can become swollen if there is a large amount of bacteria, virus, or other cancerous cells in the body. (first the closest, and then the furthest away), the tissues of the abdomen or pelvis, the peritoneum*A smooth membrane that lines the viscera, abdominal wall, and lesser pelvis that keeps the organs within the abdominal cavity., the kidneys, the adrenal glands*Glands located within the abdomen and involved in hormone production (cortisol, aldosterone, androgens, adrenaline, and noradrenaline)., the liver, the lungs, and so on.

Preventing Colorectal Cancer

It is important to lead a healthy lifestyle, the cornerstones of which are regular exercise, eating healthily, refraining from smoking, and limiting alcohol consumption. In terms of diet, this means eating lots of fiber (for example fruit, vegetables, and whole grains), while limiting consumption of red meat and animal fats.

Fiber contributes to increasing stool volume and accelerating the transit of food through the colon (the intestinal transit), and also keeps the digestive system functioning well.

The benefits of exercise for preventing colorectal cancer are irrefutable. Inversely, living a sedentary lifestyle is associated with an increased risk of developing the disease. Colorectal cancer affects people who are overweight or obese more regularly.

After the age of 50, regular screening for intestinal cancer is recommended. Since July 1, 2013, health insurance providers in Switzerland have covered the cost of this screening for people aged between 50 and 69. This involves testing for blood in the stools or a visual examination of the colon using a flexible probe (colonoscopy).


When Should You Contact the Doctor?

As colon cancer generally progresses slowly from precancerous lesions, people who are at an average risk (the general population who are asymptomatic and aged under 50) are advised to undergo screening, and people who have a high risk (for example people with a personal or family history of the disease) are advised to undergo additional medical monitoring.
The following signs and symptoms warrant medical attention:


  • unexplained and persistent diarrhea or constipation, or both in alternation,
  • persistent abdominal cramps and flatulence,
  • changes in the color of stools due to the presence of blood,
  • bleeding from the rectum and/or pain in the rectum or abdomen,
  • the appearance of a mass in the abdomen or rectum,
  • the feeling of not having fully emptied your bowels after a bowel movement,
  • a sudden loss of appetite and/or weight,
  • a blockage in the intestines (occlusion),    
  • jaundice.

Care at Hôpital de La Tour

If colon cancer is suspected, the first step is as follows:

  • a clinical assessment including the patient's medical history including a summary of symptoms, previous health issues, and risk factors,
  • a physical examination including palpation of the abdomen and potentially a digital rectal exam,
  • a blood test to detect any chronic internal bleeding in the colon or rectum,
  • stool tests can also be performed.

A colonoscopy*A visual examination of the colon performed using a probe to highlight any lesions. is the reference technique for diagnosing or ruling out colon cancer. It is used to view the inside of the intestines by inserting a flexible probe equipped with a miniature camera (endoscope) into the anus. Tissue samples can be taken at the same time for analysis. This biopsy will be used to work out whether cancer is present.

If necessary, additional medical imaging examinations can be performed (for example. ultrasound*A medical imaging technique that uses ultrasound to “see” the inside of the body., MRI*A medical imaging technique used to obtain 2D or 3D images of the inside of the body., computed tomography*A medical imaging technique used to obtain a 3D reconstruction of the different organs of the body., or positron emission [tomography*|A medical imaging technique used to reconstruct an object using a series of images.).

Multidisciplinary and Highly Specialized Care

Hôpital de La Tour offers multidisciplinary care highly specialized in colorectal cancer thanks to our comprehensive, state-of-the-art facilities and on-site specialists with the necessary expertise. To ensure every patient affected by this disease receives the best possible treatment, a multidisciplinary Tumor Board meets each week bringing together specialists from different disciplines. This gives specialists the chance to discuss treatment options, validate a protocol taking into account all opinions, and then put in place optimum monitoring. 


The number

In industrialized countries, colorectal cancer is the number three cancer in terms of prevalence and number two in terms of mortality. Every year in Switzerland, there are some 4000 new cases and 1600 deaths, which represent over 10% of cancers.

Did you know ?

A diet rich in red meat increases the risk of colorectal cancer. In addition, cooking meat at high temperatures (typically, grilling) releases chemical molecules that are carcinogenic, meaning they can cause cancer. These substances, called heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH) are, in fact, linked to an increased risk of developing colorectal cancer.

Who should I see about these symptoms?

We recommend that you see the following health professional(s) :