Bowel cancer, colon cancer

Colon cancer is one of the most common types of cancer.


Colon cancer is one of the most common types of cancer. The malignant tumour (carcinoma) is formed in the inner lining of the intestinal tract (intestinal mucosa), from where it spreads to other tissues. The risk of developing bowel cancer is increased by an unhealthy lifestyle and pre-existing bowel diseases, among other things. Changes in the stool, whereby stool colour can change to red or black, are an important symptom.


  • There are almost no specific early symptoms
  • Sometimes anaemia occurs, without any digestive problems
  • Bowel movements: bloody, possibly black or slimy stools
  • Constipation alternating with diarrhoea, bloating or very narrow stools (“pencil-thin stool”)
  • Cramping pains, bloating and increasing abdominal girth
  • General symptoms of a tumour: anaemia with paleness, fatigue, drop in performance, weight loss

Causes and treatment


The exact cause has not been determined. Risk factors include:

  • Age: 90% of all patients are over 50
  • Adverse living conditions and dietary habits
  • Obesity
  • Long-standing nicotine and alcohol abuse
  • Lack of exercise
  • Intestinal polyps
  • Chronic inflammatory bowel diseases
  • Genetic factors
  • First-degree relative has/had colorectal cancer (higher risk based on family history)
  • Congenital intestinal polyps
  • HNPCC= hereditary nonpolyposis colorectal cancer

Further treatment by your doctor / in hospital

Possible tests
  • Physical examination
  • Stool analysis (search for blood)
  • Imaging procedures
    • Colonoscopy with removal of tissue samples (biopsy) for microscopic evaluation
    • Ultrasound
    • CT scan (computed tomography), if necessary
Possible therapies
  • Operation
  • Removal of tumour
  • Removal of all regional metastases (in lymph nodes), if possible
  • Fitting of temporary or permanent artificial bowel outlet (stoma)
  • Chemotherapy or radiation

What can I do myself?

  • High-fibre, low-fat/low-meat and varied diet
  • Avoid excess weight, lack of exercise, alcohol and nicotine
  • Go for recommended preventive examinations (especially if personal risk factors are high)
  • Don’t ignore your body’s warning signals

Get a personal Preventive Care Recommendation now.

When to see a doctor?

  • Digestive disorders
  • Changes in the stool
  • Constant constipation (possibly alternating with diarrhoea)
  • Stool is pencil-thin
  • Blood in stools, water in toilet is stained red
  • Black or red stools
  • Fever, weight loss, drop in performance

Further information

Krebsliga Schweiz (Swiss Cancer League)

Selbsthilfe Schweiz (Self-Help Support Switzerland)


bowel cancer, colon cancer, colon carcinoma, rectal carcinoma, colorectal cancer

Exclusion of liability

CSS offers no guarantee for the accuracy and completeness of the information. The information published is no substitute for professional advice from a doctor or pharmacist.