Overview of Colorectal Cancer

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What is Colorectal Cancer?

Colorectal Cancer is a cancer that occurs in the colon (large intestine) and the rectum. Within Colorectal cancer, about 70% of malignancies occur in the colon, and 30% appear in the rectum.


  • There are 1.2 million new cases diagnosed annually worldwide. 
  • More than 450,000 citizens in Europe are newly diagnosed every year with Colorectal Cancer
  • Over 600,000 deaths annually; 8% of all cancer deaths.
  • It is the second most common cause of cancer-related deaths in the developed world.

Most colorectal cancer develops gradually over a number of years. Usually tumour growth begins as a non-cancerous polyp on the inner lining of the colon or rectum.

Two kinds of polyps exist:

  • Adenomatous poplyps (adenomas) - can change into cancer.
  • Hyperplastic polyps and inflammatory polyps - not pre-cancerous. 


Diagram 1 - Colon & Small Intestine Diagram 2 - Colon Polyps


Quick Colorectal Cancer Questions and Answers:

What are the causes?  Family History of the disease Usually occurs in those over 50 Women are at slightly higher risk than men. Diet – High-meat, high-fat, low-fibre diet may encourage the production of carcinogens. 
What are the symptoms? There may be no symptoms. It may very widely depending on the location of the cancer within the large intestine. Abdominal pain, blood in the stool, and rectal bleeding are common symptoms. 
Can colorectal cancer be prevented? Detection:


Early detection is key to help controlling cancer. Colorectal cancer as polyps, which are small, non-cancerous growths that form on the inner lining of the colon. 

There are many tests which can help identify colorectal cancer:

· Flexible Sigmoidoscopy

· Colonoscopy

· CT Colonography

· Fetal Occult Blood Test

· Fecal Immunochemical Test

Lifestyle Factors  Lifestyle:


Lifestyle can also have an impact.

A healthy diet that is low in fat, and high in fruits, vegetables, and fibre has been linked with decreased risk of colorectal cancer. Other factors that can increase the risk of colorectal cancer include obesity, physical inactivity, smoking, and heavy alcohol use.