While the exact causes of bowel cancer are unknown, there are known risk factors for an increased chance of developing the disease. These include:
Most bowel cancers occur is people over the age of 50, but no age group is immune.
- Family history
The lifetime risk of bowel cancer for the average Australian is one in 12. This risk of doubles if a first-degree relative (parents, children or siblings) develops bowel cancer, especially if they developed bowel cancer or polyps younger than age 50; or if more than one relative on the same side of a family has had the condition.
- Inflammatory bowel disease
People with a long-standing history of Ulcerative Colitis or Crohn’s Colitis, have an increased risk of developing bowel cancer.
- Hereditary bowel conditions
There are two rare bowel conditions that can run in families and a small percentage of bowel cancers are caused by these inherited genetic conditions:
- Familial adenomatous polyposis (FAP) is an inherited condition where the lining of the bowel contains hundreds of polyps. It is a rare condition but people who are affected by the disease, if untreated, will develop bowel cancer.
- Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an inherited condition is characterised by early age of onset of bowel cancer. The children of those affected with Lynch Syndrome have a 50% chance of inheriting the same condition.
Polyps (wart-like growths which grow on the wall of the bowel) are a risk factor for bowel cancer. If polyps are removed, the risk of bowel cancer is significantly reduced.
- Diet & Lifestyle
Lifestyle issues may be important in reducing the risk of bowel cancer. Obesity, lack of exercise, a diet high in fat and low in fibre can increase the risk of many cancers, including bowel cancer. Consuming alcohol and smoking can also increase risk.
If you have identified risk factors for polyps or bowel cancer, you may need to start screening at an earlier age. Speak to your GP to discuss the benefits of increased or earlier bowel screening based on your own circumstances.
And remember, you should never be told you are too young to have bowel cancer. While bowel cancer is more common in people aged 50 and over, no age group is immune.