Colorectal Cancer Causes

Colorectal Cancer - Causes and Risk Factors

The exact cause of colorectal cancer is not known but certain risk factors such as age, having certain medical conditions, inherited genetic syndromes, diet and lifestyle can contribute to the development of colorectal cancer.

Having risk factors increases the likelihood of developing the colorectal cancers but it does not guarantee that the condition will develop. Understanding risk factors can help with prevention and recommended screening.

Factors that can increase the risk of colorectal cancer include:

Older age – Colorectal cancer is often diagnosed in people aged 50 years and above. However, younger people can also be diagnosed with the cancer.
History of colorectal polyps or cancer – Having colorectal polyps or cancer in the past increases the risk of developing colorectal cancer.
Inflammatory bowel diseases – Having ulcerative colitis, Crohn’s disease or other diseases that cause inflammation of the intestines can increase the risk of developing colorectal cancer.
Family history of cancer or conditions – Having one or more blood relatives, who have had colorectal cancer or an inherited condition such as Lynch syndrome or familial adenomatous polyposis, increases the risk of developing the disease.
Diabetes - Having diabetes and insulin resistance elevates the risk of developing colorectal cancer.
A low-fibre, high fat diet – Some research has shown that eating a diet low in fibre and high in fat and calories, a typical Western diet, increases the risk of developing colorectal cancer.
A sedentary lifestyle – Being inactive and not engaging in regular physical activity can increase the risk of developing the disease.
Smoking – As with most cancers, smoking is a risk factor for developing colorectal cancer.
Heavy use of alcohol – Drinking copious amounts of alcohol can increase the risk of colorectal cancer.

There are some complications that may arise as colorectal cancer progresses and even after treatment. These include:

Bowel obstruction can happen when the tumour grows and blocks the intestines
Low blood counts may result from blood losses from bleeding tumours
Cancer spread or metastases to other organs, such as the liver, lungs, peritoneum and lymph nodes.
Cancer recurrence is when cancer develops again after initial treatment and remission. A recurrence may develop at the same site of the previous colorectal cancer or may spread and develop in other organs.