Colorectal Cancer Risk Factors

A risk factor is something that increases the likelihood of developing a disease. Below are several risk factors that have been shown to be linked to an increased chance of developing colorectal cancer.

Lifestyle risk factors, such as not being physically active or eating a diet high in red and processed meats, can be changed. Other risk factors, such as a family history of colorectal cancer or inherited syndromes, cannot. Recognizing these risk factors and participating in a colorectal cancer screening program tailored to your specific needs can help to minimize your chances of developing cancer.

Risk factors that increase the chance of developing colorectal cancer

  • Inflammatory bowel disease, such as ulcerative colitis

  • Having benign (noncancerous) polyps

  • A personal history of colorectal cancer

  • A family history of colorectal cancer

  • Inherited syndromes, such as Lynch syndrome

Risk factors that increase the chance of developing colorectal cancer include:

Risk factors

  • inflammatory bowel disease, such as ulcerative colitis

  • having benign (noncancerous) polyps

  • a personal history of colorectal cancer (you have had colorectal cancer before)

  • a family history of colorectal cancer (a first-degree relative such as a parent, sibling, or child has had colorectal cancer)

  • inherited syndromes, such as Lynch syndrome

If you have had inflammatory bowel disease such as ulcerative colitis or Crohn’s disease for a long period of time, you may be at a higher risk of developing colorectal cancer.

If you have already had colorectal cancer or polyps in the past, you are more likely to develop new cancers in others parts of the colon or rectum.

The older you are, the more likely you are to develop colorectal cancer. Most people who are diagnosed with colorectal cancer are 50 years or older; however, it is becoming more common in people under the age of 50 when screening is less common and symptoms often go unnoticed. For more resources on early-onset colorectal cancer, please see our Never too Young program.

You are more likely to develop colorectal cancer if someone in your immediate family (parent, sibling or child) has been diagnosed with it. The risk of colorectal cancer increases if you have two or more close relatives who have been diagnosed with colorectal cancer or if a relative is diagnosed with it before the age of 50.

You can download our Colorectal Cancer Family History Chart to better understand your family history of the disease.

There are certain inherited syndromes that increase a person’s risk of developing colorectal cancer or polyps. Five to ten percent of patients with colorectal cancer have an inherited genetic mutation that puts them at a greater risk of colorectal cancer.

Hereditary nonpolyposis colorectal cancer (HNPCC), which is also known as Lynch syndrome, is responsible for a small percentage of colorectal cancers (2% to 5% of patients). Though people affected by HNPCC have few polyps, the polyps are more likely to become cancerous and at a faster rate.

Familial adenomatous polyposis (FAP), also accounts for only a small number of colorectal cancers (1% of patients). People affected by FAP can develop thousands of polyps (also called adenomas) along the inside wall of the colon. These polyps are likely to turn cancerous by the time a person reaches their early 40s, so FAP is best treated by preventative surgery to remove the colon.

Another condition called Peutz-Jeghers Syndrome is characterized by the development of benign polyps in the gastrointestinal tract. These can lead to a greater risk in the development of cancerous polyps over time.

Understanding the risk factors above is important to determine at what age you should start screening and how often you should get screened. Be sure to discuss any risk factors with your doctor.