The risk of colorectal cancer increases as a person gets older. This is why experts recommend screening for people who are age 45 or older, even if the person does not have additional risk factors.

Some people have additional factors that increase their risk of colorectal cancer. Some of these impact recommendations for when to begin screening, while others do not.

Risk factors that may affect screening recommendations

Some conditions significantly increase a person’s risk of colorectal cancer. Doctors often recommend that people with these conditions begin colorectal cancer screening earlier than people considered to be at average risk.

Genetic familial syndromes

While uncommon, certain syndromes that are passed down in families can increase a person’s risk of developing colorectal cancer. They include:

  1. Familial adenomatous polyposis (FAP): FAP is an uncommon inherited condition in which hundreds of polyps (or more) develop throughout the colon beginning in adolescence. Nearly all people with this condition will develop colorectal cancer during their lifetime, and most of these cancers occur before the age of 45 years.
  2. Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer [HNPCC]): Lynch syndrome is another inherited condition associated with an increased risk of colorectal cancer. It is slightly more common than FAP but is still uncommon, accounting for less than 1 in 20 cases of colorectal cancer. About 70 percent of people with Lynch syndrome will develop colorectal cancer by the age of 65. Cancer also tends to occur at younger ages. People with Lynch syndrome are also at risk for other types of cancer, including cancer of the uterus, stomach, bladder, kidney, and ovary.
  3. There are other rarer inherited conditions that increase risk of colorectal cancer, including mutY DNA glycosylase gene (MUTYH)-associated polyposis, hamartomatous polyposis, Peutz-Jeghers syndrome, and juvenile polyposis syndrome.

If any of these conditions run in your family, you can get genetic testing to find out whether you have the abnormal gene.

Personal or family history of colorectal cancer or polyps

People who have previously had colorectal cancer have an increased risk of developing a new colorectal cancer. People who have had adenomatous polyps before the age of 60 years are also at increased risk for developing colorectal cancer.

Having a first-degree relative (a parent, brother or sister, or child) with colorectal cancer increases your risk of developing colorectal cancer. In addition, having a relative who had adenomatous polyps is also believed to increase your risk. Your risk may be further increased depending on how many family members are affected and the age at which their cancer or polyps were detected.

Inflammatory bowel disease

People with Crohn disease or ulcerative colitis have an increased risk of colorectal cancer.

The amount of increased risk depends upon the amount of inflamed colon and the duration of disease; pancolitis (inflammation of the entire colon) and colitis of 10 years’ duration or longer are associated with the greatest risk for colorectal cancer.

Lifestyle risk factors

Certain lifestyle factors also seem to increase a person’s risk of developing colorectal cancer. These include:

  1. A diet high in fat and red or processed meat and low in fiber
  2. A sedentary lifestyle
  3. Cigarette smoking
  4. Alcohol use
  5. Obesity

Modifying these risk factors may help lower your risk of colorectal cancer, in addition to improving your overall health.

Factors that may decrease risk

As discussed above, improving your diet, increasing physical activity, cutting back on alcohol, and quitting smoking (if you smoke) can all help lower your risk of developing colorectal cancer.

Using aspirin for prevention of cardiovascular disease may also decrease the risk of developing colorectal cancer, but this should be discussed with your doctor to understand the benefits and risks of taking aspirin. Because taking aspirin regularly comes with risks of its own, it’s a good idea to talk with your health care provider before trying this.