Colorectal Cancer Screening and Prevention

Why have a colorectal cancer screening?

The large intestine (also called the large bowel), consists of the colon and rectum, which is the final part of your digestive system. Cancer of the lining of the large intestine is called colorectal cancer.

Although colorectal cancer is the second most common cause of death from cancer in the United States, it is one of the few cancers that can be prevented. If cancer is present, it can also be caught at an early stage. Colorectal cancer prevention and early detection are done through screening, which means testing people who do not have symptoms.

Most colorectal cancers start out as small growths (polyps) that form on the lining of the large intestine. Over a period of about ten years, some of these polyps can become cancers. During a colonoscopy (which is one type of colorectal cancer screening test) a doctor can find and remove polyps in the large intestine. Removing polyps is entirely painless. Finding and removing these polyps dramatically reduces the chances of cancer developing. About 40% of people who are screened for colorectal cancer are found to have polyps.

A very small minority of people may be found to already have colorectal cancer on a screening exam. If colorectal cancer is found at an early stage, a person's chances of living five years or longer may be as high as 90% or more. If colorectal cancer is found at a late stage, a person may have only a 10% chance of living for five years. The earlier cancer is found, the easier it is to treat and the better the chances of survival.

Because most polyps and many colorectal cancers have no symptoms, it's very important to have a colorectal cancer screening to find the polyps and prevent them from having a chance to develop into colorectal cancer.

Who should have a colorectal cancer screening?

  • Anyone with a personal history of colorectal polyps 
  • Anyone with a personal history of colorectal cancer 
  • Anyone with a family history of colorectal cancer or polyps 
  • Anyone who is at least 50 years old, or younger if there is history of colorectal cancer in a close relative.
  • Anyone with inflammatory bowel disease (a long-term disease of the intestines, diagnosed by a doctor) 
  • How often should I have a colorectal cancer screening?

Doctors recommend that anyone at average risk (no personal or family history) who is at least 50 years old have one of the following:

  • A yearly high sensitivity fecal occult blood test (FOBT) such as FIT or Hemocult II Sensa stool sample test, or
  • A flexible sigmoidoscopy every five years, or every 10 years with a yearly FIT/FOBT or 
  • A colonoscopy every 10 years (if normal exam), or 
  • A Stool DNA test every 3 years, or
  • A virtual colonoscopy (CTC) every 5 years.

If any test other than a colonoscopy is positive, a colonoscopy should be done.
It is recommended that anyone at increased risk (people with a personal or family history of colorectal cancer or polyps) have a colonoscopy beginning at age 40 OR 10 years before the age of the youngest relative at time of diagnosis (whichever comes first), then every 5 years or as per test results, such as polyps.

Healthy habits to help lower the chances of colorectal cancer

In addition to having regular screenings, there are other ways to keep you healthy and lower the risk of colorectal cancer:

  • It is extremely important to avoid smoking 
  • Eat a high-fiber, low-fat diet, with plenty of fruits and vegetables 
  • Lose weight if you are overweight 
  • Keep to a regular exercise program (this can be as simple as taking a short walk three times a week) 
  • Talk with your provider about vitamins or medications that may help keep you healthy and prevent colorectal cancer

Additional information available from New Hampshire Colorectal Cancer Screening Program (NHCRCSP)