Colorectal Cancer: What You Should Know

Doctor discussing colonoscopy report with patient.

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Last year in the United States, more than 136,000 people were diagnosed with—and more than 50,000 died from—colorectal cancer, according to the National Cancer Institute. It is the second leading cause of cancer-related deaths in the United States, striking some groups more often than others. The toll this disease takes on minorities is especially high, said Jonca Bull, M.D., director of FDA’s Office of Minority Health. Populations with limited access to screening and early treatment die much more often from the disease—African Americans, Hispanics, and American Indians and Alaska Natives. But there is a way of confronting this hazard, she added: “Early detection, referral, and treatment can significantly reduce disparities in deaths from colorectal cancer.”

Screening saves lives

Colorectal cancer usually starts from polyps or other precancerous growths in the rectum or the colon (large intestine). People with precancerous growths or signs of colorectal cancer don’t always show symptoms. That’s why screening is important—doctors can see and remove growths or suspicious tissue before they become cancerous.

Your risk for colorectal cancer increases if you:

Smoke
Have a history of inflammatory bowel disease, ulcerative colitis, or Crohn’s disease
Have a family history of colorectal cancer
Have a personal history of colorectal cancer or colon polyps
Have certain genetic syndromes (for example, Lynch or FAP)
Have diabetes

You should see your doctor also if you have any of these symptoms, even though they do not necessarily indicate colorectal cancer:

A change in bowel habits (for example, diarrhea, constipation, feeling that the bowel does not empty all the way)
Bright or dark blood in stool
Stools narrower than usual
Frequent gas pains, bloating, fullness, or cramps
Weight loss for no known reason
Feeling very tired
Vomiting

When and how should I get screened?

You should begin getting screened at age 50 if you are at average risk of developing colorectal cancer. However, some people at higher risk for colon cancer may need to be screened earlier and some may need to undergo more frequent screening. Discuss with your doctor the best strategy for you. Here are several options:

A colonoscopy— A doctor uses this thin tube with a light and lens to look inside the rectum and colon for growths, other abnormal tissue, or cancer. You will need to prepare for the test and will be sedated during it.
Routine screening: every 10 years.
Flexible sigmoidoscopy—A doctor uses a thin tube with a light and lens to look inside the rectum and lower third of the colon for growths, other abnormal areas tissues, or cancer. This thin tube may also include a tool for removing abnormal tissue for examination. You will need to prepare for the test.
Routine screening: every 5 years.
Fecal blood test (gFOBTor FIT test)—Using an at-home kit from your physician, you take a sample of your stool and return it to a lab, where it is checked for hidden blood, sometimes a sign of cancer. If blood is found, you will need a colonoscopy to find out why.
Routine screening: once a year.
Stool DNA test —Using an at-home kit from your physician, you take a sample of your stool and return it to a lab, where it is checked for blood as well as for genetic changes sometimes found in cancer and precancer cells. If the test is positive, you will need a colonoscopy.
Routine screening: every 3 years.
Computed tomography colonography or “virtual colonoscopy”—An X-ray imaging procedure that produces 2D and 3D views of the colon from the rectum to the lower end of the small intestine as well as some visualization of the small bowel. The colon will be gently and temporarily inflated with air through a thin tube tip placed in the rectum. You will need to prepare for the test.
Routine screening: every 5 years.

Remember to ask your doctor about colorectal cancer screening.

“Regular screening, beginning at age 50, is the key to preventing colorectal cancer,” said Alberto Gutierrez, Ph.D., an FDA expert on screening devices. “People at higher risk of developing colorectal cancer should begin screening at a younger age, and may need to be tested more frequently. Currently, individuals have several options for testing based on their risks and preferences. You should talk with your doctor to determine which screening program is right for you.”

What’s the good news?

More people who get the disease are surviving or are surviving longer with the help of screening, surgery and/or drugs approved for the treatment of patients with colorectal cancer. Because not all populations react the same way to every treatment, scientists are also developing “companion diagnostics,” tests to determine, for example, if a mutation in a particular gene found in tumors will render a drug effective, ineffective, or even harmful among certain groups.

Researchers study new ways to prevent, treat, and manage the disease. Patients who want to know about clinical trials—research studies that involve people—may want to discuss this option with those close to them and with their doctor.

How can I reduce my risk?

A number of factors may put you at risk for colorectal cancer: your age, medical history, race or ethnicity. But you can reduce that risk. Here’s how:

Exercise regularly and vigorously
Maintain a healthy diet (high in vegetables and fruits; low in red and processed meats)
Maintain a healthy weight
Limit the amount of alcohol you drink
Don’t smoke and avoid second-hand smoke