Colorectal cancer often begins as a growth called a polyp inside the colon or rectum. Finding and removing polyps can prevent colorectal cancer. Explore the links on this page to learn more about colorectal cancer prevention, screening, treatment, statistics, research, clinical trials, and more.

Colon Cancer Treatment

  • Colon cancer is a disease in which malignant (cancer) cells form in the tissues of the colon.
  • Health history affects the risk of developing colon cancer.
  • Signs of colon cancer include blood in the stool or a change in bowel habits.
  • Tests that examine the colon and rectum are used to detect (find) and diagnose colon cancer.
  • Certain factors affect prognosis (chance of recovery) and treatment options.

The colon is part of the body’s digestive system. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The colon (large bowel) is the first part of the large intestine and is about 5 feet long. Together, the rectum and anal canal make up the last part of the large intestine and are about 6-8 inches long. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).

Gastrointestinal stromal tumors can occur in the colon. See the PDQ summary on Gastrointestinal Stromal Tumors Treatment (Adult) for more information.

See the PDQ summary about Unusual Cancers of Childhood Treatment for information about colorectal cancer in children.

Health history affects the risk of developing colon cancer.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk to your doctor if you think you may be at risk for colorectal cancer.

Risk factors for colorectal cancer include the following:

  • Having a family history of colon or rectal cancer in a first-degree relative (parent, sibling, or child).
  • Having a personal history of cancer of the colon, rectum, or ovary.
  • Having a personal history of high-risk adenomas (colorectal polyps that are 1 centimeter or larger in size or that have cells that look abnormal under a microscope).
  • Having inherited changes in certain genes that increase the risk of familial adenomatous polyposis (FAP) or Lynch syndrome (hereditary nonpolyposis colorectal cancer).
  • Having a personal history of chronic ulcerative colitis or Crohn disease for 8 years or more.
  • Having three or more alcoholic drinks per day.
  • Smoking cigarettes.
  • Being black.
  • Being obese.

Older age is a main risk factor for most cancers. The chance of getting cancer increases as you get older.

Rectal Cancer Treatment

Rectal cancer is a disease in which malignant (cancer) cells form in the tissues of the rectum.
Health history affects the risk of developing rectal cancer.
Signs of rectal cancer include a change in bowel habits or blood in the stool.
Tests that examine the rectum and colon are used to detect (find) and diagnose rectal cancer.
Certain factors affect prognosis (chance of recovery) and treatment options.

See the following PDQ summaries for more information about rectal cancer:

  • Unusual Cancers of Childhood Treatment (see Colorectal Cancer section)
  • Colorectal Cancer Prevention
  • Colorectal Cancer Screening
  • Gastrointestinal Stromal Tumors Treatment (Adult)
  • Genetics of Colorectal Cancer

Signs of rectal cancer include a change in bowel habits or blood in the stool.

These and other signs and symptoms may be caused by rectal cancer or by other conditions. Check with your doctor if you have any of the following:

  • Blood (either bright red or very dark) in the stool.
  • A change in bowel habits.
    • Diarrhea.
    • Constipation.
    • Feeling that the bowel does not empty completely.
    • Stools that are narrower or have a different shape than usual.
  • General abdominal discomfort (frequent gas pains, bloating, fullness, or cramps).
  • Change in appetite.
  • Weight loss for no known reason.
  • Feeling very tired.

Childhood Colorectal Cancer Treatment

The colon is part of the body’s digestive system. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the mouth, throat, esophagus, stomach, and the small and large intestines. In an adult, the colon (large bowel) is the first part of the large intestine and is about 5 feet long. Together, the rectum and anal canal make up the last part of the large intestine and are 6 to 8 inches long. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).

Colorectal Cancer Prevention 

  • Colorectal cancer is a disease in which malignant (cancer) cells form in the tissues of the colon or the rectum.
  • Colorectal cancer is the third leading cause of death from cancer in the United States.
  • Avoiding risk factors and increasing protective factors may help prevent cancer.
  • The following risk factors increase the risk of colorectal cancer:
    • Age
    • Family history of colorectal cancer
    • Personal history
    • Inherited risk
    • Alcohol
    • Cigarette smoking
    • Race
    • Obesity
  • The following protective factors decrease the risk of colorectal cancer:
    • Physical activity
    • Aspirin
    • Combination hormone replacement therapy
    • Polyp removal
  • It is not clear if the following affect the risk of colorectal cancer:
    • Nonsteroidal anti-inflammatory drugs (NSAIDs) other than aspirin
    • Calcium
    • Diet
  • The following factors do not affect the risk of colorectal cancer:
    • Hormone replacement therapy with estrogen only
    • Statins
  • Cancer prevention clinical trials are used to study ways to prevent cancer.
  • New ways to prevent colorectal cancer are being studied in clinical trials.

Colorectal Cancer Screening

The number of new colorectal cancer cases and the number of deaths from colorectal cancer are decreasing a little bit each year in adults aged 55 years and older. But in adults younger than 55 years, there has been a small increase in the number of new cases and deaths from colorectal cancer in recent years. Colorectal cancer is found more often in men than in women.

What is Cancer?

  • Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Normally, human cells grow and divide to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.

  • Cancer prevention is action taken to lower the risk of getting cancer. This can include maintaining a healthy lifestyle, avoiding exposure to known cancer-causing substances, and taking medicines or vaccines that can prevent cancer from developing.

  • Cancer can cause many different symptoms. Most often these symptoms are not caused by cancer, but by benign tumors or other problems. If you have symptoms that last for a couple of weeks, your doctor will do a physical exam and order tests or other procedures to find out what is causing your symptoms.