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Colorectal cancer includes malignant or cancerous tumors of the colon and/or the rectum.

  • The colon extends from the end of the small intestine to the rectum. It consists of ascending, transverse and descending segments.
  • The sigmoid colon is roughly S-shaped and is the lower portion of the descending colon, leading into the rectum.
  • The rectum is part of the digestive system. It makes up the final five inches of the colon.
  • Colorectal cancer can affect any of these areas.


  • This year, about 147,000 Americans will be diagnosed with colorectal cancer.
  • The disease affects men and women equally.

General Risk Factors

The majority of colorectal tumors are found in patients over age 50. However, the disease can happen at any age so it is important to know your family history and the following risk factors.

  • Diet high in fat and red meat and low in fruits and vegetables.
  • Personal history of colon cancer.
  • History of polyps in the colon, ulcerative colitis or Crohn’s Disease.


Often there are no obvious signs of colorectal cancer, but some symptoms can include:

  • Change in bowel frequency, such as alternating episodes of diarrhea and constipation.
  • Bloody bowel movements or rectal bleeding.
  • General abdominal discomfort.
  • Unexplained weight loss.
  • Chronic fatigue.
  • Bloating.
  • Unexplained anemia.

Screening for Colorectal Cancer

The American Cancer Society recommends that, beginning at age 50, both men and women be screened for colorectal cancer according to one of the following schedules:

  • A yearly fecal occult blood test where your stool will be checked for blood.
  • A double-contrast barium enema every five years. During this test, your colon is filled with a fluid containing barium. The barium is then drained out and air is put into the intestine. X-rays of the area are then taken to look for abnormalities.
  • Every 10 years, a colonoscopy where the doctor uses a long, lighted tube to look inside the rectum and the entire colon for polyps or other abnormal areas that may be cancerous.

People who have any of the colorectal cancer risk factors should consult with their doctor about earlier, more frequent screening.

Diagnosing Colorectal Cancer

Special tests to evaluate the colon and rectum are used to detect and diagnose colorectal cancer.

  • A physical exam to assess your overall health, including a digital rectal exam (DRE) to evaluate the rectum for abnormal masses.
  • Fecal occult blood test.
  • A sigmoidoscopy to look inside the rectum and sigmoid colon for polyps or other abnormal areas that may be cancerous using a thin, lighted tube.
  • A double-contrast barium enema.
  • A colonoscopy.

To determine for sure if you have cancer, some tissue will be removed during sigmoidoscopy or colonoscopy and examined under a microscope. This test is called a biopsy. Your doctor may also request a CT or PET scan to see if other body parts are affected.

Treating Colorectal Cancer

The primary treatment for cancers of the colon and rectum is surgery. For cancers that have not spread, surgery alone may cure your cancer.

  • Depending on the location and stage of your cancer, your doctor may recommend chemotherapy and/or radiation therapy either before or after surgery.
  • For rectal cancer, radiation is usually given with chemotherapy. It can be given before surgery (called preoperative or neoadjuvant therapy) or after surgery (called postoperative or adjuvant therapy). Depending on the location and stage of your tumor, preoperative therapy may allow the surgeon to spare your anal sphincter. This would avoid the need for a permanent colostomy and may reduce the chance of the cancer coming back.