Colorectal Cancer

ExitCare ImageColorectal cancer is an abnormal growth of tissue (tumor) in the colon or rectum that is cancerous (malignant). Unlike noncancerous (benign) tumors, malignant tumors can spread to other parts of your body. The colon is the large bowel or large intestine. The rectum is the last several inches of the colon.


The exact cause of colorectal cancer is unknown. However, the following factors may increase your chances of getting colorectal cancer:

  • Age older than 50 years.  

  • Abnormal growths (polyps) on the inner wall of the colon or rectum.  

  • Diabetes.  

  • African American race.  

  • Family history of hereditary nonpolyposis colorectal cancer. This condition is caused by changes in the genes that are responsible for repairing mismatched DNA.  

  • Personal history of cancer. A person who has already had colorectal cancer may develop it a second time. Also, women with a history of ovarian, uterine, or breast cancer are at a somewhat higher risk of developing colorectal cancer.

  • Certain hereditary conditions.

  • Eating a diet that is high in fat (especially animal fat) and low in fiber, fruits, and vegetables.

  • Sedentary lifestyle.

  • Inflammatory bowel disease, including ulcerative colitis and Crohn disease.  

  • Smoking.  

  • Excessive alcohol use.  


Early colorectal cancer often does not cause symptoms. As the cancer grows, symptoms may include:

  • Changes in bowel habits.

  • Diarrhea.  

  • Constipation.  

  • Feeling like the bowel does not empty completely after a bowel movement.  

  • Blood in the stool.  

  • Stools that are narrower than usual.  

  • Abdominal discomfort, pain, bloating, fullness, or cramps.

  • Frequent gas pain.  

  • Unexplained weight loss.  

  • Constant tiredness.  

  • Nausea and vomiting.  


Your health care provider will ask about your medical history. He or she may also perform a number of procedures, such as:

  • A physical exam.

  • A digital rectal exam.

  • A fecal occult blood test.

  • A barium enema.  

  • Blood tests.  

  • X-rays.  

  • Imaging tests, such as CT scans or MRIs.  

  • Taking a tissue sample (biopsy) from your colon or rectum to look for cancer cells.  

  • A sigmoidoscopy to view the inside of the last part of your colon.  

  • A colonoscopy to view the inside of your entire colon.  

  • An endorectal ultrasound to see how deep a rectal tumor has grown and whether the cancer has spread to lymph nodes or other nearby tissues.  

Your cancer will be staged to determine its severity and extent. Staging is a careful attempt to find out the size of the tumor, whether the cancer has spread, and if so, to what parts of the body. You may need to have more tests to determine the stage of your cancer. The test results will help determine what treatment plan is best for you.

  • Stage 0—The cancer is found only in the innermost lining of the colon or rectum.  

  • Stage I—The cancer has grown into the inner wall of the colon or rectum. The cancer has not yet reached the outer wall of the colon.  

  • Stage II—The cancer extends more deeply into or through the wall of the colon or rectum. It may have invaded nearby tissue, but cancer cells have not spread to the lymph nodes.  

  • Stage III—The cancer has spread to nearby lymph nodes but not to other parts of the body.  

  • Stage IV—The cancer has spread to other parts of the body, such as the liver or lungs.  

Your health care provider may tell you the detailed stage of your cancer, which includes both a number and a letter.


Depending on the type and stage, colorectal cancer may be treated with surgery, radiation therapy,  chemotherapy, targeted therapy, or radiofrequency ablation. Some people have a combination of these therapies. Surgery may be done to remove the polyps from your colon. In early stages, your health care provider may be able to do this during a colonoscopy. In later stages, surgery may be done to remove part of your colon.


  • Only take over-the-counter or prescription medicines for pain, discomfort, or fever as directed by your health care provider.  

  • Maintain a healthy diet.  

  • Consider joining a support group. This may help you learn to cope with the stress of having colorectal cancer.  

  • Seek advice to help you manage treatment of side effects.  

  • Keep all follow-up appointments as directed by your health care provider.  

  • Inform your cancer specialist if you are admitted to the hospital.  


  • Your diarrhea or constipation does not go away.  

  • Your bowel habits change.

  • You have increased abdominal pain.  

  • You notice new fatigue or weakness.

  • You lose weight.