Colorectal Cancer: 10 Things to Know

  • Serious man
    Colorectal Cancer Facts
    Colorectal cancer is cancer of the large intestine and it is the third most common cancer in men and women. The average American has about a 5% risk of developing colorectal cancer during his or her lifetime. Here are some of the most important facts to know about colorectal cancer.
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    1. Age is a main risk factor.
    Anyone can get colorectal cancer, but about 90% of these cancers occur in people age 50 and older. Besides age, other risk factors include being African American, having a family history or personal history of colorectal polyps or cancer, and having a personal history of inflammatory bowel disease. Up to 10% of colorectal cancers are related to gene mutations and genetic syndromes. Lifestyle factors, such as obesity, not getting enough exercise, smoking, poor diet, and heavy alcohol use, can also increase your risk.
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    2. There are often no symptoms in the early stages.
    When colorectal cancer symptoms develop, they can include abdominal cramping or pain, bloody or very dark stool, rectal bleeding, and a feeling of incomplete emptying after a bowel movement. You may also notice changes in bowel habits, such as diarrhea, constipation, changes in consistency, or narrowing of the stool. Other signs and symptoms include tiredness or weakness, weight loss, loss of appetite, and a low red blood cell count. Other conditions, such as hemorrhoids, share some of these symptoms. See your doctor for the right diagnosis.
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    3. Screening finds many colorectal cancers before symptoms develop.
    About 95% of colorectal cancers develop slowly over 10 to 15 years. They arise in the gland cells that make lubricating mucus for the colon and rectum, starting as non-cancerous polyps in the lining of the colon or rectum. Noninvasive occult fecal blood testing is an extremely reliable screening technique. Your doctor can check for polyps with routine colonoscopy, which often finds these polyps before they become cancerous. There are various screening methods, so talk with your doctor about your options.
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    4. A biopsy is the only way to know for sure if a polyp is cancerous.
    Screening tests are the most effective way to diagnose colorectal cancer in early, highly treatable stages. Colonoscopy is a common screening tool that allows your doctor to collect a biopsy. A biopsy removes a small tissue sample to check it for cancer; it is the only way to know for sure if the tissue is cancerous or benign. Your doctor may even be able to completely remove a suspicious area during the exam.
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    5. A complete diagnosis is necessary to stage colorectal cancer.
    After diagnosing colorectal cancer, your doctor may order imaging exams, such as CT and MRI, to determine the extent of cancer. Genetic testing of the biopsy samples may also be necessary for a complete diagnosis. All of this information helps your doctor stage and classify the cancer and plan the most effective treatment.
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    6. Colorectal cancer stage guides treatment decisions.
    There are five stages for colorectal cancer: 0, I, II, III and IV. Lower stage cancers usually have a better outlook because they are more likely to respond to treatment. Higher numbers indicate more severe disease. The stage of your cancer depends on how deep the tumor is in the wall of your colon and whether it has spread to your lymph nodes or other organs. Once your doctor knows the stage, you and your doctor can develop a treatment plan that is right for you.
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    7. Surgery is the main treatment for all stages of colorectal cancers.
    In early stages, colorectal cancer surgery may involve removing only a small part of the colon. This treatment has a high success rate and may be the only treatment necessary. Doctors may still recommend surgery if the tumor is large or has spread. However, they may need to remove an entire section of intestine or rectum. If there isn’t enough tissue left to reconnect the ends, the surgeon will create a colostomy—an opening for stool to pass.
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    8. Radiation therapy and chemotherapy are other common treatments.
    Doctors often add radiation therapy and chemotherapy—alone or together—starting in stage II. These treatments can shrink a tumor before surgery and kill any remaining cancer after surgery. Doctors also use these treatments to shrink tumors that have spread to other parts of the body. Radiation and chemotherapy are also useful for people who can’t have surgery, and to help relieve symptoms such as pain or rectal bleeding in advanced stages.
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    9. Targeted therapy may be useful in advanced stages.
    Targeted therapies are medicines that target specific markers present only on cancer cells. In some cases, targeted therapies work when standard chemotherapy does not. Doctors most often use targeted therapies for advanced colorectal cancer, first testing tissue from the tumor to see if it has the markers that would make this treatment worthwhile.
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    10. You can take charge of your colorectal health.
    Screening exams are one of the most effective steps you can take to prevent colorectal cancer. You can also reduce your risk by minimizing risk factors you can control, including not smoking, drinking alcohol only in moderation, and eating a balanced diet with a variety of whole grains and fresh fruits and vegetables. It’s also important to maintain a healthy weight and get regular exercise with moderate to vigorous activities most days of the week.
Colorectal Cancer: 10 Things to Know

About The Author

Sarah Lewis is a pharmacist and a medical writer with over 25 years of experience in various areas of pharmacy practice. Sarah holds a Bachelor of Science in Pharmacy degree from West Virginia University and a Doctor of Pharmacy degree from Massachusetts College of Pharmacy. She completed Pharmacy Practice Residency training at the University of Pittsburgh/VA Pittsburgh Healthcare System. 
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  6. Colorectal Cancer Signs and Symptoms. American Cancer Society.
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  12. Treatment of Colon Cancer by Stage. American Cancer Society.
  13. What Is Colorectal Cancer? American Cancer Society.
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Last Review Date: 2021 Feb 24
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