Colorectal Cancer

Background Information

Colorectal cancer is the third most-common form of cancer and the second leading cause of cancer-related deaths in the Western world. In the United States, colorectal cancer affects about two of every 1,000 people. The American Cancer Society has estimated that there will be about 105,000 new cases of colon cancer and 40,000 new cases of rectal cancer this year, resulting in some 56,000 deaths. The incidence of colorectal cancer in the United States has steadily declined during the past 15 years, primarily due to the early detection and removal of polyps before they become cancerous.
What Causes Colorectal Cancer?
The exact cause of colorectal cancer is uncertain, but it is known to be associated with the following:
  • Age (>50 years)
  • Low-fiber diets that are high in fat and calories
  • The presence of polyps (benign growths) in the colon
  • A family history of colon cancer
  • The presence of longstanding ulcerative colitis
  • A lack of exercise
  • Being overweight
  • Smoking
  • The heavy consumption of alcohol

What are the Symptoms of Colorectal Cancer?
Colorectal cancer symptoms vary but are known to include the following:

  • A change in bowel habits
  • Diarrhea, constipation, or a feeling that the bowel does not empty completely
  • Blood (either bright red or very dark) in the stool
  • Stools that are narrower than usual
  • General abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps)
  • Unexplained weight loss
  • Constant tiredness
  • Nausea and vomiting

How is Colorectal Cancer Diagnosed?

Proper diagnosis, staging, and treatment are critical phases in countering colorectal cancer. In performing a colonoscopy, your gastroenterologist will remove small tissue specimens (biopsies). These tissue samples are then microscopically examined by a pathologist – a physician who specializes in the diagnosis of disease via microscopic examination of a tissue sample – to determine if cancer or another abnormality exists and, if so, whether it is benign or malignant. If a malignancy is discovered, the pathologist’s evaluation of its type and extent (stage) will be the key determinant in deriving the most appropriate treatment option.

Treatment Options for Colorectal Cancer:

  • Surgery – The surgical removal of a malignancy is the most common form of treatment. Normally, the surgeon will remove the cancer along with a portion of healthy tissue. The surgeon will also remove the draining lymph nodes. These specimens will then be examined under a microscope by a surgical pathologist who will determine if the cancerous tissue has been fully excised.
  • Chemotherapy – This therapy involves the use of drugs to destroy cancer cells. This type of therapy is systemic because the drugs are administered directly through the bloodstream or are taken orally and travel throughout the entire body. Chemotherapy medication intervals will vary, depending upon the drug used and whether it is administered by injection, pill, or intravenously (via a thin tube placed into a vein). Chemotherapy may be used to control a tumor, relieve symptoms, or destroy cancer cells that remain in the body after surgery.
  • Radiation Therapy – This therapy involves the use of high-energy rays to kill cancer cells and shrink tumors. Similar to surgery (and normally administered in a hospital), radiation therapy is focused directly upon the affected area. Radiation therapy is often used with patients whose cancer is located within the rectum. Physicians may use radiation to shrink a tumor prior to surgery or to destroy remaining cancer cells after surgery. Radiation may come from an external source or may be implanted into or adjacent to a tumor, e.g., via the use of a radioisotope.

Measures You Can Take to Monitor Your Condition:

  • Monitor your bowel habits and consult your physician if you experience any of the following:
    • Changes in routine bowel movements
    • Abdominal changes
    • Unexplained weight loss
    • Blood in your stool
  • Maintain a high-fiber diet that is low in fat and calories; consult your physician for proper diet and nutrition information.
  • Undergo periodic (routine) colonoscopies to detect and remove new polyps, which may be precursors to colorectal cancer.

Important Questions to Ask Your Doctor:

  • What is the stage of my colorectal cancer?
  • What are my treatment options?
  • What are the risks and side effects of these treatment options?
  • Will I need a colostomy and, if so, will it be permanent?
  • What can I do to take care of myself during and after treatment?
  • How long will the treatment last, and what will be my follow-up?

Sources of Additional Information:
American College of Gastroenterology :

American Gastroenterological

National Institutes of Health :


This Patient Diagnostic Fact Sheet is provided to you as a service by AmeriPath. It is intended for patient education and information only. It does not constitute advice nor should it be taken to suggest or replace professional medical care from your physician. Your treatment options may vary, depending upon your medical history and current condition. Only your physician and you can determine your best treatment option.