Colorectal Cancer Awareness

Yvette C. Terrie, BSPharm, RPh
Published Online: Monday, August 1, 2005
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The American Cancer Society (ACS) estimates that, in the year 2005, ~145,290 people will be diagnosed with colorectal cancer and ~56,290 patients will die of the disease.1 Colorectal cancer is the third most commonly diagnosed cancer and the second most common cause of cancer death in the United States.1 Although many health organizations recommend that colorectal cancer screening begin at the age of 50 for people at average risk, <50% of people 50 years old or older get tested.1

Colorectal cancer usually develops slowly over a period of many years. It may begin as a noncancerous polyp that develops into cancer. More than 95% of colorectal cancers are adenocarcinomas, which evolve from glandular tissue.1

Risk Factors

Ninety percent of cases of colorectal cancer occur in patients over age 50, and ~75% of these cases occur in patients with no known medical risk factors for developing the disease.2 Examples of some of these risk factors1,2 are as follows:

  • Age—risk increases after age 50
  • Gender—incidence is >35% higher in men than in women1
  • Ethnicity—incidence and mortality are highest among African Americans1
  • Family history of colorectal cancer
  • History of bowel disorders, such as chronic inflammatory bowel disease, or history of adenomatous polyps

Signs and Symptoms

In many cases, there are no signs or symptoms during the early stages of this cancer. When present, they may include the following:

  • Changes in bowel habits, such as worsening constipation or recurring diarrhea
  • Blood in the stool (either bright red or very dark)
  • Stools that are narrower than usual
  • Frequent abdominal pain (gas pains, cramps, or bloating)
  • General feeling of malaise
  • Unexplained weight loss
  • Vomiting

Patients should be encouraged to consult a physician to discuss any of these symptoms.

Detection

Colorectal cancer can be highly curable if detected in the early stages. Individuals 50 years old or older should be screened regularly. Those with known risk factors should begin extensive testing and screening even earlier. The ACS recommends that patients over age 50 have a fecal occult blood test annually and a sigmoidoscopy every 5 years.2

Screening tests available include the following2:

  • Fecal occult blood test—This test checks for hidden blood in the stool. Two OTC tests are ColoCARE and EZ Detect stool blood tests. Studies have shown that, when this type of test is done every 1 to 2 years, the number of deaths due to colorectal cancer is reduced by as much as 30%.3
  • Sigmoidoscopy—This examination explores the rectum and lower third of the colon for precancerous and cancerous growths
  • Double contrast barium enema—In this test, the contrast material used expands the colon and allows a radiologist to see whether large polyps are present
  • Colonoscopy—This test examines the rectum and the entire colon. It can find both precancerous and cancerous growths.

Treatment Options

Individuals diagnosed with colorectal cancer may receive surgery, chemotherapy or radiation, or a combination of these therapies. The type of treatment is dependent upon the stage of the cancer, whether the cancer is a recurrence, and/or the individual's general health status.

Examples of Some New Pharmacologic Therapies

Oxaliplatin (Eloxatin, Sanofi- Aventis) was first approved by the FDA in 2002 for the treatment of advanced colorectal cancer, and it is now approved as first-line treatment when combined with 5-fluorouracil (FU) and leucovorin (LV).4 Oxaliplatin, used in combination with infusional 5-FU/LV, is indicated for adjuvant treatment of stage III colon cancer patients who have undergone complete resection of the primary tumor. The indication is based on an improvement in diseasefree survival, but with no demonstrated benefit in overall survival after a median follow-up of 4 years.5

In 2004, the FDA approved 2 new pharmacologic treatments for advanced colorectal cancer. These agents, bevacizumab (Avastin, Genentech) and cetuximab (Erbitux, ImClone Systems Inc and Bristol-Myers Squibb) are part of the drug class known as monoclonal antibodies. Bevacizumab is indicated for use in combination with intravenous 5-FU-based chemotherapy as first-line treatment of patients with metastatic carcinoma of the colon or rectum.6 Cetuximab is indicated for use in combination with irinotecan for the treatment of epidermal growth factor receptor-expressing, metastatic colorectal carcinoma in patients who are refractory to irinotecan- based chemotherapy.7 Cetuximab is the first monoclonal antibody approved to treat this type of cancer.8

Preventing Colorectal Cancer

Although the exact cause of colorectal cancer still is not known, there are many measures that can be taken to prevent it. The most powerful tool is routine screening, because this cancer can be diagnosed in the early stages, thus increasing the chance for survival. Other measures that can aid in preventing or decreasing the risk of developing this cancer include the following:

  • A diet rich in fruits, vegetables, and whole grains and a limited intake of high-fat foods
  • Exercise—moderate levels of activity, at least 30 minutes a day, for 5 or more days a week

Studies in the prevention of colorectal cancer suggest that risks can be lowered by the following factors3,9:

  • Intake of vitamins and calcium—studies suggest that taking a daily multivitamin with folic acid can lower one's risk. Calcium and vitamin D also can help.
  • Use of nonsteroidal anti-inflammatory drugs
  • Hormone replacement therapy in postmenopausal women
  • Use of statins—studies have shown that these drugs inhibit the growth of colon cancer cells grown in the laboratory9

Conclusion

Although there are many treatments for colorectal cancer, the most effective strategies are early detection and preventive measures to lessen the possibility of developing the disease. Pharmacists should remind and encourage patients to get screened regularly and to consult their physicians when needed. For more information, one should visit the American Cancer Society Web site at www.cancer.org or the National Cancer Institute Web site at www.cancer.gov.

Ms. Terrie is a clinical pharmacy writer based in the northern Virginia area.

For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. A. Stahl, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: astahl@ascendmedia.com.



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