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Ask the Expert

Colorectal Cancer – It Can Be Prevented

Dr. Allen Wolland

This month's Ask the Doc is brought to you by Dr. Allen Wolland. Dr. Wolland, who is a Board-certified colon and rectal surgeon, received his undergraduate degree from Brooklyn College and his medical degree from Georgetown University Medical School . He completed his surgical residency training at Georgetown University Hospital , and his colon-rectal fellowship training at Suburban Hospital . He is a member of the Suburban Hospital Board of Trustees, and he is chairman-elect of the medical staff at Suburban Hospital . Dr. Wolland has been performing colon and rectal surgery since 1979. He is in private practice in Rockville , Maryland .

What is colorectal cancer?

Colorectal cancer occurs when some of the cells that line the colon or the rectum become abnormal and grow out of control. The abnormal growing cells create a tumor, which can be cancerous. The colon is a six-foot long muscular tube connecting the small intestine to the rectum. The colon, which along with the rectum is called the large intestine, is a highly specialized organ that is responsible for processing waste so that emptying stool is easy and convenient. The colon removes water from the stool, and stores the solid stool. Once or twice a day it empties its contents into the rectum to begin the process of elimination. The rectum is an eight-inch chamber that connects the colon to the anus. It is the rectum's job to receive stool from the colon, to let you know that there is stool to be evacuated, and to hold the stool until it can be released.

How common is this type of cancer?

Despite the fact that approximately 90 percent of colorectal cancers and deaths are thought to be preventable , colorectal cancer is the third most common cancer found in men and women in this country. The American Cancer Society estimates that there will be 106,680 new cases of colon cancer and 41,930 new cases of rectal cancer in 2006 in the United States . Combined, they will cause about 55,170 deaths. During March, which is National Colorectal Cancer Awareness Month, everyone should take some time to learn more about this disease.

Who is at risk for colorectal cancer?

Although the exact cause of colorectal cancer is unknown, certain risk factors have been identified that may increase a person's chance of developing the disease. These include:

  • Age : The majority of colon cancers are diagnosed in people aged 50 or older, although the disease affects all ages.
  • Family history/genetic factors : People with a strong family history of colorectal cancer, as defined by cancer or polyps in a first-degree relative younger than 60 or two first-degree relatives of any age, are at increased risk for developing colon cancer. Knowing your family history is important in screening for colorectal cancer. If there are cases of polyps or colorectal cancer in your family, your doctor may recommend a colonoscopy or other tests prior to age 50.
  • Bowel disease : A history of colorectal cancer, intestinal polyps and diseases such as chronic ulcerative colitis and Crohn's disease increase a person's chance of developing colon cancer.
  • Ethnic background and race : African-Americans and Hispanics have a higher death rate caused by colon cancer, which may be caused by insufficient screening and limited access to health care.
  • Diet and exercise : A diet high in fat, particularly from animal sources and an inactive, sedentary lifestyle, can increase a person's chance of developing colon cancer. Because colorectal cancer can take years to develop, a dietary intervention of just three or four years may not be long enough to make a real difference. Diet may have an influence in the early development of cells and tissue which years later become polyps that may turn malignant.
  • Smoking and alcohol : Several recent studies reveal that tobacco use may significantly increase your risk of developing colorectal cancer. Research suggests that e xcessive use of alcohol may also increase your risk for colorectal cancer.

What are the symptoms of colorectal cancer?

  • 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 such as frequent gas pains, bloating, fullness or cramps.
  • Weight loss with no known reason.
  • Constant fatigue.

What is the most common treatment?

The most common treatment—regardless of the stage of the disease—is surgery. Depending on the extent of the colon or rectal cancer, and the size of the tumor, a physician may use a number of different surgical methods. Various minimally invasive and laparoscopic surgery options are also available to help patients quickly return to their normal activities. It is not unusual for radiation and chemotherapy to be used in concert with surgery.

Are there any other treatments for colorectal cancer?

Radiation therapy, chemotherapy, and biological treatment also are commonly used to treat colorectal cancer.

Radiation therapy destroys cancer cells and shrinks tumors through the use of x-rays or other high-energy rays. It may be used as the sole treatment for colorectal cancer, or it may be used along with surgery and chemotherapy. The source of the radiation can come from a machine (external radiation therapy) or from placing thin plastic tubes into the intestine. This is known as internal radiation therapy.

Chemotherapy involves the use of cancer-fighting drugs to kill cancer cells. Chemotherapy drugs can be taken in pill form or injected into veins. Chemotherapy is known as a systemic treatment, because the drug enters the bloodstream and travels throughout the body. That way, the drugs can kill cancer cells outside the colon. After surgery, chemotherapy can increase the survival rate for colorectal cancer patients.

Sometimes called immunotherapy, biological treatment is an attempt to get a patient's body to fight cancer. By using materials made by the body (or in a lab) it can boost, direct or restore the body's natural defenses against disease.

Once I've been treated for colorectal cancer, do I still need to be monitored?

Yes. According to a report in the Journal of Clinical Oncology, a more intensive and closely monitored surveillance for patients with colon and rectal cancers proved to reduce the occurrence of cancer recurrence. This was compared to the less aggressive, clinical evaluation approach, which is followed by most hospitals. Researchers found that an intensified follow-up of patients who have finished their surgery and/or chemotherapy and are the in disease -free survival state increased the chances of early diagnosis of cancer recurrence, which could help in treatment and cancer survival.

What can I do to prevent colorectal cancer?

The most effective way to prevent colorectal cancer is through screening tests. Most cases of the disease begin as non-cancerous polyps — grape-like growths on the lining of the colon and rectum. Colorectal cancer screenings often detect polyps, which can be removed before they become cancerous. Because there are often no symptoms related to polyps, it is important to be routinely screened . Your physician may suggest one or more of the tests listed below for colorectal cancer screening.

The following guidelines are for people who do not have an increased risk for colorectal cancer: fecal occult blood test (FOBT) every year; sigmoidoscopy every five years; and colonoscopy every 10 years.

A fecal occult blood test (FOBT) checks for hidden blood in the stool . Studies have proven that this test, when performed every one to two years in people ages 50 to 80, reduces the number of deaths due to colorectal cancer by as much as 30 percent.

A sigmoidoscopy is an examination of the rectum and lower colon using a lighted instrument called a sigmoidoscope . Sigmoidoscopy can find precancerous or cancerous growths in the rectum and lower colon. Studies suggest that regular screening with sigmoidoscopy after age 50 can reduce the number of deaths from colorectal cancer. A polypectomy, which is a procedure to remove a polyp, may be performed during either a colonoscopy or sigmoidoscopy.

An optical colonoscopy is an examination of the rectum and entire colon using a lighted instrument called a colonoscope . Colonoscopy can find precancerous or cancerous growths throughout the colon, including the upper part of the colon, where they would be missed by sigmoidoscopy. However, it is not known whether this benefit outweighs the risks of colonoscopy, which include bleeding and puncturing of the lining of the colon. More research is needed to address these issues.

A digital rectal exam ( DRE ) is often part of a routine physical examination . The health care provider inserts a lubricated, gloved finger into the rectum to feel for abnormal areas. DRE allows for examination of only the lower part of the rectum.

How does a virtual colonoscopy differ from a optical colonoscopy, which is normally performed?

A virtual colonoscopy is a procedure that uses special x-ray equipment to produce pictures of the colon. A computer then assembles these pictures into detailed images that can show polyps and other abnormalities. A study published in 2004 concluded that optical colonoscopy is more sensitive than virtual colonoscopy or air contrast barium enema in detecting polyps and cancers. While optical colonoscopy remains the “gold standard,” virtual colonoscopy could improve the current colonoscopy screening rate of less than 10% in individuals over the age of 50 by being more acceptable, since it is a non-invasive technique. Other studies have suggested that optical colonoscopy is superior to virtual colonoscopy for the detection of lesions less than 10 mm, but are relatively comparable in detecting larger lesions.

Are there any other tests I should consider?

If you have a strong family history of colon cancer, you may want to talk to your doctor or a counselor about having a blood test to look for changed genes. Genetic testing can tell you whether you carry a changed, or mutated, gene that can cause colon cancer. Having certain genes greatly increases your risk of colon cancer. Genetic mutations are more common in certain ethnic groups, such as Ashkenazi Jews (Jews whose ancestors were from Eastern Europe ).

What new advances are developing to test for and treat colorectal cancer?

Today, there are 49 new medicines in development for colorectal cancer, offering patients hope for continued progress.

Twelve years ago there was only one effective chemotherapeutic drug available, fluorouracil. Today, five new drugs in combination with the standard fluorouracil treatment have significantly increased patient survival rates. Combinations of these medicines following surgery have been found to increase average survival to 14 to 20 months compared with a survival rate of only six months with no drug therapy.

In 2004, two new targeted medicines were approved, cetuximab and bevacizumab. They attack specific cancer cells without harming normal cells, reducing the likelihood of side effects associated with traditional chemotherapy. While not a cure, these medicines offer colorectal cancer patients longer lives with an improved quality of life.

Genetic testing of stool samples is also under study as a possible way to screen for colorectal cancer. The lining of the colon is constantly shedding cells into the stool. Testing stool samples for genetic alterations that occur in colorectal cancer cells may help doctors find evidence of cancer or precancerous polyps.

For more information on colorectal cancer, go to the National Cancer Institute ( www.cancer.gov ). If you are in need of a physician, call Suburban Hospital 's physician referral service at (301) 896-3939.



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