Colon Cancer -- June 30, 2008 -- Dr. Bernard Burgess & Dr. Patrick Murphy - NewsChannel5.com | Nashville News, Weather & Sports

Colon Cancer
Bernard Burgess, M.D.
Medical Mondays news notes
June 30

In the United States, colorectal cancer is the fourth most common cancer in men, after skin, prostate and lung cancers. It is also the fourth most common cancer in women, after skin, lung and breast cancers. No one knows the exact causes of colorectal cancer, also called colon cancer. Doctors seldom can explain why one person develops the disease and another does not.

Risk factors

Research has shown that people with certain risk factors are more likely than others to develop colorectal cancer. These include:

• Age: Colorectal cancer is more likely to occur as people get older. More than 90 percent of people with this disease are diagnosed after age 50. The average age at diagnosis is the mid-60s.
• Colorectal polyps: Polyps are growths on the inner wall of the colon or rectum. They are common in people over age 50. Most polyps are benign (noncancerous), but some polyps can become cancer. Finding and removing polyps may reduce the risk of colorectal cancer.
• Family history of colorectal cancer: Close relatives (parents, brothers, sisters or children) of a person with a history of colorectal cancer somewhat are more likely to develop this disease themselves, especially if the relative had the cancer at a young age. If many close relatives have a history of colorectal cancer, the risk is even greater.
• Personal history of colorectal cancer: A person who already has had colorectal cancer may develop colorectal cancer a second time. Also, women with a history of cancer of the ovary, uterus or breast are at a somewhat higher risk of developing colorectal cancer.
• Ulcerative colitis or Crohn's disease: A person who has had a condition that causes inflammation of the colon for many years is at increased risk of developing colorectal cancer.
• Diet: Studies suggest that diets high in fat (especially animal fat) and low in calcium, folate and fiber may increase the risk of colorectal cancer. Also, some studies suggest that people who eat a diet very low in fruits and vegetables may have a higher risk of colorectal cancer. More research is needed to better understand how diet affects the risk of colorectal cancer.
• Cigarette smoking: A person who smokes cigarettes may be at increased risk of developing polyps and colorectal cancer.

People who think they may be at risk should discuss this concern with their doctor. Physicians may be able to suggest ways to reduce the risk and can plan an appropriate schedule for checkups.  

Screening

Colon cancer screening can detect polyps, early cancers and changes that can be treated before symptoms develop. Regular screenings may decrease deaths and prevent pain caused by colorectal cancer. Colon cancer screening is as effective as breast cancer screening when it comes to saving lives.

There are three ways to screen for colon cancer:

1. A stool test examines bowel movements to check for blood.
2. A sigmoidoscopy exam uses a flexible, small scope to look at the lower part of the colon. Because it only looks at the large intestine, it may miss some cancers. Most health care providers recommend the stool test and the sigmoidoscopy be used together.
3. The third method is a colonoscopy exam. A colonoscopy is similar to a sigmoidoscopy, but it allows the entire colon to be viewed. The patient usually will be mildly sedated during a colonoscopy.

The American Cancer Society makes the following recommendations:

Beginning at age 50, both men and women should be screened for colon cancer. Some recommend that African Americans begin screening at age 45. People with certain digestive diseases (such as ulcerative colitis) or a family history of colon cancer may need earlier and more frequent testing. The Centers for Disease Control reports that incidence of colon cancer has decreased significantly by 2.3 percent per year from 1998 to 2004 for men and women combined, and that success can be attributed in part to screenings.

Screening options for patients with an average risk for colon cancer:

• Colonoscopy every 10 years
• Double-contrast barium enema every five years
• Fecal occult blood test (FOBT) every year - if results are positive, a colonoscopy is needed
• Flexible sigmoidoscopy every five years
• Virtual colonoscopy every five years
• Yearly FOBT plus sigmoidoscopy every five years - this combination is preferred over the two tests alone

There is not enough evidence to determine which screening method is best. Colonoscopy is the most thorough method, but it takes longer, requires sedation, is slightly riskier and is much more expensive than a sigmoidoscopy.

Signs and Symptoms

While possible signs of colon cancer include a change in bowel habits or blood in the stool, other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur.

• A change in bowel habits
• Blood (either bright red or very dark) in the stool
• Diarrhea, constipation or feeling that the bowel does not empty completely
• Stools that are narrower than usual
• Frequent gas pains, bloating, fullness or cramps
• Weight loss for no known reason
• Feeling very tired
• Vomiting

Treatment   

Treatment depends partly on the stage of the cancer. In general, treatments may include:

• Chemotherapy to kill cancer cells
• Surgery to remove cancer cells
• Radiation therapy to destroy cancerous tissue

Stage 0 colon cancer may be treated by removing the cancer cells, often during a colonoscopy. For stages I, II and III cancer, more extensive surgery is needed to remove the part of the colon that is cancerous.

There is some debate as to whether patients with stage II colon cancer should receive chemotherapy after surgery. You should discuss this with your oncologist.

Almost all patients with stage III colon cancer should receive chemotherapy after surgery for approximately six to eight months. The chemotherapy drug 5-fluorouracil has been shown to increase the chance of a cure in certain patients.

Chemotherapy also is used to treat patients with stage IV colon cancer.

For patients with stage IV disease that has spread to the liver, various treatments can be directed specifically at the liver.