Colorectal Cancer: What You Need to Know

  

Richard F. Carter, MD
Richmond Surgical

In 2014, about 143,000 people in the United States will be diagnosed with colorectal cancer, and it is estimated there will be 50,000 deaths. Common in both men and women, it carries an average lifetime risk of 5%. Most colorectal cancers develop slowly over several years, but with the implementation of effective screening, early detection is leading to better outcomes and better chances for a cure. The exact causes of colorectal cancer are unknown; however, research has shown that certain factors do indicate higher risk. These risk factors include being over age 50, colorectal polyps, family history, and certain genetic alterations.

Colorectal cancer is a disease in which cells in the colon or rectum become abnormal and divide without control, forming a mass called a tumor. Before a cancer develops, a growth of tissue usually begins as a non-cancerous polyp on the inner lining of the colon or rectum, which can ultimately develop into cancer.

The wall of the colon and rectum is made up of several layers. If cancer forms in a polyp, it can eventually grow into the wall of the colon or rectum. When cancer cells are in the wall, they can grow into blood vessels or lymph vessels. Once cancer cells spread into blood or lymph vessels, they can travel to nearby lymph nodes or other parts of the body, such as the liver. Physicians describe colorectal cancer by stage, or extent of the disease. The stage is based on whether the tumor has invaded nearby tissues, whether the cancer has spread and, if so, to what parts of the body.

Polyps may be small and produce few, if any, symptoms. Additionally in its early stage, colorectal cancer usually produces no symptoms. Some important warning signs include:

• Any notable change in bowel movement consistency or frequency.
• Dark or light blood in the stool or rectal bleeding.
• Abdominal discomfort or bloating.
• Unexplained fatigue, loss of appetitie, and/or weight loss.

Because symptoms may not be present in early stages, doctors recommend regular screening tests to help prevent colon cancer by identifying polyps before they become colon cancer. Treatment is more likely to be effective when the disease is found early. The choice of treatment depends mainly on the location of the tumor in the colon or rectum and the stage of the disease. Treatment for colorectal cancer may involve surgery, chemotherapy, biological therapy, radiation therapy, or some combination thereof. 

The U.S. Preventive Services Task Force (USPSTF) recommends regular screening for colorectal cancer using high-sensitivity fecal occult blood testing, sigmoidoscopy, or colonoscopy beginning at age 50 years and continuing until age 75 years. People at higher risk of developing colorectal cancer should begin screening at a younger age, and may need to be tested more frequently. The decision to be screened after age 75 should be made on an individual basis. To find polyps or early cancer, health care providers may suggest one or more tests for colorectal cancer screening:

• Flexible sigmoidoscopy every 5 years. Physicians use a flexible, lighted tube (sigmoidoscope) to look at the interior walls of the rectum and part of the colon.
• Colonoscopy every 10 years. Physicians use a flexible, lighted tube (colonoscope) to look at the interior walls of the rectum and the entire colon. During this procedure, samples of tissue may be collected for closer examination, or polyps may be removed.
• Double-contrast barium enema every 5 years. Patients are given an enema with a barium solution, and air is pumped into the rectum. Several x-ray pictures are taken of the colon and rectum, where polyps or tumors may present.
• CT colonography (virtual colonoscopy) every 5 years. This method is under investigation. Advanced CT scan of the colon and rectum that produces 2 and 3-dimensional images of the colon and rectum that allows a doctor to look for polyps or cancer. 
• Fecal occult blood test (FOBT) every year, checking for hidden blood in three consecutive stool samples.
• Digital rectal exam, often part of a routine physical examination.

For those with increased or high risk of colorectal cancer, screening should begin before age 50 and/or more frequently. Patients at higher risk include those with a personal history of colorectal cancer or adenomatous polyps, history of inflammatory bowel disease (ulcerative colitis or Crohn's disease), strong family history of colorectal cancer or polyps, or a known family history of a hereditary colorectal cancer syndrome (HNPCC or FAP).

While screening rates have increased in the U.S., not enough people are being screened still.  In 2009, only approximately 63% of adults aged 50–75 years were screened as recommended. While screening rates continue to rise in the U.S., 22 million people are still not up-to-date with colorectal cancer screening. Patients should talk to their doctor about when to begin screening for colorectal cancer.

For further inquiries about colon health or colorectal cancer, contact Richard Carter, MD, of Richmond Surgical at 804.285.9416.