Tests for Colon Cancer

According to the National Cancer Insitute, 2009 will see the diagnosis of about 106,100 new colon cancer cases. The large intestine is separated into two parts called the colon, which is the first 4 to 5 feet, and the rectum, which is the last several inches. Diagnosis of colon cancer is based on screening results, risk factors, physical examination, blood tests to rule out other causes of the symptoms, imaging tests and a biopsy. Not all tests are indicated for every person suspected of having colon cancer.

Risks

• According to the National Cancer Institute, 90% of people diagnosed with colon cancer are over the age of 50. African-Americans are at an increased risk of colon cancer than other races. Certain diseases or conditions can increase the risk of colon cancer including personal or family history of colon cancer, Crohn's disease, ulcerative colitis, familial adenomatous polyposis, Lynch syndrome, history of radiation therapy to the abdomen, presence of polyps on the inner wall of the colon and diabetes. Risk factors related to lifestyle include obesity, a low-fiber and high-fat diet, a sedentary lifestyle, smoking and heavy alcohol use.

Signs and Symptoms

• According to the National Cancer Insitute, signs and symptoms of colon cancer include diarrhea or constipation, feeling that your bowel doesn't empty completely, bright red or dark blood in the stool, narrower than usual stools, frequent gas pains, feeling full or bloated, unexplained weight loss, constant tiredness, nausea and vomiting. The presence of these symptoms may indicate other conditions as well as the presence of colon cancer.

Screening

• Screening tests are performed to find colon cancer early and to detect the presence of polyps. Early cancer detection improves your outcome. People at a normal risk of colon cancer should begin screening tests at age 50. According to the Mayo Clinic, several options of colon cancer screening include annual testing to check the presence of blood in the stool, flexible sigmoidoscopy every five years, double-contrast barium enema every five years, colonoscopy every 10 years or a virtual colonoscopy every five years. If you are at a high risk for developing colon cancer, your physician will recommend a screening schedule based on your medical history.

Physical Examination

• Your physician will usually begin a colon cancer diagnosis based on an evaluation of your risk factors, asking questions about the presence and duration of signs and symptoms, perform a digital rectal examination to feel for abnormalities, testing to detect the presence of blood in the stool and order blood tests such as a complete blood count and organ function tests. Based on your physician's findings, he or she may order additional imaging tests.

Imaging Tests

• Imaging tests allow your physician to examine inside your body to better detect abnormalities and to assess the spread of the cancer. Imaging tests used to diagnose colon cancer are also options for colon cancer screening. Colon cancer imaging tests include endoscopic tests such as a colonoscopy or sigmoidoscopy, a barium enema which uses a dye to create a silhouette of your colon and a virtual colonoscopy to create a detailed image of your colon. Sigmoidoscopy and colonoscopy are also used to biopsy a small piece of tissue for examination as well as to find and remove polyps.