Although the axiom by Benjamin Franklin, “an ounce of prevention is worth a pound of cure” was first used in reference to fire prevention, it has often been used while talking about health. This is very applicable to colorectal cancer.
Colorectal cancer is the fourth most diagnosed cancer in the United States. It is also the fourth leading cause of cancer related deaths, accounting for 14 percent of cancer deaths. Treatment for colorectal cancer includes surgical resection and/or chemotherapy.
The good news, just like any other cancer, the earlier you catch it the better the prognosis. The removal of adenomatous polyps prevents cancer. Studies have showed that patients with adenomatous polyps that were removed had lower rates of colorectal cancer than the general population. So, it is important to detect polyps early.
There are several effective ways to catch colon cancer early. The American Cancer Society (ACS) recently updated their colorectal cancer screening guidelines. ACS guidelines now make a recommendation to begin screening persons at average risk for CRC at age 45 years. The guidelines also now offer six testing options to select among:
- Colonoscopy every 10 years
- Computed tomographic colonography (CTC) every five years
- Sigmoidoscopy every five years
- Take-home high-sensitivity guaiac-based fecal occult blood testing yearly
- Take-home fecal immunochemical testing yearly
- Cologuard, multitargeted stool-DNA test every three years
The most important thing is that you choose one screening plan and stick to it. It is good to know the pros and cons of the options above and discuss with your gastroenterologist the best option for you. We will discuss the stool-based tests available.
There are a variety of guaiac-based fecal occult blood tests, these are the Hemoccult-SENSA, Hemoccult, Hemoccult-II, and Hemoccult-R. Guaiac testing of stool samples identifies a product of hemoglobin, which is the part of our blood that carries oxygen. The product of the hemoglobin causes the paper for the guaiac stool test to turn blue. Because the Guaiac stool test only tests for a product of hemoglobin it is not specific for blood just from the large intestine. In the case of an upper gastrointestinal bleed the hemoglobin would be broken down as it went through the small intestine and would give positive results for the test as well. There are also certain kind of meats and foods that can give a false positive result. The newest Guaiac-based fecal occult blood test is the Hemoccult-SENSA test. This is done by taking a sample of three successive bowel movements at home. The older Hemoccult cards are no longer recommended. It is also not recommended to have a Guaiac-based fecal occult blood test to be tested after a digital rectal exam, due to higher false positives.
Fecal immunochemical testing test for human hemoglobin. It is more specific than the guaiac fecal occult blood test. The American College of Gastroenterology has recommended abandoning the Guaiac stool testing, in favor of the fecal immunochemical testing. The fecal immunochemical testing tests for human hemoglobin. It won’t have the false positives that the Guaiac stool test have from upper gastrointestinal bleeds and foods. Fecal immunochemical testing should be done every year, it is very convenient, it can be done at home, and is non-invasive.
The newest recommended test is the multitargeted stool-DNA test, or Cologuard. It is more sensitive than the other two stool testing methods. It uses the fecal immunochemical test for hemoglobin as well as tests for DNA mutations that can lead to cancer. It only needs to be done every three years if it is negative.
If any of the stool tests have a positive result, make sure you schedule an appointment promptly with a gastroenterologist for a follow up colonoscopy.