By Kenneth Chao, MD
The basic idea behind cancer screening is to catch it early, before symptoms from the cancer occur. A consistent wisdom in maximizing the chance of curing any form of cancer is if you catch it early, you have the best possibility of success. While not all cancers lend themselves to be screened easily, colorectal cancer is one that can be because of its predictable progression from pre-cancerous polyps to malignant tumors.
Cancer Screening Techniques
The simplest forms of colorectal cancer screening are stool-based tests. This includes guaiac and immunohistochemical tests that detect presence of fecal hemoglobin. While simple to perform, compliance may be low due to need for dietary restrictions in some forms of the test. Another drawback with this test is that by itself, the test is not very sensitive and requires follow-up with additional testing for any abnormal results.
The “gold-standard” for colorectal cancer screening involves the direct visualization of the intestine via endoscopy. There are two forms of endoscopy, sigmoidoscopy, in which the endoscopic camera is passed into the latter half of the colon, or colonoscopy, which reaches into the entire colon. These endoscopic procedures are useful not only in diagnosing malignant tumors, but they are useful in identifying pre-cancerous polyps and removing them before development of actual cancerous lesions.
To avoid the invasiveness of direct endoscopies, specialized cameras that are the size and form of medicine pills have been developed. These cameras can be swallowed and allow visualization of the colon without the discomfort of traditional sigmoidoscopies or colonoscopies. Another method of visualizing the colon is the use of computed tomography (CT), which can render a virtual reconstruction of the colon as well as any tumors or polyps within. However, these procedures still require adequate preparation of the colon, and an actual direct endoscopy will still need to be done if an abnormality is identified for the purpose of obtaining biopsies.
Recent studies have substantiated the benefit of colorectal screening in reducing fatality rates from these types of cancers. In order for screening to work, the population at large must understand the benefits of these tests. Hopefully, with improved awareness and better public knowledge about these procedures, along with their associated risks and benefits, more lives may be saved as we promote dedicated compliance with these screening tests.
Dr. Chao is a board certified Radiation Oncologist with Epic Care, a group of experts in the diagnosis and comprehensive treatment of cancer and blood disorders. www.epic-care.com