Cancer screening is the focus of intense research to determine which are the most effective and cost efficient approaches. Through systematic study we have learned that certain cancer screening tests are useful in specific types of cancer including colon, breast, prostate and some other less common cancers. For example, research tells us that screening techniques have been instrumental in significantly lowering the death rate due to colon cancer. This is because colon cancer begins as a polyp which, over time, transforms into cancer. Colon examination allows not only for detection but also removal of polyps before they become malignant, thus preventing cancer. It is also helps to discover and remove cancers in their earliest stages when the chance for cure is highest. Clinical studies have confirmed that for those over 50 years old and younger people who have high risk factors (eg, family history, genetic disorders and inflammatory bowel disease) screening for colon cancer is better than no screening at all.
Though there are a number of screening options, a multi-agency national task force has determined that the current “gold standard” for colon cancer screening is colonoscopy. Other techniques such as rectal examination or tests that identify blood in the stool, though better than no screening at all, can only detect cancer once it has occurred. CAT scan of the colon (also called “virtual” colonoscopy) and barium enemas may disclose abnormalities. However, individuals still need to complete the bowel preparation beforehand and abnormal areas need to be biopsied in a separate procedure afterwards. Also, Medicare does not cover the expense for this procedure. Capsule endoscopy is a newer digital technique useful for locating sites of bleeding in the small intestine. With this approach, patients ingest a capsule that has a miniature camera which takes pictures of the intestines as it passes along the tract. Images from the camera are downloaded to a computer which can be examined by physicians. The advantages seem obvious. Patients do not need a hospital procedure and sedation or anesthesia is not required. Though the ease of the procedure is intriguing, as with the other tests, capsule endoscopy requires pretest bowel cleansing; and, if there are abnormal findings, subsequent procedures to address the condition discovered. In addition, the capsule is expensive, costing hundreds of dollars. Recently scientists initiated a study involving several hundred people to evaluate the usefulness of this technique as compared to colonoscopy. The technique was found to be considerably less accurate in locating polyps and cancer, confirming that colonoscopy remains the gold standard for colon cancer screening.
As to the role of screening for other cancers, it has long been demonstrated that mammography helps detect breast cancer at a much earlier and, therefore, more curable stage of disease. Prostate cancer screening with digital rectal examinations and prostate specific antigen (PSA) has been used to detect early prostate cancer. It should be noted, however, that PSA levels continue to increase with age. So, the significance of elevated PSA levels must be carefully evaluated by the physician. Performing CAT scans on people with at high risk for lung cancer (eg, people who smoke), have also been used as a screening method. The expense and other problems with these studies have not led to widespread use of CT scanning to detect lung cancers. Screening for other cancers such as blood cancers (leukemia), cervical cancer, ovarian cancer, liver cancer, and esophageal cancer are useful in select populations, but are not recommended for all patients. Scans of the entire body have not shown any advantage. Individuals with a family history of cancer can benefit from more careful screening plans that often involve additional testing not regularly used average risk people. It is important to discuss cancer screening options with your physician to determine the particular plan that is best for you.
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