Within a few years, cancer is on track to overtake heart disease as the #1 cause of death among Americans, and one out of every two of us is expected to be diagnosed with cancer at some point in our lives. Cancer is extremely prevalent, and a big question is how best to fight it. History has shown us that the survival rates are much higher when treating cancer in its earliest stages, and so one main focus of our healthcare system is to diagnose cancer as soon as possible.
I think almost everyone has had at least some experience with cancer screening. We are always told to check ourselves for suspicious lumps or weird pains - things like breast or testicular self-exams. We also undergo screening during our annual checkups. Mammograms (breast cancer), prostate-specific antigen tests (PSA, prostate cancer), colonoscopy (colon cancer) and PAP smears (cervical cancer) are the most common. Other tests that can be used are chest x-rays (lung cancer) and MRI or CT scans (for anything else).
Yet if you read the news, there seems to be a lot of controversy over what kind of tests are necessary. Recently, the US Preventative Services Task Force advised that healthy men should not receive PSA testing. The same task force has also advised against mammography for women under the age of 50. At first glance, this may seem odd - if there is a test that can diagnose cancer, why not perform it all the time?
A good test must be able to accurately detect when cancer is present. But what many people don't consider is this: what happens when the test is wrong? In this post, I'll go over some of the science of screening for cancer, and hopefully explain why the guidelines are set the way they are.
Read more after the break.
