Major media has largely ignored the potential harms of cancer screening. The WSJ wisely addresses it:
While it may seem like a no-brainer to get a lung scan to find cancer early, it isn’t clear whether doing so will prolong your life. As a result, patients need to be aware of the risks of the screening procedure itself. One concern is radiation exposure. Each low-dose lung CT scan exposes you to about a year’s worth of ambient radiation, which is the radiation we are exposed to every day from our environment. A one-year dose isn’t much, but if a patient decides to undergo annual screening for 20 years, the numbers can add up.Another concern is a false positive. False positives can range from 10% to 50%. This means a radiologist sees something on your scan that looks like cancer but isn’t. If that happens, you may need additional scans and in some cases, a lung biopsy for benign growths. About 10% of the time a biopsy can result in a collapsed lung or other complications.
The biggest risk of scanning is unnecessary surgery. Some experts think many of the lesions found on CT scans look like cancer in the biopsy, but they don’t act like cancer — meaning they aren’t aggressive and don’t spread. The problem is that it is impossible to tell the difference between aggressive and nonaggressive cancers and so they are all removed, along with a big portion of the patient’s lung. In one recent study, the chance of a patient undergoing a lung resection went up 10 times if he or she was screened.
With the recent flurry of similar blog posts, you may think that I’m against cancer screening. Not true. I most definitely support evidence-based (i.e. studies showing a mortality improvement) cancer screening. Too many stories recently, such as breast MRIs and chest CTs for lung cancer, falsely hype tests without the benefit the evidence behind them. Doctors that don’t present a balanced view do their patients a disservice.
