Lung Cancer: To Screen or Not to Screen

Kenneth W. Lin, MD, MPH


January 16, 2015

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Editor’s Note: On February 5, 2015, CMS announced that it will cover the costs of lung cancer screening for patients up to 77 years of age, rather than the previously announced upper age of 74 years.

Hi, everyone. My name is Dr Kenny Lin. I am a family physician at Georgetown University School of Medicine, and I am also a blogger for Common Sense Family Doctor.

Today, I am going to talk to you about lung cancer screening. In November of last year, the Centers for Medicare & Medicaid Services (CMS) approved paying for a "counseling and shared decision making visit" with high-risk patients about the benefits and harms of [low-dose] CT screening for lung cancer.[1] This is where family physicians come in.

Who among your patients do you need to be having this discussion with, and what topics should you be talking about with them? First, you need to make sure they are eligible for lung cancer screening. This means that your patient needs to be between 55 and 74 years old, have at least a 30-pack-year smoking history, and also either be a current smoker or have quit within the past 15 years. They also need to be in reasonably good health and willing to undergo curative lung surgery, if necessary.

You can tell these patients that, in a large national study, 1 out of every 320 patients who received a yearly CT scan for 3 years in a row had lung cancer death prevented by screening.[2] That is the good news. The bad news is that more than 80% of lung cancer deaths are not preventable by screening, and lung cancer screening does not prevent against other cancers caused by smoking—nor does it prevent other diseases, such as heart disease, that are caused by smoking.

In fact, a patient who quits smoking is much more likely to avoid lung cancer death than a patient who continues smoking and undergoes lung cancer screening, although there is no reason why they can't do both at the same time.

It is important to discuss a few other downsides of lung cancer screening with your patients. The first and most common of these is false positive results. Ninety-six out of every 100 positive results in the national lung cancer screening study was actually a false positive, and 1 in 3 patients in the study actually experienced at least one false positive. Some experienced more than one.

Also, many incidental findings turn up from CT scans, most of which are essentially benign but some of which cause patients to have to endure additional scans and anxiety. These additional scans make it uncertain whether the cumulative radiation exposure that a patient might get from having a CT scan every year for 20 years might also be likely to cause cancer, given the high false-positive rate of CT lung cancer screening.

Finally, one thing to mention is that 1 in 5 lung cancers detected by screening is most likely overdiagnosed, meaning that a patient will experience symptoms from lung cancer screening that they would not have developed in the absence of screening but would be treated, in these cases unnecessarily.

CMS recommends that you use a shared decision-making aid with the patient. There are several of these available online. My favorite one is the Dartmouth-Hitchcock Medical Center shared decision-making aid, which I think illustrates the benefits and harms of screening very well.

This is really a difficult decision, and these are difficult discussions, but it is good that CMS has chosen to pay family physicians for having them. I hope that my talk has helped guide you a little bit about the topics that you need to cover.


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