Back in 2013, the U.S. Preventive Task Forces recommended annual lung cancer screening in adults ages 55 to 80 who had a 30 pack-year smoking history and currently smoke, or have quit within the past 15 years.

This was determined after a 2011 study called the National Lung Screening Trial (NLST) found that screening could prevent lung cancer deaths in high-risk people.

Now, a new study just published in JAMA Internal Medicine finds that implementing such a lung cancer-screening program may be challenging and complex—and even unreliable in offering insights about whether someone actually has cancer or not.

Undertaken by the Veterans Administration (VA), the study found that the rate of false positives was more than double that which was found in the NLST. Of the 2,106 patients screened, about 60 percent had nodules, but only about 2 percent required further evaluation—and just 1.5 percent actually had lung cancer.

“Lung cancer screening is particularly fraught with difficulty and always has been,” says Leena Gandhi, M.D., Ph.D., of NYU Langone’s Perlmutter Cancer Center.

One reason? The test itself, which relies on CT scans, is less reliable at specifically picking up cancer than other tests are, she says. (These 5 tests can save your life.)

“When you use a CT scan, you pick up all kinds of things that aren’t cancer, especially on a smoker or former smoker,” she says. Those include benign nodules and inflammation. When doctors see them, it sparks false positives that could lead to more invasive procedures like biopsies—not to mention a whole lot of anxiety.

What’s more, CT scans also emit radiation, which in itself has been shown to be a cancer risk with cumulative exposure, Dr. Gandhi notes.

Finally, another sticking point is that lung cancer screening requires a sophisticated screening program that’s backed by a lung cancer team—something not found in many areas, says Dr. Gandhi. The VA study was only done in certain parts of the country where those programs were in place, she adds.

So, should you get screened? It turns out that’s a more difficult question than it seems.

The best strategy is to talk with your doctor about risk factors. If you’re a smoker and experiencing symptoms like chronic cough, and/or you have a history of lung cancer in your immediate family, it’s likely that screenings will be used as a diagnostic tool. (Reduce your risk by stop smoking now. These 3 guys who finally quit smoking tell you how.)

But for younger guys who either don’t smoke or quit more than 15 years ago, and have no symptoms and no family history, a screening is usually not used as a preventive test.

This article originally appeared on MensHealth.com.