CT Scans to Find Lung Cancer in Smokers

When you need them—and when you don’t

A low-dose spiral CT (“cat”) scan is a type of medical test. It is used to look for early signs of lung cancer. If the test finds cancer, treatment can start early.

But the test is not helpful for light smokers or people who quit smoking more than 15 years ago. And it’s not usually recommended for people younger than age 55 or older than 80.

Even heavy smokers get only a small benefit from the test. So you should think twice before you get the test. Here’s why:

The test may help high-risk people.

Studies show a slight benefit from CT scans for:

  • People age 55 to 80 who smoked two packs or more a day for 15 years.
  • People who smoked a pack or more a day for 30 years.

If 1,000 high-risk smokers get the test, about three will find lung cancer early and not die. Thirteen others will also find lung cancer, and will die anyway.

The test doesn’t help low-risk people.

CT scans have no benefits for low-risk people. There is no evidence from research that the test helps save lives in low-risk groups.

The test creates false alarms.

CT scans cause many false alarms, even in high-risk people. If 100 high-risk smokers get the test, about 40 will show something that can cause concern. But only two or three actually have lung cancer.

The false alarms often lead to follow-up tests. Usually, you need to get several more CT scans. Or you may need a biopsy, or even surgery. This can sometimes cause complications, like bleeding, or a collapsed lung.

If your risk is low, a false alarm causes unnecessary worry.

CT scans expose you to radiation.

A low-dose spiral CT scan uses about 20 times more radiation than a standard chest X-ray. The more radiation you get, the higher your risk of getting cancer. So, it’s good to avoid radiation when you can.

The test is expensive.

A spiral CT scan costs from $100 to $300, or more. Insurance usually pays for the test for lung cancer screening only if you have a very high risk for developing lung cancer. And the test often leads to other costs. Many people have false alarms that lead to more tests and procedures.

When is a CT scan worth the risks?

You should consider getting a CT scan if:

  • You are 55 to 80 years old and have smoked at least a pack of cigarettes a day for 30 years.
  • You’ve smoked two packs a day for 15 years, and are still smoking or have quit less than 15 years ago.

In high-risk smokers, the benefits of CT scans may be greater than the risks. But that’s not true for others. The test has no proven benefit for other people.

The best way to prevent lung cancer.

If you want to prevent lung cancer, quit smoking. Quitting gives you much better protection than CT scans do.

This report is for you to use when talking with your health-care provider. It is not a substitute for medical advice and treatment. Use of this report is at your own risk.

© 2014 Consumer Reports. Developed in cooperation with the American College of Chest Physicians/American Thoracic Society.