Lung cancer screening

Lung cancer screening is a way to detect cancer before patients begin to experience symptoms of the disease. Since lung cancer often doesn’t cause any noticeable symptoms until it’s already progressed to an advanced stage, screening may help diagnose the disease earlier.

According to the American Cancer Society (ACS), lung cancer is the second-most common cancer and the leading cause of cancer death in the United States. By screening patients who have a higher risk of lung cancer, doctors may be able to detect lung cancer while it’s still small. If identified before it spreads, more treatment options may be available. Here’s what adults concerned about their lung cancer risk need to know about lung cancer screening.

Low-dose CT lung cancer screening

The only screening method recommended for lung cancer by the U.S. Preventive Services Task Force (USPSTF) is low-dose computed tomography—also referred to as a low-dose CT scan or LDCT.

During an LDCT, patients lie down on an exam table and a CT machine uses low doses of radiation to take photos of the lungs.

This screening method is recommended annually for adults between the ages of 50 and 80 who smoke a pack a day or have quit within the past 15 years. The procedure takes a few minutes, is noninvasive and doesn’t cause discomfort.

After the procedure is complete, the patient’s medical team examines the images to look for signs of lung cancer.

Lung cancer screening guidelines

Both the ACS and the USPSTF offer guidelines for annual lung cancer screening. The ACS, however, is currently reviewing its guidelines and recommends patients follow the USPSTF lung cancer screening guidelines.

USPSTF recommends that patients who meet all of the following criteria should undergo screening:

• Those in reasonably good health between ages 50 to 80
• Current smokers or former smokers who quit smoking within the last 15 years
• People with a 20 pack-year history of smoking ( pack-year refers to how many packs of cigarettes were smoked by that patient per day, combined with the number of years smoked. For example, smoking one pack of cigarettes per day over 20 years or smoking two packs per day over 10 years both equal a 20 pack-year history.)

Per USPSTF, the following groups of patients recommended to stop screening:

• Are 81 and over
• Have gone more than 15 years since they quit smoking
• Have developed another health condition that would make it difficult to undergo lung cancer surgery

Before undergoing screening, patients should also discuss the benefits and risks of screening with their doctor. Screening should also be done in a facility that has experience with both lung cancer screening and treatment.

For smokers, it’s important to know that cigarette smoking is the biggest risk factor for lung cancer, so quitting, while not a substitute for screening, may help reduce the lifetime risk. While undergoing screening, the patient’s medical team is available to provide support and resources that may help them quit smoking.

Benefits and risks

Lung cancer screening has both benefits and risks, so patients should know that it's important to talk to their doctor and be informed before making the decision to screen. The benefits of lung cancer screening include:

• Screening has been shown to reduce the risk of dying of lung cancer in high-risk patients.
• If lung cancer is found early, the patient may have more treatment options available to them.

The risks associated with screening include:

• Widespread screening may lead to overdiagnosis, where cancers are found and treated that otherwise wouldn’t have caused health problems, putting the patient through unnecessary treatment.
• Screening may show false positives, where the test indicates cancer is present when it isn't. This may cause emotional distress, along with additional unnecessary tests and treatments, like surgeries, that could have risks.
• Frequent LDCT scans expose patients to radiation, which may increase the risk of developing cancer.

To mitigate these risks as much as possible, screening is only recommended for high-risk patients. Patients should talk to their doctor to learn more about the benefits and risks of lung cancer screening.