Lung Cancer Screening

January 24, 2025

This page was reviewed under our medical and editorial policy by Jyoti Malhotra, M.D., M.P.H., associate professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Orange County Lennar Foundation Cancer Center; and Jae Y. Kim, M.D., associate professor, Division of Thoracic Surgery, Department of Surgery, City of Hope Cancer Center Duarte

Lung cancer screening may be recommended for patients without any symptoms of the disease. Screening means examining someone for signs of cancer before they develop any noticeable symptoms.

With lung cancer, screening may be recommended for certain groups of people who have a higher risk for developing the disease. The aim is to find cancer when it is still small and in the early stages because more lung cancer treatment options are then available.

This guide to lung cancer screening is designed to help patients learn more.

Lung Cancer Screening Guidelines

Guidelines are in place to determine which patient groups would benefit most from lung cancer screening. Both the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) recommend yearly lung cancer screening for people in the following groups, based on both smoking history and age:

• Between 50 and 80 years old
• Are current smokers or have quit smoking within the last 15 years
• Have a 20 pack-year of smoking history

A pack-year is a measurement of how often someone smokes cigarettes or other tobacco products. It is based on an average of smoking 20 cigarettes (the equivalent of one pack) daily over the course of one year. A 20 pack-year would mean smoking 20 cigarettes a day for 20 years or smoking 40 cigarettes a day for 10 years.

It may be confusing to understand who should undergo lung cancer screening, so patients should always ask their medical team for guidance.

When to Stop Lung Cancer Screening

Both the CDC and the USPSTF recommend halting lung cancer screenings if:

• At least 15 years have passed since the person quit smoking
• The patient has developed an illness that reduces life expectancy significantly
• The patient is unable or unwilling to undergo curative intent therapy

The CDC further indicates that patients who are at least 81 years old may stop being screened for lung cancer.

Talk to a pulmonologist, family doctor or other care team member to determine when the time is right to discontinue lung cancer screenings.

Screening With a Low-Dose CT Scan

A low-dose computed tomography (LDCT) scan is the only recommended screening tool for lung cancer.

An LDCT is a type of imaging test that uses computers, X-ray machines and low doses of radioactive materials to take 3D pictures of the lungs. Doctors use the resulting images to look for evidence of lung cancer.

In the past, chest X-rays and mucus tests (sputum cytology) were used for lung cancer screening, but they are not used for this purpose anymore.

How Accurate is a CT Scan for Lung Cancer Screening?

LDCT testing is very accurate when screening for lung cancer, with the sensitivity of these devices ranging from 59% to 100%, according to the U.S. Preventive Services Task Force. This means that LDCT testing was able to determine if a patient was positive for lung cancer 59% to 100% of the time.

The National Cancer Institute notes that annual LDCT screening for three years in groups at increased risk of lung cancer lowered the chance of lung cancer deaths by 20% in a major trial.

Lung Cancer Screening Results

Screening may sometimes find abnormalities in the lungs or other nearby organs, but in most cases, they are caused by things other than lung cancer. If screening shows abnormal results, additional testing may be done.

Results should be ready in several days, although it may take longer. Doctors always discuss the results with each patient, explaining what they mean and what happens next.