Screening for Lung Cancer: Recommendations from the U.S. Preventive Services Task Force

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The summary below is from the full reports titled "Lung Cancer Screening: Recommendation Statement" and "Lung Cancer Screening with Sputum Cytologic Examination, Chest Radiography, and Computed Tomography: An Update for the U.S. Preventive Services Task Force." They are in the 4 May 2004 issue of Annals of Internal Medicine (volume 140, pages 738-739 and pages 740-753). The first report was written by the U.S. Preventive Services Task Force; the second report was written by L.L. Humphrey, S. Teutsch, and M. Johnson.

What is the U.S. Preventive Services Task Force?

The U.S. Preventive Services Task Force (USPSTF) is a group of health experts that reviews published research and makes recommendations about preventive health care. The USPSTF and its review of the published research are supported by the Agency for Healthcare Research and Quality (AHRQ).

What is the problem and what is known about it so far?

Lung cancer is the most common cause of cancer-related death among both men and women in the United States. Since smoking is the major risk factor for lung cancer and 24% of U.S. adults smoke, lung cancer will continue to be a major problem. Lung cancer is difficult to treat unless it is found at very early stages. Unfortunately, most people do not develop symptoms until the cancer has spread. Symptoms include cough, spitting up blood, weight loss, and difficulty breathing. Tests that can detect lung cancer before patients have symptoms include chest x-rays, computed tomography (computerized x-rays, also called CT scans), or sputum cytologic examination (looking for cancer cells in the fluid that patients cough up). Screening for lung cancer would involve using one of these tests to look for lung cancer in people who have no lung cancer symptoms. In 1996, the USPSTF recommended that doctors not use these tests to screen for lung cancer because studies suggested that the harms were greater than the potential benefits. Since 1996, additional studies have become available.

How did the USPSTF develop these recommendations?

The USPSTF reviewed published research about the benefits and harms of screening for lung cancer.

What did the authors find?

The authors found 4 fair-quality studies of lung cancer screening with chest x-ray, sputum cytologic examination, or both. None of these studies showed a benefit of screening. Five fair-quality studies from Japan suggested a possible benefit of screening, but these studies had important problems, so the findings are not definitive. Six uncontrolled studies have shown that CT scans can detect lung cancer before patients have symptoms, but none of these studies looked to see whether finding the disease early helped patients. These studies also showed that CT scans often have false-positive results. "False positive" means that the test suggests that a patient has lung cancer when he or she does not. False-positive test results can lead to unnecessary worry, additional tests, and even surgery.

What does the USPSTF suggest that patients and doctors do?

The USPSTF recommends neither for nor against using chest x-ray, computed tomography (CT scan), or sputum cytologic examination to look for lung cancer in people who have no symptoms to suggest the disease. If screening is being considered, doctors and patients should discuss the pros and cons of screening before going ahead with x-ray, CT scan, or sputum cytologic examination to screen for lung cancer. Patients should be aware that there are no studies showing that screening helps people live longer. They should also know that false-positive test results are common and can lead to unnecessary worry, testing, and surgery.

What are the cautions related to these recommendations?

Two high-quality studies of using chest x-ray or CT scans to screen for lung cancer are under way; these recommendations may change when the results of these studies become available.