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Screening for Lung Cancer: Insufficient Evidence

The third U.S. Preventive Services Task Force (USPSTF) has been releasing new and updated guidelines during the past 3 years (guidelines homepage; Journal Watch May 15 2001; and Journal Watch Apr 13 2004).

USPSTF 3 concludes each of its guidelines with a recommendation, graded as follows:

A -- The intervention is strongly recommended.

B -- The intervention is recommended.

C -- The USPSTF makes no recommendation for or against the intervention.

D -- The intervention is not routinely recommended.

I -- Evidence is insufficient to recommend for or against the intervention.

The USPSTF has updated and revised its recommendation on lung cancer screening. The 1996 recommendation stated that such screening should not be performed in asymptomatic people; the task force now concludes that the evidence is insufficient to recommend for or against lung cancer screening in asymptomatic people. Recommendation: I

The task force found fair evidence that screening would detect lung cancer at an earlier stage than would no screening. In six cohort studies (without control groups), researchers investigated screening with low-dose computed tomography. The proportion of detected stage 1 cancers was higher than would be expected with usual care, but evidence that screening decreased mortality was lacking. In four of six case-control studies with fair-to-poor methodologic quality, investigators found decreases in early (but not late) lung cancer deaths to be associated with radiographic screening. Seven controlled trials, in which chest radiographs with or without sputum cytology testing were used for screening, demonstrated no significant differences among groups, although control groups were contaminated with some screened patients. Furthermore, the task force identified harms of screening that resulted from false-positives on the most sensitive screening tests and from invasive confirmatory testing.

Comment: The American Cancer Society also recommends against mass lung cancer screening, although their guidelines state that individual physicians and patients might reasonably choose to pursue testing after discussing potential harms and benefits. They recommend that such testing be done at centers that are experienced in lung cancer screening and, preferably, within the context of clinical trials. For most people, however, smoking cessation continues to be the best preventive measure. At the time of publication, the full text of the recommendation statement and the systematic review was available free of charge.

— Richard Saitz, MD, MPH, FACP, FASAM

Published in Journal Watch General Medicine May 21, 2004

Citation(s):

U.S. Preventive Services Task Force. Lung cancer screening: Recommendation statement. Ann Intern Med 2004 May 4; 140:738-9.

• Original article (Subscription may be required)
• Medline abstract (Free)

Humphrey LL et al. Lung cancer screening with sputum cytologic examination, chest radiography, and computed tomography: An update for the U.S. Preventive Services Task Force. Ann Intern Med 2004 May 4; 140:740-53.

• Original article (Subscription may be required)
• Medline abstract (Free)