Not enough evidence to support regular screening for lung cancer

Manser R, Irving LB, Stone C, Byrnes G, Abramson MJ, Campbell D

Published Online:

January 20, 2010

Lung cancer is the most common cause of cancer related death in the western world. It takes about 20 years to develop and cigarette smoking is a known cause. Most lung cancers are not found early in the development of the disease. Regular screening is offered to those considered to be at high risk of contracting the disease. Trials were made of early detection methods such as the testing of sputum, x-ray and computed tomography (CT) scanning of the chest to see whether they made a difference to the number of people who were treated by surgery and the number of people who died as a result of the disease. This review examined the evidence from the trials and found that the early screening does not appear to have much impact on either. The review found that frequent chest x-ray may cause harm to the patient. More research is needed in this area.

Abstract (click to read)

Background:

Population based screening for lung cancer has not been adopted in the majority of countries, however it is not clear whether sputum examinations, chest radiography or newer methods such as computed tomography (CT) are effective in reducing mortality from lung cancer.

Objectives:

To determine whether screening for lung cancer, using regular sputum examinations, chest radiography or CT scanning of the chest, reduces lung cancer mortality.

Search strategy:

We searched electronic databases (the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 4), MEDLINE (1966 to 2007), PREMEDLINE and EMBASE (to 2007)) and bibliographies. We handsearched the journal Lung Cancer (to 2000) and contacted experts in the field to identify published and unpublished trials.

Selection criteria:

Controlled trials of screening for lung cancer using sputum examinations, chest radiography or chest CT.

Data collection and analysis:

We performed an intention-to-screen analysis. Where there was significant statistical heterogeneity, we reported relative risks (RR) using the random-effects model. For other outcomes we used the fixed-effect model.

Main results:

We included seven trials (six randomised controlled studies and one non-randomised controlled trial) with a total of 245,610 subjects. There were no studies with an unscreened control group. Frequent screening with chest x-rays was associated with an 11% relative increase in mortality from lung cancer compared with less frequent screening (RR 1.11, 95% CI 1.00 to 1.23). We observed a non-statistically significant trend to reduced mortality from lung cancer when screening with chest x-ray and sputum cytology was compared with chest x-ray alone (RR 0.88, 95% CI 0.74 to 1.03). Several of the included studies had potential methodological weaknesses. There were no controlled studies of spiral CT.

Authors' conclusions:

The current evidence does not support screening for lung cancer with chest radiography or sputum cytology. Frequent chest x-ray screening might be harmful. Further methodologically rigorous trials are required.

This record should be cited as:

Manser R, Irving LB, Stone C, Byrnes G, Abramson MJ, Campbell D. Screening for lung cancer. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD001991. DOI: 10.1002/14651858.CD001991.pub2

Assessed as up to date:

January 11, 2009

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Primary Review Group:

Lung Cancer Group

Health topics:

Cancer > Lung > Prevention & early detection

Lungs & airways > Lung cancer > Prevention & early detection

Cancer > Screening

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Not enough evidence to support regular screening for lung cancer

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