Low dose CT screening for lung cancer could save 12 000 US lives a year, researchers claim

BMJ 2013; 346 doi: (Published 26 February 2013) Cite this as: BMJ 2013;346:f1302
  1. Janice Hopkins Tanne
  1. 1New York

If current and former smokers aged 55 to 74 who smoked a pack a day for 30 years, or an equivalent amount, received low dose computed tomography screening, about 12 000 deaths from lung cancer could be avoided each year in the United States, a study published online in Cancer on 25 February has found.1

The number of people potentially saved by screening is about 7.6% of the lung cancer deaths each year in the US. About 443 000 Americans die each year from lung cancer, the leading cause of cancer death.

Researchers from the American Cancer Society based their study on results from the National Lung Cancer Screening Trial conducted from 2006 to 2009. It showed that low dose CT screening reduced lung cancer deaths by 20% compared with screening with chest radiography.2

Since 2010 about 8.6 million Americans—14.3% of the US population aged 55 to 74—have met the criteria for lung cancer screening that were used in the national trial; 5.2 million of them are men. Low dose CT screening could potentially delay or prevent about 12 250 lung cancer deaths, the report says.

In the national screening trial, over 6.5 years 20% fewer lung cancer deaths were reported in the group screened with low dose computed tomography than in the group screened with chest radiography. All participants had smoked at least 30 pack years.

The estimated cost to prevent one lung cancer death by low dose CT screening ranged widely—from $240 000 (£158 000; €184 000) to $2500, according to several studies quoted in the paper.

In an accompanying editorial in Cancer, Dr Larry Kessler of the University of Washington Health Sciences Center, asks whether the estimates based on the national screening trial show that results can be improved or that a 20% reduction in mortality is all that can be hoped for.3 He notes that lung cancer mortality reached a plateau in US men in the late 1980s and in US women in about 2004.

Smoking rates have declined in the US since the Surgeon General’s 1964 report linking smoking to lung cancer. About 43 million Americans are current smokers and, unless they quit, about half will die from smoking related diseases.

The drawbacks of low dose CT scanning are the high number of false positive results seen in the national screening trial and the costs of investigations, costs of treatment of findings that would not benefit patients, and costs to the Medicare system, Kessler writes.

If screening is implemented in the US, questions need answering about who should be screened and what follow-up is needed for people who are diagnosed and treated surgically for early stage lung cancer. Also, Dr Kessler asks whether costs of screening should be shared among current and former smokers; tobacco companies; health insurance companies; and local, state, and federal governments.

Antismoking campaigns have been the most important factor in the declining mortality, Dr Kessler says. According to one estimate, more than 70 000 lung cancer deaths were averted in 2000 alone by antismoking campaigns.4 “No one should interpret a 20% reduction in mortality as a license to ignore the importance of primary prevention, including clinicians trying to assist patients with smoking cessation as well as public campaigns directed at reducing smoking prevalence,” he writes. Screening and antismoking campaigns must go hand in hand.


Cite this as: BMJ 2013;346:f1302