In people at risk of lung cancer, does population based screening with chest radiography reduce mortality?

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Note: This question was open for public comment from 19 August 2016 to 3 October 2016. This content is not part of the public consultation from 3-30 July 2017 and is therefore not open for comment.


Background

In the previous Australian lung cancer guidelines, it was noted that no forms of population screening for lung cancer, including regular chest radiography, with or without sputum cytology even in high-risk groups, have been shown to improve outcomes and screening is not recommended.

Since then a number of articles have been published (as linked) with two notable papers, the results of the PLCO (prostate, lung, colon and ovarian) cancer screening study of chest radiography in male and female subjects aged 55–74 years[1] and a high quality Cochrane Systematic Review by Manser et al.[2]

PLCO started in 1992, recruiting 154,901 participants, with 50% women and 45% never smokers; randomly assigned to screening or usual care.[1] The research question was whether annual single-view (posterior-anterior) chest radiograph reduced lung cancer mortality compared to usual care. Initially all participants randomised to screening were invited to receive a baseline and three annual chest x-ray screens; the protocol later changed to screen never-smokers only three times. Screening adherence was 86.6% at baseline and 79% to 84% at years 1 through 3; the rate of screening use in the usual care group was 11%.

Cumulative lung cancer incidence rates through 13 years of follow-up were 20.1 per 10 000 person-years in the intervention group and 19.2 per 10 000 person-years in the usual care group (rate ratio [RR]; 1.05, 95% CI, 0.98-1.12). At 13 years of follow-up, 1,213 lung cancer deaths were observed in the intervention group, compared with 1,230 lung cancer deaths in the usual-care group (mortality relative risk, 0.99; 95% CI, 0.87–1.22). Sub-analyses suggested no differential effect by sex or smoking status.

Some Investigators have suggested that a possible small benefit from chest radiography may be possible as the reporting time of PLCO may have been too late.[3] Also, a benefit, smaller than the 20% reduction in lung cancer mortality resulting from the 90% study power is not excluded. For instance, in higher risk PLCO participants matching the National Lung Screening Trial (NLST) criteria[1], an absolute reduction in the number of deaths was observed 316 versus 334 (rate ratio 0.94; with 95% CI 0.81 - 1.10).

The 2013 Cochrane Review is an updated version of the original review published in The Cochrane Library in 1999 and updated in 2004 and 2010.[2] The Authors reported that the meta-analysis of studies comparing different frequencies of chest x-ray screening, 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); noting though that several included had potential methodological weaknesses. Manser et al also observed a non-statistically significant trend to reduced lung cancer mortality with chest x-ray and sputum cytology was compared with chest x-ray alone (RR 0.88, 95% CI 0.74 to 1.03).[2]

Overall, the bulk and consistency of evidence, as well as the lack of significant benefit observed in the PLCO trial supports the conclusion that lung cancer screening with chest radiology does not reduce lung cancer mortality.


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Evidence summary and recommendations

Evidence summary Level References
There is no evidence to support reduced lung cancer mortality through screening for lung cancer with chest x-rays. I [2]
Evidence-based recommendationQuestion mark transparent.png Grade
Chest radiography is not recommended for lung cancer screening in asymptomatic individuals.
A

Research underway

The National Health and Medical Research Council (NHMRC) has recently funded an international multicentre trial (Australia-Canada) of risk stratification to improve the performance of lung cancer CT screening (the International Lung Screen Trial (ILST)), which will in the near future provide additional data likely to be highly relevant to screening in the Australian context.

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References

  1. 1.0 1.1 1.2 Oken MM, Hocking WG, Kvale PA, Andriole GL, Buys SS, Church TR, et al. Screening by chest radiograph and lung cancer mortality: the Prostate, Lung, Colorectal, and Ovarian (PLCO) randomized trial. JAMA 2011 Nov 2;306(17):1865-73 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/22031728.
  2. 2.0 2.1 2.2 2.3 Manser R, Lethaby A, Irving LB, Stone C, Byrnes G, Abramson MJ, et al. Screening for lung cancer. Cochrane Database Syst Rev 2013 Jun 21;6:CD001991 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/23794187.
  3. Sagawa M, Nakayama T, Sobue T, JECS Study Group. A different interpretation of the efficacy of lung cancer screening in the PLCO trial. Eur J Epidemiol 2015 Jul 22 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/26197850.

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Appendices


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