Five reasons for caution in advocating low-dose computerized tomographic lung cancer screening

Current Controversies in Cardiothoracic Imaging: Overdiagnosis at Lung Cancer Screening-Not So Bad After All-Counterpoint

Initially introduced into the medical literature in research publications from "Special Project #1" of the Council for Tobacco Research, the concept of overdiagnosed lung cancer (OD LC) has consistently served to misinform and confuse the medical community, contributing to interminable delays in implementation of population lung cancer screening. Estimates of overdiagnosis vary enormously (9.5% to 75%). Careful, judicious application of diagnostic algorithms and clinical practice guidelines prevents overtreatment of potentially OD LC and offers a safe and effective method to prevent tens of thousands of LC-related deaths. Speculative concern over potential OD should not further block availability of computed tomography screening to those at risk.

[Lung cancer screening among the smoker population]

CONTEXT

Lung cancer is the most common cancer in men and the leading cause of cancer death worldwide. This cancer, often diagnosed at an advanced stage, mainly affects smokers and survival could increase with early detection. Screening by chest x-ray has not shown its effectiveness, then several randomized trials have been carried out about screening by thoracic low-dose computed tomography in smokers.

METHODS

A systematic review of these trials was conducted according to the PRISMA criteria as well as a point of the difficulties of setting up screening following these trials.

RESULTS

Among five trials that published mortality results, only the US one, the National Lung Screening Trial (NLST) was showed a 20% decrease in lung cancer mortality in smokers screened by low-dose computed tomography compared to chest x-ray. However, besides the lack of power of the other trials, a great heterogeneity of the methods makes the synthesis of the results difficult. While many expert groups are in favor of testing, only the United States has implemented a screening program, whose adherence remains low.

CONCLUSION

Many persistent questions about the eligible population, the organization, the side effects, and finally the cost-benefit, need additional research around these issues.

Blood based biomarkers beyond genomics for lung cancer screening

While there is considerable interest at the present time in the development of so-called liquid biopsy approaches for cancer detection based notably on circulating tumor DNA, there are other types of potential biomarkers that show promise for lung cancer screening and early detection. Here we review approaches and some of the promising markers based on proteomics, metabolomics and the immune response to tumor antigens in the form of autoantibodies.