We read with interest the article entitled, "Estimation of the risk of lung cancer in women participating in a population-based breast cancer screening program", published by González-Marron et al., and we would like to highlight some issues with this paper.1 First, the authors assume that the results of the NELSON study are valid, although these had not been published in full at the time of submission of this letter. The only results available are from the presentation made by the lead author of the study at the World Conference on Lung Cancer in 2018, where he pointed out that the NELSON study does not have sufficient power in women, since they accounted for only 16% of the sample (the author states: "includes a small subgroup of women" and, "the trial was initially powered for high risk males"). Accordingly, we believe it is arguable that the results of the NELSON study are applicable to women in this study.2

Second, the title of the article itself is confusing. Strictly speaking, the study presented does not make a risk estimate, but quantifies the percentage of women who would meet the screening criteria proposed by the NLST and NELSON studies, respectively. Equating "risk estimation” with the fulfillment of screening criteria could confuse readers, especially when numerous recently published studies have suggested that risk estimation in lung cancer (LC) screening, if performed, should be individualized for each patient, as the criteria used by both studies, particularly the NLST, imply a high percentage of false positives.

Third, LC screening continues to be the subject of debate in Europe and the United States.3 It is remarkable that the possibility of screening in Spain is being suggested when experts cannot even agree on the periodicity of this screening. The NELSON and NLST studies have different screening schedules, and the NELSON study also has rounds of varying duration. Few people know, moreover, that although the Medicare and Medicaid Committees indicated that the benefit/risk ratio of LC screening was unfavorable,4 LC screening was introduced in the United States following pressure from senators and congressmen.

Finally, the authors should have highlighted the enormous opportunity cost of funding smoking cessation treatments compared to the implementation of screening, as has been shown in Spain.5 This funding would prevent respiratory, cardiovascular, and numerous types of cancer, significantly increase life expectancy in these new ex-smokers and, in addition, involves far less iatrogenesis than participation in an LC screening program. In our opinion, more emphasis should have been placed on the need to promote strategies such as the World Health Organization’s MPOWER measures (https://www.who.int/tobacco/mpower/en/) to reduce tobacco use in Spain, particularly among women who can attend any population screening program, not just for breast cancer.