Letter to the Editors concerning the paper “Ambient air pollution and lung cancer in Poland: research findings and gaps”

In his recent paper on “Ambient air pollution and lung cancer in Poland: research findings and gaps”, Mark Parascandola evaluates available evidence on the etiology of lung cancer as related to air pollution exposure in Poland [1].
The author makes an important remark that estimating the cancer burden of air pollution in a given country requires country-specific data, including information on effects of the exposure on cancer. He correctly says that current estimates of both the relative and attributable risk “are based on relatively limited data, applying risk estimates from studies in other countries to mortality rates in Poland”, which requires numerous assumptions in the case of estimating cancer risk. He then states that “(…) the necessary data sources and studies to estimate the size of this (exposure) burden are lacking in Poland”.
Mark Parascandola identifies several gaps, which should be overcome in order to provide more in-depth assessment of the burden of air pollution on lung cancer in Poland. Two of them are crucial, namely the lack of epidemiological studies and the deficiencies due to limited availability of historical data on ambient air pollution. There is no doubt that the results of prospective cohort studies are generally much more valid when the relationship between air pollution exposure and cancer outcomes is investigated. Poland has never undertaken such a project. The data deriving from ecological and case-control studies, as reviewed by Mark Parascandola, are inconsistent and have substantial limitations due to the challenge of estimating historical exposure to air pollution and weakness of the study design.
However, we strongly disagree that, in view of the lacking local studies, the available global evidence is insufficient to estimate the burden of air pollution exposure to cancer risk in Poland or in any other country, with no local epidemiological study completed (i.e., most of the world). Such global evidence is constantly growing owing to the large cohort studies conducted in the United States, Canada, Europe, China, and South East Asia. Only after the Huang et al. [2] meta-analysis was conducted, several papers were published supporting and strengthening earlier conclusions and risk estimates. Some are based on millions of people followed for a decade or more [3, 4]. They include a prospective cohort study of around 190 thousand adults followed for 16 years in China [5]. Notably, an analysis of...


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