To what extend does exposure to air pollutants is linked with death in lung cancer patients with COVID-19 diagnosis? Primary observations by the Cancer Registry of Crete

Background: Emerging evidence, during the COVID-19 pandemic, supports a link between air pollution and other environmental factors and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and COVID-19 susceptibility and severity. These effects seem to be even more intense in patients with chronic conditions, such as cancer. Aim: To assess the differences in COVID-19 deaths, hospitalizations and survival in cancer patients with high or low exposure to air pollutants. Methods: We included 584 lung cancer patients with verified histological diagnosis from 2020 to March 2022 (107 of them had positive antigen or PCR test). The cases were obtained from the Cancer Registry of Crete and linked with data of outdoor air pollutants (OAP). The OAP indicators included measurements on particulate matter (PM)2.5, between 2.5 and 10 μm (PM2.5-10), PM10, PM2.5 absorbance (black carbon measure), nitrogen dioxide (NO2), and nitrogen oxides (NOx). The case fatality rate (CFR) of COVID-19 deaths in lung cancer patients per AOP exposure group was calculated and the Net-Survival was estimated (Kaplan-Meier Curves). Results: The prevalence of COVID-19 in lung cancer patients was 18.3% in the Cretan cohort. In these 107 case-series, the 71.9% required long hospitalization with median stay of 15 days. The vast majority of them (80.5%) were highly exposed to AOP, whereas only the 19.4% has low levels of AOP exposure (p=0.03). All patients were of stage I or II and presented an overall CFR of 74.6% during the 6-month follow-up period, with the majority being highly exposed to AOP (p<0.001). The 6-month Net-Survival for patients with high AOP exposure was 11.2% versus 33.5% in those with low AOP exposure. Conclusions: The role of AOP seems to be integral in lung cancer patients survival during the COVID-19 pandemic, but further studies using genome-wide cohorts are required to establish a causal association.