Impact of air pollution on the progress-free survival of non-small cell lung cancer patients with anti-PD-1/PD-L1 immunotherapy: A cohort study

Air pollution is a well-established risk factor for lung cancer, but limited evidence exists on its impact on the treatment of lung cancer. The objective of this study was to investigate the impact of key pollutants on the efficacy of PD-1/PD-L1 inhibitor immunotherapy in non-small cell lung cancer (NSCLC) patients, thereby providing clinicians with evidence to potentially enhance the efficacy of PD-1 therapy and inform policy decisions for cancer care. To this end, we conducted a study involving 361 NSCLC patients who received PD-1/PDL1 inhibitor immunotherapy, examining the correlation between air pollution exposure and progression-free survival (PFS) following immunotherapy treatment. Their moving-average ambient levels up to 1 year of PM2.5 and its constituents (organic matter (OM), black carbon (BC), nitrate (NO3- ), sulfate (SO42- ), and ammonium (NH4+)), as well as ozone (O3) were estimated using the Tracking Air Pollution in China dataset. Cox proportional hazards models were adopted to estimate the effects of exposure to each pollutant on PFS risk for NSCLC. 179 patients obtained the progression of NSCLC. While PM2.5 exposure prior to the immunotherapy was not associated with NSCLC progression, long-term exposure to BC and OM, the important organic components of PM2.5, were significantly associated with a higher risk of NSCLC progression with corresponding hazard ratios (HRs, 95% confidence intervals) of 2.42 (1.39, 4.23) and 2.41 (1.40, 4.14) for 1-year moving average, respectively. Short-term exposure to O3 was also associated with PFS with a HR of 1.64 (1.08, 2.50) for 3-month averaged exposure. Monotonic increasing dose-response relationships were further observed for the associations of BC, OM and O3 with PFS. Our findings imply the need of implementing effective measures for targeted reduction in specific sources of PM2.5 constituents (especially BC and OM) and O3 at different time windows to improve the prognosis of NSCLC patients especially for their PFS.