Effects of the Coronavirus disease 2019 pandemic on mortality in patients with lung cancer: A multiple mediation analysis in Japan

COVID-19 pandemic has had a substantial effect on healthcare systems worldwide, including the care of patients with lung cancer. The impact of healthcare disruptions and behavioral changes on lung cancer mortality is unclear. Patients newly diagnosed with lung cancer during the pandemic period 2020-2021 were compared with those diagnosed in the pre-pandemic 2018-2019. The primary outcome was all-cause mortality within 1 year. Cox proportional hazards regression analyses were conducted to estimate the changes in mortality between pandemic and pre-pandemic. Multiple mediation analyses were performed to determine the factors that accounted for the changes in mortality. In total, 5785 patients with lung cancer were included in this study. The overall mortality rate was significantly higher during the pandemic compared with the pre-pandemic (crude hazard ratio HR: 1.19, 95% confidence interval CI: 1.05, 1.29). Mediation analyses showed that not receiving tumor-directed treatment, diagnosis at an older age, and decreased diagnosis through cancer screening significantly accounted for 17.5% (95%CI: 4.2, 30.7), 13.9% (95%CI: 0.8, 27.0), and 12.4% (95%CI: 3.0, 21.8) of the increased mortality, respectively. This study revealed a significant increase in mortality risk in patients with lung cancer who have not received tumor-directed treatment or cancer screening, despite potential selection bias for follow-up status. Efforts should be focused on ensuring timely access to healthcare services, optimizing treatment delivery, and addressing the unique challenges faced by patients with lung cancer during the pandemic to mitigate the impact of the pandemic on lung cancer outcomes and provide clinical care to vulnerable populations.