Deviations from pre-pandemic lung cancer mortality trends in the United States: a 25-year counterfactual analysis (1999-2023).

[BACKGROUND] The COVID-19 pandemic coincided with substantial disruptions to cancer care services worldwide. However, comprehensive population-level assessments of deviations from expected lung cancer mortality trends during the pandemic period using rigorous counterfactual methods remain limited, particularly regarding heterogeneity across demographic and geographic subgroups.

[METHODS] We performed a counterfactual analysis examining lung cancer mortality trends among United States adults aged 45 years and older (1999–2023) using CDC WONDER mortality data. Joinpoint regression characterized pre-pandemic trends (1999–2019) to project expected mortality rates for 2020–2023. Mortality gaps were calculated as differences between observed and expected age-adjusted rates across 66 demographic and geographic strata. Interrupted time series analysis evaluated pandemic-associated trend modifications. Population-weighted linear regression assessed dose-response relationships between state-level COVID-19 burden and lung cancer excess mortality.

[RESULTS] National age-adjusted lung cancer mortality rates declined from 156.03 per 100,000 in 1999 to 94.90 in 2019 (annual percent change: -4.56, 95% CI: -4.92 to -4.20). During the pandemic period, cumulative excess lung cancer mortality totaled 11.26 per 100,000, with statistically significant positive gaps emerging in 2021 (+ 3.67), 2022 (+ 2.77), and 2023 (+ 4.99). Non-Hispanic White populations exhibited three-fold greater 2023 lung cancer excess (+ 6.21) compared to Hispanic populations (+ 1.81). Age-stratified analysis revealed sixteen-fold gradients in lung cancer mortality gaps, from + 1.53 per 100,000 in the 45–54 years cohort to + 24.75 in those aged 85 years and older. State-level cumulative lung cancer mortality gaps ranged from − 40.72 to + 63.16 per 100,000. A significant positive ecological association was observed between state-level cumulative COVID-19 mortality and cumulative lung cancer mortality gaps (β = 0.056, 95% CI: 0.010–0.103,  = 0.022).

[CONCLUSIONS] The COVID-19 pandemic was associated with deviations from expected lung cancer mortality trends, exhibiting substantial demographic and geographic heterogeneity. These patterns may reflect differences in healthcare system capacity across populations. Population-specific surveillance systems and infrastructure investments warrant consideration to maintain cancer care continuity during future public health emergencies.

[SUPPLEMENTARY INFORMATION] The online version contains supplementary material available at 10.1186/s12889-026-26429-x.