Divergence between expected and observed national cancer mortality after the COVID-19 pandemic: A population-based analysis.

Abstract

303 Background: The COVID-19 pandemic disrupted cancer screening, diagnosis, and treatment, yet its long-term impact on cancer mortality remains uncertain. Aggregate mortality trends continued to decline during the pandemic, potentially obscuring site-specific deviations from historical trajectories. We evaluated whether individual malignancies diverged from expected mortality patterns following the pandemic. Methods: We conducted a national analysis using U.S. Multiple Cause of Death data (2003–2023), restricted to malignant neoplasms (ICD-10 C00–C97), representing >10 million deaths. Age-standardized mortality rates (ASMRs) were calculated. Expected rates for 2020–2023 were projected from pre-pandemic trends (2003–2019) using log-linear regression. Excess mortality was defined as percent deviation between observed and expected rates, with uncertainty estimated via parametric bootstrap and false discovery rate correction. Results: Overall cancer mortality largely followed projected trends. However, counterfactual analysis revealed significant site-level divergence. Hodgkin lymphoma demonstrated increased mortality (+9.5%, 95% CI 2.7–17.2), and historically stable prostate cancer mortality rose (+7.9%, 95% CI 2.8–13.2), with additional site-level increases and decreases observed. Divergence signals strengthened over time, peaking in 2022. In contrast, several malignancies exhibited below-expected mortality, consistent with potential diagnostic, coding, or competing-risk effects during periods of health-system strain. Conclusions: Aggregate cancer mortality trends mask meaningful disease-specific consequences of pandemic disruption. Divergent increases in malignancies such as Hodgkin lymphoma and prostate cancer may represent early signals of delayed diagnosis or treatment disruption. These findings highlight the need for targeted surveillance strategies to address post-pandemic cancer mortality shifts. Top site-level divergence from expected cancer mortality (2020–2023). Cancer site Excess mortality (%) 95% CI Direction Other & ill-defined sites +15.2 6.0–24.8 ↑ Hodgkin lymphoma +9.5 2.7–17.2 ↑ Malignant neoplasm without specification of site +8.5 4.3–12.8 ↑ Prostate +7.9 2.8–13.2 ↑ Bladder −6.3 −9.7 to −3.9 ↓ Mature T/NK-cell lymphomas −14.0 −19.8 to −6.5 ↓ Liver & intrahepatic bile ducts −15.5 −19.5 to −11.3 ↓ Excess mortality represents percent deviation between observed and expected age-standardized mortality rates for 2020–2023, where expected rates were projected from pre-pandemic trends (2003–2019) using log-linear regression. Direction indicates whether observed mortality was above (↑) or below (↓) projected values. False discovery rate correction was applied across cancer sites.