The effects of the COVID-19 pandemic on cancer incidence and cancer-specific mortality.

10589 Background: The 2020 COVID-19 pandemic had a significant impact on cancer screening rates and cancer-related outcomes. The purpose of our study was to determine how the pandemic has affected cancer incidence, incidence by Surveillance, Epidemiology and End Results (SEER) stage, and cancer-specific mortality for the most common cancers in incidence and cancer-specific mortality. Methods: The data for our population-based cohort study was accessed by permission from the SEER dataset. We aggregated data for incidence and cancer-specific mortality regarding the leading ten cancers in incidence and cancer-specific mortality, plus cervical cancer, between January 1, 2017 and December 31, 2022 and further divided this time period into two 36-month pre-pandemic and post-pandemic groups. Demographic variables were collected for stratified analyses. Poisson regression models were used to estimate incidence and mortality rates for each cancer type, incorporating the natural logarithm of the total population as an offset term to account for differences in population size. Results: Nine of eleven cancers showed significantly higher IRRs (incidence rate ratios) for distant SEER stages during the 36-month post-pandemic period. Most importantly, several cancers with established screening modalities had significantly increased IRRs for distant SEER stage of disease including prostate cancer (IRR 1.175, 95% CI: 1.155-1.195, p<0.001), breast cancer (IRR 1.060, 95% CI: 1.040-1.080, p<0.001), and colorectal cancer (IRR 1.034, 95% CI: 1.020-1.048, p<0.001). Cancer-specific mortality showed significantly increased post-pandemic mortality rate ratios (MRRs) for pancreatic cancer (MRR 1.049, 95% CI: 1.041-1.056, p<0.001), prostate cancer (MRR 1.042, 95% CI: 1.032-1.051, p<0.001), and liver cancer (MRR 1.026, 95% CI: 1.016-1.036, p<0.001). Lung cancer (MRR 0.931, 95% CI: 0.927-0.935, p<0.001), Non-Hodgkin’s Lymphoma (MRR 0.972, 95% CI: 0.961-0.983, p<0.001) and breast cancer (MRR 0.989, 95% CI: 0.981-0.996, p=0.004) all had significantly lower cancer-specific mortality in our post-pandemic period. Conclusions: In this large population-based cohort, we observed a shift towards more distant SEER stage cancer diagnoses in the post–pandemic period. The increase in advanced-stage diseases reflects a higher burden of disease and is particularly concerning for cancers with proven screening benefit. These findings suggest persistent downstream effects of disruptions in routine healthcare and cancer screening which have added to the public health crisis of the COVID-19 pandemic.