Author ORCID Identifier

https://orcid.org/0000-0001-6819-1788

Date Available

8-2-2025

Year of Publication

2025

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Public Health

Department/School/Program

Epidemiology and Biostatistics

Faculty

Krystle A. Kuhs

Abstract

The COVID-19 Pandemic led to global societal disruptions as political leaders and public health authorities attempted to control the spread of the newly discovered SARS- CoV-2 virus. While these measures were designed to lessen morbidity and mortality from a novel pathogen, their impact was also felt in many other, often unintended ways. The purpose of this dissertation is to use cancer surveillance research methods to examine the association between COVID-19 Pandemic-related disruptions and changes in the normal diagnosis and care of cancer in the United States.

The first two studies of this dissertation analyzed reductions in cancer diagnoses in the US during 2020 and 2021 using cancer incidence data from high-quality, population- based cancer registries. Autoregressive integrated moving average models and joinpoint regression models were used to predict expected incidence rates based on pre-pandemic trends, and differences in observed from expected rates were assessed.

In the first study, we found an overall reduction of 13.0% in all cancer sites incidence, with particularly concerning reductions for colorectal, cervical, and lung cancers, and among individuals aged 65 years or older and those living in states with more restrictive COVID-19 responses. Estimated reductions equated to a potential underdiagnosis of 134,395 cancer cases in 2020. The second study showed that rates of cancer incidence remained below expected through the second year of the pandemic, with a significant reduction from expected of 2.7% across all cancer sites in 2021. Recovery was observed for female breast cancer and among individuals aged younger than 65 years, while disruptions remained for lung and cervical cancers.

The third study of this dissertation used linked cancer incidence and mortality data to evaluate whether patients diagnosed with cancer in 2020 experienced worse short-term survival outcomes than those diagnosed prior to the COVID-19 Pandemic. One-year cause- specific survival trends from 2015-2019 were used to project expected survival in 2020, and differences in observed from expected survival rates were assessed. We found a significant 1.2% absolute reduction in one-year cancer-specific survival in 2020 resulting in an estimated 13,517 more deaths than expected within one year of diagnosis.

The collected findings of these three studies demonstrate that substantial changes in cancer diagnosis and outcomes were associated with the onset of the COVID-19 pandemic in the US. Various potential explanations for these changes and implications for contemporary response and future disaster planning are explored.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2025.311

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