The Impact of the COVID-19 Pandemic on Cancer Patients: From Mortality Patterns to Long-term Sequelae
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Authors
Wang, Lingchen
Issue Date
2025
Type
Dissertation
Language
en_US
Keywords
Alternative Title
Abstract
The COVID-19 pandemic has constituted one of the most significant public health challenges of this century, profoundly impacting global mortality patterns and healthcare systems. In addition to the immediate consequences of acute infection, a considerable proportion of individuals experience persistent symptoms that extend well beyond the acute phase. Cancer patients are particularly vulnerable to pandemic-related changes, as they are already burdened by chronic illness, immunosuppression, and complex treatment needs. Although previous research has documented an increased risk of severe COVID-19 outcomes among individuals with cancer, there remains a notable lack of population-level studies examining its real-world impact on cancer mortality. Simultaneously, there is an urgent need for large-scale, nationally representative research to evaluate the long-term consequences of COVID-19 among cancer survivors. Furthermore, in modern clinical contexts, the co-occurrence of multiple chronic health conditions—including cancer—has become increasingly common, raising concerns about whether individuals with multimorbidity face elevated risks of developing long COVID.This dissertation aimed to investigate the multifaceted consequences of the COVID-19 pandemic on cancer patients, focusing on changes in mortality patterns and long-term health outcomes:
The first study examined cancer-related mortality changes in the state of Nevada during the first two years of the pandemic (2020–2021), comparing observed deaths to expected values based on pre-pandemic data from 2015 to 2019. The findings showed that overall cancer-related mortality—defined as deaths where cancer was listed as either the underlying or a contributing cause—experienced a modest decline during the pandemic. More specifically, deaths with cancer as the underlying cause declined relative to expectations, while deaths listing cancer as a contributing cause increased. These shifts may be attributed to the mortality shifting from cancer to COVID-19, reduced diagnosis during the pandemic, and potential omissions or misclassification on death certificates.
The second study utilized nationally representative data from the 2022 Behavioral Risk Factor Surveillance System (BRFSS) to assess the prevalence of long COVID among cancer survivors. The results indicated that cancer survivors had significantly higher odds of experiencing long COVID compared to individuals without a cancer history, with the disparity being most pronounced among younger adults. Additionally, the study found that cancer survivors required a higher number of COVID-19 vaccine doses to achieve a significant association with reduced odds of long COVID, compared to those without cancer.
The third study, based on 2023 BRFSS data, explored the relationship between chronic health conditions (CHCs) and long COVID across three dimensions: individual CHCs, cumulative CHC burden, and multimorbidity patterns. All CHCs tested were significantly associated with elevated odds of long COVID. A clear dose-response relationship was observed between the number of CHCs and the odds of long COVID. Furthermore, multimorbidity clusters identified through latent class analysis (LCA) were significantly associated with increased odds of long COVID, with the Severe Multimorbidity Cluster showing the strongest association. In most multimorbidity groups, COVID-19 vaccination was not significantly associated with a reduction in long COVID odds.
Collectively, these studies provide new insights into changes in mortality patterns during the COVID-19 pandemic and the long-term consequences of infection among populations with cancer. The findings highlight the importance of enhancing long-term surveillance, implementing targeted follow-up and supportive care strategies, and promoting COVID-19 vaccination to reduce pandemic-related health disparities in this high-risk population.