Impact of Modifiable Diet and Lifestyle Factors on Prostate Cancer Progression and Mortality

With over 3.6 million men living with prostate cancer nationally, identifying ways these men can minimize their risk of disease progression is an important public health need. Intervening on modifiable behavioral factors may prevent disease progression and improve quality of life following prostate cancer diagnosis. Several studies have examined the associations of various modifiable factors with prostate cancer progression. These studies have sometimes yielded apparently conflicting results, in particular for dietary factors, potentially confusing clinicians and patients regarding which behaviors to modify. This may be due in part to the limitations of studying a single dietary or other behavioral factor in isolation. Specifically, this approach does not accurately reflect the complex interplay between multiple factors and their ability to act synergistically or antagonistically to impact health. A better understanding of the biological processes relating lifestyle patterns to disease progression is also warranted, as it may aid our understanding of progression risk. The first chapter of my dissertation is a comprehensive summary of the existing evidence relating various diet and other modifiable behaviors with prostate cancer recurrence and progression, prostate cancer-specific mortality, and overall mortality. Across these outcomes, results from this study identified consistently positive associations with body mass index, smoking, and intake of whole milk, saturated fats, and red and processed meats, as well as consistently inverse associations with physical activity and moderate wine intake. These results provided the evidence for the prostate cancer-specific composite risk score evaluated in Chapter 2. In addition to this disease-specific composite risk score, Chapter 2 also explores the association of cancer prevention and survivorship guidelines published by the World Cancer Research Fund / American Institute for Cancer Research and the American Cancer Society, as well as an evidence-based composite risk score created for the risk of developing lethal prostate cancer among disease-free men. Chapter 3 utilizes dietary and lifestyle indices developed to predict biomarkers of inflammation and insulin secretion, to examine the biological mechanisms driving prostate cancer progression and prostate cancer-specific mortality. As a body of work, my dissertation provides insights into the modifiable risk factors driving prostate cancer progression and prostate cancer-specific mortality and improves our understanding of the underlying mechanisms, providing a foundation for future research. Clinically, these findings can inform patient recommendations and aid behavioral change in the survivorship care setting