Emerging evidence suggests that childhood cancer survivors treated without central nervous system (CNS) directed therapies are at significant risk for neurocognitive impairment that is associated with decreased social attainment and quality of life. However, the underlying biological mechanisms of neurocognitive impairment in this population are poorly understood limiting our ability to prevent or alleviate these adverse outcomes. Long- term survivors of childhood cancer have a higher frequency of frailty and chronic health conditions than sibling controls suggesting cancer therapy may accelerate the physiological and biological aging process, which may lead to neurocognitive impairment. Studies in the general population indicate systemic inflammation and oxidative stress increase with age and are associated with increased morbidity, mortality, and cognitive decline. Inflammation and oxidative stress are also important regulators of telomere length and epigenetic changes which have been associated with neurocognitive impairment in aging non-cancer populations. These biomarkers have yet to be extensively examined in childhood cancer survivors treated without CNS directed therapies. The objective of this K99R00 is to identify aging-related biological predictors of neurocognitive impairment and subsequent decline in order to inform the design of future interventions using existing data and biospecimens from 300 HL survivors and 200 community controls in the St. Jude Lifetime cohort. Specifically, the K99 phase aims to examine cross-sectional associations between markers of inflammation, oxidative stress, immunosenescence, and cellular aging (telomere length and epigenetic age acceleration) with neurocognitive impairment in long-term Hodgkin lymphoma survivors (HL). The R00 phase will expand on these findings by first describing the trajectory of neurocognitive decline in long-term HL survivors and then by examining longitudinal associations between these biomarkers and subsequent neurocognitive decline. Further, these studies will provide data on the influence of modifiable risk factors (e.g. exercise, smoking, nutrition) on these biomarkers to inform future development of interventions to mitigate neurocognitive impairment in cancer survivors. Dr. Williams is an emerging translational cancer control epidemiologist focused on underlying pathophysiologic and biologic mechanisms of neurocognitive function in cancer survivors. The K99R00 allows Dr. Williams to develop expertise in 1) neurobiology and cancer biology and treatment specific to HL, 2) aging-related biomarkers and molecular epidemiology, 3) complex statistical methods and 4) clinical and behavioral intervention trials. Dr. Williams' mentoring team has extensive expertise in neurocognitive assessments, neuropathology, molecular epidemiology, childhood cancer, and statistical methods. St. Jude Children's Research Hospital is an international leader in cancer control and survivorship and provides a resource-rich training environment for Dr. Williams. The combined training and research plan will ensure Dr. Williams' transition to independence by providing the skills and preliminary data to successfully compete for future R01-level grants.
Despite having no therapy directed to the brain, many childhood cancer survivors experience treatment-related morbidities including cancer-related neurocognitive impairment decades after treatment. Understanding the biological mechanisms driving long-term neurocognitive impairment would identify high-risk groups and inform on potential interventions to prevent or alleviate symptoms. Therefore, we propose to study several potential aging-related biomarkers and their associations with neurocognitive impairment and decline over time in long- term survivors of Hodgkin lymphoma.