Currently due to improved screening, earlier detection, and advanced cancer therapy, two thirds U.S. cancer patients can live longer than five years. There were more than 15.5 million U.S. cancer survivors alive in 2016. However, cancer patients have eight times higher risk of developing cardiovascular disease (CVD) than non-cancer patients, due to the cardio-toxic cancer therapies and shared risk factors. Since multisystem comorbidity requires care from multiple specialties, an effective relationship between oncologists and cardiologists may be essential to achieving optimal care. However, the question of how to build such an effective relationship between oncologists and cardiologists to obtain optimal outcomes remains unanswered. To assist decision making of cancer patients, providers and communities, Zhi Pan’s proposed PhD dissertation aims to provide an understanding of the oncologist-cardiologist relationship and thereby facilitate better design of more effective approaches for pursuing optimal prevention, treatment, and population health of adult cancer patients at high risk of developing CVD. This study has three aims: (1) Identify distinct patterns of the oncologist cardiologist relationship in caring for the target population. (2) Determine the impact of oncologist cardiologist relationship on outcomes and quality of care for the target population. (3) Test whether payer status and coverage, provider features, patient demography, and community characteristics affect the oncologist-cardiologist relationship and patient outcomes for the target population.