PROJECT SUMMARY/ABSTRACT Since 2005, 199 rural hospitals have closed in the US. These closures have resulted in a loss of primary care physicians, surgical services, limited access to care, preventive services, and treatments, leading to poor outcomes for rural populations. However, the impact of rural hospital closures on cancer outcomes remains largely unknown. Recent studies indicate that rural-urban disparities in cancer care are widening, especially among racial/ethnic minority populations. This disparity could be attributed to the closure of rural hospitals over the last few decades. There is a limited understanding of the impact of these closures on cancer outcomes and racial disparities among rural cancer survivors. To address this gap, we propose a systematic examination of the impact of rural hospital closures on rural cancer survivors among Medicare beneficiaries diagnosed with lung, breast, prostate, and colorectal cancers. The objective of this study is to investigate how rural hospital closures affect cancer outcomes from screening to survivorship and impact racial/ethnic disparities. We will employ a difference-in-differences methodology to conduct this retrospective longitudinal study using Surveillance, Epidemiology, and End Results (SEER) and Medicare linkage data from 2000-2019. We hypothesize that rural counties experiencing hospital closures will exhibit greater disparities in cancer care continuum than those without rural hospital closures. Therefore, the study's specific aims are to: (1) assess the effects of rural hospital closures on cancer screening, diagnosis, treatment, mortality, and survivorship care in rural counties, and (2) examine the impact of hospital closures on minority populations and identify mediators contributing to these disparities. The findings will help bridge the gap in rural cancer care and guide healthcare professionals and policymakers in allocating resources for rural hospitals more effectively. Additionally, this study will provide foundational evidence for the development of alternative medical care services tailored to rural communities. Ultimately, this research aims to optimize healthcare services for rural cancer survivors and reduce racial and ethnic disparities associated with rural hospital closures.