Project Summary COVID-19, the disease caused by the SARS-coV-2 virus, has now affected nearly 100 million people globally, with nearly 2 million deaths. Patients with cancer have a unique risk profile in this pandemic. Many patients, especially those actively on treatment, have high levels of contact with the health care system. This can include provider visits, phlebotomy, imaging, social work and financial consultations, and infusion room visits for anti-cancer therapy and supportive care such as blood transfusions. Despite heroic efforts to reduce viral transmission in these shared spaces, patients are at an increased risk for COVID-19 exposure. Additionally, most cancer patients are immunocompromised through the marrow toxic effects of anti-cancer drugs, supportive medications such as steroids, and/or the cancer itself; and over 60 years of age, putting them in the highest-risk category for COVID-19-related morbidity and mortality. Finally, incidences of important comorbidities can be considerably elevated in several cancers, such as chronic obstructive pulmonary disease in lung cancer or inflammatory bowel disease in colorectal cancer, further exacerbating their vulnerability to this novel pathogen. Given an acute lack of knowledge and concern for extreme vulnerability, the COVID-19 and Cancer Consortium (CCC19) was formed in March 2020 to understand how the novel virus affects cancer patients. While this national effort began organically, primarily through social media, membership has quickly grown to over 450 healthcare professionals and patient advocates representing over 125 institutions and organizations in the US, Canada, and Mexico. Included in this membership are the majority of the NCI-designated Comprehensive Cancer Centers, NCI-Designated Cancer Centers and large networks of community practices, many of which are NCORP sites. The driving goal of the consortium is to collect prospective, granular, uniformly organized information to help generate hypotheses for translational science, and to arm treating providers with the most complete data resource as rapidly as possible on cancer patients infected with COVID-19. As of January 2021, CCC19 has collected over 8000 case reports of high analytical quality, and has published initial results in The Lancet, Cancer Discovery, Cancer Cell, and Nature Cancer. As the Research Coordinating Center for the consortium, we establish and propagate best practices for governance, data collection, and data dissemination. We host the main data registry, conduct data cleaning, quality assurance, and central data analysis, and will work with participant institutions who choose to set up mirrored local databases.