Healthcare providers in all 50 states are required by law to report new cases of cancer to their state’s cancer registries. The National Cancer Institute’s (NCI’s) Surveillance, Epidemiology, and End Results (SEER) Program, collects data on each and every cancer patient in SEER covered areas. This data includes demographics, a description of their cancer, limited initial treatment information, and patient follow-up including cause of death for deceased patients. In the past the main source of registry data came from Hospitals. With the increasing complexity of cancer care and delivery systems, patients are being increasingly treated exclusively at physicians’ offices. Thus, for SEER to continue capturing all cancer cases and their treatment information SEER is interested in obtaining other sources of data such as claims data from oncology practices. Oncology practice claims has proven to be a rich source of information on detailed systemic therapy, including agents, doses administration dates etc. Beginning in 2015, the NCI SEER Program began supporting the procurement of oncology practice claims data for six (6) SEER central cancer registries from Unlimited Technology Systems, LLC. Unlimited Technology Systems, LLC provides healthcare information systems to a national community of oncology practices. In addition to obtaining cancer treatment information for cases recently diagnosed, SEER is interested in evaluating the long history of claims to assess longitudinal treatment as well as progression and/or cancer recurrence. To do this, it is crucial to have a very long series of longitudinal claims on the same cancer patient. The SEER Program has already obtained claims for a substantial number of SEER cancer patients for the years 2013-2017 for Georgia, Kentucky, Louisiana, New Mexico and Utah, and year 2018 for Iowa from oncology practices and oncologists, referenced here as providers. The current Unlimited Technology Systems, LLC providers have already provided consent to Unlimited Technology Systems, LLC to send claims to the respective central cancer registries to fulfil their obligation in reporting cancer cases. These claims are currently being used by SEER registries to ascertain new cancer cases more rapidly as the claims are received weekly, to capture systemic therapy and to ascertain follow-up information in terms of vital status of cancer patients. The SEER Program is interested in continuing to support the transmission of claims data for current providers, as well as to support the expansion of this capability, for additional providers within the SEER regions, or new states/areas covered by cancer registration that the Program identifies as important to obtain claims data information. This project is critical in order for SEER to continue being relevant and advance cancer surveillance and research.