SEER-Medicare Policies

The data owners (SEER registry PIs and CMS) hold NCI responsible for tracking the use and location of all released SEER-Medicare data. Given that interest in SEER-Medicare data continues to grow exponentially, there is an ever increasing number of data requests that need to be tracked. In order to ensure that NCI is knowledgeable about how the data are being used, who is using the data and to avoid a change in scope, limitations on the number of data updates, data retention and data sharing are warranted.

Data Updates

Investigators are able to add newly released files to an approved project. Investigators will need to follow the following steps:

  • Update the approved Application to add the new data being requested and the reasoning behind the request
  • Complete a change request form (DOCX, 31 KB)
  • Update the project's DUA

Submit all documents to the SEER-Medicare contact for review and approval by the NCI. Approved data updates will be invoiced. Please utilize the data cost calculator to estimate new data rates. The maximum number of times data can be obtained for the same project is three: initial data request and then updated data from the next two subsequent linkages. If additional updates are desired, investigators will need to submit a new application for review and approval.

Data Retention

The Data Use Agreement (DUA) states the data retention time period is 5 years. If additional time is necessary to complete the approved project, investigators can request an extension to the DUA. Without an approved extension, all SEER-Medicare data must be destroyed. This destruction must include all raw data files, all analytic files, all back-up files, and the original media. Please be aware that any DUA established prior to December 2020 will not be extended. Investigators will need to submit a new application for review and approval if they desire to continue work on the project.

Data Sharing

Data sharing is permitted with NCI review and approval. Investigators will be allowed to submit new applications to re-use / share data with colleagues at their institution only if the data:

  • pertain to the same cohort (e.g., the same cancer site)
  • were purchased within the previous 2 years

Investigators will need to submit a full Application (application, IRB, DUA) and specifically state in the application, as well as in the submission email, that they are requesting to share previously approved data along with the original project's title. If Investigators of a proposed project are requesting use of a colleague's previously approved data, they will need to provide the title of the approved SEER-Medicare project and a letter of support from the project's Primary Investigator with all other required application materials.

Please note that the data retention period for the shared data will commence from when the data for the initial project was received not when the request to share the data was submitted.

Combining Data Released Before and After 2020

As a result of new agreements with the Centers for Medicare and Medicaid Services (CMS), all Medicare data released via SEER-Medicare in 2020 and moving forward will come from CMS’s Chronic Conditions Warehouse (CCW). These files are in a different format from files that were released in prior years. Researchers who have open SEER-Medicare projects and are using data released prior to 2020 will be able to complete their studies using the data files that they currently have for as long as their DUAs are valid. However, to not prolong the complete switch to the CCW files, researchers will not be allowed to request new CCW files to combine with older files that they previously received. If additional data are required to complete an open project, an entirely new request can be made via usual processes.

Researchers will be able to combine data received in 2020+.

Last Updated: 22 Jan, 2026