This page highlights any significant changes to the data or request process for each annual release. Every year, there are also a number of minor updates to the data and fields released. Details of those types of changes can be found in the SEER*Stat Databases Documentation.

April 2024 Release

Starting with the 1975-2021 SEER Data, released on April 17, 2024, the following changes were made.

U.S. Census Populations Updated Using the 2020 Census Populations

The U.S. populations have been updated to include the 2010-2020 intercensal populations that are estimated using both the 2010 and 2020 U.S. Census. The 2021 populations are estimated/projected using the 2020 U.S. Census populations. These populations series are named Vintage 2022 populations.

Impact of COVID on SEER Data

The November 2023 SEER data submission includes new cancer cases diagnosed in 2021, the second year of the COVID-19 pandemic. SEER databases include both 2020 and 2021 cases. SEER still recommends exclusion of 2020 data from trends analysis and risks of developing cancer (DevCan) (see Impact of COVID on the April 2024 SEER Data Release).

April 2023 Release

Starting with the 1975-2020 SEER Data, released on April 19, 2023, the following changes were made.

Impact of COVID on 2020 Incidence Data

The November 2022 SEER data submission includes new cancer cases diagnosed in 2020, the first year of the COVID-19 pandemic. In 2020, the highly publicized impact of COVID on health services and the consequential delays and reductions in cancer screening and diagnosis led to a decline in the 2020 incidence rates for most cancer sites. Learn more about the Impact of COVID on the April 2023 SEER Data Release.

Policy Change for Research Plus Data Access

It is no longer possible to request access to the Research Plus Data for personal use or without one of the approved login methods described below. 
To access the Research Plus Data you now must login with one of the following accounts for user authentication:

  • an eRA Commons account that is associated with an institutional email address (.edu, .gov, .org, or work email address), or
  • an HHS account.

Refer to How to Request Data Access for the request process and the SEER Data FAQs for more information on how to obtain an eRA Commons account. 

For users who previously had Research Plus access and are no longer eligible under this policy change, you will be able to keep access to the previous releases of the Research Plus Data if you keep your account active. You cannot access the latest release of Research Plus Data if you do not comply with the new policy. Refer to the FAQ about the policy change for more details.  

Treatment Data Now Available in Research Databases

The Research databases now include treatment data that were formerly only included in the Research Plus databases.  All users are now required to read and agree to the terms of the SEER Treatment Data Limitations document when requesting the data.

New Variable for Race and Hispanic Origin

SEER now includes a system-supplied merged variable, "Race and origin (recommended by SEER)". It includes the five mutually exclusive race and ethnicity categories SEER uses for reporting cancer statistics.

April 2022 Release

Starting with the 1975-2019 SEER Data, released on April 15, 2022, the following changes were made to the data.

Registry Groupings

The registry groupings have changed with the November 2021 databases due to changes in which registries are included with this data submission. The new groupings are now SEER 8, SEER 12, SEER 17, and SEER 22. Detroit is no longer included in any databases, and Illinois and Texas are included in the new 22 registry database. Refer to Registry Groupings in SEER Data and Statistics for details.

Statistics by Race and Origin

SEER's recommendations for producing statistics by race and origin changed with the November 2021 databases. Geographic considerations to select correct population/denominators are also required when producing rates by certain race/ethnicities, e.g., American Indian/Alaska Native. Refer to Race and Hispanic Ethnicity Changes for more information.

County Attributes

County attributes that are available in different SEER*Stat session types have changed with the November 2021 databases and SEER*Stat version 8.4.0.

  • Incidence-based mortality databases — time-dependent county attributes are linked by year of death rather than years of diagnosis.
  • Prevalence sessions — county attributes are not available in prevalence calculations.
  • MP-SIR — limited to static attributes.
  • Case listing — limited to minimal set of time-dependent attributes that are permitted to be included in case listing results.
Refer to County/Tract Attributes for more information.

April 2021 Release

Starting with the 1975-2018 SEER Data, released on April 15, 2021, the following changes were made to the data.


SEER now uses "Behavior code ICD-O-3" rather than the "Behavior recode for analysis" field in SEER*Stat and any published statistics. This has the following impact:

  1. The default behavior selection in SEER*Stat for all November 2020 SEER databases is “Behavior code ICD-O-3 = Malignant", for prior submissions it is “Behavior recode for analysis = Malignant".
  2. All cases that were coded as "Behavior recode for analysis = No longer reportable in ICD-O-3" have been excluded from all databases. This includes approximately 10,000 cases diagnosed between 1973-2000, all of which had ICD-0-3 behavior of borderline and almost all of which were ovary cancers.
  3. The "Behavior recode for analysis" field is still available in the database.

Read more about the Behavior Variable Changes.

Site Recode Variables

Several new or revised site recode variables have been added and are used for SEER's published statistics. They include:

April 2020 Release

SEER has a long history of enabling and supporting data access to researchers, clinicians and patients. We are committed to continuing that mission. However, as SEER expands the data captured in terms of detail and longitudinal information, the risk of re-identifiability of individuals is increased. Further, in recent years software algorithms have been developed that could leverage other data sources combined with the current limited dataset that has been the primary research file available from the SEER program to re-identify individuals (see References). For these reasons, it is imperative that SEER take measures to protect the confidentiality of the patients within the limited dataset held within the SEER program, to further reduce any risk of re-identifiability. This requires a change in how users can access the data.  

We will continue to support free and open access to our data, but additional requirements for authentication and authorization will be required depending on the data product access being requested. The SEER program is working hard to continue to support the needs of the research community and others who utilize the SEER data while simultaneously increasing assurance of patient confidentiality.

Two SEER Data Products: Research and Research Plus

Starting with the 1975-2017 SEER Data, released on April 15, 2020, there are two data products available: SEER Research and SEER Research Plus. The Research Plus Data require a more rigorous process for access that include user authentication. For more information, see the Comparison of Data Products.

Other Data Changes in this Release

  1. SEER no longer excludes Louisiana cancer cases in all Research and Research Plus databases. This is a change from previous releases. See Adjustments for Areas Impacted by Hurricanes Katrina and Rita for more information.
  2. Data files are no longer available for download in ASCII text or binary file formats. Data can only be accessed through SEER*Stat in client-server mode. If you need to work with individual cancer cases and export SEER*Stat results for use in SAS, R, or other software refer to the SEER*Stat Case Listing Tutorials.
  3. "Insurance Recode (2007+)" is being re-evaluated and has been removed from the November 2019 databases. This field and new SEER-Medicaid fields will be available in specialized data in the future.