The easiest way to explore and test the APIs is to use the Swagger documentation. From that page you can test all the APIs and see both the headers that are returned as well as the data.

The complete OpenAPI definition (download JSON or YAML) is available for importing into other tools.

Disease database /rest/disease

A searchable database of hematopoietic and lymphoid neoplasms and solid tumor diseases.

This API replaces the previous Hematopoietic API. It allows the user to retrieve data for both Hematopoietic and Solid Tumors, however, please note that the while the Hematopoietic data is currently production-ready, the Solid Tumor data is provided only as a preview. Solid Tumor data editing is still ongoing and this data should not be thought of as complete. A notification will be sent out when the Solid Tumor data is ready for production use.

Please also note that the Hematopoietic data is now updated regularly in order to correct mistakes. Major releases will be announced via the SEER website.

Glossary /rest/glossary

A glossary of cancer-related terms.

HCPCS /rest/hcpcs

Healthcare Common Procedure Coding Systems (HCPCS) nomenclatures. The information is maintained through CanMED.

Multiple Primary and Histology /rest/mph

The SEER implementation of the Multiple Primary and Histology Coding Rules. The implementation combines Hematopoietic rules, SEER Multiple Primary and Histology Coding Rules.

NAACCR Documentation /rest/naaccr

The NAACCR API provides programmatic access to documentation for the NAACCR Standards for Cancer Registries Volume II. It includes field level documentation as well as information about file layout.

National Drug Code Directory /rest/ndc

A searchable mirror of the National Drug Code Directory from the FDA website. This database is updated weekly. Additional oncologic information is provided from CanMED.

SEER*Rx – Antineoplastic Drugs Database /rest/rx

SEER*Rx was developed as a one-step lookup for coding oncology drug and regimen treatment categories in cancer registries. The databases are scheduled to be updated annually. The information in this database is effective for cancer diagnoses made on January 1, 2005 and after. Review and recoding of drugs from previous years is not required or recommended.

SEER Incidence Site Recode /rest/recode

The values of SEER site recode variables are based on the primary site and histology data fields submitted to SEER by the registries. The site recode variables define the major cancer site/histology groups that are commonly used in the reporting of cancer incidence data. For example, there is a section of the SEER Cancer Statistics Review for each major site corresponding to groupings in a site recode variable. The site recode variables are added to SEER databases as a convenience for researchers.

More information can be found on the SEER web site.

SEER Site-Specific Surgery Codes /rest/surgery

The SEER Coding Manual provides surgery tables for specific groups of sites. The API supports year-specific codes from 1998 to the present.

Staging Algorithms /rest/staging}

The staging APIs can be used to perform tasks associated with data collection and cancer staging. The API currently supports the TNM and Collaborative Stage (CS) algorithms. The APIs perform schema matching, return the data items required to be collected for each schema (CS for cases diagnosed in years prior to 2016, TNM for cases diagnosed on or after 2016), and also calculate stage.

A Java library with this same data is also available at and can be used for applications without a connection to the REST API. Detailed documentation on the staging methods can be found at

Collaborative Stage

Collaborative Stage is a unified data collection system designed to provide a common data set to meet the needs of all three staging systems (TNM, SEER EOD, and SEER SS). It provides a comprehensive system to improve data quality by standardizing rules for timing, clinical and pathologic assessments, and compatibility across all of the systems for all cancer sites.

The staging method provided here has been verified to produce the same results for stage as does the v02.05.50 C DLL. These APIs are provided for vendors who are looking for an alternative mechanism for accessing the CS v02.05.50 data for building data entry screens or for calculating stage.


TNM is a widely accepted system of cancer staging. TNM stands for Tumor, Nodes, and Metastasis. T is assigned based on the extent of involvement at the primary tumor site, N for the extent of involvement in regional lymph nodes, and M for distant spread. Clinical TNM is assigned prior to treatment and pathologic TNM is assigned based on clinical information plus information from surgery. The clinical TNM and the pathologic TNM values are summarized as clinical stage group or pathologic stage group.

For each cancer site, or schema, valid values, definitions, and registrar notes are provided for clinical TNM and stage group, pathologic TNM and stage group, and relevant Site-Specific Factors (SSFs).

TNM categories, stage groups, and definitions are based on the Union for International Cancer Control (UICC) TNM 7th edition classification. UICC 7th edition and AJCC 7th edition TNM categories and stage groups are very similar; however, there are some differences.

WARNING: SEER Primary Tumor, SEER Regional Nodes, and SEER Mets (renamed EOD Primary Tumor, EOD Regional Nodes and EOD Mets) are not used in 2016-2017!!

In 2016-2017, SEER Summary Stage 2000 will continue to be used. For those schemas and site/histology combinations that are not defined in TNM, SEER Summary Stage 2000 should be collected manually.

NCI has developed SEER Summary Stage 2018, which is effective for diagnosis year 2018. In preparation for SEER Summary Stage 2018, three data fields have been defined, EOD Primary Tumor, EOD Regional Nodes and EOD Mets. Some work was done to define these fields in 2016, but they do NOT apply in 2016-2017 and should be ignored. Do not utilize these fields for data collection in 2016-2017. Only use the SEER Summary Stage 2000 directly coded field.

Extend of Disease (EOD)

Extent of Disease (EOD) is a set of three data items that describe how far a cancer has spread at the time of diagnosis. EOD 2018 is effective for cases diagnosed in 2018 and later.

In each EOD schema, valid values, definitions, and registrar notes are provided for

  • EOD Primary Tumor
  • EOD Lymph Nodes
  • EOD Mets
  • Summary Stage 2018
  • Site-Specific Data Items (SSDIs), including grade, pertinent to the schema

For cancer cases diagnosed January 1, 2018 and later, the NCI SEER program will collect Extent of Disease (EOD) revised for 2018 and Summary Stage 2018. The schemas have been developed to be compatible with the AJCC 8th Edition chapter definitions.

All of the standard setting organizations will collect the predictive and prognostic factors through Site Specific Data Items (SSDIs). Unlike the SSFs, these data items have formats and code structures specific to the data item.

Pediatric Data Collection System (PDCS or Pediatric)

Pediatric Data Collection System (Pediatric) is a set of three data items that describe how far a cancer has spread at the time of diagnosis for Pediatric cancers. PDCS can be collected for cases diagnosed in 2018 and later.

In each Pediatric schema, valid values, definitions, and registrar notes are provided for

  • Pediatric Primary Tumor
  • Pediatric Lymph Nodes
  • Pediatric Mets
  • Site-Specific Data Items (SSDIs)

For cancer cases diagnosed January 1, 2024 and later, the NCI SEER program will collect the Pediatric Data Collection System fields. The schemas have been developed to be compatible with the Toronto Staging v1.1 definitions.