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 SEER's reporting of cancer incidence data and published statistics. The site recode variables are added to the SEER databases as a convenience for researchers.

The table below contains definitions for the available site recode variables. Follow the links to view the values of primary site and histology for each grouping. Each definition shows the coding for an additional Site Recode in which mesothelioma and Kaposi sarcoma are separate categories.

SEER converts data originally coded in versions prior to ICD-O-3 to ICD-O-3, and uses the ICD-O-3 site recodes based on these converted data and cases originally coded in ICD-O-3. If all histologies for all years have been converted to ICD-O-3, use the ICD-O-3 (1/27/2003) recode. If the analyses includes any cases diagnosed 2010+, the ICD-O-3 recode with adjustment for WHO 2008 hematopoietic histologies should be used.

For cases originally coded and not converted, the ICD-O-2 (1/27/2003) and ICD-O-3 (1/27/2003) definitions can be used for cases coded in ICD-O-2 and ICD-O-3, respectively, and include the same set of site groups to ensure comparability to one another. Do not continue to use the ICD-O-2 (4/15/2002) recode except for historic analysis of ICD-O-2 cases only. Any comparisons between recodes dated 1/27/2003 and 4/15/2002 are invalid.

Version Details
Current Definitions
Site Recode ICD-O-3/WHO 2008
  • Based on ICD-O-3, updated for Hematopoietic codes based on WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (2008).
  • Recommended variable for analyses with any cases diagnosed in 2010 and later.  SEER will use this recode for analyses that includes any cases diagnosed 2010+. 
  • Recommended variable for reporting based on the 1973-2010 SEER Research Data (November 2012 submission) and later releases.
  • Can be used with Site Recode ICD-O-2 (1/27/2003) for consistent site/type definitions over time when data includes ICD-O-2 cases not converted to ICD-O-3.
  • Implemented in SEER*Prep 2.5.1.
Site recode WHO/2008 (for SIRS)
  • Preferred site recode used by the Division of Cancer Epidemiology and Genetics
  • Included in the 1975-2018 SEER Research Data (November 2020 submission) and later releases.
  • Definition is the same as Site Recode ICD-O-3/WHO 2008 except for the more detailed breakdown of four cancer sites:
    1. "Trachea, Mediastinum and Other Respiratory Organs" split as:
      • C339: "Trachea"
      • All other sites in the category: "Mediastinum and Other Respiratory Organs"
    2. "Kidney and Renal Pelvis" split as:
      • C649: "Kidney"
      • C659: "Renal Pelvis"
    3. "Eye and orbit" split as:
      • All histologies in the category except 8720-8799: "Eye and Orbit - Non-Melanoma"
      • Histologies 8720-8799: "Eye and Orbit - Melanoma"
    4. "Other Endocrine including Thymus" split as:
      • C379: "Thymus"
      • C740-C749: "Adrenal Gland"
      • C750-C759: "Other Endocrine"
Site Recode ICD-O-3 2023 Revision Definition
  • Included in the 1975-2020 SEER Research Data (November 2022 submission).
  • Not used by SEER to report cancer statistics.
  • Based on ICD-O-3.2, implemented in 2021.
  • Updated to include additional anatomic sites and different groupings for Hematopoietic neoplasms.
Site Recode ICD-O-3 2023 Revision Expanded Definition
  • Included in the 1975-2020 SEER Research Data (November 2022 submission).
  • Not used by SEER to report cancer statistics.
  • Based on ICD-O-3.2, implemented in 2021.
  • Updated to include additional anatomic sites and clinically relevant groupings for Hematopoietic neoplasms.
Historic Definitions
Site Recode ICD-O-3
(1/27/2003)
  • Used with Mesothelioma and Kaposi Sarcoma as separate groupings to produce the SEER Cancer Statistics Review, 1975-2001 and later versions which do not include any 2010+ cases.
  • Recommended variable for reporting based on the 1973-2001 SEER Research Data (November 2003 submission), and later releases up to 1973-2009.
  • Can be used with Site Recode ICD-O-2 (1/27/2003) for consistent site/type definitions over time when data includes ICD-O-2 cases not converted to ICD-O-3.
  • The definition was updated on 5/25/2012 to exclude skin cancers with histology 8046. Implemented in SEER*Prep 2.4.6 and treated as other non-reportable skin cancers.
Site Recode B ICD-O-3/WHO 2008
  • Based on ICD-O-3
  • Included in the 1973-2010 through 1975-2017 SEER Research Data (November 2012 - 2019 submissions).
  • Developed for use in SEER*Stat within the MP-SIR session in collaboration with the Division of Cancer Epidemiology and Genetics
  • Differs from the original site recode variables in that it includes additional site subtotals, and in some cases, more detailed breakdown of sites
  • Not typically used by SEER to report incidence cancer statistics
Site Recode B ICD-O-3
(12/19/2003)
  • Based on ICD-O-3
  • Included in the 1973-2009 SEER Research Data (November 2011 submission) and earlier releases.
  • Developed for use in SEER*Stat within the MP-SIR session in collaboration with the Division of Cancer Epidemiology and Genetics
  • Differs from the original site recode variables in that it includes additional site subtotals, and in some cases, more detailed breakdown of sites
  • Not typically used by SEER to report incidence cancer statistics
Site Recode ICD-O-2
(1/27/2003)
  • Based on ICD-O-2
  • Used in tandem with Site Recode ICD-O-3 (1/27/2003) for consistent site/type definitions over time
  • Used to produce the SEER Cancer Statistics Review, 1975-2000
  • Recommended variable for reporting based on the 1973-2000 SEER Research Data (November 2002 submission).
Site Recode ICD-O-2
(4/15/2002)
  • Use only to duplicate prior analysis of cases diagnosed prior to 2001
  • Based on ICD-O-2
  • Used to produce the SEER Cancer Statistics Review, 1973-1999
  • Recommended variable for reporting based on the 1973-1999 SEER Research Data (November 2001 submission)
  • Not available in SEER*Prep 2.2 and later. Listed as "Site Recode (old-4/2002)" in SEER*Prep 2.0 and 2.1. Listed as "Site Recode" in SEER*Prep 1.9.