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North American Association of
Central Cancer Registries

Standards for Cancer Registries
Volume II

Data Standards and Data Dictionary

Twenty Second Edition
Version 21
Implementation: January 1, 2021

Edited By
Monica Thornton

August 2020
(Revised August, 2020, September 2020, October 2020, November 2020, May 2021)

Sponsoring Organizations

American College of Surgeons Cancer Programs
Canadian Partnership Against Cancer
Centers for Disease Control & Prevention
National Cancer Institute
National Cancer Registrars Association
Public Health Agency of Canada

Sponsor with Distinction

American Cancer Society

Edited By

Monica Thornton
North American Association of Central Cancer Registries, Inc. (NAACCR).

Comments and suggestions on this and other NAACCR standards documents are welcome. Please send your comments to the Editor or any member of the NAACCR Board of Directors.

The other volumes in the series, Standards for Cancer Registries, are:

Copies of all standards documents can be viewed or downloaded from NAACCR's website at:

Suggested citation

Thornton ML, (ed). Standards for Cancer Registries Volume II: Data Standards and Data Dictionary, Version 21, 22nd ed. Springfield, Ill.: North American Association of Central Cancer Registries, August 2020, revised Sept. 2020, Oct. 2020, Nov. 2020, May 2021.


We are very grateful to the members of NAACCR's Uniform Data Standards Work Group for their dedication and the many hours contributed to prepare this document.

Funding for this project was made possible in part by a contract with Federal funds from the National Cancer Institute, National Institutes of Health, Department of Health & Human Services under Contract number HHSN261201400004I / HHSN26100002. Additionally, funding for this project was made possible in part by a cooperative agreement with Federal funds from the Centers for Disease Control and Prevention Cooperative Agreement number 5NU58DP006458. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NCI and CDC. The NAACCR Board of Directors adopted these standards in August 2020.


Randi K. Rycroft, MSPH, CTR

Cancer Data Registry of Idaho
Telephone: (208) 489-1386
Email: [email protected]

Winny Roshala, BA, CTR

Cancer Registry of Greater California
Telephone: (916) 779-0313
Email: [email protected]

Maria J. Schymura, PhD

New York State Cancer Registry
Telephone: (518) 474-2255
Email: [email protected]

Executive Director:
Betsy A. Kohler, MPH, CTR

Telephone: (217) 698-0800 ext. 2
Email: [email protected]

Representative, Sponsoring Member Organizations:

Lori Swain, BA, MS

National Cancer Registrars Association
Telephone: (703) 299-6640 ext. 313
Email: [email protected]


Isaac Hands, MPH
Kentucky Cancer Registry
Telephone: (859) 218-3196
Email: [email protected]

Monique Hernandez, PhD

Florida Cancer Data System
Telephone: (562) 556-5298
Email: [email protected]

Mary Jane King
Ontario Cancer Registry, Ontario Health
Telephone: (416) 217-1424
Email: [email protected]

Monique Hernandez
Florida Cancer Data System
Telephone: (562) 556-5298
Email: [email protected]

Lorraine Shack
Alberta Cancer Registry
Telephone: (403) 973-0320
Email: [email protected]

Kevin C. Ward, PhD, MPH, CTR
Georgia Cancer Registry
Telephone: (404) 727-8455
Email: [email protected]



The Uniform Data Standards Work Group provides a formal mechanism to review and recommend proposed changes in data codes and/or the addition of new items submitted by NAACCR members to ensure that data remain comparable among central registries and other standard setters. Further, the WG provides a formal mechanism for reviewing and recommending edits of NAACCR-approved data items.

Susanne Schwartz, MS, CTR

New Jersey State Cancer Registry
Telephone: (609) 633-0500
Email: [email protected]


Jeannette Jackson-Thompson, MSPH, PhD
Missouri Cancer Registry and Research Center
Telephone: (573) 882-7775
Email: [email protected]



American Joint Committee on Cancer (AJCC)
633 N. Saint Clair Street
Chicago, IL 60611-3211
Telephone: (312) 202-5290
Email: [email protected]

Centers for Disease Control and Prevention (CDC)
National Program of Cancer Registries (NPCR)
Division of Cancer Prevention and Control
National Center for Chronic Disease
Prevention and Health Promotion
4770 Buford Hwy, NE
MS F76
Atlanta, GA 30341-3717
Telephone: (770) 488-4783
Fax: (770) 488-4759

Canadian Council of Cancer Registries (CCCR)
c/o Statistics Canada
Canadian Cancer Registry
Health Statistics Section
Health Statistics Division
Main Building, Room 2200, Section F
120 Parkdale Avenue
Ottawa, ON K1A 0T6
Telephone: (800) 263-1136
Email: [email protected]

Commission on Cancer (CoC)
633 N. Saint Clair Street
Chicago, IL 60611-3211
Telephone: (312) 202-5085
Email: [email protected]

National Cancer Institute SEER Program
US Mail:
National Institutes of Health
National Cancer Institute
Surveillance Research Program
Division of Cancer Control and Population Sciences
9609 Medical Center Drive
Bethesda, MD 20892
Courier services:
Rockville, MD 20850
Phone: (240) 276-6740
Fax: (240) 276-7908
Email: [email protected]

National Cancer Registrars Association (NCRA)
1340 Braddock Place #203
Alexandria, VA 22314
Telephone: (703) 299-6640
Fax: (703) 299-6620
Email: [email protected]

North American Association of Central Cancer Registries, Inc. (NAACCR)
2050 West Iles Ave, Suite A
Springfield, IL 62704-4194
Telephone: (217) 698-0800
Fax: (217) 698-0188
Email: [email protected]


NAACCR continues with its strong commitment to maintain standardization of cancer registry data. The collaboration and cooperation of our membership and sponsoring members is vital for achieving consensus to collect timely and accurate data. Standardization of cancer registry data is a core component of cancer registration and surveillance and provides the foundation for developing comparable data among registries throughout North America. Standardization also allows data from different registries to be used for comparison of variations in cancer rates among different populations and across geographic boundaries.

The Standards for Cancer Registries, Data Standards and Data Dictionary, Version 21 includes new data items to collect site-specific data, neoadjuvant therapy, post therapy yc, surname and API versioning; and, it includes revisions to existing data items. All revisions can be easily identified in Appendix F, Tables and Data Dictionary Revisions.

A major change in Version 21 is that the XML data exchange format transition period ended; hence, the fixed-width format is no longer supported as it has been replaced by the XML specification. As XML does not rely on starting and ending positions to be specified, all references to column positions (start and end) have been removed in the Version 21 Data Standards and Data Dictionary.

I would like to thank Suzanne Schwartz and Jeannette Jackson-Thompson Co-chairs of the Uniform Data Standards Work Group (UDS WG), for their leadership and dedication. I would also like to thank the UDS WG for sharing their valuable time and knowledge to review all of the revisions to the Data Standards and Data Dictionary. A special acknowledgement goes to Monica Thornton for her attention to detail and diligent efforts in bringing this document to completion.

Lori A. Havener, CTR
Program Manager of Standards




In the late 1980s, increased efforts to pool data collected by different cancer registries drew attention to problems resulting from insufficient data standardization. This lack of standardization had a substantial cost and limited more widespread use of valuable data. Three groups especially felt the impact: state registries receiving data from hospital registries, the NAACCR Data Evaluation and Publication committee, and the Commission on Cancer's (CoC) National Cancer Data Base (NCDB).

The lack of standardization took many forms. Data items used by different registries or software systems varied in their definitions and codes, even when they had the same name and were intended to represent the same information. Blanks, dashes, and defined codes were all used to indicate “unknown” data. Other substantial discrepancies were less easy to detect and correct. Hospitals and software providers faced conflicting standards and requirements when they were both reporting to a central registry and maintaining a database consistent with CoC standards.


Many NAACCR sponsoring organizations, including the National Cancer Institute (NCI), the Centers for Disease Control and Prevention (CDC), and CoC, recognized increasing standardization as an essential step in decreasing the costs associated with data collection, making more efficient use of increasingly limited human resources needed for data collection, management, and analysis, and obtaining more useful data that could be compared across registries and geographic areas.

Preparation of a statement of consensus on data standards for cancer registries was proposed by the NAACCR Data Exchange Committee (originally called the Data Exchange Standards Committee) spearheaded by NCDB, and the task fell to the newly formed Committee on a Unified Database which later morphed into NAACCR's Uniform Data Standards Committee, now called the Uniform Data Standards Work Group. Later, the CDC entered into an agreement with NAACCR, and one project under that agreement was the preparation of broader standards for population-based cancer registries. These efforts were complementary. Continued support from the NCI, the CoC, and the CDC has enabled continued development and maintenance of standards. The results of these efforts are the following standards documents published to date:

NAACCR Data Exchange Standard Formerly NAACCR Standards Volume I:

NAACCR Standards Volume II:

NAACCR Standards Volume III:

NAACCR Standards Volume IV:

NAACCR Standards Volume V:


The goal of this volume is to define NAACCR cancer registration data standards for use by central registries, hospital-based registries, and other groups in North America to abstract cancer diagnosed on or after January 1, 2021.

Objectives of the standardization effort, and this document, are to:

This document will be used by new and existing facility-based and central cancer registries to ensure that their program's standard definitions and codes are consistent with those used by regional and national databases. Other potential users include registry software providers and those using registry data, especially if they are combining data from multiple sources or exchanging data. National standard-setting groups, such as CoC, CDC, NAACCR, NCI and the Canadian Council of Cancer Registries (CCCR) will also benefit.

This Data Dictionary describes all current data items; those that are new or have been modified since the preceding Data Dictionary are listed in Appendix F. Highlighting in Chapter X also indicates changes.

The present volume uses the same structure and philosophy as NAACCR's data exchange standards. Where a standard exists for an item or type of data, the standard is incorporated by reference. Where a variety of standards are in use, alternate coding schemes accommodate them, but the different coding schemes are recorded separately, or another data field is used to indicate which coding standard was used.


The present document is limited to standards regarding data, rather than procedures. More specifically, it focuses on a subset of possible data standards that NAACCR considers important to establish. These include:

Refer to Data Exchange Standard, XML Specification for Cancer Registry Records1or Data Standards & Data Dictionary, Volume II, Version 21, Chapter X for additional information on record layouts.

Where possible, the NAACCR item name is the same as that used by the standard setter. However, the following constraints are placed on the names: