Summary Stage 2018

See Summary Stage 2018 for the current version of the Summary Stage 2018 Manual and complete coding instructions for the Breast schema. This is a condensed version.

See Summary Stage 2018 (SS2018) | SEER Training website for general information on Summary Stage.

Summary Stage is the most basic way of categorizing how far a cancer has spread from its point of origin. It is used by the National Cancer Institute’s (NCI) Surveillance, Epidemiology and End Results (SEER) program and the Centers for Disease Control and Prevention’s (CDC) National Program of Cancer Registrars (NPCR).

For Summary Stage, there is one general rule “code what you know.” For example, if you know there is lymph node involvement, and no metastatic disease, yet you have no information on the extension, code to 3 for regional lymph node involvement.

For Summary Stage, if there is no information on lymph node involvement or metastatic disease, assume there is no involvement and code Summary Stage based on the extension/size of the tumor.

Note: If you are doing AJCC and your AJCC stage is unknown, do not assume that Summary Stage will also be unknown. Summary Stage is not based on tumor size (only whether it’s a localized or regional tumor), nor the number of lymph nodes or where they are located (only whether regional lymph nodes are involved).

General guidelines and codes for coding Summary Stage 2018 for Breast Cancer
Summary Stage Code Staging Details
Code 0: In situ (IS) Behavior must be /2 (in situ) AND NO lymph node or metastatic involvement
Exception: A primary tumor that is in situ WITH regional lymph node involvement is code 3: Regional Lymph Node involvement or
WITH metastatic disease is code 7: Distant metastasis
  • Both of these would be behavior /3 (malignant)
  • See Summary Stage 2018 Manual, General Instructions, #5, bullet point iv.
Code 1: Localized (L) Tumor confined to breast
  • No skin involvement
  • No lymph node involvement
  • No metastatic involvement
Code 2: Regional extension (RE) Tumor confined to breast WITH skin involvement OR
Inflammatory Carcinoma
  • No lymph node involvement
  • No metastatic involvement
Note: See notes 4, 5, & 6 in the Summary Stage Manual Breast Section for additional information
Code 3: Regional Lymph Nodes (RN) Tumor confined to breast
  • No skin involvement
  • Regional lymph node involvement
    • Size and number of regional lymph nodes do not affect Summary Stage
  • No metastatic involvement
Note: See notes 7 & 8 in the Summary Stage Manual Breast Section for Additional information
Code 4: Regional extension and Regional Lymph Nodes (RE+RN) Tumor confined to breast WITH skin involvement OR
Inflammatory Carcinoma
  • Regional lymph node involvement
    • Size and number of regional lymph nodes do not affect Summary Stage
  • No metastatic involvement
Code 7: Distant metastasis Metastatic involvement
  • Including distant lymph node, organs, bone, etc.
Note 1: Supraclavicular lymph nodes (ipsilateral and contralateral) are Summary Stage distant.
Note 2: See note 9 in the Summary Stage Manual Breast Section for Additional information
Code 9: Unknown This code is used for the following
  • Historical cases
  • Cases with limited information
  • Death certificate only cases (Central Registries only)

Updated: January 10, 2025