Grade

See Schemas | SSDI and Grade DataExternal Website Policy for the current version of the Grade manual, including general coding instructions and schema specific instructions (Breast schema). Grade data items, including codes and descriptions, can also be found in SEER*RSA (Note: SEER*RSA does not include the general instructions).

Note: For Grade, it is very important that you read the general instructions (see link above) first. After the general instructions are reviewed, you move to the Schema specific instructions.

Grade is the measurement of how closely the tumor cells resemble normal cells of the parent tissue (organ of origin). There are 4 different grade data items.

  • Grade Clinical [NAACCR item # 3843]
  • Grade Pathological [NAACCR item # 3844]
  • Grade Post-therapy Clinical [NAACCR item # 1068]
  • Grade Post-therapy Pathological [NAACCR item # 3845]

There are two grade systems for breast: in situ (behavior /2), and invasive/malignant (behavior /3).

  1. For in situ tumors, a 3 grade Nuclear based system is used, with grades Low (L), Intermediate (M) and High (H).
  2. For invasive cancers, the Bloom Richardson or Nottingham score is used, these are a 3-grade systems based on three different factors.
    1. Tubule formation (Histologic grade): how much of the tumor tissue has normal breast ducts
    2. Nuclear pleomorphism (Nuclear grade): The size and shape of the nuclei in the tumor cells
    3. Mitotic count: How many dividing cells are present, which is a measure of how fast the tumor cells are growing
    4. Each component is assigned a value of 1 (favorable) to 3 (unfavorable), then the scores are totaled for all three categories (Lowest value is 3, highest value is 9). Grade is determined based on the final value.
      1. Grade 1 (Nottingham/SBR score of 3, 4, 5 points) (Low combined histologic grade)
      2. Grade 2 (Nottingham/SBR score of 6, 7 points) (Intermediate combined histologic grade)
      3. Grade 3 (Nottingham/SBR score of 8, 9 points) (High combined histologic grade)

Document grade details in NAACCR Item # 2570 Text-Dx Proc-Path.

Updated: January 10, 2025