Brain

Summary Stage Code Staging Details
Code 1: Localized (L) Tumor confined to the rain

  • Infratentorial tumor confined to infratentorial sites
  • Supratentorial tumor confined to supratentorial sites
Code 2: Regional extension (RE) Tumor extends to connective tissue or adjacent organs
(See Summary Stage manual for complete list)

  • Tumor crosses the midline (this is not the same thing as a midline shift)
  • Infratentorial tumor invades the supratentorial sites
  • Supratentorial tumor invades the infratentorial sites
Code 7: Distant metastasis Metastatic involvement

  • Including distant lymph node, organs, bone, etc.
    • There are no regional lymph nodes for brain, but there can be distant lymph nodes
  • Circulating cells in cerebral spinal fluid
  • Other direct extension outside CNS
  • Drop metastasis
Code 8: Benign/borderline Applicable for Central Nervous System tumors only for year 2004+

  • Use code 8 when the behavior is /0 (benign) or /1 (borderline)
  • Size and extent of tumor is not relevant
Code 9: Unknown This code is used for the following

  • Historical cases
  • Cases with limited information
  • Death certificate only cases (Central Registries only)

Updated: September 23, 2026

Suggested Citation

SEER Training Modules: Brain. U.S. National Institutes of Health, National Cancer Institute. Cited 24 September 2026. Available from: https://training.seer.cancer.gov.