EOD Primary Tumor

Most breast cancers are confined to the breast. Tumor Size (NAACCR Data Item # 756-Tumor Size Summary) is critical for breast cancers.

Breast cancer and Tumor Size

• Use the size of tumor reported on the pathology report for the best information. Record the size of the invasive component only.
• If tumor size is not documented on the pathology report, use the following information from: imaging (including mammography and ultrasound) and/or the physical examination.
• If the tumor is described as diffuse or inflammatory carcinoma, record tumor size of 998 if a tumor size is not documented.
• Multifocal tumors in the same breast (and abstracted as single primaries-see Solid Tumor Rules) should be staged according to the size of the largest tumor.

See the current version of the SEER Program Coding Manual under Reporting Guidelines, Section IV: Description of this neoplasm for complete coding instructions for tumor size.

Coding extension for the breast is based on several different factors

• Is the tumor in situ.
  • Behavior must be /2 (in situ) AND NO lymph node or metastatic involvement.
• Is the tumor confined to the breast WITHOUT skin involvement.
• Is the tumor confined to the breast WITH skin involvement (minimal).
• Does the tumor extend to the chest wall, intercostal or serratus anterior muscles, or extend to the adjacent rib (ipsilateral).
• Is there extensive skin involvement WITHOUT a diagnosis of inflammatory carcinoma.
• Is there a diagnosis of inflammatory carcinoma and how much of the skin is involved.
  • Note: Inflammatory carcinoma is a clinical diagnosis based on involvement of the skin. Do not use the histology code for inflammatory carcinoma unless the pathology report specifically documents it. Most of these tumors will be assigned histology to ductal carcinoma, or Carcinoma, NOS.

See SEER*RSA, Breast, for the current version of EOD and complete coding instructions for the Breast schema.

Updated: January 10, 2025