Breast Carcinoma Staging
The recommended approach for staging breast carcinoma is to use the American Joint Committee on Cancer (AJCC) TNM staging system, which should include comprehensive clinical, pathological, and biomarker assessment to determine prognosis and guide treatment decisions. 1
Clinical Staging Components
Initial Diagnostic Evaluation
- Bilateral mammography and ultrasound are cornerstone diagnostic tools
Laboratory Assessment
- Minimum blood work-up required 1:
- Full blood count
- Liver and renal function tests
- Alkaline phosphatase
- Calcium levels
Imaging for Staging
- For early-stage, asymptomatic patients: Comprehensive radiological staging is not recommended 1, 2
- For higher-risk patients: Imaging of chest, abdomen, and bone is recommended 1
- Higher-risk defined as: high tumor burden, aggressive biology, or clinical/laboratory signs suggesting metastases
- When conventional methods are inconclusive: FDG-PET-CT scanning may be useful 1
- May replace traditional imaging for staging in high-risk patients
Pathological Assessment
Core Elements
- Histological type and grade according to WHO classification 1, 2
- TNM classification according to AJCC system 1
- T (tumor): size and local invasion
- N (nodes): extent of lymph node involvement
- M (metastasis): presence of distant metastases
- Resection margins including minimum margin in millimeters and anatomical direction 1
- Lymph node status including total number removed and number positive 1
Biomarker Assessment
- Mandatory biomarkers 1, 2:
- Estrogen receptor (ER) status by immunohistochemistry
- Progesterone receptor (PR) status by immunohistochemistry
- HER2 receptor status by IHC or FISH/CISH for ambiguous (2+) cases
- Ki67 or other proliferation markers (when available)
Post-Neoadjuvant Assessment
- Residual Cancer Burden (RCB) is the preferred method for quantifying residual disease 1
- Pathological Complete Response (pCR) must be clearly stated if achieved 1
- Defined as no invasive disease in both breast and axilla
- Presence/absence of residual DCIS must be described
Prognostic Assessment
Risk Stratification
Traditional prognostic factors 1:
- Age
- Tumor size
- Histopathological grade
- Vascular invasion
- Axillary lymph node involvement
- ER/PR status
- HER2 status
Validated gene expression profiles may be used to gain additional prognostic information 1:
- Examples include MammaPrint® or Oncotype DX® Recurrence Score
- Particularly valuable in ER-positive early breast cancer
- Helps predict response to adjuvant chemotherapy
Common Pitfalls to Avoid
Relying solely on mammography in dense breast tissue - sensitivity is only ~50% in this population 2
Over-reliance on a single imaging modality - no single modality is most accurate for tumor size 2
Performing comprehensive radiological staging in all patients - unnecessary for early-stage, asymptomatic patients 2
Inconsistent measurement of tumor size after neoadjuvant therapy - standardized approaches are needed for accurate assessment 1
Failure to document treatment effect - presence or absence of treatment effect in breast and lymph nodes should be reported 1
Multidisciplinary Approach
Treatment planning should involve a multidisciplinary team including oncologists, breast surgeons, radiologists, radiation oncologists, and pathologists to integrate local and systemic therapies in the appropriate sequence 1, 2.
The breast unit/center should preferably be certified by an accredited body and handle a minimum of 150 new early breast cancer cases per year to ensure optimal outcomes 1.