What are the National Comprehensive Cancer Network (NCCN) guidelines for breast cancer staging?

NCCN Breast Cancer Staging Guidelines

The NCCN guidelines for breast cancer staging utilize the AJCC TNM (Tumor, Node, Metastasis) anatomic staging system, supplemented by prognostic biological markers including ER/PR status, HER2 status, and tumor grade to guide treatment decisions and estimate prognosis. 1

Staging Workup by Clinical Stage

Stage 0 (DCIS) and Early-Stage Disease (Stage I, IIA, IIB)

For patients with clinical stage 0, I, or II disease, the baseline staging workup should include: 1

• History and physical examination 1
• Bilateral diagnostic mammography 1
• Breast ultrasound as clinically indicated 1
• Pathology review (NCCN endorses the College of American Pathologists protocol for all breast specimens) 1
• Determination of ER and PR status 1
• HER2 status determination (by IHC or FISH) 1
• Complete blood count, platelet count, and liver function tests 1
• Genetic counseling if high-risk for hereditary breast cancer 1

Additional staging studies (bone scan, CT, or other abdominal imaging) are NOT indicated for asymptomatic patients with stage I or II disease. 1, 2 These tests should be reserved only for patients with signs or symptoms suggestive of metastatic disease. 2

Stage III Disease (Locally Advanced)

For patients with clinical stage III breast cancer, the staging evaluation expands to include: 1

• All components of the stage I/II workup listed above 1
• Chest imaging (required) 1
• Bone scan (category 2B recommendation) 1
• Abdominal imaging with CT, ultrasound, or MRI (category 2B) 1
• PET or PET/CT scans should generally be discouraged except when other staging studies are equivocal or suspicious (category 2B), as biopsy of suspicious sites provides more definitive staging information 1

Baseline staging tests using either anatomic or metabolic imaging modalities should be considered for all women with stage III breast cancer regardless of symptoms or biomarker profile. 2

Role of MRI in Staging

Breast MRI is optional for staging and should be performed using a dedicated breast coil by a team capable of MRI-guided biopsy. 1 The NCCN guidelines note important caveats: 1

• MRI has a high false-positive rate 1
• MRI use has not been shown to increase likelihood of negative margins or decrease conversion to mastectomy 1
• No randomized prospective data demonstrate improved long-term outcomes with MRI staging 1
• Patients should not be denied breast-conservation therapy based on MRI findings alone without tissue sampling 1

MRI should be considered for: 1

• Women with very dense breast tissue whose breasts cannot be adequately imaged with mammography and ultrasound 1
• Women with positive axillary nodes and occult primary tumor presumed to originate in the breast 1
• Evaluation of chest wall involvement 1
• Assessment of extent of disease in Paget's disease 3

Prognostic and Predictive Factors

The NCCN staging approach integrates both anatomic and biological factors: 1, 4

Anatomic Factors:

• Primary tumor size (T) 4
• Regional lymph node involvement (N) 4
• Distant metastasis (M) 4

Biological Markers:

• ER/PR status (essential for determining benefit of endocrine therapy) 1
• HER2 status (critical for targeted therapy decisions) 1
• Tumor grade 1, 4
• Ki-67 proliferation index (when applicable) 4

The 8th edition AJCC staging system integrates these molecular markers with disease extent for more optimal estimation of prognosis, which can result in stage migration compared to purely anatomic staging. 4

Special Staging Considerations

DCIS with Comedo Necrosis

Comedo necrosis is an important prognostic factor that should be documented in pathology reports, as it is an independent predictor of ipsilateral breast tumor recurrence. 5 Complete pathologic assessment must document its presence. 5

Paget's Disease

When Paget's disease is diagnosed, MRI should be considered to assess extent of disease and identify additional disease. 3 The workup includes bilateral diagnostic mammography with ultrasound as necessary, followed by full-thickness skin biopsy of the involved nipple-areolar complex. 1, 3

T3N1M0 Disease

Patients with clinical T3N1M0 disease require additional staging studies including bone scan, abdominal imaging, and chest imaging, as they are at higher risk for occult metastatic disease. 1

Common Pitfalls to Avoid

• Do not order routine staging scans (bone scan, CT, PET) for asymptomatic stage I or II patients – this represents overutilization without evidence of benefit 2
• Do not rely on MRI alone to exclude breast conservation – tissue confirmation is required for suspicious MRI findings 1
• Do not omit ER/PR and HER2 testing – these are essential for treatment planning and prognostic staging 1, 4
• Do not perform complete axillary lymph node dissection for apparent pure DCIS without evidence of invasive cancer or proven axillary disease 1