Should a woman with stage two breast cancer undergo a positron emission tomography (PET) scan and a breast biopsy?

PET Scan and Breast Biopsy in Stage II Breast Cancer

For women with stage II breast cancer, a PET scan is generally NOT recommended for routine staging, and a breast biopsy is essential for diagnosis and treatment planning.

Diagnostic Approach for Stage II Breast Cancer

Initial Diagnostic Workup

• Core biopsy of the breast mass is mandatory to confirm invasive carcinoma and determine:
  • Histological type and grade
  • Hormone receptor status (ER/PR)
  • HER2 status
  • Proliferation markers (Ki67)

Imaging Recommendations

Standard Imaging (Recommended)

• Bilateral diagnostic mammogram
• Breast ultrasound
• Axillary ultrasound (to assess lymph nodes)

PET Scan (Not Routinely Recommended)

• According to NCCN guidelines, PET/CT scanning is not indicated in the staging of clinical stage I, II, or operable stage III breast cancer 1
• The use of PET scans should be discouraged for routine evaluation as they have limited value in early-stage disease 2
• For stage IIA breast cancer specifically, PET scan is generally not recommended due to low detection rate of distant disease 2
• For larger stage IIB tumors (T3N0 or T2N1), PET scan may be considered only when:
  • Conventional imaging results are equivocal or suspicious 1, 2
  • There are signs or symptoms suggesting metastatic disease 1

Systemic Staging

• Routine systemic staging is not indicated for early breast cancer in the absence of symptoms 1
• Consider systemic staging only if signs and symptoms are present:
  • Chest diagnostic CT
  • Abdominal ± pelvic diagnostic CT or MRI
  • Bone scan (category 2B)

Importance of Breast Biopsy

Diagnostic Value

• Core biopsy is essential to confirm invasive carcinoma 1
• Pathological confirmation is required for definitive diagnosis and treatment planning

Treatment Planning Value

• Biopsy provides critical information for treatment decisions:
  • Hormone receptor status guides endocrine therapy decisions
  • HER2 status determines need for anti-HER2 therapy
  • Tumor grade and proliferation markers help determine chemotherapy benefit

Preoperative Considerations

• If neoadjuvant therapy is planned, core biopsy with placement of image-detectable marker(s) must be done to demarcate the tumor bed 1
• Biopsy of suspicious axillary lymph nodes should be performed with clip placement if positive 1

Common Pitfalls to Avoid

1. Overreliance on imaging alone: Diagnosis of breast cancer requires pathological confirmation through biopsy, not just imaging findings 3

2. Unnecessary PET scans: Ordering PET scans for early-stage breast cancer increases costs without improving outcomes and may lead to false positives 2

3. Missing receptor status changes: If a patient has suspected metastatic disease, biopsy of metastatic lesions should be considered as receptor status can change in 14-40% of cases compared to the primary tumor 3, 4, 5

4. Inadequate sampling: Ensure adequate tissue is obtained during biopsy for complete biomarker testing (ER, PR, HER2)

Special Considerations

• For inflammatory breast cancer, skin punch biopsies (at least two) are strongly recommended to document dermal lymphovascular tumor emboli 1

• If neoadjuvant therapy is being considered, additional biopsies may be needed to place clips for surgical planning 1

• For patients with suspected metastatic recurrence, biopsy of the metastatic site is recommended as approximately 14.6% of cases show changes in ER status, 16.7% in PR status, and 8.3% in HER2 status 5

By following these evidence-based recommendations, clinicians can ensure appropriate diagnosis and staging for women with stage II breast cancer while avoiding unnecessary tests and procedures.