What is the treatment approach for breast cancer?

Breast Cancer Treatment Approach

The treatment of breast cancer requires a multidisciplinary approach involving surgery, radiotherapy, and systemic therapies (chemotherapy, endocrine therapy, targeted therapies), with the specific treatment plan determined by tumor characteristics, disease stage, and patient factors. 1

Specialized Care and Patient Involvement

• Treatment should be carried out in specialized breast units/centers by a multidisciplinary team consisting of medical oncologists, breast surgeons, radiation oncologists, breast radiologists, breast pathologists, and breast nurses 1
• Patients should be actively involved in all management decisions and provided with comprehensive information both verbally and in writing 1
• The breast unit should have access to plastic/reconstructive surgeons, psychologists, physiotherapists, and geneticists when appropriate 1

Treatment Strategy Determination

• Treatment decisions should be based on:
  • Tumor burden and location (size, location, number of lesions, lymph node involvement) 1
  • Tumor biology (pathology, biomarkers including ER, PgR, HER2, Ki67) 1
  • Patient factors (age, menopausal status, general health, preferences) 1
• Age should not be the sole determinant for withholding or recommending treatment 1
• In younger premenopausal patients, fertility preservation options should be discussed before starting systemic treatment 1

Local Treatment Approaches

Surgery

• Breast-conserving surgery (BCS) with radiotherapy is the preferred approach for 60-80% of newly diagnosed cancers 1
• Mastectomy is indicated for:
  • Large tumors relative to breast size
  • Multicentric tumors
  • Inability to achieve negative margins after multiple resections
  • Contraindications to radiotherapy
  • Patient preference 1
• Oncoplastic procedures can improve cosmetic outcomes, especially for large breasts or challenging tumor locations 1
• Sentinel lymph node biopsy should be performed for axillary staging in clinically node-negative patients 1

Radiotherapy

• Breast radiotherapy is strongly recommended after breast-conserving surgery 1
• Post-mastectomy radiotherapy is recommended for patients with four or more positive axillary nodes and suggested for T3 tumors regardless of nodal status 1

Systemic Treatment Approaches

Neoadjuvant (Preoperative) Therapy

• Neoadjuvant therapy should be preferred for:
  • Triple-negative and HER2-positive tumors >2 cm
  • Tumors with positive axilla
  • Cases where breast conservation is desired but not initially feasible 1

Adjuvant Systemic Therapy

Hormone Therapy

• For hormone receptor-positive tumors:
  • Premenopausal women: tamoxifen with ovarian ablation is standard 2
  • Postmenopausal women: aromatase inhibitors are superior to tamoxifen in first-line therapy 2
  • Standard tamoxifen treatment is 5 years at 20 mg daily 2

HER2-Targeted Therapy

• Patients with HER2-positive breast cancer should receive trastuzumab with non-anthracycline-containing chemotherapy 3
• Cardiac monitoring should be performed before and during trastuzumab therapy due to risk of cardiomyopathy 3

Chemotherapy

• Selection of chemotherapy should be based on tumor and patient characteristics 4
• Single-agent chemotherapy is generally preferred over combination therapy for better quality of life in metastatic disease 4

Treatment by Disease Stage

Early Breast Cancer (Stages I, II)

• Treatment typically involves surgery (BCS or mastectomy) followed by appropriate adjuvant therapy 5
• Adjuvant therapy decisions depend on lymph node involvement, hormone receptor status, HER2 status, and patient factors 5

Locally Advanced Breast Cancer (Stage III)

• Often requires induction chemotherapy to downsize the tumor before surgery 6
• Inflammatory breast cancer requires induction chemotherapy followed by mastectomy rather than BCS, plus axillary lymph node dissection and chest wall radiation 6

Metastatic Breast Cancer (Stage IV)

• Treatment goals shift to improving length and quality of life rather than cure 5
• For hormone receptor-positive/HER2-negative metastatic disease, endocrine therapy should be first-line unless there is rapidly progressive visceral disease 4
• For HER2-positive metastatic disease, trastuzumab with chemotherapy is standard 1
• Bisphosphonates are effective for hypercalcemia and bone metastases 1

Special Considerations

• Ductal carcinoma in situ (DCIS) is treated with lumpectomy and radiation or mastectomy, with endocrine therapy for ER-positive disease 5
• Regular follow-up with clinical breast examination and mammography is crucial for monitoring response and detecting recurrence 7
• Breast reconstruction (immediate or delayed) is an integral component of breast cancer care and should not interfere with other treatments 1

Common Pitfalls to Avoid

• Undertreating elderly patients solely based on age 1
• Overlooking fertility preservation discussions in young patients 1
• Using combined chemo-endocrine therapy in the metastatic setting, which is not recommended 2
• Prescribing hormone therapy to women with tumors that do not express estrogen receptors 2
• Failing to monitor cardiac function in patients receiving trastuzumab 3