What are the current treatment options for breast cancer management?

Current Breast Cancer Management: Evidence-Based Treatment Strategies

Surgical Management

Breast-conserving surgery (lumpectomy) with axillary staging and whole breast radiotherapy is the standard treatment for localized breast cancer that can be completely excised with clear margins and satisfactory cosmetic outcomes. 1

Primary Surgical Approach

• Sentinel lymph node biopsy (SLNB) is the preferred method for axillary staging in clinically node-negative patients, avoiding the morbidity of complete axillary dissection 1
• Axillary dissection should only be performed after invasive carcinoma is histologically confirmed—never perform primary axillary dissection without tissue diagnosis 1, 2
• All tissue margins must be examined pathologically to ensure adequate excision 1
• "No ink on tumor" is the sufficient standard for negative margins in invasive breast cancer—pursuing wider margins compromises cosmetic outcomes without reducing recurrence 1

When Mastectomy is Required

• Modified radical mastectomy is indicated for extensive microcalcifications at diagnosis, positive margins with residual microcalcifications, or when breast conservation is not feasible 3
• For locally recurrent disease previously treated with breast-conserving surgery, mastectomy should be performed 3

Radiation Therapy

Whole breast radiotherapy is mandatory following lumpectomy, as it significantly reduces local recurrence rates (Level of Evidence A). 1, 2

Radiation Protocols by Age

• For patients under 50 years old: Whole breast radiation PLUS boost to the tumor bed is standard 1
• For patients over 50 years old: Boost to tumor bed is optional, recommended only if other risk factors for recurrence are present 1
• Post-operative mammogram at 2 months is mandatory if microcalcifications were present to verify absence of residual lesions 1, 2

Systemic Therapy by Molecular Subtype

Hormone Receptor-Positive/HER2-Negative Disease (70% of cases)

• CDK4/6 inhibitors combined with endocrine therapy are recommended for appropriate patients, showing significant progression-free survival benefits 1
• Endocrine therapy for 5-10 years is essential for ER-positive early breast cancer 4
• Only a minority of hormone receptor-positive patients require chemotherapy in addition to endocrine therapy 5

HER2-Positive Disease (15-20% of cases)

• For advanced HER2+ disease, trastuzumab with vinorelbine or a taxane is preferred for first-line therapy 1, 6
• Trastuzumab is FDA-approved as a single agent for HER2-overexpressing breast cancer in patients who have received one or more chemotherapy regimens for metastatic disease 6
• For adjuvant treatment, trastuzumab is indicated as part of a treatment regimen with doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel 6
• Paclitaxel 175 mg/m² IV over 3 hours every 3 weeks for 4 courses is the recommended adjuvant regimen, administered sequentially to doxorubicin-containing combination chemotherapy 7

Triple-Negative Breast Cancer (15% of cases)

• Chemotherapy remains the primary systemic treatment option for triple-negative breast cancer 1
• Triple-negative breast cancer has the highest recurrence risk, with 85% 5-year breast cancer-specific survival for stage I disease compared to 94-99% for other subtypes 5
• Median overall survival for metastatic triple-negative breast cancer is approximately 1 year versus approximately 5 years for other subtypes 5

Metastatic Disease Management

For metastatic breast cancer, the primary goal is palliation and quality of life maintenance, not cure—realistic treatment goals should be discussed with the patient from the beginning. 3

Treatment Selection Principles

• Sequential single-agent chemotherapy produces equivalent survival to combination regimens with significantly less toxicity for most patients 3, 2
• The choice between sequential versus combination therapy should prioritize quality of life unless rapid disease control is urgently needed 3, 2
• Systemic treatment options include endocrine therapy, chemotherapy, and biological agents such as trastuzumab, bevacizumab, and lapatinib 3

Palliative Radiation Therapy

• Radiation therapy is integral for palliative treatment of bone metastases (painful or at risk of fracture), brain metastases, and painful/fungating soft tissue masses 3
• Stereotactic radiosurgery can be used as an alternative to surgical resection for single or few brain metastases, with improved local control and fewer side effects than whole brain radiotherapy 3

Bone Metastases Management

• Bisphosphonates should be used for treatment of hypercalcemia and clinically evident bone metastases to palliate symptoms and decrease risk of bone events 3
• Bisphosphonates should start following diagnosis of bone metastases, and long-term treatment seems wise given ongoing risk of skeletal events, especially at times of disease progression 3

Follow-Up Protocol

• Structured surveillance includes history and physical examination every 3-6 months for 3 years, then every 6-12 months thereafter 3, 1
• Documentation of normalization of parameters adversely affected by chemotherapy at first follow-up visit 3
• Routine staging should include full blood counts, routine chemistry including liver enzymes, alkaline phosphatase, calcium, and contralateral mammography 3

Critical Pitfalls to Avoid

• Never perform frozen section or primary axillary dissection in the absence of confirmed invasive carcinoma 1, 2
• Always perform post-operative mammogram 2 months after surgery if microcalcifications were present 1, 2
• Do not pursue wider margins than "no ink on tumor" in invasive cancer—this compromises cosmetic outcomes without reducing recurrence 1
• For patients receiving paclitaxel, all patients must be premedicated with dexamethasone, diphenhydramine, and H2-blocker to prevent severe hypersensitivity reactions 7
• Courses of paclitaxel should not be repeated until neutrophil count is at least 1,500 cells/mm³ and platelet count is at least 100,000 cells/mm³ 7