Primary Treatment Approaches for Breast Cancer

Introduction to Treatment Approaches

The primary treatment approaches for breast cancer include surgery, radiation therapy, and systemic therapies, with treatment selection based on tumor characteristics, stage, and receptor status 1, 2

Breast-conserving surgery with radiotherapy or mastectomy are the standard surgical approaches for early breast cancer 1
Contraindications to breast-conserving surgery include multicentric tumors, large tumors in small breasts, retro-areolar localization, and tumor-involved margins after resection 3
Sentinel node biopsy should only be performed in centers with documented experience and accuracy, and should not be performed in cases with palpable axillary nodes, T3 or T4 tumors, multicentric tumors, prior axillary surgery, after breast reconstruction, during pregnancy/lactation, or after neoadjuvant systemic treatment outside clinical trials 4

Breast radiotherapy is strongly recommended after breast-conserving surgery [Level I, A evidence] [3, 4]
Post-mastectomy radiotherapy is recommended for patients with four or more positive axillary nodes [Level II, B evidence] and is suggested for T3 tumors independent of nodal status [Level III, B evidence] [5]
For patients over 70 years with receptor-positive invasive breast cancer and clear postoperative margins, adjuvant tamoxifen may be considered instead of radiation therapy [Level II, B evidence] [1]

Treatment decisions are based primarily on two factors: endocrine responsiveness of tumor tissue and risk of relapse 4, 2
Tumors with clear expression of ER and/or PgR are considered endocrine responsive 4, 6
Patients with endocrine responsive tumors may receive endocrine treatment alone or combined with chemotherapy 4
Patients with uncertain endocrine responsiveness typically receive both endocrine therapy and chemotherapy 4
Patients with endocrine non-responsive tumors derive greater benefit from chemotherapy and should not receive endocrine therapy 4
Patients with HER2 overexpression/amplification should be considered for adjuvant trastuzumab treatment 4

Primary systemic therapy is indicated for locally advanced breast cancer [Level III, B evidence] [1]
It can also be used for large operable breast cancers to allow breast-conserving surgery [Level I, A evidence] [1]
Before primary systemic therapy, a biopsy for histology and analysis of predictive factors should be performed, along with full clinical staging to rule out metastatic disease 1

Underestimating the importance of multidisciplinary treatment planning that integrates local and systemic therapies 7
Failing to assess hormone receptor and HER2 status, which are crucial for treatment selection 2
Omitting radiation therapy after breast-conserving surgery, which reduces local recurrence risk by two-thirds and has a beneficial effect on survival 1
Not considering primary systemic therapy for locally advanced disease or large operable tumors that might benefit from downstaging 4
Administering endocrine therapy to patients with endocrine non-responsive tumors 4

Risk categories help guide treatment decisions 1, 6
Factors considered include tumor size, grade, lymph node status, peritumoral vascular invasion, HER2 status, and age 6
Decision-making tools like "Adjuvant! Online" and National Comprehensive Cancer Network guidelines can help with treatment decisions 4