Molecular Biology Nuances in Breast Cancer Surgery: Experience-Based Algorithms and Recommendations from a Practice in LMIC

Background: The growing awareness of breast cancer’s molecular diversity has not changed the technical foundations of surgery itself, but it has profoundly reshaped how surgeons think about surgery. Rather than molecular biology prescribing specific surgery, it is the surgeon’s interpretation of biological behavior—tumor subtype, genomic risk, treatment responsiveness—that influences surgical timing, extent, and feasibility. This is particularly important in the developing world, where mastectomy continues to be the default surgery, not always because it is required, but because biological nuance is underutilized in surgical planning. This review integrates existing evidence, guidelines, and real-world clinical experience to show how a surgeon who understands tumor biology can meaningfully expand safe breast conservation, de-escalate axillary surgery, and align operative choices with systemic therapy. In essence, molecular biology becomes a lens through which surgeons can practice more personalized, precise, and less invasive surgery, without compromising oncologic safety. Recent findings: We present evidence-based algorithms focusing on Luminal A, Luminal B, HER2-positive, and triple-negative subtypes, while discussing the nuances of multifocal and multicentric disease, metaplastic histologies, and discordant lesion management. The review addresses axillary management in the molecular era, specifying the appropriateness of sentinel lymph node biopsy, targeted axillary dissection, or completion axillary dissection, and how subtype-specific nodal responses to neoadjuvant therapy can guide de-escalation strategies. Through clinical vignettes, we exemplify how molecular integration into surgical planning can modify clinical courses, enabling oncoplastic conservation in downstaged tumors and justifying definitive resection in chemo-resistant cases. We examine the implications of germline and somatic genetic testing on surgical decision-making, particularly in relation to BRCA1/2 and PALB2 mutation carriers, alongside ethical and practical counseling considerations. Additionally, we review emerging biomarkers—such as circulating tumor DNA and immune and radiomic signatures—and propose research priorities for their incorporation into surgical trials. Conclusions: Effective implementation necessitates enhanced surgeon education, standardized assays, and multidisciplinary coordination to promote equitable access, consistent utilization of biology-driven algorithms, and rigorous quality oversight. This review furnishes breast surgeons with a pragmatic framework for translating molecular knowledge into multidisciplinary, patient-centered care pathways that optimize oncological safety, aesthetic outcomes, and overall quality of life.