THE CLINICAL UTILITY OF CIRCULATING TUMOR DNA (CTDNA) IN BREAST CANCER: FROM DIAGNOSIS TO TREATMENT RESPONSE A NARRATIVE REVIEW

Abstract

Background: Breast cancer remains a leading cause of cancer-related morbidity and mortality among women worldwide, highlighting the urgent need for more accurate, minimally invasive diagnostic and monitoring tools. Circulating tumor DNA (ctDNA), derived from tumor cell apoptosis, necrosis, or active secretion, has emerged as a promising biomarker capable of providing real-time insights into tumor dynamics. Its use in oncology aligns with the growing shift toward precision medicine, offering the potential to overcome the limitations of conventional tissue biopsy and imaging techniques. ObjectivE': This narrative review aims to explore the clinical utility of ctDNA in breast cancer - from early detection and disease monitoring to prognostication and treatment response evaluation- while addressing current challenges and filture directions in its clinical application. Main Discussion Points: Recent advancements in ctDNA detection technologies, including digital PCR and next-generation sequencing (NGS), have enhanced analytical sensitivity and broadened clinical applicability. The review discusses ctDNA's role in detecting minimal residual disease (MRD), identifying resistance mutations, and tracking therapeutic efficacy across different breast cancer subtypes. Furthermore, it examines limitations such as biological variability, clonal hematopoiesis, assay standardization, and cost-effectiveness, emphasizing the need for robust validation and regulatory frameworks to support clinical integration. Conclusion: CtDNA-based liquid biopsy represents a paradigm shift in breast cancer management, enabling personalized and dynamic patient care. However, its translation into routine practice demands multicenter validation, technological standardization, and equitable global accessibility to fillly harness its potential in precision oncology.