Liquid biopsy in breast cancer: a practical guide for surgeons.

Breast cancer remains a global health challenge, requiring innovative strategies for early detection, diagnosis, treatment monitoring, and recurrence detection. Liquid biopsy-leveraging circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), microRNAs (miRNAs), exosomes, immune-based biomarkers, and tumor-educated platelets (TEPs)-has emerged as a promising tool to address these needs. CTCs and ctDNA provide critical insights into tumor heterogeneity, therapeutic targets, and resistance mechanisms, while miRNAs, exosomes, and other non-CTC-based markers reflect the tumor microenvironment and offer potential biomarkers for disease progression. Importantly, liquid biopsy offers distinct advantages in early detection and precise diagnosis, as well as in identifying therapeutic resistance in real time, allowing clinicians to adapt treatment strategies effectively. The non-invasive nature of liquid biopsy further enables real-time tumor monitoring, paving the way for personalized treatment approaches. However, several challenges hinder its routine clinical adoption, including technical complexity, economic constraints, and variations in detection sensitivity due to low biomarker abundance. Additionally, a lack of standardization in methodology and interpretation limits its widespread application. Rigorous standardization and clinical validation are essential to address these barriers, ensuring equitable access across diverse healthcare settings and transforming breast cancer care for millions worldwide. Future directions include integrating artificial intelligence and multi-omic approaches to enhance diagnostic accuracy and clinical utility.