Review of ctDNA in breast cancer - present utility and future perspectives.

Breast cancer is the second most commonly diagnosed cancer worldwide and remains a major cause of cancer-related mortality. Despite advances in treatment, challenges like tumor heterogeneity, recurrence, and drug resistance persist. A critical unmet need in breast cancer management is the lack of validated, real-time biomarkers to monitor disease progression and treatment response. Circulating tumor DNA (ctDNA), a key component of liquid biopsy, offers a promising, non-invasive approach to address this gap. Circulating tumor DNA is released into the bloodstream by tumor cells through apoptosis, necrosis, or active secretion and provides a dynamic snapshot of the tumor's genetic profile. Its short half-life allows real-time monitoring of tumor burden, therapeutic response, and minimal residual disease. Circulating tumor DNA analysis has demonstrated potential in early cancer detection, predicting recurrence, and identifying emerging drug resistance, often surpassing the sensitivity of conventional imaging. Furthermore, its non-invasive nature enables repeated sampling with minimal patient discomfort. As technological advances continue to improve sensitivity and specificity, ctDNA is emerging as a powerful tool in the personalized management of breast cancer. Its integration into clinical practice could transform current paradigms of diagnosis, treatment monitoring, and long-term follow-up, paving the way for truly individualized cancer care.