Cell-Free DNA and Circulating Tumor Cells: Comprehensive Liquid Biopsy Analysis in Advanced Breast Cancer

Area of Science:

• Oncology
• Molecular Biology
• Biomarkers

Background:

• Liquid biopsy offers real-time monitoring for metastatic breast cancer (MBC).
• Combining circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) may enhance prognostic accuracy in MBC.

Purpose of the Study:

• To evaluate the combined utility of CTCs and ctDNA as prognostic markers in patients with MBC.
• To assess the correlation between CTC enumeration, ctDNA characteristics, and patient survival outcomes.

Main Methods:

• Retrospective analysis of 91 locally advanced breast cancer and MBC patients.
• CTC enumeration using CellSearch and ctDNA analysis via Guardant360.
• Survival analysis performed using Kaplan-Meier curves.

Main Results:

• 84% of blood samples detected mutations, with TP53, PIK3CA, and ERBB2 being commonly altered.
• Significant differences in progression-free survival (PFS) and overall survival (OS) were observed based on CTC counts (<5 vs. ≥5) and ctDNA fraction (<0.5% vs. ≥0.5%).
• A strong association was found between the number of ctDNA alterations and ctDNA fraction (P < 0.0001).

Conclusions:

• Liquid biopsy, combining CTCs and ctDNA, serves as an effective prognostic tool for MBC.
• ctDNA fraction and number of alterations are significant prognostic indicators.
• This approach provides valuable real-time insights for managing MBC patients.