Evolving roles of liquid biopsy in precision medicine for colorectal cancer: from single-gene analysis to broad genomic profiling.

Journal: Nature reviews. Clinical oncology

This review focuses on the current and emerging roles of circulating tumor DNA (ctDNA) analysis from liquid biopsy in the management of colorectal cancer.

Key points:

  • Tumor heterogeneity and resistance: Colorectal cancer is molecularly heterogeneous, and evolving pathway alterations contribute to progression and treatment resistance, particularly in the metastatic setting.
  • Metastatic disease – real-time molecular profiling:

    • ctDNA from liquid biopsy is used to capture tumor molecular heterogeneity and clonal evolution.
    • It enables identification of actionable genomic alterations for precision oncology (for example, predicting eligibility for targeted therapies).
    • Serial ctDNA assessments can detect emerging resistance mechanisms under treatment pressure, supporting adaptive treatment strategies.
  • Localized disease – minimal residual disease (MRD):

    • ctDNA detection after surgery or locoregional therapy has been clinically validated as a marker of MRD in colon and rectal cancer.
    • Post-treatment ctDNA status offers refined prognostic stratification beyond standard clinicopathologic factors.
    • This can inform adjuvant therapy decisions—escalating treatment in ctDNA-positive patients at higher relapse risk and potentially de-escalating in ctDNA-negative patients to reduce overtreatment.
  • Technological evolution and comprehensive genomic profiling (CGP):

    • The field has moved from PCR-based assays focused on a few mutations to broad next-generation sequencing panels assessing hundreds of genes.
    • Liquid biopsy-based CGP provides a more complete picture of an individual patient’s tumor genomics and its temporal evolution.
  • Clinical implications:

    • Liquid biopsy is minimally invasive and easily repeatable, allowing dynamic monitoring over the disease course.
    • The authors summarize evidence for current clinical applications in metastatic colorectal cancer and review data supporting integration of MRD-directed strategies in earlier-stage disease, with the dual goals of improving cure rates and limiting unnecessary systemic therapy.

Overall, the article positions ctDNA-based liquid biopsy—particularly when coupled with comprehensive genomic profiling—as a central tool for personalized, adaptive management of colorectal cancer across both metastatic and localized settings.

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