The Fluid Future of Liquid Biopsy

Clinical lab scientists will help expand ctDNA applications from what can be measured to what should be measured, and why

By
Patrick Hurban, PhD
October 14, 2026
8 min

The Pathologist

At a Glance

Category	Detail
Condition	Liquid biopsy in precision oncology
Key Mechanisms	Analysis of circulating tumor DNA (ctDNA), including tumor-specific mutations, cancer-associated methylation patterns, and DNA fragment characteristics, for molecular assessment and longitudinal monitoring.
Target Population	People with cancer, including patients undergoing curative-intent treatment and those with metastatic disease; the article discusses studies across multiple cancer types.
Care Setting	Oncology care and clinical laboratory settings, where liquid biopsy is discussed as a complement to tissue testing for treatment assessment and disease monitoring.

Key Highlights

Liquid biopsy can provide molecular information without repeated tumor-tissue sampling and supports serial assessment during treatment.
Across studies presented at ASCO 2026, post-treatment ctDNA positivity was associated with worse disease-free survival or distant recurrence risk.
In early triple-negative breast cancer, a study reported that ctDNA surveillance detected MRD before clinical or radiographic evidence of relapse.
Researchers are evaluating mutation, methylation, and fragmentomic signals together to improve sensitivity and add biological context.
Results described for daraxonrasib in previously treated metastatic pancreatic cancer showed activity in KRAS-mutant and non-mutant populations.

Guideline-Based Recommendations

Diagnosis

The article describes liquid biopsy as complementary to tissue sampling and does not recommend replacing tissue testing.
The article describes MRD approaches that identify tumor-specific mutations and search for them in circulating free DNA.

Management

The article states that serial liquid-biopsy assessments may inform decisions about continuing or modifying treatment.
The article reports prognostic and surveillance findings but does not establish a treatment algorithm based on ctDNA results.

Monitoring & Follow-up

The article describes liquid biopsy as enabling longitudinal assessment of tumor evolution, treatment response, and recurrence risk.
In a Phase 2 study of early triple-negative breast cancer, ctDNA surveillance detected MRD before clinical or radiographic evidence of relapse.

Risks

The article identifies sensitivity in distinguishing rare tumor-derived DNA from normal circulating DNA as a challenge.
The article raises questions about the added predictive value, complexity, cost, and laboratory consistency of multimodal testing.

Patient & Prescribing Data

The article discusses patients with cancer across tumor types, including patients after curative-intent treatment, patients with early triple-negative breast cancer, and patients with previously treated metastatic pancreatic cancer.

The article describes ctDNA as a potential source of prognostic and monitoring information. It reports daraxonrasib activity across KRAS-mutant and non-mutant populations in the RASolute 302 Phase III study; it provides no prescribing instructions or dosing information.

Clinical Best Practices

The article frames liquid biopsy as complementary to tissue sampling, not as a universal replacement.
The article reports prognostic associations and early MRD detection but does not specify a treatment response to a positive ctDNA result.
The article describes mutation, methylation, and fragmentomic approaches as under evaluation and raises questions about predictive value, cost, and consistent laboratory implementation.