Oncology Insight Report

Liquid Biopsies & ctDNA in Practice: Why Oncologists Act on the Signal, But Resist Treating It Alone

Liquid biopsy is no longer an abstract precision-oncology promise. In this MDForLives survey, oncologists report meaningful ctDNA use, but the strongest pattern is not immediate escalation. It is controlled response, intensified surveillance, confirmatory testing, and a persistent need for outcome-level proof.

SGID: 8871888

Audience: Oncology specialists

Markets: USA, UK, Canada, Italy, France, Germany

Status: June Oncology Insight Survey

– Core Study Snapshot

total responses captured in the MDForLives oncology insight survey.

complete responses

partial responses

completion rate

0 %

oncology specialty base

– Quick Read — Key Findings

Signal without escalation

65.4%

choose accelerated surveillance after molecular-only positivity

Most oncologists respond to ctDNA before imaging changes, but only 8.6% escalate treatment immediately.

Evidence threshold

50.6%

cite lack of OS data as the main hesitation

The central barrier is not disbelief in ctDNA, but uncertainty about whether early intervention changes outcomes.

CHIP caution

51.9%

use PBMC control testing for low-VAF variants

Clinicians are treating low-VAF findings as interpretation problems, not automatic precision-therapy signals.

What happens when the blood test moves faster than the treatment pathway?

This summary captures how oncology peers convert liquid biopsy signals into surveillance, caution, verification, and selective clinical action.

Insight framing

Liquid biopsy adoption is real, but its hardest use case is not detection. It is deciding what to do when detection arrives early.

The survey points to a practice landscape where ctDNA is already embedded in oncology workflows. 74.4% of respondents order or review a liquid biopsy/ctDNA assay for at least five patients per month, and more than one-third report reviewing it for more than 15 patients monthly. Yet the strongest decision pattern is cautious action rather than treatment acceleration.

When faced with a positive ctDNA signal and clean scans, 65.4% choose accelerated surveillance, while only 8.6% treat it as molecular relapse and escalate immediately. This reveals a clinically important middle ground: oncologists are not ignoring molecular information, but many are not ready to let it override radiographic and outcome-based evidence.

The ctDNA signal is strong enough to shorten the surveillance window, but not strong enough for most clinicians to treat alone.

MDForLives synthesis

Clinical hesitation

The barrier is less about technology acceptance and more about proving that early molecular action changes outcomes.

The largest hesitation driver is the absence of prospective randomized overall survival evidence. 50.6% cite lack of OS data as the primary reason not to escalate immediately, while 14.8% point to institutional or guideline ambiguity. Together, these responses suggest that molecular relapse is clinically persuasive, but not yet operationally settled.

Interpretation risk

Low-VAF findings are creating a verification culture around CHIP, rather than a reflexive treatment culture.

Potential CHIP variants remain one of the clearest examples of liquid biopsy complexity. Only 10.1% assume low-VAF findings are tumor-derived and alter therapy pathways. In contrast, 51.9% order paired PBMC control testing and 17.7% refer for clonal hematology or cardio-oncology assessment. This creates a workflow burden, but also protects against over-interpreting biological noise as actionable cancer signal.

De-escalation tension

Negative ctDNA is useful, but most respondents stop short of using it to omit treatment entirely.

66.7% say they use a negative ctDNA/MRD result to lower treatment intensity but never to omit therapy entirely. Another 17.9% report zero confidence that a negative result can rule out low-shedding or sanctuary-site disease. This shows that negative ctDNA may support de-escalation conversations, but it is not yet a stand-alone exit ramp from care for most respondents.

False reassurance and cost

Clinical value is not universal. Tumor biology, anatomical sites, and confirmatory testing still shape confidence.

Respondents most often identify CNS primary tumors or isolated brain metastases as unreliable for plasma-based ctDNA due to low-shedding or sanctuary-site limitations. They also name early/oligometastatic disease, mucinous or signet-ring carcinomas, RCC, and sarcomas. In cost-effectiveness, the largest group calls liquid biopsy cost-neutral, while 28.6% see it as an additive burden because tissue confirmation is still often needed.

Where plasma ctDNA feels least reliable

CNS or brain mets

0 %

40 responses

RCC

0 %

40 responses

Early/oligometastatic

0 %

30 responses

Mucinous/signet-ring

0 %