- A new liquid biopsy blood test can detect circulating tumor DNA (ctDNA), potentially identifying signs of lung cancer recurrence months before tumors become visible on scans.
- Detectable ctDNA may indicate minimal residual disease and help identify those at higher risk of cancer recurrence, while negative results are associated with continued remission.
- Blood test results could help doctors identify patients who may benefit from additional treatment or closer monitoring, potentially reducing unnecessary treatment and its associated side effects.
- Although promising, larger clinical studies are necessary to establish whether using liquid biopsy results to guide treatment decisions improves long-term outcomes and survival.
Non-small cell lung cancer (NSCLC) accounts for the
For people diagnosed with early-stage NSCLC, surgery
However, despite successful initial treatment, recurrence remains a major clinical challenge, with some evidence suggesting that cancer may return in roughly a third of patients.
Currently, doctors generally use imaging tests, such as CT scans, to monitor patients following treatment. Although these scans can identify tumors, they may not detect very small amounts of cancer that remain in the body.
This creates a potential gap between the time cancer begins to recur and the point at which the disease becomes visible on imaging. A more sensitive method of monitoring could help doctors identify patients at increased risk during this period.
Now, a new blood test that detects traces of lung cancer DNA could help identify patients at risk of recurrence months before the disease becomes visible on scans. The findings may pave the way for more personalized follow-up care and treatment after surgery.
The study, published in The Journal of Molecular Diagnostics, suggests that liquid biopsies could eventually complement standard imaging and help doctors tailor follow-up care according to each patient’s risk of recurrence. However, further research is necessary to establish how best to use these tests in routine clinical practice and whether acting on their results improves long-term survival.
How does the blood test detect cancer?
Cancer cells can release small fragments of their DNA into the bloodstream. These fragments, known as circulating tumor DNA (ctDNA), can carry genetic changes associated with a particular tumor.
By analyzing tumor-specific genetic signatures in a blood sample, researchers can look for evidence that cancer may still be present or has returned.
In the study, the researchers used repeated blood samples to monitor ctDNA levels in patients with lung cancer at different stages of treatment. The approach allowed them to track changes over time rather than relying solely on periodic imaging.
A positive result indicated that tumor-associated DNA was detectable in the blood, potentially signaling residual disease or recurrence. A negative result suggests that the test had not detected these genetic traces.
Importantly, a negative result does not necessarily mean that cancer is absent. The amount of tumor DNA in the bloodstream can be very low, and some cancers may not release enough DNA for a test to detect.
What did the researchers find?
The study found that liquid biopsy testing could identify molecular signs of lung cancer recurrence months before tumors became visible on scans.
“The key potential advantage is earlier, minimally invasive detection of molecular evidence of recurrence,” lead investigator Matija Snuderl, MD, of NYU Langone Health and the Laura and Isaac Perlmutter Cancer Center in New York, explained to Medical News Today.
“Conventional imaging detects a tumor once it is anatomically visible, whereas this blood-based approach looks for a patient-specific cancer DNA signature in circulating cell-free DNA. In addition, whole-genome analysis can potentially help distinguish a true recurrence from a new, independent lung primary—an important distinction that can sometimes be difficult based on imaging and pathology alone.”
– Matija Snuderl, MD
The researchers reported that a positive ctDNA result was a sensitive marker of minimal residual disease and could help identify those at increased risk of relapse. Conversely, negative test results were strongly associated with continued remission.
“(T)his type of test fulfills a real need for studies which want to further definitively set the timeline for when things happen as a timeline of insidious lung cancer development and progression,” co-lead investigator Harvey Pass, MD, of the Department of Cardiothoracic Surgery at NYU Langone Health, told MNT.
“The evolution of lung adenocarcinoma starts with normal tissue and early precursors. Many of the mutations that continue along this road occur early,” Pass added.
“These mutations along with changes in circulating proteins which are later consequences as lung cancer goes from AIS to invasive cancer as a combined series of temporal biomarkers may synergize to make our non-invasive, pre imaging prediction of a developing lung cancer even more accurate than cfDNA alone (…) That’s the hope,” he told us.
These findings suggest that monitoring ctDNA could provide doctors with additional information about a patient’s cancer status between scheduled imaging appointments. Notably, the blood test may be able to detect ctDNA months before a tumor is visible on a scan.
“In this retrospective cohort of 42 patients with stage IA lung adenocarcinoma, the assay detected ctDNA in 9 of 12 patients who ultimately recurred, corresponding to a sensitivity of 75%. Specificity was 83%, with a negative predictive value of 89%,” Snuderl stated.
“Among patients with both a positive ctDNA result and confirmed recurrence, ctDNA preceded clinical or radiologic recurrence by a median of 16.7 months. These results are promising, but they need confirmation in larger prospective studies before routine clinical use.”
– Matija Snuderl, MD
Could liquid biopsies change lung cancer treatment?
If further studies confirmed the findings, liquid biopsy testing could have several potential applications in lung cancer care.
Identifying patients who may need additional treatment
Detecting ctDNA after surgery could help doctors identify patients who may have residual cancer and a higher risk of relapse. This information could support discussions about additional treatment, closer monitoring, or participation in clinical trials.
However, a positive test would not automatically mean that further treatment is necessary. Doctors would need to consider the test result alongside other clinical findings and evidence about the benefits and risks of available treatments.
Reducing unnecessary treatment
Patients with negative ctDNA results may have a lower risk of recurrence. This information could help doctors assess whether some people could safely avoid additional treatment that offers limited benefit but carries a risk of side effects.
However, a negative result alone would not be sufficient to justify withholding recommended treatment. Researchers would first need to establish how reliably these tests identify patients who can safely avoid further therapy.
Supporting earlier intervention
Detecting molecular signs of recurrence before a tumor appears on imaging could give doctors more time to investigate and consider treatment options.
In some cases, this might create an opportunity to intervene while the amount of cancer in the body is still very small.
Whether earlier intervention based on ctDNA results leads to better survival outcomes remains an important question for future clinical trials.
Providing additional information between scans
Waiting for follow-up scans can be a source of uncertainty for people who have completed cancer treatment. Repeated blood testing could provide additional information about disease status between imaging appointments.
However, the result may also create anxiety, particularly if there is no visible tumor to target or if the most appropriate next step is unclear.
Clear guidance on interpreting results and communicating uncertainty will therefore be important if liquid biopsies become part of routine follow-up care.
What are the limitations of the research?
Although the findings are promising, several questions remain before liquid biopsy testing can be widely adopted for monitoring early-stage lung cancer.
First, detecting ctDNA does not confirm a person will experience a clinically significant recurrence. Doctors need to understand how accurately the test predicts relapse across different patient groups and cancer stages.
Second, a negative result cannot completely rule out residual disease. Some tumors release very little DNA into the bloodstream, meaning that a test may not detect cancer even when it remains in the body.
Third, identifying recurrence earlier does not necessarily guarantee that treatment will be more effective. Studies must determine whether making treatment decisions based on ctDNA results improves outcomes compared with standard follow-up care.
Further clinical studies will be necessary to determine how the test should be used, how frequently people should be tested, and which treatment decisions should follow a positive or negative result. For now, the findings represent a promising development rather than a replacement for standard follow-up scans.
“If validated prospectively, ctDNA monitoring could complement (not immediately replace) imaging surveillance after surgery. A persistent or newly positive ctDNA result could identify patients who may warrant closer radiological follow-up or evaluation in clinical trials, while repeatedly negative results may provide additional reassurance,” said Snuderl.
“Importantly, this study supports risk stratification in a population in which most patients are cured with surgery but a meaningful minority experience recurrence,” he concluded.
