Liquid Biopsy for Lung Cancer: Types, Uses, and Risks
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What Is a Liquid Biopsy for Lung Cancer?

What Is a Liquid Biopsy for Lung Cancer?
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Updated on June 2, 2025
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A liquid biopsy is a blood test designed to detect cancer cells or DNA fragments of cancer cells circulating in the bloodstream. While a liquid biopsy may be useful for spotting several types of cancer, researchers are particularly excited about its potential in the diagnosis and treatment of lung cancer.

Types of Liquid Biopsies for Lung Cancer

Liquid biopsies are used to detect biomarkers (cancer-related compounds) during lung cancer diagnosis or to guide lung cancer treatment decisions. These tests identify cancer in two primary ways: a mutation-based method or a methylation-based method. Both approaches can detect disease by identifying biomarkers in bodily fluids, usually blood.

Mutation-Based Detection

This liquid biopsy method focuses on finding specific genetic mutations typical for certain cancers. These tests look at the biomarkers called circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs). This method works best when a healthcare provider already knows the tumor’s DNA profile and wants to check for changes.

Methylation-Based Detection

A new approach for detecting lung cancer may be on the horizon. Though it’s still being studied, epigenomic signature-based detection, or methylation-based detection, looks for DNA changes characteristic of certain cancers. This method works best in finding epigenetic alterations that mutation-based detection may miss. Researchers believe that further development of these methods may improve lung cancer survival and quality of life.

Biomarkers for Liquid Biopsies

Liquid biopsies may look for specific biomarkers:

  • Circulating Tumor DNA Tumor cells release DNA fragments into the bloodstream. When analyzing a liquid biopsy, technicians can recognize these ctDNA fragments, which may reveal genetic mutations that give information on a growing cancer.

     This is the most standard use of liquid biopsies.
  • Circulating Tumor Cells Intact cancer cells can detach from the main tumor into the bloodstream. CTCs found in a liquid biopsy can tell providers a lot about the tumor and how likely it is to spread.

  • Extracellular Vesicles Tumor cells release these small particles, which hold protein, RNA, and DNA. These clues can help healthcare providers detect and monitor cancer growth.

Who Typically Needs a Liquid Biopsy for Lung Cancer?

You may need a liquid biopsy if your cancer has spread or treatments aren’t working. Lung cancer is often not symptomatic until later stages, when it’s harder to treat.

In recent years, scientists have identified a variety of genetic mutations and genetic markers in some lung cancer cells, and these markers can give healthcare providers valuable insights for prognosis and treatments. More and more oncologists are using liquid biopsies in addition to standard tissue biopsies to gain additional detail about lung cancers.

A liquid biopsy can help with:

  • Prognosis prediction: Higher CTCs in the blood can mean a worse prognosis. Frequent monitoring of CTCs can indicate how fast your cancer is spreading or improving.
  • Treatment guidance: Liquid biopsy results can suggest what kinds of treatments may work best. For example, if a cancer cell has a certain DNA change that is the main driver of cancer growth, targeted therapy can attack that specific DNA change in order to shut down the specific pathway promoting cancer growth.
  • Traditional biopsy replacement: If a patient is unable to have a more invasive traditional biopsy, a liquid biopsy may offer the same information, depending on the cancer.

How Is a Liquid Biopsy for Lung Cancer Performed?

A liquid biopsy is essentially a blood test. Typically, a doctor will take blood from a vein in the arm with a small needle.

 The blood sample then goes to a lab for analysis.

In research studies, experts have explored using other body fluids to perform liquid biopsies. These include:

  • Cerebrospinal fluid: Gathered through a lumbar puncture (also known as a spinal tap), this body fluid may soon offer monitoring for lung cancer which has spread to the brain and nervous system.

  • Urine: Cancer biomarkers in urine could one day provide a lung cancer screening tool.

  • Saliva: New techniques show analysis of cancer biomarkers in saliva to determine lung cancer prognosis and guide treatment.

Blood remains the most commonly used fluid for liquid biopsies, but as research continues, these other methods may become more available.

What Are the Potential Risks Associated With a Liquid Biopsy for Lung Cancer?

A liquid biopsy procedure carries very little risk. Blood draw complications include:

  • Pain after procedure
  • Nerve injury from poor technique
  • Hematoma — blood gathering from lack of pressure

These risks are uncommon and avoidable if the healthcare provider drawing the blood has been trained in proper technique.

What’s Next?

After your procedure, you can go about your life as you normally would, without restrictions. The analysis usually takes one to two weeks, after which your healthcare provider can explain the results and their implications.

 If you receive a negative result, your doctor will probably order a tissue biopsy as confirmation.
Studies show that liquid biopsies have a high specificity but a varying sensitivity, ranging from 60 to 85 percent.

 That means the blood test is very accurate at identifying a positive result, but a negative result may not be as precise.

“The amount of DNA in the blood might be dependent on the size of the tumor and the stage,” says Fred R. Hirsch, MD, PhD, the executive director of the center for thoracic oncology at the Mount Sinai Tisch Cancer Institute in New York City. “Sometimes there is not enough DNA for reliable examination. Sometimes there’s a discrepancy between the molecular findings in the blood and in the tumor.”

Scientists are making rapid progress in developing more sensitive liquid biopsy technologies, says Dr. Hirsch.

In the future, the role of liquid biopsies in treating lung cancer may expand. “I see a role for liquid biopsy in the treatment decisions for individual patients,” Hirsch says.

“I also see a future role in monitoring treatment effects and an early determination of when a tumor gets resistant to the given molecular therapy or immunotherapy,” he says. “A liquid biopsy may detect increasing abnormal tumor DNA in the bloodstream, indicating tumor progression, for instance, well before it can be seen on a CT scan.”

Questions to Ask Your Doctor

  • Could I benefit from a liquid biopsy?
  • What type of liquid biopsy do you recommend for me?
  • How long will it take to get my results?
  • What are the risks involved with a liquid biopsy?
  • What are you hoping to discover with this test?
  • What are my options after the test results are back?

The Takeaway

  • Liquid biopsies can help doctors identify the mutations in a cancer without surgery or invasive procedures to obtain tumor tissue.
  • This type of biopsy may be particularly helpful for improving the diagnosis and treatment of lung cancer.
  • Liquid biopsies can help identify a tumor’s genetic mutations, which can help patients get more pinpointed therapy and improve their prognosis.
  • There are some limitations with liquid biopsies, but continuing research and development will likely improve its role in diagnosing and treating lung and other cancers.

Resources We Trust

EDITORIAL SOURCES
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Resources
  1. Nikanjam M et al. Liquid Biopsy: Current Technology and Clinical Applications. Journal of Hematology & Oncology. September 12, 2022.
  2. Kwon HJ et al. Advances in Methylation Analysis of Liquid Biopsy in Early Cancer Detection of Colorectal and Lung Cancer. Scientific Reports. August 19, 2023.
  3. Batool SM et al. The Liquid Biopsy Consortium: Challenges and Opportunities for Early Cancer Detection and Monitoring. Cell Reports Medicine. September 15, 2023.
  4. Casagrande GMS et al. Liquid Biopsy for Lung Cancer: Up-to-Date and Perspectives for Screening Programs. International Journal of Molecular Sciences. January 28, 2023.
  5. de Alencar VTL et al. Lung Cancer in Never Smokers: Tumor Immunology and Challenges for Immunotherapy. Frontiers in Immunology. August 24, 2022.
  6. Li W et al. Liquid Biopsy in Lung Cancer: Significance in Diagnostics, Prediction, and Treatment Monitoring. Molecular Cancer. January 20, 2022.
  7. Liquid Biopsy. Cleveland Clinic. August 11, 2022.
  8. Azad TD et al. Quantification of Cerebrospinal Fluid Tumor DNA in Lung Cancer Patients With Suspected Leptomeningeal Carcinomatosis. NPJ Precision Oncology. May 28, 2024.
  9. Dalal E et al. Urinary Metabolite Diagnostic and Prognostic Liquid Biopsy Biomarkers of Lung Cancer in Nonsmokers and Tobacco Smokers. Clinical Cancer Research. August 15, 2024.
  10. Ren F et al. Liquid Biopsy Techniques and Lung Cancer: Diagnosis, Monitoring and Evaluation. Journal of Experimental & Clinical Cancer Research. April 1, 2024.
  11. Srikanth KK et al. Phlebotomy. StatPearls. August 28, 2023.
  12. Kim M. A Simpler Way to Sample: Liquid Biopsies in Lung Cancer. CURE. April 20, 2020.
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Conor Steuer, MD

Medical Reviewer
Castle Connolly Top Doctor

Conor E. Steuer, MD, is medical oncologist specializing in the care of aerodigestive cancers, mesothelioma, and thymic malignancies and an assistant professor in the department of hematology and medical oncology at the Emory University School of Medicine in Atlanta. He joined the clinical staff at Emory's Winship Cancer Institute as a practicing physician in July 2015. He currently serves as chair of the Lung and Aerodigestive Malignancies Working Group and is a member of the Discovery and Developmental Therapeutics Research Program at Winship.

Dr. Steuer received his medical degree from the New York University School of Medicine in 2009. He completed his postdoctoral training as a fellow in the department of hematology and medical oncology at the Emory University School of Medicine, where he was chief fellow in his final year.

He has been active in research including in clinical trial development, database analyses, and investigation of molecular biomarkers. He is interested in investigating the molecular biology and genomics of thoracic and head and neck tumors in order to be able to further the care of these patient populations. Additionally, he has taken an interest in utilizing national databases to perform clinical outcomes research, as well as further investigate rare forms of thoracic cancers.

Steuer's work has been published in many leading journals, such as Cancer, the Journal of Thoracic Oncology, and Lung Cancer, and has been presented at multiple international conferences.

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Abby McCoy, RN

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Abby McCoy is an experienced registered nurse who has worked with adults and pediatric patients encompassing trauma, orthopedics, home care, transplant, and case management. She is a married mother of four and loves the circus — that is her home! She has family all over the world, and loves to travel as much as possible.

McCoy has written for publications like Remedy Health Media, Sleepopolis, and Expectful. She is passionate about health education and loves using her experience and knowledge in her writing.

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