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Liquid biopsy: a new era in cancer diagnosis
What is a liquid biopsy?
Liquid biopsy is non-invasive method of detecting cancer cells or tumor genetic material in biological fluids, most often in the blood. Unlike a traditional biopsy, which requires a tissue sample, a liquid biopsy allows for the analysis of tumor changes without surgical intervention.
The main goal is detection of circulating tumor DNA (ctDNA), tumor cells or exosomes that enter the bloodstream from the primary or metastatic site.
This method is already actively used in the USA, Europe and is being implemented in clinical practice in Ukraine, in particular within the framework of precision oncology.
What liquids can be used?
Blood (plasma) — most often
Urine — for some urological tumors
Cerebrospinal fluid — for brain tumors
Saliva, bile, pleural effusion — for research in individual cases
What can a liquid biopsy detect?
| Possibility | Practical application |
|---|---|
| Detection of mutations in ctDNA | Choosing targeted therapy (EGFR, KRAS, BRAF, ALK, and others) |
| Definition of minimal residual disease | Monitoring after surgery or chemotherapy |
| Early diagnosis | Tumor detection before clinical symptoms appear |
| Evaluation of treatment effectiveness | Decreasing ctDNA levels indicate a response to therapy |
| Relapse detection | ctDNA appears in the blood even before clinical progression |
Oncologist Igor Savin explains:
«Liquid biopsy does not replace tissue biopsy, but it gives the doctor a unique tool to track changes in the tumor in almost real time. This is invaluable in the treatment of metastatic forms of cancer.»
Advantages of liquid biopsy
Security — does not require surgical intervention
Patient comfort — routine blood draw
Possibility of multiple control — dynamics of tumor changes
Access to genetic information — even if the fabric is not available
Speed of getting results — 7–10 days in most laboratories
Who can be prescribed a liquid biopsy?
Patients with suspected cancer, from which it is impossible to take a tissue sample
Patients who are already receiving targeted or immunotherapy
If necessary residual disease assessments after treatment
For choosing an individual treatment protocol in case of relapse
Within screening programs (at the stage of clinical trials)
Liquid biopsy and precision oncology
Modern oncology is moving from a «one treatment fits all» approach to individual therapy, which is based on mutational profile of the tumor. Liquid biopsy allows:
to find the exact genetic target
change therapy if any appear new mutations
monitor resistance to drugs
save time on expensive tests if treatment is ineffective
Limitations and challenges
Not all tumors secrete sufficient amounts of ctDNA
Maybe not sensitive enough in the early stages
Needed high standardization of laboratories and technologies
Price research still remains high for widespread use
Liquid biopsy is technology of the future, which is already changing the lives of cancer patients. It allows you to see the tumor not only under a microscope, but also at the molecular level, respond to changes instantly and build treatment based on an individual genetic portrait.
