How do I obtain a liquid biopsy?

From the Guidelines

To obtain a liquid biopsy, you should consult with your healthcare provider who will determine if this test is appropriate for your specific medical situation and order it if necessary. A liquid biopsy involves collecting a blood sample, which is typically drawn from a vein in your arm using standard blood collection procedures, as mentioned in the guidelines for gastric cancer management 1. The sample is then sent to a specialized laboratory for analysis of circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), or other biomarkers.

Key Points to Consider

• Your doctor will schedule the blood draw either at their office, a hospital, or an outpatient laboratory facility.
• Unlike traditional tissue biopsies, liquid biopsies are minimally invasive and require no special preparation beyond what's typical for a regular blood test.
• Liquid biopsies are primarily used in cancer care for detecting genetic mutations, monitoring treatment response, identifying drug resistance, or screening for early cancer recurrence, as supported by recent guidelines 1.
• They're particularly valuable when tissue biopsies are difficult to obtain or when repeated sampling is needed to track disease progression.

Important Considerations

• Insurance coverage varies, so it's essential to check with your provider and insurance company regarding costs and coverage before proceeding.
• The use of liquid biopsies is becoming more frequent in patients with advanced disease, especially those unable to undergo a traditional biopsy for disease surveillance and management 1.
• A negative result should be recommended in all newly diagnosed patients, highlighting the importance of discussing the implications of test results with your healthcare provider.

From the Research

Obtaining a Liquid Biopsy

To obtain a liquid biopsy, the following steps can be taken:

• Consult a healthcare professional or an oncologist to discuss the suitability of a liquid biopsy for your specific situation 2, 3, 4.
• Liquid biopsies typically involve a blood test or the collection of other body fluids, such as urine or cerebrospinal fluid, to analyze for circulating tumor cells, circulating tumor DNA, or other biomarkers 5, 6.
• The collected sample is then sent to a laboratory for analysis, where various techniques such as droplet digital polymerase chain reaction, beads, emulsion, amplification, and magnetics (BEAMing) or tagged-amplicon deep sequencing (TAm-Seq) may be used to isolate and analyze the biomarkers 5.
• The results of the liquid biopsy can provide valuable information on tumor dynamics, treatment response, and disease progression, which can be used to guide personalized treatment decisions 3, 4.

Types of Liquid Biopsy Analytes

Some common types of liquid biopsy analytes include:

• Circulating tumor cells (CTCs) 2, 3, 4, 5, 6
• Circulating tumor DNA (ctDNA) 2, 3, 4, 5, 6
• Exosomes 2, 4
• MicroRNA 2, 4
• Circulating RNA 2
• Tumor platelets 2
• Tumor endothelial cells 2

Clinical Applications of Liquid Biopsies

Liquid biopsies have various clinical applications, including:

• Early detection of cancer or tumor recurrence 3, 4, 6
• Individual risk assessment 6
• Therapy monitoring 3, 4, 6
• Predicting response and resistance to targeted therapy and chemotherapy as well as immunotherapy 5
• Assessing shed DNA from multiple metastatic sites 5
• Analyzing prognosis and tumor burden 5