What Is a Liquid Biopsy?

2 min

Biopsy, which involves taking a sample of a suspicious tissue, is a common medical procedure, and an effective diagnostic tool for a wide range of conditions, especially cancer. A pathologist who examines the sample under a microscope can discover vital information about it. Biopsied tissue may reveal indicators of a malignancy, or it may provide peace of mind if the results are negative. Most importantly, it provides knowledge that allows doctors and patients to decide whether and what kind of treatment is needed.

Extracting a specimen for traditional biopsy can be as simple as scraping a tiny amount of skin tissue or as complicated as an image-guided surgical procedure. Many biopsies, including those from the breast, prostate, lung, or thyroid are minimally invasive – long, thin needles can extract tiny samples for study, others require more invasive techniques.

• Core needle biopsies use larger, hollow needles to extract more tissue.
• An endoscopic biopsy is performed using a special tool with a camera that allows a surgeon to find and reach a suspicious growth.
• Bone marrow biopsies are used to diagnose or rule out blood cancers.
• Surgical biopsies, which typically involve either removing a larger sample for study or an entire growth, may be recommended when less invasive tests are inconclusive.

A “liquid biopsy” isn’t really a new procedure; it refers to testing performed on a blood sample, which can be taken quickly, painlessly, and repeatedly. This testing methodology makes it easier and faster to obtain highly specific information about abnormalities from blood rather than from other tissue samples. Advances in “liquid biopsies” are now making it more accurate as well as easier to detect, monitor, and analyze certain cancers. That’s because no matter where in the body it is, a tumor may release certain biomarkers into the bloodstream. These include the tumor’s DNA, RNA, or tumor cells themselves, all of which provide information about the growth’s makeup. This utilization of liquid biopsy is being used increasingly in precision medicine. That emerging field aims to match a tumor’s unique biology and metabolism to a specific, tailored treatment.

Even the least invasive biopsy can be intimidating for a patient, especially when it has to be repeated, either to get additional samples or to monitor how a tumor is changing in response to treatment. That’s why advances in a liquid biopsy for conditions that have traditionally required an invasive biopsy are so promising. Extracting a physical sample of a suspicious growth would no longer be necessary; ideally, the test would instead allow identification of markers in blood that indicate the presence of cancer.

Using the genetic profile of a tumor to select the most effective treatment is just one extremely interesting development. Researchers are currently looking at other potential uses of liquid biopsy, including detecting the presence of cancer cells before a tumor has even formed. There may be additional benefits still to be discovered. I look forward to more studies and more clinical trials to advance these new uses of sampling blood.

Andrew Weil, M.D.

Sources
Shegekar T, Vodithala S, Juganavar A. The Emerging Role of Liquid Biopsies in Revolutionising Cancer Diagnosis and Therapy. Cureus. 2023 Aug 17;15(8):e43650. doi: 10.7759/cureus.43650. PMID: 37719630; PMCID: PMC10505053.

Nikanjam M, Kato S, Kurzrock R. Liquid biopsy: current technology and clinical applications. J Hematol Oncol. 2022 Sep 12;15(1):131. doi: 10.1186/s13045-022-01351-y. PMID: 36096847; PMCID: PMC9465933. pubmed.ncbi.nlm.nih/36096847/

Zerbino DD. Biopsiia: istoriia, sovremennost’, perspektivy [Biopsy: its history, current and future outlook]. Lik Sprava. 1994 Mar-Apr;(3-4):1-9. Russian. PMID: 7975522. pubmed.ncbi.nlm.nih/7975522/