Evaluating the Potential and Limitations of Liquid Biopsies in Cancer Screening

Liquid biopsies, which analyze blood samples to detect circulating DNA, proteins, and other biomarkers associated with various cancers, are garnering significant interest for their potential to identify tumors that are otherwise difficult to detect early. Several laboratory-developed multi-cancer detection (MCD) tests—such as OneTest, Galleri, OncoSeek, and the newly launched Cancerguard—are available for purchase online with a doctor's note, although none have received approval from the U.S. Food and Drug Administration (FDA). These tests are priced around $950 and aim to enhance early detection, especially for cancers lacking standard screening options, which account for up to 70% of cancer-related deaths.

However, the effectiveness of these tests in real-world settings remains uncertain. A comprehensive review of 20 studies involving over 109,000 individuals revealed significant variability in test accuracy depending on the type of cancer, the study design, and the population tested. Currently, there's a lack of controlled, clinical trials demonstrating that MCD tests improve cancer detection rates, reduce mortality, or enhance quality of life. The primary concern is the potential for false positives, which can lead to unnecessary invasive procedures, anxiety, and stress for healthy individuals.

Experts emphasize that, despite the technological advancements, the scientific community needs more rigorous research to establish the clinical benefits of liquid biopsies. The current evidence does not sufficiently weigh the benefits against the harms, and insurance coverage for such tests is often unavailable.

In conclusion, while liquid biopsies hold promise for revolutionizing cancer screening, their widespread use should be approached with caution. Additional controlled studies are essential to determine their true utility and to develop guidelines for their integration into clinical practice.

source: https://medicalxpress.com/news/2025-09-liquid-biopsies-cancer-screening.html