Liquid Biopsy Technology: From Advanced Cancer Management to a Life-Saving Era of Early Detection
GRAIL's multi-cancer early detection test Galleri® received a favorable vote toward approval from the FDA's Medical Devices Advisory Committee. Coming after the approval of Guardant Health's Shield® test for colorectal cancer screening, this development shows that liquid biopsy technology, which reads cancer DNA from the blood, is moving from the management of advanced cancer into the era of early detection.
23 September 2026 — Galleri®, the multi-cancer early detection (MCED) test developed by GRAIL, passed a historic threshold by receiving a favorable vote toward approval from the FDA's Medical Devices Advisory Committee. The decision follows the FDA approval granted in July 2024 to Guardant Health's Shield® test specifically for colorectal cancer screening.
Liquid biopsy technology, which we use as a standard in our clinical practice to detect clones that develop resistance to treatment in patients with advanced cancer, or to understand whether the disease is recurring at the molecular level after curative treatment (surgery), is opening the door to a new, life-saving era in oncology. This powerful genomic technology, which reads cancer DNA from the blood, is now entering use as a screening test to catch early stage cancers before the disease reaches a physical size that would appear on standard radiological imaging.
Beyond the Limits of Imaging and the Power of Early Detection
There is an indisputable scientific truth in cancer treatment: early detection saves lives. Cancer cells begin shedding their own genetic material (cfDNA) into the blood long before they form a tangible mass of a size that can be noticed on radiological imaging (PET/CT, computed tomography or MRI). By reading these cellular footprints from the blood, these new generation screening tests catch cancer at a microscopic stage before it causes any symptoms, and they also determine with high accuracy which organ the signal comes from (Cancer Signal Origin / Tissue of Origin).
So what is the technological and practical difference between the MRD (Minimal Residual Disease) monitoring we have used in our clinical practice for years and these new Early Detection (Screening) tests? Let us explain with an example clinical scenario:
- MRD Monitoring (Follow-up After Cure): Our 55-year-old patient's colon cancer operation (or breast cancer surgery) has been completed successfully and adjuvant (preventive) chemotherapy has ended. All radiological scans look "completely clean". However, we perform an MRD test on the blood to understand whether the disease remains in the body at a microscopic level or is silently returning months later. If tumor DNA is caught in the blood sample while imaging cannot yet detect any mass, we intervene proactively, long before the recurrence becomes clinically apparent.
- Early Detection (Screening): A healthy 50-year-old with no history or complaints of cancer has a Galleri or Shield blood test as part of a routine health check. The test detects a cancer signal of colon origin in the person's blood. The person is immediately referred for colonoscopy, a stage 1 tumor that is still difficult to detect radiologically is found, and their life is saved with a single local operation, without even needing heavy systemic treatments.
Advanced Disease Management and Our Molecular Tumor Board (MTB)
At our clinic, we actively use the core principles of these deep genomic technologies (cfDNA analysis, epigenomic profiling and artificial intelligence), which are receiving approvals one after another in early detection, in the management of far more complex and advanced cases. In the multidisciplinary evaluations of our Molecular Tumor Board (MTB), this innovative infrastructure serves the following critical purposes:
- Detection of Resistance Clones: Capturing, in real time and from the blood without the need for a surgical tissue biopsy, the new genetic resistance mutations that develop over time against smart drugs or chemotherapies and drive cancer progression.
- Resolving Cancers of Unknown Primary (CUP): Just as in the origin-finding logic of early detection tests, analyzing the genetic and methylation profiles of tumors that have spread through the body but whose primary source cannot be found, in order to determine the tumor's point of origin with cellular evidence and build rational targeted combinations.
💬 Important Information for Our Patients
Although the multi-cancer early detection tests whose technological basis is discussed in this article, and the other molecular genetic liquid biopsy (cfDNA/MRD) panels used at our clinic, have been evaluated by international medical authorities and have begun to enter guidelines, the official licensing, supply conditions and Social Security Institution (SGK) reimbursement status of these specific devices and tests in Turkey may vary. Our clinic manages the process by transparently sharing with our patients the legal and clinical accessibility aspects of the latest oncological diagnostic and dynamic monitoring technologies in our country.
Conclusion
Being able to follow a tumor's gene-level characteristics from the blood has become a powerful scientific tool of oncology across a wide spectrum, from catching the disease at its earliest stage to building patient-specific smart strategies in the most advanced, resistant cases.
References
- GRAIL. (23 September 2026). FDA Advisory Committee Votes in Favor of Approval of GRAIL's Galleri Multi-Cancer Early Detection Test.
- Targeted Oncology. (2024). FDA Approves Shield Blood Test for Colorectal Cancer Screening.