John Strickler, MD, assistant professor of medicine, Duke University School of Medicine, gastrointestinal oncologist, Duke Cancer Institute, discusses applications for liquid biopsies in gastrointestinal (GI) cancer.

Currently, tissue biopsies are still the standard in routine clinical practice, but liquid biopsies are being used in select circumstances to help guide treatments for patients. Sometimes, Strickler says, there is simply not enough tissue in a patient’s tumor to perform an effective biopsy. Then, a liquid biopsy would be used. If a patient’s tumor biology is thought to have evolved over some period of time, the best choice would be to use a liquid biopsy, as a tissue biopsy may no longer be representative of the current tumor. He adds that liquid biopsies should also be used if a re-biopsy is determined to be infeasible or not in the best interest of the patient.

Researchers also believe that liquid biopsies can provide a more precise snapshot of a patient’s tumor histology because certain alterations can only be picked up in the plasma. There are several ongoing trials looking to confirm the clinical utility of this procedure.

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John Strickler, MD, assistant professor of medicine, Duke University School of Medicine, gastrointestinal oncologist, Duke Cancer Institute, discusses applications for liquid biopsies in gastrointestinal cancer.

Dr. Strickler on Applications for Liquid Biopsies in GI Cancer

John Strickler, MD, assistant professor of medicine, Duke University School of Medicine, gastrointestinal oncologist, Duke Cancer Institute, discusses improvements in the treatment of metastatic colorectal cancer (mCRC).

It is an exciting time for clinical development in mCRC and gastrointestinal malignancies in general, Strickler says. There have been incremental improvements in survival with new therapies, as well as new strategies for selection. One of these strategies is cell-free DNA (cfDNA), also known as liquid biopsy, which is being used to aid in understanding the genomic drivers of acquired resistance. cfDNA has been useful thus far in the treatment of patients with mCRC, as it can identify markers that inform treatment decisions.

The paradigm is shifting, Strickler says, particularly with the use of microsatellite instability (MSI) as a tool to select patients for immunotherapy. For example, patients with mCRC who are microsatellite instability-high can receive pembrolizumab (Keytruda). There are also patients with rare alterations that are highly actionable. These patients can experience exceptional benefit if these alterations are identified and targeted, Strickler says.

John Strickler, MD, assistant professor of medicine, Duke University School of Medicine, gastrointestinal oncologist, Duke Cancer Institute, discusses improvements in the treatment of metastatic colorectal cancer.

John Strickler, MD

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Dr. Strickler on Applications for Liquid Biopsies in GI Cancer

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