PHILADELPHIA – From using fluid in the lungs to better understand the potential of immunotherapy treatments in lung cancer, to tracking circulating tumor cells in prostate cancer, to conducting RNA sequencing of cancer cell clusters from the blood of pancreatic cancer patients, to finding new ways to biopsy tissue from patients who may have esophageal cancer, a series of studies from the Perelman School of Medicine at the University of Pennsylvania demonstrate the promise of new diagnostic methods. Three of the studies focus on liquid biopsies, an innovation which uses blood tests instead of surgical procedures in hopes of detecting cancer. Each research team will present their findings during the 2017 American Association for Cancer Research Annual Meeting in Washington, D.C.
The first study is focused on biopsies and immunotherapy treatments for non-small cell lung cancer (NSCLC) – the most common form of the disease. One of the most promising immunotherapies for NSCLC targets the PD-1/PD-L1 pathway – which is known to suppress the immune system’s ability to fight off cancer. These therapies inhibit this pathway, allowing the body to fight back. Currently, patients must undergo a biopsy to determine if they are candidates for this therapy.
Because obtaining biopsy tissue may cause patient discomfort and can sometimes be difficult or impossible to obtain due to location of the tumor, Penn researchers wanted to find a less invasive way to test these patients. They focused on malignant pleural effusions – fluid surrounding the lungs – which is a frequent complication in patients with advanced NSCLC (Abstract 3736).
“The common treatment for this is to drain the lungs, but as we do that, we can use that fluid to test the levels of PD-L1,” said the study’s lead author Erica Carpenter, MBA, PhD, a research assistant professor of Medicine in the division of Hematology Oncology. “The hope is that such a test, once clinically validated, may save the patient from undergoing a separate, invasive biopsy while still letting us find out if they are good candidates for checkpoint inhibitors.”
The study evaluated the fluid from 66 patients. Researchers found circulating tumor cells (CTCs) – cancer cells that have moved into the blood stream – in 63 of them. Twenty-three percent of patients with a malignant pleural effusion were found to have detectable PD-L1 expression using this technology, which is similar to previous studies. Carpenter said the results show this method may work on a larger scale, but that more research is needed.
