Like many hospitals affiliated with medical schools and medical research, doctors at Vidant Health in Eastern North Carolina had been dabbling in the use of liquid biopsies, to both ease the burden of invasive tissue biopsy procedures, and to learn about how well it could provide relevant information to guide cancer treatment.
Last March, Paul Walker, chief of hematology/oncology with the affiliated Brody School of Medicine at East Carolina University, took the leap to have every patient that presented with non-small cell lung cancer (NSCLC) undergo a liquid biopsy as part of their treatment and diagnostic regimen.
“Once we ended up getting it on everybody, it was one of those “wow” things,” Dr. Walker said. “We were seeing things that we had never seen before, and once you see those things, you start thinking in a radically different way.”
For Dr. Walker, the benefits of turning to liquid biopsy for NSCLC were twofold: significantly shorter time to answer via liquid biopsy; and the ability to more narrowly define the appropriate treatment regimen for a significant subset of patients whose liquid biopsy results returned the presence of specific mutations in their cancer.
“If you have an actionable mutation, a targeted therapy, by and large, is going to be better than slug-it-out, industrial-strength, nontargeted chemotherapy,” he said.
But aside from the EGFR and KRAS mutational markers that have received significant attention since a publication by Dana Farber researchers last April confirmed liquid biopsy’s effectiveness at identifying these markers to inform cancer care, Dr. Walker has found additional insight via his use of the technology.
“For example, younger than the age of 40, the number one mutation in people with lung cancer is not EGFR, which everybody thought, but it is actually an ALK gene rearrangement and fusion, and ALK will tend to be platinum resistant,” Dr. Walker pointed out.
“So if I was going to give a young person an aggressive cisplatin-based chemotherapy—almost half of the patients end up having an ALK mutation—you are giving them the wrong treatment and you go down the wrong path and things can go bad very quickly,” he said.
In addition, he noted, more than 60% of patients with ALK-mutated lung cancer will eventually develop a brain metastases. Knowing this allows for the application of a targeted tyrosine kinase inhibitor, proven as effective central nervous system penetrants, which may obviate the need for a more aggressive treatment approach such as whole brain radiation treatment.