Findings from a new lung cancer study suggest that liquid biopsies may soon replace invasive tissue biopsies. Researchers at Boston's Dana-Farber Cancer Institute found that a simple blood test can accurately detect mutations in two key genes in non-small cell lung tumors, the most common form of lung cancer.
Liquid biopsy, or rapid plasma genotyping, involves analyzing blood samples to detect mutations or abnormalities in DNA. It works by detecting cell-fee DNA or genetic material from dead tumor cells that spill into the bloodstream.
Researchers said that liquid biopsies are becoming more common in medical research for identifying the genetic and molecular makeup of different kinds of tumors.
"We see plasma genotyping as having enormous potential as a clinical test, or assay - a rapid, noninvasive way of screening a cancer for common genetic fingerprints, while avoiding the challenges of traditional invasive biopsies," said Geoffrey Oxnard, senior author of the current study and thoracic oncologist and lung cancer researcher at Dana-Farber and Brigham and Women's Hospital.
"Our study was the first to demonstrate prospectively that a liquid biopsy technique can be a practical tool for making treatment decisions in cancer patients," Oxnard added. "The trial was such a success that we are transitioning the assay into a clinical test for lung cancer patients at Dana-Farber/Brigham and Women's Cancer Center."
The latest study involved 180 patients diagnosed with non-small cell lung tumors. Researchers noted that 120 of the patients had been newly diagnosed and the other 60 had become resistant to previous treatments. All participants underwent liquid and traditional tissue biopsies.
After comparing the results, researchers found that liquid biopsies were quicker and, in some cases, more accurate than tissue biopsies.
"In some patients with the EGFR resistance mutation, ddPCR detected mutations missed by standard tissue biopsy," Oxnard explained. "A resistant tumor is inherently made up of multiple subsets of cells, some of which carry different patterns of genetic mutations. A single biopsy is only analyzing a single part of the tumor, and may miss a mutation present elsewhere in the body. A liquid biopsy, in contrast, may better reflect the distribution of mutations in the tumor as a whole."
"The test has great utility both for patients newly diagnosed with non-small cell lung tumors and for those with a recurrence of the disease," said Dr. Lynette Sholl, a pathologist at Dana-Farber and Brigham and Women's Hospital.
"It's fast, it's quantitative (it indicates the amount of mutant DNA in a sample), and it can be readily employed at a cancer treatment center," she added.
The findings were published in the journal JAMA Oncology.
