One of the hopes for liquid biopsies is that clinicians can keep pace with mutations that crop up in patients' tumors and adjust treatment plans accordingly, but Technology Review's Antonio Regalado reports that the data isn't in yet on the accuracy of these tests or whether they help extend patients' lives.
Many insurers in the US, he notes, say liquid biopsies are unproven and don't cover their use, though the American Society of Clinical Oncology and the US National Cancer Institute have both announced trials to examine how well targeted drugs work in conjunction with DNA testing.
As the research goes on, a number of companies are beginning to offer such tests, Regalado says.
He also recounts the story of Deborah Fletcher, a breast cancer patient who'd heard about liquid biopsies through a radio program and sought one of the physicians for her own care. Massimo Cristofanilli, an oncologist at Thomas Jefferson University, ordered two tests for her that both uncovered a PIK3CA mutation in Fletcher's cancer that could be making it resistant to Herceptin, the drug she was on.
Because of that, Cristofanilli switched her to Afinitor, and when follow-up testing found the PIK3CA mutation to be gone and that a new one had developed, Fletcher was switch back on Herceptin. Regalado notes that her case was featured in a medical report. Still, Fletcher's condition worsened, and there were no other drugs to try and she died.
Regalado asks Cristofanilli whether he thinks this approach had extended Fletcher's life. "I think in a way that she survived a year more," Cristofanilli says, noting that Fletcher came to him with serious disease. But, Regalado says, Cristofanilli isn't sure.
"I do not think we have yet the data to show an extension of life," Cristofanilli says.