Q: My doctor suggested that I get a liquid biopsy to determine what therapy will be most effective for treating my prostate cancer, even though my insurance won't pay for it. Is it more accurate, less risky? What's the deal?-Jack H., Orlando, Florida
A: The concept of a liquid biopsy is a great one: It uses a simple blood draw to see what DNA mutations related to prostate cancer are present in your circulation. No incisions, no risk of infection nor complications from the biopsy itself. Identifying those mutations is supposed to help doctors predict a patient's response to immunotherapy, and if it turns out that the DNA mutations are not responsive, then the doctor can select another therapy that may be more effective.
Sounds perfect. And one day it might be, but not now. A new Johns Hopkins study took blood draws to obtain DNA samples from 40 study participants and then divided each one so that identical samples could be sent to two separate, well-accredited labs for analysis. Unfortunately, the lab results matched only 7.5 percent of the time (that's three of the 40 participants), and only 15 percent of the time did the two companies' results match for at least one mutation.
These results come on the heels of an earlier study published this year in JAMA Oncology that found that mutations identified in tumor tissue samples and in liquid biopsy results from the same patients had what Johns Hopkins calls "a similar lack of congruence." That means doctors looking at differing results may come to different conclusions about which treatments will be most effective for you.
Ask your doctor about the Johns Hopkins findings, and offer this quote from the researchers: "Liquid biopsy is a promising technology, with an exceptional potential to impact our ability to treat patients, but it is a new technology that may need more time and experience to improve."
Mehmet Oz, M.D. is host of "The Dr. Oz Show," and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email your health and wellness questions to Dr. Oz and Dr. Roizen at [email protected].
(c) 2018 Michael Roizen, M.D.,
and Mehmet Oz, M.D.