Today, we go to the frontlines of cancer treatment for a case study on the use of ctDNA testing in the clinic. ctDNA, or circulating tumor DNA, is now used as a biomarker in new testing to detect cancer in a patient’s blood. Oncologists, such as today’s guest, Dr. Ben Weinberg, are increasingly using this testing. Dr. Weinberg is an associate professor of medicine and an attending physician specializing in colorectal cancer at MedStar Georgetown University Hospital.“Even though I give chemotherapy for a living, I would love to give less chemotherapy,” he says in today’s show, speaking about the primary use for ctDNA testing.   “We have to break apart some of the older paradigms of how we stage patients."Ben says that if a patient is ctDNA undetectable, it may not matter if they are stage 2 or stage 3.  Staging has been part of the guidelines suggesting that the doctor must give chemotherapy because there’s a survival benefit. “That was true in large randomized studies, but that may not be true for the patient sitting in front of us,” he says.Where are we at in the treatment of colorectal cancer today, and how is this new testing impacting oncology are the questions of today’s program.  Ben ends with the hope that this could also be a new biomarker for drug development. This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.mendelspod.com/subscribe