The hope for many cancer patients who go through surgery is that they’ll be cured after the surgeon removes the tumor. The question that lingers is whether they got it all out — if the surgery happened in time before cancer cells scattered off of the primary tumor to seed unseen metastases or if some microscopic malignancy was left behind near the original cancer site.
To answer this question, clinicians are increasingly turning to blood tests that detect circulating tumor DNA, known as ctDNA. The idea is that finding tumor DNA in the blood probably means that cancer cells are still growing somewhere in the body, even at a low level. These tests are starting to be used in a variety of cancers — and for the most part, clinicians agree that if the test is positive, the cancer will likely recur. The trouble is that scientists aren’t sure what should happen next.
“We are all recognizing that if a patient has detectable circulating tumor DNA, it’s not a question of if the cancer’s coming back, but when,” said Van Morris, a gastrointestinal medical oncologist at MD Anderson Cancer Center. “The field recognizes the power of this tool, but I think there remain many questions of how best do we utilize that in the day-to-day management of patients.”
