Could a Blood Test Predict Breast Cancer's Return?
Study suggests routine sample might provide information critical to treatment
The results suggest these tumor cells may help predict the spread of breast cancer both before and after chemotherapy, the researchers concluded.
Patients with CTCs in their blood before and after treatment had the shortest disease-free survival time compared to the other three groups.
In general, the chance of being disease-free three years after surgery was lower for those with CTCs than for those without, the results indicated.
Among those who died during the follow-up period, about 41 percent had CTCs in their blood. Of those who survived, only about 21 percent had CTCs.
While the study is promising, it's too soon to know what to do when a patient has a positive CTC, said Dr. Arnold Schwartz, author of an editorial accompanying the study. "Should we change chemo, or give more chemo? Clearly we can tell the patient that this is something we need to follow. But the data is not definitive yet," he said.
The test might be informative in terms of prognosis and management, but the data isn't entirely clear, Schwartz wrote. "Many patients with [cancer that has spread] do not demonstrate expected CTCs, and several case patients with CTC positivity did not have recurrence within the three-year follow-up," he noted.
Schwartz, a professor of pathology and surgery at George Washington University in Washington, D.C., said he believes that as CTC technology improves, physicians will better understand the circulating cells' unique characteristics, such as their sensitivity to chemotherapy and the way they reproduce and disseminate.
For now, he is cautious about the implications of the study. "Science is a very plodding march. Everyone will say this is an important step in the understanding of how tumors spread and biomarkers of breast cancer," he said. "But what are you going to do with the data? Can a person with a negative CTC be relaxed? Life is a risk."