The diagnostic tool, which looks for circulating tumor cells, or CTCs, in the blood, can spot one malignant cell among the millions of cells in the bloodstream, says Winfried H. Albert, Ph.D., chief scientific officer of AdnaGen, the German biotech company that developed the technology.
"You can tell almost immediately if the treatment was successful or if the disease has spread," he tells WebMD.
That's because circulating tumor cells quickly die off in the bloodstream, Albert says. So if they are present, there has to be an active source — such as cancer cells left behind after surgery, or cancer recurrence.
Since metastatic spread of malignant cells is the primary cause of death among women with breast cancer, early detection of metastatic spread is crucial to a woman's prognosis, he adds. "If a woman tests positive, the doctor may want to consider more aggressive therapy," Albert says.
Test Helps Guide Treatment
Speaking at a meeting of the American Association for Cancer Research, Albert says the technology produced only three false positive results in tests on 100 healthy people.
He cites several examples in which the tool helped doctors choose the right course of therapy.
One woman had circulating tumor cells in her blood before and after surgery as well as during chemotherapy. After she underwent successful radiation treatment, CTC could no longer be detected.
In contrast, CTC remained elevated in another woman despite surgery, drug therapy, and radiation. "This told us to focus on monitoring disease progression and palliative care," he says.
After a few weeks of chemotherapy, a third woman developed resistance to the drug. A switch to another drug led to an immediate disappearance of CTC, which indicated a good response, he said.
Additional Study Under Way
Loaie Maraga, M.D., a breast cancer researcher at St. James University Hospital in Leeds, England, says further study is needed.
If the technology pans out, "we need to target the right patients," he tells WebMD.
"If someone has aggressive disease, it won't change my management," Maraga says. "Where it might alter my choice of treatment is in the woman with seemingly good prognostic features. If she tests positive, it means further treatment may be needed."
AdnaGen is already marketing its breast cancer assay in Europe. The company is awaiting results from a clinical trial underway at the University of Texas' M.D. Anderson Cancer Center in Houston before applying for FDA approval to make the test available in the United States.
SOURCES: Molecular Diagnostics in Cancer Therapeutic Development Meeting, Chicago, Sept. 12-15, 2006. Winfried H. Albert, PhD, chief scientific officer, AdnaGen, Langenhagen, Germany. Loaie Maraga, MD, research fellow, breast cancer surgery, St. James University Hospital, Leeds, England.
By Charlene Laino
Reviewed by Louise Chang