FRIDAY, Dec. 10 (HealthDay News) -- High levels of breast cancer
tumor cells circulating in the blood during the first round of
chemotherapy are a sign that the patient may not do well in the
This was true even after other markers of survival were taken
into account, French researchers reported Friday at the annual San
Antonio Breast Cancer Symposium in Texas.
The information from the study is not entirely new, said Dr.
Andrew J. Armstrong, an assistant professor of medicine and surgery
at Duke University and Duke Cancer Institute in Durham, N.C. "It's
already known that circulating tumor cells are prognostic,"
Armstrong said. "The more you have, the worse you do."
But this study is the largest-to-date to look at the issue, the
authors said. The study also measured other tumor markers, finding
that circulating tumor cells (CTCs) predicted outcome even after
taking these other markers into account.
Circulating tumor cells "are cancer cells that are broken off
from the main tumor and are finding their way to other parts of
body," Armstrong explained. "You can order this test as a clinician
because it's a proven prognostic test."
The study presented at the Texas symposium involved 267 people
whose cancer had spread to other parts of their body and who were
receiving chemotherapy for the first time. Many were also receiving
other treatments. They were followed for 16 months.
Researchers detected one or more CTCs in two-thirds of them and
five or more in 44 percent.
And, consistent with other reports, the more CTCs someone had,
the worse that person did.
Even so, the authors stated, it's not yet clear if measuring CTC
levels actually has an effect on the course of the breast cancer.
Research presented at medical meetings has not been reviewed by
outside experts, unlike studies that are published in peer-reviewed
"There's not a very clear correlation between actually watching the tumor shrink and the number of tumor cells," confirmed Dr. Jay Brooks, chief of hematology/oncology at Ochsner Health System in Baton Rouge, La.
And it's far from clear that this simple blood test would be a
good replacement for imaging to track the progress of the cancer,
Nor do CTCs tell you which treatment may be best, like certain
other markers, including HER2/neu and estrogen-receptor status,
added Armstrong, although he said it might indicate the need for a
more aggressive approach.
Still, Armstrong said, "these CTCs are likely to become very
important because they're not just a protein. They're the actual
cancer cell, so if you can isolate them and measure things that
have gone wrong inside the cancer cell, you could eventually use
them to guide therapy for an individual. [And] you could monitor it
over time especially to assess response to treatment and modify
treatment [if necessary]. Cancer cells mutate and can develop
abnormalities that can be an Achilles' heel for drugs. Without that
information, it's very hard to guide therapy."
Other studies being presented at the symposium confirm the
potential importance of CTC levels in predicting the odds for a
recurrence, or a patient's general prognosis after treatment.
One report, from German researchers, found that the presence of
only a few CTCs in the blood -- this time, involving early-stage
patients -- roughly doubled the risk for a recurrence and death.
Five or more of the tumor cells increased the chances of a relapse
by 400 percent and death by 300 percent.
A study from scientists at the M.D. Anderson Cancer Center at
the University of Texas found that metastatic breast cancer
patients who had both chemotherapy and transplants of their own
stem cells and had CTCs in their blood also tended to fare
The stem cells may be responsible by carrying CTCs from the bone
marrow into the blood, the authors stated.
The U.S. National Cancer Institute has more on