Circulating tumor cells (CTCs) are cells that break off from a cancer tumor and move into the blood stream. Doctors think that CTCs mean that breast cancer cells may be active in areas of the body besides the breast.
The number of CTCs in the bloodstream has been linked to prognosis in people diagnosed with metastatic breast cancer (cancer that has spread to one or more parts of the body away from the breast, such as the bones or liver).
A study now has found that CTCs are linked to prognosis in people diagnosed with early-stage breast cancer. This study found that women diagnosed with early-stage breast cancer who had just one CTC in a 7.5 ml (about 0.25 ounces) sample of blood had a worse prognosis than women who had no CTCs.
The results were published online June 6, 2012, in The Lancet Oncology. Read the abstract of “Circulating tumour cells in non-metastatic breast cancer: a prospective study.”
In the study, 302 women diagnosed with early-stage breast cancer had blood drawn just before surgery (and before any other cancer treatments). The blood sample was analyzed for CTCs. After breast cancer surgery, the women were followed for 2 years. The researchers looked for links between CTCs and the women’s health 2 years after treatment.
Most women had no CTCs in their blood samples; 24% of the women had CTCs:
- 14% of the women had one CTC
- 10% of the women had two or more CTCs
Two years after surgery, the likelihood of having breast cancer come back (recurrence) was much higher for women who had one or more CTCs, compared to those who had no CTCs. Cancer recurrence at 2 years was:
- 4.6 times more likely when one or more CTCs were found
- 5.5 times more likely when two or more CTCs were found
- 6.7 times more likely when three or more CTCs were found
Although most of the women were alive 2 years after surgery whether or not they had CTCs, survival was lower in women with CTCs. Women who had one or more CTCs were 4 times more likely to have died from breast cancer 2 years after surgery.
This and other smaller studies suggest that CTC testing could help doctors better figure out the risks of cancer coming back and overall prognosis in women diagnosed with early-stage breast cancer. This information could allow for more customized treatment plans based on CTC test results. For some women, CTC testing might suggest that a more aggressive treatment plan is needed. For other women, CTC testing might suggest a less aggressive treatment plan is needed and could spare them possible treatment side effects. Tracking CTCs during treatment also might help doctors evaluate how well a woman is responding to treatment.
These results are promising, but more research is needed to help doctors understand the best ways to use CTC test results to recommend a treatment plan that makes the most sense for a woman's unique situation. Still, if you've been diagnosed with breast cancer, you may want to ask your doctor if a CTC test might help plan your treatment or determine your response to treatment.
Stay tuned to Breastcancer.org to learn more about research that may lead to better ways to diagnose and treat breast cancer.