San Antonio 2010 Take Aways: Predicting Recurrence with Circulating Tumor Cells
One of the hardest decisions a breast cancer patient may have to make is whether to do chemotherapy. A large tumor or cancer in the lymph nodes clearly indicates that she needs a systemic drug. However, the staging system that measures how advanced a cancer is according to tumor size, does not take into account that very small tumors may still be aggressive and need chemotherapy. Old models of determining treatment based on stage have not worked well.
Making a judgment about whether a cancer is likely to recur has been difficult. The Oncotype test is one good tool that can help patients and doctors understand whether a tumor is likely to spread. Here at HealthCentral we get many letters from women whose Oncotype score falls into an intermediate range. So even with the best possible information, they are still in a quandary. They want to eradicate the cancer, but they want to avoid chemo if they do not really need it.
Recent news from the San Antonio Breast Cancer Symposium in December 2010 indicates that there is another way to predict a woman's risk of recurrence. The study led by Brigitte Rack of the University of Munich in Germany found that if circulating tumor cells (CTC) are in the blood stream, the chance of recurrence is higher. In fact, even one CTC almost doubled recurrence risk in patients with early breast cancer. This information could really help women decide how much treatment they need. This study extended previous research that had found that CTC's indicated a poor prognosis in women with metastatic breast cancer.
But how, you might ask, can doctors know if there is a tumor cell somewhere in my blood stream? They can't take out all of my blood and search for it. Since 2004, scientists have had a way to find that tumor cell. Researchers at Veridex, a subsidiary of Johnson and Johnson, developed the CellSearchTM System that has been able to check for CTC's in patients with metastatic breast, prostate, and colon cancers. Doctors have been able to watch patients to see if their cancers are stable or progressing with this test.
However, the test has not been approved for non-metastatic cancers. It is a complicated, multi-stage test that can not be done in the local doctor's office. Blood samples have to be sent away.
A new study is underway at Massachusetts General Hospital in Boston to develop a better, more efficient test that can be used for earlier stage cancers. Researchers hope that a new version of the test will be easy to administer in a clinical setting. With a blood sample, doctors hope they will be able to find the tumor cell that would tell a woman if cancer is in her blood stream and whether she needs systemic therapy to kill it before it can kill her.
The information from the Munich study and the new technology being developed at Massachusetts General may soon give women and their doctors another tool for making medical decisions that can save lives while sparing many the hardship of chemotherapy.