A clinical trial from the National Cancer Institute will study whether women with metastatic (stage IV) breast cancer with elevated levels of circulating tumor cells (CTCs) after their first chemotherapy treatment can live longer by changing to a different chemotherapy regimen immediately rather than waiting until their disease progresses.
The Phase III trial, called Treatment Decision Making Based on Blood Levels of Tumor Cells in Women With Metastatic Breast Cancer Receiving Chemotherapy or SWOG-S0500, may help women affected by advanced breast cancer and their doctors to more quickly determine the most effective course of treatment.
Why Is This Trial Important?
A new test called CellSearch measures the number of circulating tumor cells in a sample of blood.
An earlier study of 123 women with advanced breast cancer published in the Journal of Clinical Oncology suggested that the presence of CTCs may help doctors determine the aggressiveness of a woman’s cancer. For example, a blood sample that contains fewer than five CTCs may indicate a cancer that will be slower to spread; a blood sample with five or more CTCs may suggest a cancer more likely to progress quickly.
Many women affected by advanced breast cancer undergo first-line, or initial, chemotherapy to treat their cancers. In most cases, women with advanced disease receive a treatment until the cancer grows (as seen by the doctor on physical exam or using imaging tests) or until the side effects impact their quality of life. Researchers hope that by measuring the CTC count before a woman begins treatment and following it over time, they may be able to determine whether the treatment is working before symptoms of progression appear.
Goals of the CTC Trial
This purpose of this trial is to determine the value of CTCs and to see whether information gathered from the CellSearch test may give doctors more information about the aggressiveness of a cancer.
The trial also will establish the value of regularly measuring CTC levels and will evaluate the degree to which women with and without elevated CTC levels experience treatment side effects.
Structure of the Trial
This phase III trial will compare the effectiveness of choosing a course of chemotherapy based on CTC levels to the standard treatment strategy of selecting a course of chemotherapy based on disease progression.
Women who enter this trial must be receiving chemotherapy for the first time for advanced breast cancer. Before the first course of chemotherapy, doctors will measure the baseline (starting) CTC levels of a 7.5ml sample of each participant’s blood. The participants will then be divided into groups based on their results. All participants with fewer than five CTCs will be assigned to group one. Participants with five or more CTCs will have their blood levels analyzed three weeks later, after their first course of chemotherapy, and be assigned to either groups two or three:
Group 1 participants will have fewer than five CTCs at the start of the trial and a low risk of early progression. They will continue to receive regular chemotherapy treatment.
Group 2 participants will have fewer than five CTCs after completing one course of chemotherapy and a moderate risk of early progression. Their CTC levels will have decreased during treatment. They will continue to receive their current chemotherapy without change.
Group 3 participants will have a CTC level greater than five with a high risk of early progression. They will be divided based on HER2 status and disease type (metastasis to the bone versus measurable metastasis to other areas of the body) and will be randomly assigned to one of two treatment arms:
- Arm 1 participants will continue to receive their current chemotherapy (the standard treatment).
- Arm 2 participants will receive a new chemotherapy (the treatment under study).
This trial is partially randomized because only Group 3 participants are randomly assigned to certain treatments. Randomization ensures that doctors analyze results objectively and do not let their predictions influence conclusions.
Participants from groups two and three will undergo blood collection throughout and at the conclusion of chemotherapy. In addition to the CellSearch test, researchers also will test each participant’s blood sample using CA 15-3, a test measuring how well invasive breast cancers respond to treatment, and CEA (carcinoembryonic antigen), a test that measures the amount of certain protein in the blood.
Can I Participate in this Trial?
The researchers seek 500 participants for this trial. They will be followed five years after completion of their treatment. You may be able to participate in this trial if you have been diagnosed with metastatic breast cancer, are female and:
- You are planning to receive first-line chemotherapy for advanced disease
- Your HER2 status has been determined
- Your disease is not leptomenigeal, meaning that it has not spread to tissues that cover the brain and spinal cord
- If you have brain metastasis, your disease has not changed in extent or severity for at least 90 days after completion of your last treatment
- You have not had another non-breast cancer within the past five years, except for certain skin cancers
- You are not pregnant or nursing
You may be eligible to participate if you have had prior hormonal therapy, bisphosphonate therapy, trastuzumab (Herceptin), bevacizumab or other hormonal therapies for metastatic disease. You must be one year since prior adjuvant chemotherapy. You must be recovered from surgery and two weeks out of minor surgery or four weeks out of major surgery.
For more information, contact: (800) 4-CANCER