The existence of circulating tumor cells (CTCs), cells that have broken away from the tumor and are traveling around in the bloodstream, has been known since 1869, and over the last few years their value as biomarkers is growing. In a study from the University of Texas MD Anderson Cancer Center, researchers have found a role for CTCs as a marker to predict the outcome of early stage breast cancer.
The researchers took samples of blood and bone marrow from early and late stage breast cancer patients and found that the presence of CTCs was linked with decreased progression-free survival and early disease recurrence. According to the researchers, this work, published in Lancet Oncology, shows that CTCs can predict which early stage breast cancer patients may need extra treatment, and is one of the first studies to show this link.
"There are a significant number of non-metastatic breast cancer patients for whom you remove their tumor, take out the lymph nodes, treat them with systemic therapy, and render them no evidence of disease. However, around two years later--a peak time for recurrence--about 25-35 percent of those women will present with metastatic disease somewhere else, and we wanted to understand why," says Dr. Anthony Lucci, a professor in MD Anderson's Department of Surgical Oncology. "We can now reliably detect circulating tumor cells in 25 percent of non-metastatic breast cancer patients with no evidence of disease, and know that their risk of recurring or dying is around four times higher than those without these cells in their blood circulation."
Finding CTCs in the blood has been linked with earlier recurrence and poor survival in metastatic breast, colorectal and prostate cancer. More research is needed, but a blood test for CTCs in early stage breast cancer could be a non-invasive alternative to axillary lymph node dissection, which is currently one of the best predictors of prognosis.