According to a recent article published in The New England Journal of Medicine, levels of cancer cells that are found in circulating blood prior to treatment and directly following treatment are indicative of long-term survival in patients with metastatic breast cancer. Patients who are predicted to have a poorer long-term survival based on these levels may wish to seek more aggressive treatment than their counterparts or participate in a clinical trial evaluating novel therapeutic options.
Breast cancer claims the lives of approximately 40,000 women annually in the United States alone. Although cure rates are high following standard therapy in patients with early breast cancer, long-term survival remains low in patients with breast cancer that has spread to distant sites in the body (metastatic breast cancer). Standard treatment for metastatic breast cancer includes chemotherapy, radiation therapy, biologic therapy and/or hormone therapy. Researchers are evaluating certain patient and disease characteristics and their potential relationships to outcomes in patients with metastatic breast cancer so that treatment may become more individualized and ultimately, long-term survival may be improved.
Patients with metastatic breast cancer often have small amounts of cancer cells circulating in the blood. Recently, researchers from several institutions in the United States conducted a clinical study to evaluate a potential association between levels of cancer cells circulating in the blood and outcomes in women with metastatic breast cancer. This study included 177 women who had their blood drawn prior to treatment and at first follow-up visit to determine the levels of cancer cells circulating in the blood. Patients who had higher levels of circulating cancer cells prior to therapy (5 cells or higher per 7.5 ml of blood) had a significantly shorter duration of progression-free survival (2.7 months) than patients with lower levels of circulating cancer cells (7.0 months). Furthermore, patients with higher levels of circulating cancer cells prior to therapy had a shorter duration of survival (10.1 months) compared with patients with lower levels of circulating cancer cells prior to therapy (more than 18 months). The level of circulating cancer cells after first follow-up also was predictive of progression-free and overall survival. Patients with higher levels of cancer cells in the blood at first follow-up had a progression-free survival and overall survival of 2.1 months and 8.2 months, respectively, and patients with lower levels of cancer cells had a progression-free survival and overall survival of 8.2 months and more than 18 months, respectively. Upon evaluation of several different variables, the level of circulating cancer cells was the only significant predictor of survival in these patients.
The researchers concluded that patients with metastatic breast cancer who have higher levels of circulating cancer cells detected in their blood prior to treatment and at first-follow-up have a significantly poorer progression-free and overall survival. Patients with metastatic breast cancer should ask their physician for a test to measure circulating cancer cells to help individualize treatment options. Patients with a poorer prognosis may wish to seek more aggressive therapeutic approaches than patients with a better prognosis, or discuss the option of participation in a clinical trial evaluating novel treatment strategies with their physician.
Reference: Cristofanilli M, Budd T, Ellis M, et al. Circulating tumor cells, disease progression, and survival in metastatic breast cancer. The New England Journal of Medicine. 2004; 351:781-791.