(ChemotherapyAdvisor) – Patients with early breast cancer with at least five circulating tumor cells (CTCs) had a fourfold increased risk of recurrence and a threefold increased of death, the first prospective study to evaluate the relevance of CTCs prior to initiation of systemic therapy concluded. The results were presented during the 8th European Breast Cancer Conference in Vienna, Austria, March 22.
Previously, the presence of CTCs in the peripheral blood potentially predicted shortened progression-free survival and overall survival in patients with metastatic breast cancer; however, their presence in early breast cancer — following surgery but prior to initiation of systemic adjuvant chemotherapy — remained unknown.
Dr. Bernadette Jäger, of Ludwig Maximilian University Hospital in Munich, Germany, and colleagues evaluated whether CTCs increased the likelihood of subsequent relapse and death in 2,026 patients with early breast cancer. CTCs were analyzed using the CellSearch System (Veridex, USA).
Participants were 2,026 patients with primary breast cancer and node positive or high-risk node negative disease enrolled in the randomized SUCCESS A trial, which compared fluorouracil, epirubicin, and cyclophosphamide (FEC)-docetaxel vs. FEC-docetaxel-gemcitabine plus five vs. two years of treatment with zoledronic acid. Patients were followed for a median of 35 months (range, 0 to 54 months). Prognostic significance of CTCs for disease-free and overall survival was assessed using Cox regression models.
The investigators detected CTCs in 435 patients (21.5%; median, 1.3; range, 1–827). Axillary lymph node involvement was more prevalent in patients with CTCs (P<0.001), but no association was found with tumor size, histopathological grading, or hormone receptor status. There were 114 recurrence events; 66 patients died. Presence of CTCs before systemic treatment was an independent predictor of poor disease-free survival (P<0.0001), distant disease-free survival (P<0.001), and overall survival (P=0.0002).
“CTC detection may be a clinically useful tool for monitoring treatment and should be tested as an indicator for secondary adjuvant treatment interventions in clinical trials,” they concluded.
Dr. Jäger and colleagues have initiated a new trial, DETECT III, which will examine the effect of adding a secondary drug, lapatinib, to standard treatment in patients with HER2-negative metastatic breast cancer and HER2-positive CTCs.
Abstract (Enter Jäger” in the author box to search for Abstract No. 301)