Prognostic significance of the immunocytochemical detection of contaminating tumor cells (CTC) in apheresis products of patients with high-risk breast cancer treated with high-dose chemotherapy and stem cell transplantation.

The aim of this study was to determine whether the detection of CTC in the apheresis product contribute significantly to treatment failure of patients with high-risk breast carcinoma treated with high-dose chemotherapy (HDC) and stem cell transplantation (SCT). Patients were with stage II and III adenocarcinoma of the breast with > or = 10 axillary lymph nodes affected after primary surgery (> or = 10 N+) who had received HDC with SCT. We analyzed retrospectively the presence of CTC as assessed by immunocytochemistry (ICC) in the apheresis products obtained after standard adjuvant chemotherapy. We compared the clinical outcome of patients who received HDC and SCT with or without CTC-positive apheresis. One hundred and twenty-seven apheresis products samples were obtained from 51 patients. Fourteen (27.4%) of these samples were CTC positive. After a median follow-up of 4.6 years, 20 patients have relapsed, 14 died from progression of their disease and 30 patients remain alive and free of progression. For the whole group of patients the 5 year probabilities of DFS and OS were 60% (IC 95%, 47-75%) and 71% (IC 95%, 55-83%), respectively. However, the 5 year probabilities of DFS were 23% (IC 95%, 0-46) and 75% (IC 95%, 60-89) for patients with CTC positive and negative, respectively. The 5 year probabilities of OS were 42% (IC 95%, 15-68) and 83% (IC 95%, 70-95) for patients with CTC positive and negative, respectively. Both univariate and multivariate analysis showed that the presence of CTC in the apheresis product was the only prognostic factor associated with a higher incidence of clinically overt disease relapse (P = 0.002) and shorter survival (P = 0.003). The presence of cytokeratin-positive metastatic cells in the apheresis product increases the risk of relapse after HDC and SCT in patients with stage II and III adenocarcinoma of the breast with > or = 10 N+.