High-dose chemotherapy for breast cancer: is another look warranted?

Complete response after high-dose chemotherapy and autologous hemopoietic stem cell transplatation in metastatic breast cancer results in survival benefit

Metastatic breast cancer is an incurable disease even with high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (ASCT). Even though phase III studies have not shown a survival advantage for this group as a whole, it is possible that a small subset of patients may benefit from HDC/ASCT with careful patient selection. A total of 198 patients from three different institutions were treated with HDC/ASCT. After complete staging, patients with central nervous system or bone marrow involvement were excluded. The HDC regimen consisted of: Carboplatin 600 mg/m(2) IV infusion over 48 hours, Thiotepa 300 mg/m(2) IV infusion over 2 hours, and Cytoxan 60 mg/kg IV infusion given over 2 hours x3 days. The median age at the time of transplant was 46 (24-62) years and median follow-up was 20 months. Hormone receptor status was known in 148 patients, of whom 84 had estrogen receptor (ER) and/or progestrone receptor (PgR)-positive tumors. Eighty patients had no evidence of disease at the time of HDC/ASCT (CR1). At the completion of HDC and ASCT, complete responses (CR) were seen in an additional 57 patients (CR2). Using Kaplan-Meier analysis, the median relapse-free survival (RFS) for the entire group was 15 months and overall survival (OS) was 27 months. The patients in CR1 had a median RFS and OS of 20.7 and 50.6 months, respectively. This was very similar to the RFS and OS in patients achieving CR2 after HDC/ASCT (p < 0.001; median: 19 and 40 months, respectively). In contrast, the patients with persistent residual disease had an RFS and OS of 7 and 12 months (p < 0.001). These data show that patients achieving a CR after HDC/ASCT have a better relapse-free and OS, when compared to patients with persistent residual disease after HDC/ASCT. This study suggests that a subset of patients with residual metastatic breast cancer after standard chemotherapy can achieve CR with HDC and ASCT which may result in better long-term outcome.

Tumor Cell Purging by Ex Vivo Expansion of Hemopoietic Stem Cells from Breast Cancer Patients Combined with Targeting ErbB Receptors

Tumor cell contamination might induce relapse after autologous transplantation in breast cancer patients. We used an ex vivo purging strategy to decrease the number of contaminating breast tumor cells in leukaphereses without altering the engraftment potential of the hemopoietic progenitor cells. This method is based on immunoselection of CD34+ cells derived from mobilized peripheral blood of patients with metastatic breast cancer and expansion in the presence of flt3 ligand, stem cell factor, interleukin 6, and thrombopoietin. Tumor contamination before and after culture was monitored by mammaglobin messenger RNA amplification by quantitative polymerase chain reaction. We analyzed both adherent and suspended cells obtained after 2 weeks of culture. Hemopoietic progenitors were increased among suspended cells. In this fraction, tumor cell contamination was decreased, whereas it increased within the adherent cell fraction. Experimental models using CD34+ cells from healthy donors spiked with breast cancer cells were also constructed to investigate whether treatment with anti-ErbB-receptor drugs could further reduce the tumor load without affecting the clonogenic potential of hemopoietic cells. For this purpose, we successfully assayed trastuzumab, a monoclonal antibody against ErbB-2, and gefitinib, an epidermal growth factor receptor tyrosine kinase receptor inhibitor. These results suggest that positively selected CD34+ cells from cancer patients contain tumor cells and that ex vivo expansion can reduce the tumor load of the suspended fraction. Target-based agents against ErbB-2, epidermal growth factor receptor, or both--such as trastuzumab or gefitinib--might increase the efficiency of purging.

Phase II feasibility and pharmacokinetic study of concurrent administration of trastuzumab and high-dose chemotherapy in advanced HER2+ breast cancer

PURPOSE

To evaluate the safety of concurrent treatment with trastuzumab and high-dose chemotherapy (HDC), using cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), with autologous hematopoietic progenitor cells support, in patients with HER2+ advanced breast cancer.

EXPERIMENTAL DESIGN

Patients with HER2-overexpressing high-risk primary breast cancer (HRPBC; defined as > or =4 involved nodes or inflammatory disease), or metastatic breast cancer (MBC) were eligible. Treatment consisted of a loading dose of trastuzumab at 4 mg/kg (day -5), HDC (days -5 to -2), autologous hematopoietic progenitor cells infusion on day 0, and weekly maintenance trastuzumab (2 mg/kg) from day +1 (minimum of 9 doses). Cardiac monitoring included serial left ventricular ejection fraction measurements before treatment and on days +20 and +65.

RESULTS

Thirty-three patients were prospectively enrolled (13 HRPBC, 20 MBC). Toxicity seemed similar to that expected with this HDC regimen alone. Neutrophils and platelets engrafted promptly. There were no cases of grade 4 or 5 toxicity. One patient experienced symptomatic grade 3 acute cardiac failure on day -4, responsive to treatment. Trastuzumab did not alter the pharmacokinetics of HDC. Eleven of twelve MBC patients with measurable disease (nine of them refractory to previous chemotherapy) experienced an objective response (9 complete and 2 partial responses). At median follow-up of 34 (13-58) months, all HRPBC patients remain alive and free of disease; the MBC group has event-free survival and overall survival rates of 45 and 70%, respectively.

CONCLUSIONS

Incorporation of trastuzumab into HDC (cyclophosphamide, cisplatin, and BCNU) is feasible, with no apparent increased toxicity or pharmacokinetic interactions.

Prognostic analysis of early lymphocyte recovery in patients with advanced breast cancer receiving high-dose chemotherapy with an autologous hematopoietic progenitor cell transplant

PURPOSE

The purpose of this study was to evaluate the prognostic effect of early posttransplant lymphocyte recovery in patients with advanced breast cancer receiving high-dose chemotherapy with autologous hematopoietic progenitor cell transplantation.

EXPERIMENTAL DESIGN

We analyzed the effect of the absolute lymphocyte count on day +15 posttransplant on freedom from relapse and overall survival in patients with high-risk primary breast cancer or metastatic breast cancer, enrolled between 1990 and 2001 in prospective high-dose chemotherapy trials, using a uniform regimen of cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea.

RESULTS

Four hundred and seventy-six patients (264 high-risk primary breast cancer and 212 metastatic breast cancer patients) were evaluated at median follow-up of 8 years (range, 1.5-11 years). The disease-free survival and overall survival rates in the high-risk primary breast cancer group were 67% and 70%, respectively. Patients with metastatic breast cancer patients had 21.8% disease-free survival and 31.5% overall survival rates. Day +15 absolute lymphocyte count correlated with freedom from relapse (P = 0.007) and overall survival (P = 0.04) in the metastatic breast cancer group, but not in the high-risk primary breast cancer group (P = 0.5 and 0.8, respectively). The prognostic effect of absolute lymphocyte count in metastatic breast cancer was restricted to those patients receiving unmanipulated peripheral blood progenitor cells (P = 0.04). In contrast, absolute lymphocyte count had no significant effect in those metastatic breast cancer patients receiving bone marrow or a CD34-selected product. In multivariate analyses, the prognostic effect of day +15 absolute lymphocyte count in metastatic breast cancer was independent of other predictors, such as disease status, pre-high-dose chemotherapy treatment, number of tumor sites, or HER2.

CONCLUSIONS

Early lymphocyte recovery is an independent outcome predictor in metastatic breast cancer patients receiving high-dose chemotherapy and an autologous peripheral blood progenitor cell transplant. These observations suggest that immune strategies targeting minimal posttransplant residual disease may prove worthwhile.

Prognostic significance of occult tumor cells in the apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy and autologous hematopoietic progenitor cell support

We prospectively evaluated the prognostic significance of occult tumor cells (OTCs) contaminating the peripheral blood progenitor cell apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy. Immunocytochemistry of peripheral blood progenitor cells was performed in 242 patients with high-risk primary breast cancer (HRPBC) and in 111 patients with metastatic breast cancer (MBC). OTCs were detected in 6.6% of HRPBC patients and in 16.2% of MBC patients (P = .005). In HRPBC, OTCs correlated with worse prognostic scores and larger tumor sizes, but not with axillary nodal status, hormone receptors, or HER2. In the MBC group, OTCs correlated with bone marrow involvement and with disease status at transplantation. The number of apheresis procedures was not associated with the risk of contamination. In HRPBC patients, at a median follow-up of 7 years (range, 1.5-11 years), the presence of OTCs correlated with worse event-free survival (P = .007) and overall survival (P = .002). In the MBC group, OTCs correlated with worse event-free survival (P = .04), but not overall survival (P = .2). In multivariate analyses, the presence of OTCs had an independent adverse effect on outcome in HRPBC, but not MBC. Our observations imply a direct role of OTCs in posttransplantation relapse in HRPBC.