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.