RESUMO
Anthracyclines are the most widely used anticancer agents for breast cancer, of which doxorubicin and epirubicin have been reported to have equal efficacy. Unfortunately, the integrity of the immune system of breast cancer patients is severely affected by chemotherapy. This study compared the effect of combination chemotherapy with epirubicin (5-fluorouracil, epirubicin, cyclophosphamide (FEC)) and doxorubicin (5-fluorouracil, doxorubicin, cyclophosphamide (FDC)) regimens on subsets of the immune cells of patients with primary malignant breast tumors. Our aim was to determine the best regimen that produces the least degree of myelosuppression. Blood from 80 breast cancer patients undergoing chemotherapy (40 FEC and 40 FDC) was taken before chemotherapy and after every cycle (3 weeks) for 6 cycles. Blood was also taken from 40 normal healthy donors who served as normal control. Subsets of lymphocytes T-helper cells (CD3(+)CD4(+)), T-cytotoxic cells (CD3(+) CD8(+)), B-cells (CD19(+) CD20(+)) and NK cells (CD16(+)/CD56(+)CD3(-)) were analyzed by flow cytometry (FacsCalibur, BD) using monoclonal antibodies (Multitest, BD). All patients in the FEC and FDC groups suffered from myelosuppressive side effects. Both regimens led to an increase in the counts of monocytes but decreased polymorphonuclear cells (PMNs) and lymphocytes. Percentages of T-cytotoxic cells and NK cells were increased, but the percentage of B-cells was dramatically decreased. The phagocytic and intracellular killing ability of PMNs were also suppressed (p<0.01). No significant difference was found between the epirubicin-based regimen and doxorubicin-based regimen with regard to numbers of immune cells, percentages of lymphocytes subsets, Th/CTL ratio, engulfment and killing abilities of PMNs. In conclusion, we found that the epirubicin-based regimen is not superior to the doxorubicin-based regimen with respect to their toxicity of the immune cells, Th/CTL ratio and PMN count and functions. Moreover, both FEC and FDC regimens appear to conserve the cell-mediated immunity response needed for fighting against cancer cells.
