Adjuvant chemotherapy for breast cancer—“one fits all”?

Changes in cellular immunity during chemotherapy for primary breast cancer with anthracycline regimens

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.

Dose variation and regimen modification of adjuvant chemotherapy in daily practice affect survival of stage I-II and operable stage III Taiwanese breast cancer patients

To assess the effect of a non-standard dose and regimen of adjuvant chemotherapy on the clinical outcome in stage I-II and operable stage III Taiwanese breast cancer patients. Variables studied included treatment variation (regimen and dose of adjuvant therapy), lymph node status, tumor size, histologic grade, and hormone receptor status. Cox's multivariate regression analyses were used to select prognostic factors significant for disease-free survival (DFS) and overall survival (OS). In the multivariate analysis, lymph node-positive, a tumor size greater than 5 cm, grade III, hormone receptor-negative status, and non-standard adjuvant chemotherapy were independent prognostic factors for DFS and/or OS. Node-positive patients treated with standard adjuvant chemotherapy had a significantly better DFS (HR=0.6; P=0.032) and OS (HR=0.54; P=0.025) than those treated with non-standard adjuvant chemotherapy. Breast cancer patients receiving standard adjuvant chemotherapy have a better DFS and OS than those receiving non-standard adjuvant chemotherapy.

GRP78 as a novel predictor of responsiveness to chemotherapy in breast cancer

The discovery of predictive factors for chemoresistance is critical for improving adjuvant therapy for cancer patients. The 78-kDa glucose-regulated protein (GRP78), widely used as an indicator of the unfolded protein response (UPR), is induced in the tumor microenvironment. In vitro studies suggest that GRP78 confers chemoresistance to topoisomerase inhibitors, such as Adriamycin (doxorubicin). Here, we report on a retrospective cohort study of 127 stage II and III breast cancer patients who were treated with Adriamycin-based chemotherapy. Archival tumor specimens were available for analysis and the relationship of GRP78 expression level to "time to recurrence" (TTR), used as a surrogate marker for drug resistance, was examined. Our data show that 67% of the study subjects expressed high level of GRP78 in their tumors before the initiation of chemotherapy and suggest an association between GRP78 positivity and shorter TTR [hazard ratio (HR), 1.78; P = 0.16]. Interestingly, subgroup analysis reveals that the HR for the GRP78-positive group increased significantly among patients who did not receive further taxane treatment (HR, 3.00; P = 0.022) and among mastectomy patients (HR, 3.33; P = 0.027). The HR was even stronger among mastectomy patients who did not receive further taxane treatment (HR, 4.82; P = 0.010). The use of GRP78 as a predictor for chemoresponsiveness and the potential interaction of GRP78 and/or the UPR pathways with taxanes warrant larger studies.

Population pharmacokinetics of the BEACOPP polychemotherapy regimen in Hodgkin's lymphoma and its effect on myelotoxicity

BACKGROUND AND OBJECTIVE

The BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisone) chemotherapy regimen for the treatment of advanced Hodgkin's lymphoma has a superior outcome, but its toxicity (mainly haematotoxicity) is pronounced and highly variable. The present study was conducted to address the role of pharmacokinetics in individual toxicity.

STUDY DESIGN

Three plasma samples and a 24-hour urine collection for day 1 of the first three cycles of chemotherapy were analysed in 30 patients, and the pharmacokinetic parameters of the respective drugs were estimated by population pharmacokinetic methods (nonlinear mixed-effects model [NONMEM] software). Demographic data, doses and durations of infusion were also recorded. The effect of these parameters on platelet counts was estimated by analysis of covariance using a general linear model.

RESULTS

The pharmacokinetic parameters and respective covariates were similar to the published data. The body surface area, peak concentrations of etoposide, urinary recovery of dechloroethylcyclophosphamide (formed by cytochrome P450 [CYP] 3A4) relative to the cyclophosphamide dose and number of cycles had a significant effect on toxicity. These factors explained 37% of the interindividual variability in the change in platelet counts from day 1 to day 8 of each cycle.

CONCLUSION

The results show that the individual pharmacokinetics of BEACOPP drugs are an important link between dosage and toxicity. Accordingly, individualisation of treatment based on pharmacokinetics may result in more uniform toxicity. Individualisation may also allow escalation of the mean dose, which is probably related to better efficacy. As a consequence of the present study, infusion rates should be standardised, and the potential of a dose reduction in the first cycle and of CYP3A4 phenotyping should be addressed in clinical studies.

Risks and consequences of chemotherapy-induced neutropenia

Neutropenia represents a major dose-limiting toxicity of chemotherapy and is associated with an increased risk of infection, impaired patient quality of life, and interference with the delivery of full-dose chemotherapy. These complications increase not only morbidity and mortality associated with cancer treatment but also the overall cost of care for cancer patients. Conversely, chemotherapy-induced neutropenia as a surrogate for delivered dose intensity has been associated with improved cancer survival. Administration of myeloid growth factors, such as filgrastim and pegfilgrastim, reduces the risk for neutropenic complications and facilitates the delivery of full-dose chemotherapy. There is an ongoing effort to identify patients at increased risk for developing neutropenic complications who would likely benefit from preemptive myeloid growth factor therapy. Appropriate use of myeloid growth factors is associated with reduced neutropenic complications, improved patient quality of life, and potentially improved disease control and long-term survival.