Adjuvant chemotherapy for breast cancer can result in blood cell profile alterations that may decrease a patient's ability to receive the prescribed dosage on the protocol timeframe, potentially diminishing survival. It has been suggested that exercise can positively affect blood cell profiles while breast cancer patients are undergoing adjuvant chemotherapy. The purpose of this investigation was to identify blood cell count changes in breast cancer patients throughout a complete dose dense Adriamycian^® and cyclophosphamide (AC) chemotherapy protocol. A secondary purpose was to investigate the effects of a specifically designed exercise intervention on blood cell counts of breast cancer patients while undergoing dose dense AC chemotherapy.

Volunteers for this study consisted of 97 female subjects with ages ranging from 28 to 71 years recruited from the greater Denver, Colorado and Salt Lake City, Utah areas. This study was a quasi-experimental/ex post facto two-group design with exercise, (n = 20, EXE) and historical control (n = 20, HIS) subject groups, with multiple measurements of the dependent variables (1) various blood cell counts and (2) relative dose intensity. The EXE group participated in moderate intensity exercise 2 times per week during chemotherapy and an additional two weeks immediately following chemotherapy (average 10.5 weeks). Blood cell counts at each chemotherapy treatment and 2 weeks post treatment were collected from the EXE and HIS subjects' medical files. Data were analyzed using repeated measures ANOVA, t-tests and Pearson correlations. Significance for main effects was set at α = .01, with Bonferroni adjustments performed on all post hoc analysis with initial significance set at α = 0.10.

Repeated measures ANOVA found that all subjects (n = 97) displayed significant changes over time in total white blood cell counts, neutrophils, lymphocytes, red blood cell counts, monocytes, hematocrit and hemoglobin (p < .001). When examining the influence of exercise across time, no main effects were identified, but a statistically significant interaction of group by time was found for total white blood cell counts and neutrophils (p < .01). The exercise group demonstrated a return to slightly above pre-chemotherapy values for total white blood cell counts and neutrophil counts 2 weeks after completion of chemotherapy, while the control group demonstrated a continued increase in counts. No significant differences were found between groups for relative dose intensity (RDI) with all subjects maintaining an RDI > than 90%. In conclusion, a specifically designed exercise intervention can mitigate certain negative alterations in blood cell counts of breast cancer patients undergoing chemotherapy, specifically total white blood cell and neutrophil counts. Since total white blood cell counts and neutrophils play an important role in determining continuation of treatment, the fact that the EXE group returned to just above pre-chemotherapy counts is considered a very important finding.