Hematologic parameters in the adjustment of chemotherapy doses in combined modality treatments involving radiation

The differential white blood cell count of a group of patients with Stages I and II infiltrating ductal carcinoma who underwent treatment in the preadjuvant chemotherapy era have been evaluated. All patients received a modified radical mastectomy followed by postoperative radiation therapy to the chest wall and draining regional lymph node chains (ipsilateral internal mammary, axillary,and supraclavicular regions). When the levels of circulating neutrophils, band cells, and lymphocytes were compared for the period beginning prior to surgery and ending 1 year after the completion of radiotherapy, it was found that radiation induced a significant lymphopenia. However, all patients maintained a neutrophil count at least twice that needed for full-dose conventional chemotherapy. Based on these observations and related preclinical and clinical information, it is proposed that future clinical trials utilizing even local radiotherapy as a component of therapy must have their chemotherapy doses based on appropriate hematologic parameters (neutrophil + band count) in order to avoid spurious and quite possibly erroneous results.