Purpose: To determine the association between changes in complete blood counts and grade 3 or 4 toxicities from cycle 1 to cycle 2 during adjuvant chemotherapy in women > or =65 years of age with breast cancer.
Design and methods: A retrospective review was performed on 1405 patients > or =65 years of age who were treated for primary invasive breast cancer at Memorial Sloan-Kettering Cancer Center between January 1998 and December 2000. From this cohort, we identified patients with stage I-III breast cancer who received adjuvant chemotherapy: cyclophosphamide, methotrexate and fluorouracil (CMF) or the anthracycline-based regimens doxorubicin and cyclophosphamide (AC) or AC followed by paclitaxel (AC-T). Patients were excluded from the analysis if they had a prior history of breast cancer or chemotherapy, or if they had no baseline blood counts available for review. Toxicities, dose modification and causality were recorded.
Results: The 104 patients who met our criteria had received either CMF (n = 58; mean age 70.6 years, range 65-78) or an anthracycline-based regimen (n = 46; mean age 68.9 years, range 65-77). Of these patients, 50% experienced treatment delay or treatment-related grade 3 or 4 toxicity. A decrease in white blood cell count and absolute neutrophil count from cycle 1 to cycle 2 was associated with grade 3 or 4 haematological toxicity, febrile neutropenia, hospitalisation and initiation of filgrastim for secondary prophylaxis. A decrease in haemoglobin was associated with febrile neutropenia and hospitalisation. Advanced age was not associated with a significant change in complete blood counts, other than a decline in absolute neutrophil count in patients receiving CMF.
Conclusions: In this cohort of older patients who received chemotherapy for breast cancer, changes in blood counts from cycle 1 to cycle 2 were associated with increased risk of treatment-related grade 3 or 4 toxicity.