Dose intensity and hematologic toxicity in older breast cancer patients receiving systemic chemotherapy.

BACKGROUND: This prospective study evaluated patient and treatment characteristics that contributed to hematologic toxicity in older breast cancer patients treated with curative intent in the community setting.

METHODS: Data were collected on 1224 patients with stage I through III breast cancer, of whom 207 were aged > or =65 years (grading determined according to the American Joint Committee on Cancer staging system). Primary outcome measures included anemia, thrombocytopenia, severe neutropenia, febrile neutropenia, and both planned and actual relative dose intensity (RDI). Comparisons between older and younger patients regarding hematologic toxicity and reductions in RDI were based on univariate and multivariate logistic regression analyses.

RESULTS: The neutropenic complication rate in older patients (45.1%) was not significantly different from that in the younger patients (43.7%). There were also no significant differences in rates of anemia or thrombocytopenia. Approximately 34.0% of the older patients received RDI <85% compared with 20.0% among younger patients (P < .01). Fewer older patients received anthracycline-based chemotherapy (64.3% compared with 83.8% in younger patients, P < .01). Fewer older patients received prophylactic white blood cell colony-stimulating factor (18.4%) compared with younger patients (28.0%) (P < .01).

CONCLUSIONS: There were no significant differences noted with regard to chemotherapy-related hematologic toxicities between older and younger breast cancer patients in this large prospective observational study. This may be explained, in part, by more frequent reductions in RDI and less frequent utilization of anthracyclines among older patients.