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

BACKGROUND: This prospective study was undertaken to evaluate patient and treatment characteristics that contribute to hematologic toxicity in older cancer patients.
METHODS: A nationwide study of 115 community oncology practices was conducted between 2002 and 2005 with data collected on 976 patients who had received chemotherapy for common malignancies, including lung cancer, colorectal cancer, breast cancer, ovarian cancer, genitourinary cancer, and lymphoma. Primary outcomes included severe neutropenia (SN) and febrile neutropenia (FN). Secondary outcomes included delivered relative dose intensity (RDI) <85%, dose delays > or =15% days, and reductions > or =15%.
RESULTS: Approximately 50% of both patients with early-stage disease and patients with advanced-stage disease received an actual RDI <85%, and this rate reached 60% in the oldest group (aged >80 years). Increasing age was associated with lower actual RDI (P = .030) and averaged 87.5% across all elderly age groups. A decreasing trend in SN or FN events occurred with increasing age (P for trend = .039), with the majority of initial neutropenic events occurring in Cycle 1 for all age groups. Among the patients who received an actual RDI > OR =85%, there was no significant difference in SN or FN by age group or disease stage. Independent risk factors for the development of SN or FN included cancer type, planned RDI > or =85%, body surface area < or =2m(2), anthracycline- or platinum-based regimens, previous chemotherapy, elevated blood urea nitrogen, and alkaline phosphatase. Neutropenic complications decreased significantly with primary colony-stimulating factor (CSF) prophylaxis (coefficient of determination [R(2)] = 0.260; c-statistic = 0.782).
CONCLUSIONS: Among cancer patients aged > or =70 years, 50% of whom received relatively full-dose chemotherapy, increasing age alone did not increase the risk of hematologic toxicity.