We investigated the incidences of febrile neutropenia (FN) and related complications in elderly (> or =65 years) breast cancer patients receiving chemotherapy supported by pegfilgrastim primary prophylaxis (PP; n=150) or current practice (CP) neutropenia management (n=104) in a subanalysis of NeuCuP (Neulasta) vs. current practice neutropenia management). Studies involving regimens with moderately high to high (> or =15%) FN risk were identified by literature review, and individual patient data were integrated for analysis. FN incidence was 6% (95% CI: 2, 10%) in the PP group and 24% (95% CI: 16, 32%) in the CP group. In cycle 1, incidences were 3 and 15%, respectively. FN-related hospitalisation incidence was 5% (PP group) and 15% (CP group), while dose reductions (>/=15%) occurred in 15 and 29% of patients. Pegfilgrastim provided effective PP in elderly patients, a population who may be vulnerable to chemotherapy-related FN and for whom current practice may not provide adequate protection.