Retrospective study shows low baseline platelet count increases febrile neutropenia risk in breast cancer patients receiving pegfilgrastim, highlighting a need for targeted monitoring.
Key Points
To assess the real-world incidence and risk factors of febrile neutropenia in breast cancer patients receiving pegfilgrastim prophylaxis during chemotherapy.
Retrospective single-center study of 378 breast cancer patients (median age 53) receiving chemotherapy and pegfilgrastim at Tokyo Medical University Hospital between February 2019 and December 2024.
Febrile neutropenia was defined as an absolute neutrophil count <500/µL (or predicted <1,000/µL) with an axillary temperature ≥37.5 °C.
Risk factors were evaluated using multivariable logistic regression across 2,784 total chemotherapy administrations (2,125 pegfilgrastim cycles).
The incidence of febrile neutropenia despite pegfilgrastim prophylaxis was 2.1% (8/378), peaking at 9.1% (2/22) in patients treated with immune checkpoint inhibitor-containing regimens.
Multivariate analysis identified low baseline platelet count as an independent risk factor for combined febrile neutropenia and grade 3–4 neutropenia (OR: 0.98, 95% CI: 0.96–0.99, P = 0.02).