Abstract
INTRODUCTION: Chemotherapy-induced myelosuppression (CIM), including neutropenia, thrombocytopenia, and anaemia, is a common and potentially life-threatening complication in breast cancer patients. Despite the clinical availability of both short-acting and long-acting Granulocyte Colony-Stimulating Factors (G-CSFs) for primary prophylaxis, evidence supporting the selection of the most appropriate therapeutic agent based on individual characteristics remains limited. This study employs a systematic review and network meta-analysis (NMA) to directly compare individualized G-CSF formulations, aiming to establish a definitive efficacy and safety ranking for clinical guidance. METHODS AND ANALYSIS: Randomised controlled trials of long-acting versus short-acting G-CSF therapy (both originator and biosimilar) in breast cancer patients with CIM will be identified via a search of PubMed, Embase, Web of Science, Cochrane Central Register for Controlled Trials, ClinicalTrials.gov, and the Chinese literature databases, CNKI, Wanfang, VIP, and SinoMed, from inception to 30 September 2025. The main outcomes include the myelosuppression incidence/severity (e.g., neutropenia, thrombocytopenia), chemotherapy relative dose intensity (or dose reductions/delays due to neutropenia), overall survival, Eastern Cooperative Oncology Group (ECOG) performance status, infection-related mortality, and adverse events. Two independent reviewers will perform document screening, study selection, and data extraction. The methodological quality of the included studies will be assessed using the Cochrane Risk of Bias tool (V.2.0). The certainty of the evidence will be rated using the Grading of Recommendations, Assessment, Development, and Evaluation System. ETHICS AND DISSEMINATION: This systematic review is based on already published data, so it does not require ethical approval. The findings of this review will be submitted to peer-reviewed journals.