Correlation Between ANC and Bone Pain in Breast Cancer Patients Receiving Long-Acting G-CSF

This prospective, multicenter, non-randomized controlled study aims to evaluate bone pain associated with prophylactic use of long-acting granulocyte colony-stimulating factors (G-CSFs) in patients with breast cancer receiving chemotherapy with a moderate-to-high risk of febrile neutropenia (FN). A total of 132 patients with breast cancer receiving neoadjuvant or adjuvant chemotherapy will be enrolled at 7 study centers in China. According to the long-acting G-CSF selected by the treating physician in routine clinical practice, patients will be included in either the Telpegfilgrastim group or the non-Telpegfilgrastim group. Telpegfilgrastim is administered as a fixed 2 mg subcutaneous dose 24 hours after chemotherapy. Patients in the non-Telpegfilgrastim group receive another approved long-acting G-CSF according to the physician's clinical decision. The study will assess the incidence and duration of bone pain during the first chemotherapy cycle as the primary outcome. Bone pain during subsequent chemotherapy cycles, use of treatment for bone pain, and dose reduction or switching of long-acting G-CSF will also be evaluated. Absolute neutrophil count (ANC) and other laboratory parameters will be monitored during treatment to explore the relationship between neutrophil changes and bone pain.