Study on the Efficacy and Safety of Different Doses of PEG-rhG-CSF for Primary Prevention of Febrile Neutropenia

Inclusion Criteria: * Age at least 18 years; 2) Confirmed diagnosis of malignant tumor through histopathology or cytological analysis; 3) Eligible for chemotherapy and capable of tolerating multiple cycles of treatment; 4) Complete medical records and a Karnofsky Performance Status (KPS) score of ≥70; 5) Normal bone marrow function (ANC ≥ 1.5×10⁹/L, platelets ≥80×10⁹/L, hemoglobin ≥75 g/L, white blood cells ≥3.0×10⁹/L); 6) Use of PEG-rhG-CSF for primary prophylaxis, administered preventively during the first cycle and subsequent cycles of chemotherapy; 7) Agreement to use effective contraception during the study period and for 6 months after discontinuation; and 8) Willingness to participate. Exclusion Criteria: (1) Blood routine, liver and kidney function, and electrocardiogram test results indicate contraindications for chemotherapy; (2) History of chemotherapy or radiotherapy within the past six months; (3) Prior treatment with PEG-rhG-CSF or rhG-CSF; (4) Concurrent uncontrolled infectious diseases; (5) Concurrent coagulation dysfunction; (6) Long-term alcohol or psychoactive drug dependence; (7) Tumor with bone marrow metastasis or bone marrow invasion; (8) History of hematopoietic stem cell transplantation; (9) Concurrent immune system disorders; (10) Pregnancy and lactation.