Objective:To evaluate the efficacy and safety of pegylated recombinant human granulocyte colony stimulating factor (PEG-rhG-CSF) therapy in the primary prevention of concurrent chemoradiotherapy-induced neutropenia.Methods:In this single-center, open-label, single-arm clinical observation, the efficacy of PEG-rhG-CSF in the primary prevention of neutropenia after concurrent chemoradiotherapy in 58 patients admitted to Tianjin Medical University Cancer Institute and Hospital from June 2018 to June 2019 was evaluated.Results:During the whole concurrent chemoradiotherapy, chemotherapy delay occurred in 6 patients (10%). Three patients (5%) had delayed concurrent chemotherapy due to leukopenia or neutropenia. The completion rate of chemotherapy cycle was 94.6%(106/112). Radiotherapy delay occurred in 10 patients (17%) including 2 patients (3%) of delayed radiotherapy due to leukopenia or neutropenia. No patient developed febrile neutropenia (FN). Subgroup analysis found that after completing 1 cycle of concurrent chemoradiotherapy, the incidence rates of grade 4 leukopenia and neutropenia were both 0. After completing 2 cycles of concurrent chemoradiotherapy, the incidence rates of grade 4 leukopenia and neutropenia were 0 and 2%.Conclusion:During the chemoradiotherapy, application of PEG-rhG-CSF in the primary preventation can significantly reduce the incidence of FN, grade 4 leukopenia and neutropenia, which is beneficial to ensure the smooth progress of concurrent chemoradiotherapy.