Comparison of the effects of pegylated granulocyte‑colony stimulating factor and granulocyte‑colony stimulating factor on cytopenia induced by dose‑dense chemotherapy in breast cancer patients

Background: Myelosuppression is one of the frequent side effects of chemotherapy in breast cancer patients. Granulocyte‑colony stimulating factor (G‑CSF) and pegylated G‑CSF are used for the prevention of neutropenia after chemotherapy. Pegylated G‑CSF has longer half‑life of action and can be used as a single dose in comparison to G‑CSF. The aim of this study is to compare the grade of cytopenia and side effects between G‑CSF and biosimilar pegylated G‑CSF in breast cancer patients treated with dose‑dense chemotherapy. Materials and Methods: In the cross‑over clinical trial study, 24 women with breast cancer were randomly divided into two groups and treated with dose‑dense chemotherapy. The first group was treated with single dose of 6 mg biosimilar pegylated G‑CSF 24 h after the first course of chemotherapy and the second course was followed by 300 μg daily injection of G‑CSF for 6 days. The chemotherapy regimen was combination of doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2. The second group was treated with G‑CSF after the first course and pegylated G‑CSF after the second course. Cell blood count (CBC) and side effects were evaluated 1 and 2 weeks after both courses of chemotherapy. Results: In this study, no significant carryover effect and treatment effect about the CBC parameters was found between pegylated G‑CSF and G‑CSF. Patients who were treated with biosimilar pegylated G‑CSF had significantly higher side effects such as bone pain (P = 0.09) and gastrointestinal effects (P = 0.005) in comparison to G‑CSF. Conclusion: G‑CSF and biosimilar pegylated G‑CSF are effective in reducing cytopenia in breast cancer patients treated with dose‑dense chemotherapy, but side effects induced by pegylated G‑CSF (Pegagen) are higher.