Chemotherapy-induced neutropenia management in a patient with metastatic breast cancer and Shwachman-Diamond syndrome (SDS): a case report

Background: Shwachman-Diamond syndrome (SDS) is a rare inherited bone marrow failure syndrome associated with cytopenia and the development of hematologic malignancies. Solid tumor occurrence is rare and, historically, these patients have had poor outcomes due to chemotherapy-induced myelosuppression and increased susceptibility to infections. We report the administration of cytotoxic systemic therapy with granulocyte colony-stimulating factor (G-CSF) in a patient with SDS and metastatic breast cancer. We describe the risk-benefit profile of utilizing G-CSF in managing this patient to improve her therapeutic outcome and review the prior literature. Case Description: A 41-year-old Caucasian female with SDS developed stage IV triple-positive [estrogen positive, progesterone positive, and human epidermal growth factor receptor 2 ( HER2 ) positive] invasive ductal carcinoma of the left breast with liver metastases. She had lifelong thrombocytopenia with other hematologic parameters within normal limits, no tumor protein 53 ( TP53 ) mutation, and no history of marrow dysplasia. Based on her underlying SDS, paclitaxel was favored over docetaxel due to the reduced risk of myelosuppression and weekly dosing schedule. Her regimen included weekly paclitaxel with trastuzumab and pertuzumab every 21 days. She experienced chemotherapy-induced neutropenia with an absolute neutrophil count of less than 1,500 leading to the utilization of G-CSF support. She received chemotherapy with twice-weekly G-CSF and did not experience severe infections. After nine cycles of therapy, she had no evidence of metastatic disease on imaging. The patient has an ongoing complete response at 18 months since treatment initiation. Conclusions: This case report describes the treatment of a patient with SDS and metastatic breast cancer with cytotoxic chemotherapy and G-CSF. G-CSF facilitated ongoing chemotherapy administration and reduced the risk of infection leading to an optimal therapeutic outcome. There should be careful consideration of early G-CSF use in patients with SDS to optimize continuous chemotherapy dosing.