A Pilot Study Indicates an Essential Link between a Mild Deterioration in Excretory Kidney Function and the Risk of Neutropenia during Cancer Chemotherapy

Neutropenia is a common adverse event during myelosuppressive oncological chemotherapy, predisposing to febrile neutropenia (FN). Patients with coexisting moderate-to-severe chronic kidney disease (CKD) have an increased risk of FN, included in the guidelines for the primary prophylaxis of FN. However, this does not include mild kidney function impairment with esti-mated glomerular filtration rate (eGFR) 60–89 ml/min/1.73m2. This prospective study analyzed the risk of neutropenia in patients on chemotherapy without indication for the primary prophy-laxis of FN. The study enrolled 38 patients starting chemotherapy, including 26 (68.4%) patients aged 65 years or more. The median duration of follow-up was 76 days. The methodology of cre-atinine assessment enabled the use of the newly recommended CKD-EPI formula for identifying patients with a mild reduction of glomerular filtration. Sixteen (42.1%) patients developed at least G2 neutropenia without episodes of FN. Only five (13.1%) patients had eGFR<60ml/min/1.73m2, while 15 (62.5%) eGFR< 90ml/min/1.73m2. The relative risk of neutro-penia in patients with impaired eGFR was over six times higher than in patients with eGFR>90 ml/min/1.73m2 (RR=6.08; 95%CI:1.45–27.29; p< 0.01). Our observation indicates that even a mild reduction in eGFR is a risk factor for the development of neutropenia and a potential risk factor for FN.