Introduction: Clear cell renal cell carcinoma is characterized by mutation or inactivation of Von Hippel-Lindau suppressor gene. The mutation of Von Hippel-Lindau mechanism is associated with the upregulation of the hypoxia-inducible factor protein, inducing the overexpression of proteins including erythropoietin and vascular endothelial growth factor. Vascular endothelial growth factor receptor-targeted tyrosine kinase inhibitors are widely used in treatment of metastatic renal cell carcinoma. In paradoxical hematological effect with tyrosine kinase inhibitor therapies, hemoglobin level may be increased, but polycythemia requiring phlebotomy is very rare.
Case description: We present here a case of renal cell carcinoma who received successive treatment with sunitinib, everolimus, and axitinib. While he had a normal hemoglobin level with prior sunitinib treatment, on the sixth week of axitinib treatment, he developed polycythemia and treatment response was seen after axitinib-associated polycythemia.
Conclusion: Progression-free survival (PFS) was 30 months in our case with third-line treatment axitinib. Higher hemoglobin levels may be associated with longer survival. Polycythemia was the first response to treatment of axitinib in our patient. It may be an indicator of persistent treatment response.
Keywords: Axitinib; erythropoietin; polycythemia; renal cell carcinoma.