2.1 Patients
The study population comprised 108 Caucasian patients with confirmed mRCC and aged 18 years old or older being treated with anti-angiogenic therapy from January 2008 to May 2019 at Hacettepe University Cancer Institute (Ankara, Turkey). The baseline demographic, clinical, and laboratory data which were previously documented to have prognostic value were obtained from our center’s electronic database [4]. Patients only with histologically proven mRCC and good performance statues (Karnofsky performance status ≥80) were included in this study. Patients who lost to follow-up and with no abdominal CT scan data at either before treatment initiation or after 3–4 months of targeted VEGF therapy were excluded from the study. The study approved by the local ethics committee and written informed consent were obtained from all of the research participants or their relatives. All procedures in the study were performed in accordance with the 1964 Helsinki declaration and its later amendments.