Effect of tyrosine kinase inhibitors on hyperfiltration response and renal functions in nephrectomized renal cell carcinoma patients

Tyrosine kinase inhibitors (TKIs) are utilized in the treatment of Renal Cell Carcinoma (RCC). This study aimed to investigate the effect of TKIs on the hyperfiltration response secondary to nephron loss after nephrectomy. A total of 248 RCC patients were included in the study. 73.3% of the patients were male, with a mean age of 64.6±10.81 years, and 75.4% of the patients underwent radical nephrectomy. 50% of the patients were in the group followed without medication, 25.8% started medication within the first 3 months, and 24.2% started medication between 3-12 months. The hyperfiltration response was estimated using the estimated glomerular filtration rate (eGFR) method. Hyperfiltration response was detected in patients who underwent partial nephrectomy, while this response was not observed in patients who underwent radical nephrectomy (p<0.001). The mean eGFR of the group starting medication in the preoperative period was lower, but there was no statistical difference (p>0.05). Postoperative eGFR loss was similar in patients using TKIs compared to the non-users (p>0.05). In the early-started medication group, it was found that the hyperfiltration response started immediately after the initiation of medication. The statistically significant decrease in eGFR averages starting from the 18th month was observed at the 24th month (p=0.04). In the late-started medication group, it was found that the hyperfiltration response was slower considering the time of medication initiation, and the eGFR average at the 3rd month postoperatively was statistically different from the other groups (p=0.03). Considering differences in the distribution of groups such as stage and mean survival, disease activity and recurrence contribute to the eGFR averages and hyperfiltration response. When the effect of patients' comorbidities on the response was examined, it was found that the presence of hypertension (HT) before diagnosis had a negative effect on renal cell carcinoma, hyperfiltration response, and eGFR loss. In conclusion, initiating treatment early in the presence of active disease positively contributes to the hyperfiltration response in the early period, while late initiation of medication in the group with lower disease activity also has a positive contribution. Disease activity, recurrence, and hypertension have a negative effect on the hyperfiltration response. Keywords: Hyperfiltration response, Tyrosine Kinase Inhibitors, Nephrectomy operation