CT-guided RFA Using a Urine-Hyperexcreting Protocol in Treating Endophytic RCC: Long-term Outcomes in a Single-Arm Study

Objectives To retrospectively assess how urine-hyperexcreting procedures influence oncologic and functional long-term outcomes of endophytic renal cell carcinomas (RCCs) treated with percutaneous radiofrequency ablation (RFA). Methods Between June 2014 and March 2021, 61 patients underwent CT-guided RFA to treat a histologically proven endophytic RCC. The median RENAL nephrometry score was 10 (7—11). Furosemide was intravenously injected just prior to beginning ablation cycles and normal saline was intravenously infused during RFA procedures. All were followed for 36—109 months (median, 54 months; mean, 58 months). A 5-year local tumor progression (LTP)-free survival rate was calculated with Kaplan-Meier Analysis. Estimated glomerular filtration rates (eGFR) before and after RFA were compared with a paired-t-test. The number of patients with an eGFR decreases to less than 60 mL/min/1.73m2 were assessed following RFA. The types or rates of major complication were recorded. Results A 5-year LTP-free survival rate was 96.7% (59/61). Two patients had LTP, which were treated with additional RFA or surgery. Pre-RFA and post-RFA eGFRs were 86.5±18.2 mL/min/1.73m2 and 77.0±19.5 mL/min/1.73m2, respectively (p < 0.001). Among 29 patients with eGFR of ≥ 60 & <90 mL/min/1.73m2, 8 (27.6%) had eGFRs decreased under 60 mL/min/1.73m2; none of the 26 patients with ≥90 mL/min/1.73m2 showed such a decrease. One patient had a major complication (1.6%) which was uretero-pelvic stricture. Conclusions CT-guided RFA using a urine-hyperexcreting protocol contributes to good oncologic and acceptable functional long-term outcomes of endophytic RCCs. Advances in knowledge CT-guided RFA using a urine-hyperexcreting protocol has the potential to safely treat endophytic RCCs in patients with normal renal function but needs further investigation to compare diuretic group and non-diuretic or pyeloperfusion group.