Thermal ablative techniques represent treatment options for patients with small renal masses who are not candidates for surgery. We conduct the study to view the oncological and functional outcome of those patient who underwent focal treatment for small renal masses in National Taiwan University Hospital.

We analyzed 112 patients with small renal mass who underwent focal therapy with cryotherapy about 25 patients and radiofrequency ablation about 87 patients from November 2011 to March 2023. The patients were followed at least one year and we collected baseline characteristics, clinical and postoperative data. Oncological data included technical success, local recurrence, and progression to metastasis were evaluated with scheduled CT and MRI scan while functional outcome evaluated with 3, 6-month post-intervention data. Multivariate analysis was performed to find predictors for postoperative complications.

A total 112 patients with 124 lesions were included in the analysis. There were 107 lesions below 4cm(T1a) and the other 17 lesions between 4 to 7 cm(T1b). The pathology report were included in total 93 patients with 98 lesions. The overall recurrence rate was 6.2% (7/112) and median time to recurrence was 6 months. Among the 7 patients, the pathology report showed three with renal cell carcinoma, two with angiomyolipoma and the other two with oncocytoma. The cancer-specific recurrence rate was 6.1%(4/65) and the median time to metastasis was 17 months. Concerning functional outcome, the percentage of newly developed stage 3 CKD or worse was 7.1%(8/112) while no diffierence bwtween the ablative techniques. Two case of previous CKD turned into ESRD after intervention. There was no Clavien-Dindo classification grade 3 or above complication developed after the intervention.

To conclude, thermal ablative techniques serve as an effective and safe alternation for management of small renal mass.