Introduction: Management options of small renal masses (SRM) include surgery, thermal ablation (TA) and active surveillance^[1]. Although recurrence and retreatment rates are higher for TA compared to partial nephrectomy (PN), cancer-specific survival and overall survival (OS) rates are comparable^[2]. This study compares functional and oncological outcomes of TA and PN for SRMs at our centre.

Methods: Patients (pts) who underwent TA or PN for SRM at UWO from 2010 to 2017 were retrospectively reviewed. TA included radiofrequency ablation, cryoablation, and microwave ablation. PN was performed via an open or robotic approach. Patients with cT1a with recorded follow-up (FU) > 12 months were included. Pts with simultaneous multiple renal lesions, known metastatic disease, or ablation for recurrences were excluded. Oncological and functional outcomes were compared between groups.

Results: 269 pts were included, 112 in the PN and 157 in the TA group. The PN pts were younger, had a lower Charlson comorbidity index and a higher eGFR. Tumor size was comparable between groups (Table 1). Complication rates were higher with PN: 31.25% vs 7% for TA. Mean postoperative eGFR decline was significantly lower (8.7 and 18.7, p<0.001), in the TA group vs. PN group. Retreatment rate was 12.1% in the TA group. Recurrence rate (beyond 3 months) was higher in the TA group 8.9% vs 2.7% for PN (p=0.038) (Table 2). No significant difference in OS was found between groups (p=0.16) (Fig.1). Being non-randomized and from a single centre are the main limitations of this series. 

Conclusions: Recurrence and retreatment rates were higher in the TA group compared to PN, but there were more complications with PN. TA could be repeated with safety and relative ease. Ablation therapy is a viable alternative for non-surgical candidates and those who prefer a minimally invasive option. Outcome differences should be discussed in a shared decision-making when counselling patients with SRM.