Renal functional outcomes for tumours in a solitary kidney managed by ablative or extirpative techniques

Abstract

Study Type – Therapy (case series) Level of Evidence 4 OBJECTIVE To present the renal functional outcomes for patients treated with open partial nephrectomy (OPN) or radiofrequency ablation (RFA) for tumours in a solitary kidney, as renal masses in a solitary kidney present a challenging treatment dilemma. PATIENTS AND METHODS A retrospective review of institutional databases identified 89 patients with 98 renal tumours in a solitary kidney managed by RFA or OPN under cold ischaemia between January 1997 and September 2007. The choice of therapy was based on patient and surgeon preference, tumour characteristics and comorbidities. Renal function was calculated using the modified Modification of Diet in Renal Disease equation. RESULTS Outcomes from 47 patients treated by RFA and 42 by OPN were analysed at a median follow‐up of 18.1 and 30.0 months, respectively (P = 0.02). The median age (65.9 vs 59.6 years, P = 0.03) and American Society of Anesthesiology score (3.0 vs 2.0, P = 0.01) were both higher in patients treated with RFA. The median tumour size was greater for tumours managed by OPN (3.9 vs 2.8 cm, P = 0.001), while the median preoperative glomerular filtration rate (GFR) was lower in the RFA group (46.5 vs 55.9 mL/min/1.73 m² for OPN, P = 0.04). Compared to RFA, patients treated with OPN had a greater decline in GFR at all times evaluated, including soon after the procedure (15.8% vs 7.1%), 12 months after surgery (24.5% vs 10.4%) and at the last follow‐up (28.6% vs 11.4%, all P < 0.001). For patients with a pretreatment GFR of > 60 or > 30 mL/min/1.73 m², there was a new onset of decline in GFR of 2 in none and 7% of patients after RFA, and in 35% and 17% after OPN. CONCLUSION Ablative techniques, which obviate ischaemic insults, might be a particularly attractive option for managing tumours in solitary renal units at risk of declining function. Renal functional outcomes compare favourably to extirpative surgery using cold ischaemia.