[Long-term follow-up of renal cell carcinomas T1a treated by percutaneous radiofrequency]

Objective: To evaluate the long-term oncological and functional results of the ablative treatment of T1a kidney malignancies by percutaneous radiofrequency (RF).

Materials and methods: Monocentric retrospective study including all patients treated for renal cell carcinoma (RCC) T1a by radiofrequency, in our center, from 2005 to 2009. All patients had a tumor biopsy before treatment. The primary endpoint was local recurrence. A total of 44 RCCs in 41 consecutive patients were treated (1 patient had 3 synchronous tumors and 1 patient had 2 tumors). There were 26 clear cell RCCs, 13 papillary RCCs and 5 chromophobe RCCs. The median age at diagnosis was 70 years [48-82]. The median American Society of Anesthesiologists (ASA) score was 2 [1-3] and the median glomerular filtration rate (GFR) was 64mL/min [26-109]. Furhman grade was defined for 39 tumors (Clear cell RCC and papillary RCC), of which 82% were grade 1-2. The median tumor size was 20mm [11-40], and the median RENAL score was 4 [4-6]. Complications were assessed according to the Clavien-Dindo classification. Overall survival, recurrence-free survival and metastasis-free survival were calculated using the Kaplan-Meier method.

Results: Median follow-up was 90.5 months [17.8-145.3]. Three (7%) local recurrences were reported within a median of 26 months [12-93]. All were treated by a 2nd RF. The overall 10-year survival was 70% (95% CI [56-85]). The 10-year recurrence-free survival was 72% (95% CI [57-88]). The 10-year metastasis-free survival was 87% (95% CI [74-97]). The median GFR on the date of the last news was 51mL/min [16-98] (P=0.05). Post-RFA complications consisted in 5 (11.3%) Clavien-Dindo 1-2 complications. No high grade (Clavien ≥3).

Conclusion: Percutaneous radiofrequency for RCC T1a is an alternative. It appears to be safe with low morbidity, satisfaying long-term oncological and functional results, but a risk of reprocessing of 7%.

Level of evidence: 3.