Introduction: Current guidelines recommend that patients who have undergone radiofrequency ablation (RFA) for renal cell carcinoma (RCC) should be monitored for up to five years; however, long-term recurrence data beyond five years are lacking. The objective of this study was to evaluate RCC recurrence rates, time to, and predictors of recurrence in patients up to 10 years post-RFA.

Methods: This was a single-center, retrospective chart review of patients undergoing RFA for any size renal tumor between 2004 and 2012. Patients with non-diagnostic tumors and cases requiring repeat RFAs or surgery were excluded. All tumors and recurrences were confirmed via imaging. Univariate and multivariate Cox proportional hazards regression and Kaplan-Meier analyses were conducted to determine predictors of recurrence and effects of variables on recurrence-free survival.

Results: A total of 142 RFAs were identified, with 58 patients included; 72.4% were male, the mean age at treatment was 67.3 (±11.2, median 65.5). The percutaneous approach was used in 40 (69%) patients, and 72.4% had clear-cell histology. The median time to recurrence was 15.7 months (range 1.0–120.0), with 14 (24.1%) patients experiencing recurrence. Mean tumor size was 2.7 cm (±0.80, range 1.4–4.5), and nine (15.5%) patients had minor complications. The mean RENAL nephrometry score was 6.6 (±1.8, median 7, range 4–10), indicating low-moderate complexity. The majority of recurrences (12) were between three and 12 months post-RFA. Fifteen patients who were not lost to followup were recurrence-free at 10 years. Analyses revealed no statistically significant predictors of recurrence.

Conclusions: A recurrence rate of 24.1% was found in this sample of 58 patients, the majority occurring in year 1 post-RFA. While there were no significant predictive variables for recurrence in this sample, evaluating data on these patients over time can aid in establishing parameters for routine followup, such as imaging and decision-making for continuing care.