Oncologic efficacy of CT-guided percutaneous radiofrequency ablation of renal cell carcinomas.

OBJECTIVE: A single institution's experience with CT-guided percutaneous radiofrequency ablation of biopsy-proven renal cell carcinomas (RCCs) was studied to determine the disease-free survival and complication rate. MATERIALS AND METHODS: Data from 125 RCCs in 104 patients treated with curative intent was reviewed. Radiofrequency ablation treatments were performed using conscious sedation and local anesthesia. Patients were followed with contrast-enhanced CT or MRI. Tumor control was defined as the absence of contrast enhancement in the tumor on CT or MRI. RESULTS: Tumor size ranged from 0.6 to 8.8 cm (mean, 2.7 cm; SD, 1.5 cm). Of the 125 treated tumors, 116 (93%) were completely ablated (109 in a single ablation session, seven after a second ablation session) with a mean follow-up interval of 13.8 months. All 95 RCCs smaller than 3.7 cm were completely ablated, and 21 (70%) of 30 larger tumors were completely ablated, with nine showing evidence of residual viable tumor on follow-up scans. Tumor size smaller than 3.7 cm was significantly associated with achieving complete tumor eradication (p < 0.001). With each 1-cm increase in tumor diameter over 3.6 cm, the likelihood of tumor-free survival decreased by a factor of 2.19 (p < 0.001). There were 8 (8%) complications, none of which resulted in long-term morbidity. CONCLUSION: CT-guided percutaneous radiofrequency ablation is a safe method to treat small RCCs. This study indicates that radiofrequency ablation can reliably eradicate RCCs smaller than 3.7 cm. Treatment of larger RCCs will result in an increased risk of residual RCC.

Long-term outcomes after percutaneous radiofrequency ablation for renal cell carcinoma.

OBJECTIVES: To assess the long-term oncological efficacy of radiofrequency ablation (RFA) for treatment of renal cell carcinoma (RCC). METHODS: In this institutional review board-approved, retrospective study, the records and imaging studies for all RCC patients treated with percutaneous RFA before 2005 were reviewed and analyzed. RESULTS: A total of 48 RCCs in 41 patients were treated with RFA. Median size of RCC treated was 2.6 cm (range: 0.7-8.2 cm). Of the 48 treated RCCs, 5 (12%) had recurrent tumor after a single ablation session. The median size of the index lesion in the cases with recurrence was 5.2 cm (interquartile range [IQR]: 4-5.3) compared with 2.2 cm (IQR: 1.7-3.1, P = .0014) without local recurrence. There were no recurrences when RCCs less than 4 cm were treated. Seventeen (41%) patients with 18 treated RCCs died during the follow-up period at a median time of 34 (IQR: 10-47) months. One patient (2%) died of metastatic RCC, whereas 16 died of unrelated causes. Twenty-four patients with 30 RCCs treated with RFA survived. For the remaining 30 RCCs, median follow up was 61 months (IQR: 54-68). No patients in this group of survivors had metastatic RCC, 1 had recurrence diagnosed at 68 months. The long-term recurrence-free survival rate was 88% after RFA. CONCLUSIONS: RFA can result in durable oncological control for RCCs less than 4 cm. RFA is an effective treatment option for patients with RCCs less than 4 cm who are poor surgical candidates. For patients with larger RCCs alternative treatments should be considered.

Percutaneous radiofrequency ablation does not affect glomerular filtration rate.

PURPOSE: To study short- and intermediate-term global renal function in patients undergoing a single percutaneous radiofrequency ablation (pRFA) for a solitary renal parenchymal tumor. MATERIALS AND METHODS: We reviewed the records of 62 patients who underwent a single pRFA for solitary renal parenchymal tumor. We used the abbreviated Modified Diet for Renal Disease equation to calculate baseline, 1-month, and 1-year glomerular filtration rate (GFR). We defined normal as >60, moderately diminished as 45-60, and severely diminished GFR as <45 cc/minute/1.73 m². We used the Wilcoxon paired rank sum method to compare 1-month and 1-year GFR to baseline. We fit a linear regression model to test the association of lesion size to GFR controlling for lesion location and baseline GFR. RESULTS: There was no difference in GFR from baseline at 1 month or 1 year (55 vs. 58 cc/minute/1.73 m², p=0.24 and 55 vs. 57 cc/minute/1.73 m², p=0.8, respectively). Tumor size did not affect GFR at 1 month or 1 year after controlling for lesion location and baseline GFR. CONCLUSIONS: A single application of pRFA does not affect GFR in the short or intermediate term.