Percutaneous radiofrequency ablation effective in small, exophytic renal cell carcinoma [Classics Series]

This study summary is an excerpt from the book 2 Minute Medicine’s The Classics in Medicine: Summaries of the Landmark Trials

1. Percutaneous radiofrequency ablation (RFA) demonstrated high efficacy and safety in patients with exophytic renal cell carcinoma (RCC) tumors up to 5 cm.

2. Large RCC tumors with central renal sinus involvement were associated with increased treatment failure.

Original Date of Publication: February 2003

Study Rundown: RCC is the most common primary kidney malignancy and results in approximately 14 000 deaths annually in the United States. Historically, definitive management of RCC consisted of invasive surgery with radical or partial nephrectomy. Non-invasive management options, including RFA, are alternative modalities for treatment of RCC for patients ineligible for surgical intervention or with the need for nephron-sparing therapy. The purpose of this landmark prospective trial was to report the effectiveness of and to delineate the tumor characteristic most amenable to RFA. The prospective trial reported the results of 34 patients that underwent RFA for treatment of RCC. The primary outcome was evidence of technical success, which was demonstrated by lack of active disease on follow-up imaging. At the conclusion of the study, all exophytic RCC tumors were successfully treated, regardless of size. The majority of tumors that underwent successful treatment required only one RFA session; large tumors (> 3 cm) were associated with multiple ablation sessions. Additionally, large tumors that demonstrated involvement of the central renal sinus were associated with an increased incidence of treatment failure. There were no cases of locally recurrent disease or development of metastatic disease in patients with successful RFA treatment. Complications occurred in a small number of patients, with no cases of death or dialysis requirement due to RFA. The trial was limited by a small sample size and did not include any data for small (< 3 cm) tumors with renal sinus involvement. However, this prospective trial demonstrated the effectiveness of using RFA in RCC up to 5 cm in size and not involving the renal pelvis.

Click to read the study in Radiology

In-Depth [prospctive cohort]: This was a prospective, single center trial analyzed the results of 34 consecutive patients with biopsy-confirmed RCC that underwent RFA in the United States. Inclusion criteria included ineligibility for surgery due to medical comorbidities, life expectancy > 1 year, and presence of solitary kidney. Patients were excluded if there was a lack of a safe percutaneous path for tumor access on imaging. The primary outcome was overall treatment success, which was defined as the absence of enhancement in the area of the tumor on 1 month follow-up imaging. Each RCC tumor was characterized with contrast-enhanced CT scan to determine size and location within the kidney. Tumors with extension into the peri-renal fat space with no involvement of the renal sinus were categorized as exophytic. Additionally, tumors greater than 3 cm in cross-sectional diameter were categorized as large. Overall, 42 tumors from 34 patients underwent RFA. All exophytic RCC tumors (n = 29) had a technically successful ablation, regardless of size. Successful ablation was achieved for size as large as 5 cm in diameter. The majority of small (89%) and large (70%) exophytic tumors only required a single session ablation therapy. Only 5 out of 12 large RCC tumors with central renal sinus involvement demonstrated successful ablation. There were no small tumors involving the central renal sinus. In univariate analysis, large tumors with involvement of the central renal sinus were a significant negative predictor of treatment success (p = 0.01). After a median follow-up of 9.9 months, there was no evidence of imaging recurrence or development of metastatic disease in patients that underwent successful RFA treatment. Four complications occurred in a total of 54 ablation sessions. These included one minor hemorrhage, two major hemorrhages, and one ureteral stricture. No patients required dialysis post-RFA treatment.

Gervais DA, McGovern FJ, Arellano RS, McDougal WS, Mueller PR. Renal Cell Carcinoma: Clinical Experience and Technical Success with Radio-frequency Ablation of 42 Tumors. Radiology. 2003 Feb 1;226(2):417–24.

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