Partial Nephrectomy and Percutaneous Ablation for cT1 Renal Masses Produce Similar Rates of Local Tumor Recurrence
Recurrence-free survival rates were similar for patients with cT1 renal masses who underwent partial nephrectomy or percutaneous cryoablation, according to the results of a retrospective trial reported by Thompson et al in European Urology. However, metastases-free survival was superior for patients who underwent partial nephrectomy and percutaneous cryoablation when compared with patients who underwent percutaneous radiofrequency ablation.
Although radical nephrectomy has long been the treatment of choice for the management of renal masses, partial nephrectomy is now being increasingly utilized after observations suggested that tumor control was similar to that seen with radical nephrectomy. Guidelines from the American Urologic Association indicate that partial nephrectomy should be considered for healthy patients with cT1a renal masses and should be discussed as an alternate standard for patients with cT1b masses.
To further challenge the treatment decision-making of clinicians, guidelines from the European Association of Urology suggest the use of thermal ablation in patients with small tumors who are not candidates for surgery. In addition, newer approaches such as percutaneous cryoablation and radiofrequency ablation are being used in patients with renal masses.
These various management approaches appear to provide more options while creating some controversy as to the best approach for a particular patient. Thus, Thompson and colleagues evaluated the role of partial nephrectomy, percutaneous radiofrequency ablation, and percutaneous cryoablation in patients with cT1 renal masses.
Study Details
The investigators analyzed the medical records of 1,803 patients with cT1,N0,M0 renal masses from 2000 to 2011. The records were obtained from the Mayo Clinic Renal Tumor Registry. In total, 1,057 patients with cT1a,N0,M0 renal masses were treated with partial nephrectomy, 180 were treated with percutaneous radiofrequency ablation, and 187 were treated with percutaneous cryoablation. Of 379 patients with cT1b,N0,M0 renal masses, 326 received partial nephrectomy and 53 received percutaneous cryoablation.
Pathologic features included tumor size, histology, and grade. Local tumor recurrence following ablation was defined as new focal enhancement in the ablation bed or enlargement of the ablation defect on follow-up imaging. Local tumor recurrence following partial nephrectomy was defined as a mass in the ipsilateral kidney. The duration of follow-up for overall survival was calculated from treatment to last follow-up.
Clinicopathologic Characteristics and Outcomes
Patients treated with partial nephrectomy were significantly younger (P < .001) and had lower Charlson scores (P < .001) compared with patients treated with percutaneous radiofrequency ablation and percutaneous cryoablation. In addition, the median tumor size was 2.4, 1.9, and 2.8 cm for patients treated with partial nephrectomy, percutaneous radiofrequency ablation, and percutaneous cryoablation, respectively (P < .001).
As for outcomes, 36 patients treated with partial nephrectomy experienced local tumor recurrence at a median of 3.0 years, whereas 5 patients treated with percutaneous radiofrequency ablation experienced local tumor recurrence at 0.8, 2.5, 3.9, 6.2, and 7.4 years, respectively. In patients treated with percutaneous cryoablation, three experienced local tumor recurrence at 2.3, 3.0, and 4.5 years, respectively. Local recurrence–free survival rates at 3 years for partial nephrectomy, percutaneous radiofrequency ablation, and percutaneous cryoablation were 98%, 98%, and 98%, respectively.
As for the comparison of patients with cT1a and cT1b masses, those with cT1a masses had similar local tumor control among the three treatment approaches, but those who underwent percutaneous radiofrequency ablation had poorer metastases-free survival rates. Overall survival was found to be superior in patients undergoing partial nephrectomy. Those patients with cT1b masses had similar lower metastases-free survival rates with both partial nephrectomy and percutaneous cryoablation. However, those with cT1b masses had higher overall survival rates after undergoing partial nephrectomy.
Closing Thoughts
The investigators noted that there was no statistically significant difference in local recurrence–free survival among the three treatments (P = .49) for all patients. Among the subset of patients with prior renal cell carcinoma, there was no significant difference in local recurrence–free survival (P = .40). Thus, their results suggest that local recurrence–free survival is similar for cT1a patients treated with partial nephrectomy, percutaneous radiofrequency ablation, and percutaneous cryoablation.
“Given the retrospective nature of this study, we interpret the metastases-free survival rates with caution and submit that our results suggest the need for a prospective randomized clinical trial,” they added.
R. Houston Thompson, MD, of the Department of Urology, Mayo Clinic, Rochester, Minnesota, is the corresponding author of the article in European Urology.
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