Oncologic Outcomes Following Partial Nephrectomy and Percutaneous Ablation for cT1 Renal Masses

Partial nephrectomy remains the preferred treatment modality for small renal masses and current guidelines assess percutaneous ablation an option for small renal masses, mainly to be considered for those patients not amenable to or unfit for surgery. The AUA guidelines also highlight a deficiency in the literature comparing partial nephrectomy and percutaneous ablation and have prioritized a need for high-quality data with long-term follow-up. This study represents the first large cohort comparison of long-term oncologic outcomes with partial nephrectomy, percutaneous radiofrequency ablation and percutaneous cryoablation in the treatment of cT1 renal masses.

This study compares 1422 patients with sporadic (i.e. no previous treatment for renal cell carcinoma [RCC]) cT1a N0M0 treated with partial nephrectomy (1055 patients), percutaneous radiofrequency ablation (180 patients) and percutaneous cryoablation (187 patients). Median follow-up amongst survivors was 9.4 years for partial nephrectomy patients, 7.5 years for percutaneous radiofrequency ablation patients and 6.3 years for percutaneous cryoablation patients. We observed no clinical or statistical difference in five-year local recurrence-free survival, five-year metastasis-free survival, and five-year cancer-specific survival when comparing percutaneous radiofrequency ablation to partial nephrectomy and percutaneous cryoablation to partial nephrectomy. When comparing percutaneous radiofrequency ablation to partial nephrectomy, we report hazard ratios (HR) for local recurrence (HR 1.49, 95% confidence interval [CI] 0.55-4.04, p=0.4), metastasis (HR 1.46, 95% CI 0.41-5.19, p=0.6) and death from RCC (HR 1.99, 95% CI 0.29-13.56, p=0.5). When comparing percutaneous cryoablation to partial nephrectomy we report hazard ratios for local recurrence (HR 1.88, 95% CI 0.76-4.66, p=0.18), metastasis (HR 0.23, 95% CI 0.03-1.72, p=0.15) and death from RCC (HR 0.29, 95% CI 0.01-6.11, p=0.4).

This study also compares 376 patients with sporadic cT1b N0M0 treated with partial nephrectomy (324 patients) and percutaneous cryoablation (52 patients). Median follow-up amongst survivors was 8.7 years for partial nephrectomy patients and 6.0 years for percutaneous cryoablation patients. We observed no clinical or statistical difference in five-year local recurrence-free survival and five-year metastasis-free survival when comparing percutaneous cryoablation to partial nephrectomy. We did observe a clinically significant difference in five-year cancer specific-survival. However, this was not statistically different. When comparing percutaneous cryoablation to partial nephrectomy we report hazard ratios for local recurrence (HR 1.22, 95% CI 0.33-4.48, p=0.8), metastasis (HR 0.95, 95% CI 0.21-4.38, p>0.9) and death from RCC (HR 1.94, 95% CI 0.42-8.96, p=0.4).

In conclusion, percutaneous ablation, with appropriate patient triage, appears to offer acceptable local, metastatic and cancer control for cT1 renal masses, particularly cT1a masses. With respect to cT1b renal masses, we observed acceptable results with percutaneous cryoablation which we feel is currently best utilized in patients who are poor surgical candidates; however further study is warranted.

Oncologic Outcomes Following Partial Nephrectomy and Percutaneous Ablation for cT1 Renal Masses

Written by: Jack R Andrews, MD, Department of Urology, Mayo Clinic and Mayo Medical School, Rochester, Minnesota; Christine M. Lohse, MD, Department of Health Sciences Research, Mayo Clinic and Mayo Medical School, Rochester, Minnesota; R. Houston Thompson, MD, Department of Urology, Mayo Clinic and Mayo Medical School, Rochester, Minnesota.

Reference:

1. Andrews, Jack R., Thomas Atwell, Grant Schmit, Christine M. Lohse, A. Nicholas Kurup, Adam Weisbrod, Matthew R. Callstrom et al. "Oncologic Outcomes Following Partial Nephrectomy and Percutaneous Ablation for cT1 Renal Masses." European urology (2019).

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