Elsevier

European Urology

Volume 71, Issue 1, January 2017, Pages 111-117
European Urology

Platinum Priority – Kidney Cancer
Editorial by Firas G. Petros and Surena F. Matin on pp. 118–119 of this issue
Cryoablation versus Partial Nephrectomy for Clinical T1b Renal Tumors: A Matched Group Comparative Analysis

https://doi.org/10.1016/j.eururo.2016.08.039Get rights and content

Abstract

Background

The traditional treatment for a cT1b renal tumor has been radical nephrectomy. However, recent guidelines have shifted towards partial nephrectomy (PN) in selected patients with cT1b renal tumors. Furthermore, practitioners have extended the role of cryoablation (CA) to treat cT1b tumors in selected patients.

Objective

To evaluate the efficacy of CA compared to PN for cT1b renal tumors.

Design, setting, and participants

We performed a retrospective review of patients who underwent either renal CA (laparoscopic or percutaneous) or PN (robot-assisted) for a cT1b renal mass (>4 cm and ≤7 cm) between November 1999 and August 2014. To reduce the inherent biases of a retrospective study, CA and PN groups were matched on the basis of key variables: tumor size, Charlson comorbidity index (CCI), age, body mass index (BMI), American Society of Anesthesiologists (ASA) score, preoperative serum creatinine, preoperative estimated glomerular filtration rate (eGFR), gender, and solitary kidney. The matching algorithm was 1:1 genetic matching with no replacement.

Outcome measurements and statistical analysis

Survival analysis was performed only for patients diagnosed with renal cell carcinoma according to histopathologic evaluation of a tumor biopsy or resected tumor specimen. Recurrence-free, overall, and cancer-specific survival were analyzed using Kaplan-Meier survival curves. Survival outcomes were compared between groups using the log-rank test.

Results and limitations

A total of 31 patients were treated using CA and 161 using PN during the study period. After matching, there was no significant difference between the PN and CA groups for tumor size (4.6 vs 4.3 cm; p = 0.076), CCI (6 vs 6; p = 0.3), RENAL score (9 vs 8; p = 0.1), age (68 vs 68 yr; p = 0.9), BMI (30 vs 31 kg/m2; p = 0.2), ASA score (3 vs 3; p = 0.3), preoperative creatinine (1.2 vs 1.4 mg/dl; p = 0.2), preoperative eGFR (63 vs 53 ml/min/1.73 m2; p = 0.2), and proportion of patients with a solitary kidney (19% vs 32%; p = 0.4). The total postoperative complication rate was higher for PN than for CA (42% vs 23%; p = 0.10). There was no significant difference in percentage eGFR preservation between PN and CA (89% vs 93%; p = 0.5). The rate of local recurrence was significantly higher for CA than for PN (p = 0.019). There was no significant difference in cancer-specific mortality (p = 0.5) or overall mortality (p = 0.15) between the CA and PN groups.

Conclusions

Patients treated with CA for cT1b renal tumors had a significantly higher rate of local cancer recurrence at 1 yr compared to those treated with PN. Until further studies are performed to clearly define the role of CA in cT1b renal tumors, CA should be reserved for patients with imperative indications for nephron-sparing surgery who cannot be subjected to the risks of more invasive PN.

Patient summary

We evaluated the efficacy of renal cryoablation compared to partial nephrectomy for clinical T1b renal tumors. The cryoablation and partial nephrectomy groups were matched to provide a better comparison. We concluded that renal cryoablation had a higher rate of local cancer recurrence.

Introduction

Over the last decade there has been a sharp increase in the detection of incidental renal tumors attributed to the ubiquitous use of abdominal imaging in current medical practice. As the incidental detection of renal masses has increased, so has our knowledge of the natural history of the disease. This knowledge has led to adoption of nephron-sparing techniques such as partial nephrectomy (PN) and focal ablative therapy options for the treatment of renal cell carcinoma (RCC). The treatment algorithm for cT1b renal tumors is still evolving and the treatment options available to practitioners are expanding. The traditional treatment for a cT1b renal tumor has been radical nephrectomy. However, guidelines have recently shifted towards PN, and state that if a cT1b renal tumor is amenable to PN, it is the treatment of choice in select patients [1], [2]. Furthermore, since the introduction of renal cryoablation (CA) in the late 1990s, practitioners have extended the role of CA to treat cT1b tumors in select patients. A recent study reported similar oncologic outcomes for cT1b renal masses treated by PN and CA [3]. The use of CA as a possible oncologically equivalent treatment option for the management of cT1b renal masses must be considered with utmost care and should not be considered oncologically equivalent to PN until further studies are performed. Our objective was to evaluate the efficacy of CA compared to PN for cT1b tumors with respect to oncologic survival outcomes.

Section snippets

Data acquisition

We reviewed our prospectively maintained CA and PN databases approved by the institutional review board. Patients included for analysis underwent either renal CA (laparoscopic or percutaneous) or PN (robot-assisted approach) for a cT1b renal mass (>4 cm and ≤7 cm and no imaging concerns regarding more advanced disease) between November 1999 and August 2014.

Our technique for CA (both laparoscopic and percutaneous) and robotic PN have previously been described [4], [5], [6]. Of note, the technique

Results

A total of 31 patients were treated using CA and 161 patients were treated using PN during the study period. Key baseline patient and tumor characteristics are listed in Table 1. The CA group consisted of patients who were treated with both laparoscopic (n = 25, 81%) and percutaneous (n = 6, 19%) approaches. All key variables except BMI and gender were significantly different at baseline between the two groups.

After 1:1 matching, the balance of the key variables was checked, and the results show

Discussion

The treatment algorithm for cT1b renal tumors has changed over the last few decades to favor the nephron-sparing PN approach, reserving the traditional treatment of radical nephrectomy for complex tumors not amenable to PN [1], [2]. To follow this trend of nephron-sparing approaches, practitioners have extended the role of CA to treat cT1b tumors in selected patients. Thompson et al [3] reported similar oncologic outcomes for PN and CA of cT1b renal masses, with 3-yr local recurrence–free

Conclusions

Patients treated with CA for cT1b renal tumors had a higher rate of local cancer recurrence than patients treated with PN. Until further studies are performed to clearly define the role of CA in cT1b renal tumors, CA should be reserved for patients with imperative indications for nephron-sparing surgery who cannot be subjected to the risks of more invasive PN.

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