Percutaneous Cryoablation of Masses in a Solitary Kidney

Percutaneous Ablation of T1 Renal Masses: Comparative Local Control and Complications after Radiofrequency and Cryoablation

The efficacy and complication rates of percutaneous radiofrequency ablation (RFA) and cryoablation (CA) in the treatment of T1 renal masses in two Northern Italy hospitals were retrospectively investigated. Eighty-two patients with 80 T1a tumors and 10 T1b tumors treated with thermal ablation from 2015 through 2020 were included. A total of 43 tumors in 38 patients were treated with RFA (2.3 ± 0.9 cm), and 47 tumors in 44 patients were treated with CA (2.1 ± 0.8 cm). The mean follow-up observation period was 26 ± 19 months. The major complications and efficacy, as measured using the technical success and local tumor recurrence rates, were recorded. There were three (6.9%) technical failures with RFA and one (2.1%) with cryoablation (p = 0.30). Among the 40 tumors that were successfully treated with RFA, 1 tumor (2.5%) developed local tumor recurrence; 5/46 tumors that were treated with cryoablation (10.8%) developed local tumor recurrence (p = 0.17). T1b lesions (4.0 ± 0.7 cm) resulted in 1/6 technically unsuccessful cases with RFA and 0/4 with CA. No recurrent disease was detected in the T1b lesions. Major complications occurred after 2.3% (1/43) of RFAs and 0/47 of cryoablation procedures. RFA and cryoablation are both effective in the treatment of renal masses. Major complications with either procedure are uncommon.

Endophytic upper tract urothelial carcinoma in a solitary kidney treated by cryotherapy: an unorthodox case for successful management

BACKGROUND

Nephroureterectomy remains the gold standard treatment for upper tract urothelial carcinoma (UTUC). Considering the high risk of developing renal function impairment after surgery, the rationale for nephron sparing approaches in treatment of UTUC has been raised. In this case, renal cryoablation was able to achieve successful oncologic control while preserving renal function during 5 years of follow up without intraoperative or post operative complications.

CASE PRESENTATION

A 79 year old male presents after three months of macroscopic hematuria. Imaging revealed a 3.6 × 3.1 × 2.7 cm endophytic mass in the interpolar region of the left kidney and an atrophic right kidney. After weighing the lesion's location with the patient's of complex medical history, he was counselled to undergo a minimally invasive percutaneous cryoablation as treatment for his solitary renal mass. A diagnostic dilemma was encountered as imaging suggested a diagnosis of renal cell carcinoma. However, the pre-ablation biopsy established an alternative diagnosis, revealing UTUC. Percutaneous cryoablation became an unorthodox treatment modality for the endophytic component of his UTUC followed by retrograde ureteroscopic laser fulguration. The patient was followed in 3 months, 6 months, then annually with cross sectional imaging by MRI, cystoscopy, urine cytology and renal function testing. After five years of follow-up, the patient did not encountered recurrence of UTUC or deterioration in renal function, thereby maintaining a stable eGFR.

CONCLUSION

Although evidence for nephron-sparing modalities for UTUC is mounting in recent literature, limited data still exists on cryotherapy as a line of treatment for urothelial carcinoma. We report successful management of a low-grade UTUC using cryoablation with the crucial aid of an initial renal biopsy and long-term follow-up. Our results provide insight into the role of cryoablation as a nephron-sparing approach for UTUC.

Oncological and Peri-Operative Outcomes of Percutaneous Cryoablation of Renal Cell Carcinoma for Patients with Hereditary RCC Diseases-An Analysis of European Multi-Centre Prospective EuRECA Registry

This study aims to evaluate the safety, efficacy, and renal function preservation of percutaneous cryoablation (PCA) for small renal masses (SRMs) in inherited RCC syndromes. Patients with inherited T1N0M0 RCCs (<7 cm) undergoing PCA from 2015 to 2021 were identified from the European Registry for Renal Cryoablation (EuRECA). The primary outcome was local recurrence-free survival (LRFS). The secondary outcomes included technical success, peri-operative outcomes, and other oncological outcomes estimated using the Kaplan-Meier method. Simple proportions, chi-squared tests, and t-tests were used to analyse the peri-operative outcomes. A total of 68 sessions of PCA were performed in 53 patients with RCC and 85 tumours were followed-up for a mean duration of 30.4 months (SD ± 22.0). The overall technical success rate was 99%. The major post-operative complication rate was 1.7%. In total, 7.4% (2/27) of patients had >25% reduction in renal function. All oncological events were observed in VHL patients. Estimated 5-year LRFS, metastasis-free survival, cancer-specific survival, and overall survival were 96.0% (95% CI 75-99%), 96.4% (95% CI 77-99%), 90.9% (95% CI 51-99%), and 90.9% (95% CI 51-99%), respectively. PCA of RCCs for patients with hereditary RCC SRMs appears to be safe, offers low complication rates, preserves renal function, and achieves good oncological outcomes.

Comprehensive Management of Renal Masses in Solitary Kidneys

BACKGROUND

A renal mass in a solitary kidney (RMSK) has traditionally been managed with partial nephrectomy (PN), although radical nephrectomy (RN) is occasionally required. Most RMSK studies have focused on patients for whom PN was achieved.

OBJECTIVE

To provide a comprehensive analysis of the management strategies/outcomes for an RMSK and address knowledge deficits regarding this challenging disorder.

DESIGN, SETTING, AND PARTICIPANTS

A total of 1024 patients diagnosed with an RMSK (1975-2022) were retrospectively evaluated. Baseline characteristics and pathologic/functional/survival outcomes were analyzed.

INTERVENTION

PN/RN/cryoablation (CA)/active surveillance (AS).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Functional outcomes, perioperative morbidity/mortality, and 5-yr recurrence-free survival (RFS) were evaluated. Kruskal-Wallis and chi-square tests were used to compare cohorts, and log-rank test and Cox proportional hazard model were used for survival analysis.

RESULTS AND LIMITATIONS

Of 1024 patients, 842 underwent PN (82%), 102 CA (10%), 54 RN (5%), and 26 AS (3%). The median tumor size and RENAL([R]adius [tumor size as maximal diameter], [E]xophytic/endophytic properties of tumor, [N]earness of tumor deepest portion to collecting system or sinus, [A]nterior [a]/posterior [p] descriptor, and [L]ocation relative to polar lines) score were 3.7 cm and 8, respectively. The median follow-up was 53 mo. For PN, 95% were clamped, and the median warm and cold ischemia times were 22 and 45 min, respectively. For PN, the median preoperative glomerular filtration rate (GFR) was 57 ml/min/1.73 m², and the median new baseline and 5-yr GFRs were 47 and 48 ml/min/1.73 m², respectively. Dialysis-free survival for PN was 97% at 5 yr. Twenty-two (2.1%) patients with clear-cell renal cell carcinoma and RENAL score ≥10 (median = 11) received tyrosine kinase inhibitors (TKIs) to facilitate PN, leading to 57% median decrease of tumor volume; PN was accomplished in 20 (91%). Forty-one patients had planned RN (4.0%), most often due to severe pre-existing chronic kidney disease (CKD), and 13 were converted from PN to RN (1.5%). Clavien III-V perioperative complications were observed in 80 (8%) patients and 90-d mortality was 0.6%. Five-year RFS for PN, CA, and RN were 83%, 80%, and 72%, respectively (p = 0.03 for PN vs RN).

CONCLUSIONS

Nephron-sparing approaches are feasible and successful in most RMSK patients. PN for an RMSK is often challenging but can be facilitated by selective use of TKIs. RN is occasionally required due to severe CKD, over-riding oncologic concerns, or conversion from PN. This is the first large RMSK study to provide a comprehensive analysis of all management strategies/outcomes.

PATIENT SUMMARY

Kidney cancer in a solitary kidney is a major challenge for achieving cancer-free status and avoiding dialysis. Although partial nephrectomy is the principal treatment for a renal mass in a solitary kidney, other options are occasionally required to optimize outcomes.

Image-guided percutaneous cryoablation of T1b renal cell carcinomas in patients with comorbidities

PURPOSE

To investigate the influence of comorbidities and tumor characteristics on outcomes following percutaneous cryoablation (PCA) of T1b renal cell carcinoma (RCC).

MATERIALS AND METHODS

Age-adjusted Charlson comorbidity index (ACCI); standardized system for quantitating renal tumor size, location, and depth (RENAL nephrometry score [RNS]); and local tumor control and survival were retrospectively investigated in 28 patients who underwent PCA for stage T1b RCC. Risk factors for elevated serum creatinine levels were also investigated.

RESULTS

Complete ablation was obtained in 27 of 28 patients. Two cases of metastasis were observed; one patient died 12 months after PCA. Overall survival at 5 years was 79.1%, with a mean follow-up of 42.0 ± 16.0 months. Local tumor control was not correlated with the ACCI and RNS. Worsening renal function 3 months after PCA was observed in ten patients, and it correlated with the presence of single kidneys (7/28 patients; p = 0.023). Significant worsening of renal function continued until 1 year after PCA (p = 0.013). Having a single kidney was a risk factor for worsened renal function after PCA (odds ratio, 8.00; 95% confidence interval 1.170-54.724).

CONCLUSION

PCA for T1b RCC confers positive local tumor control regardless of comorbidities and tumor characteristics.

Efficacy and safety of CT-guided microwave ablation for stage T1a renal cell carcinoma in patients with a solitary kidney

OBJECTIVE

To retrospectively evaluate early clinical outcomes of percutaneous microwave ablation (MWA) for stage T1a renal cell carcinomas (RCCs) in solitary kidney patients.

MATERIALS AND METHODS

15 solitary kidney patients with 16 stage T1a N0M0 biopsy-proved RCCs underwent CT-guided percutaneous microwave ablation between October 2016 and July 2020. The patients were followed up with contrast-enhanced computed tomography or magnetic resonance imaging at 1, 3, and 6 months and every 6 months thereafter. Serum creatinine levels of each patient pre MWA, 1 day after MWA and the most recent record were collected. Technical effectiveness, local recurrence, survival rates and complications were accessed.

RESULTS

Complete ablation was achieved in all 16 tumors (100%) including 13 clear cell carcinomas and 3 papillary carcinomas. Within the follow-up time (median: 24 months) no tumor recurrence or major complication was detected. No significant change in serum creatinine level was noted. The cancer-specific survival rate was 100% (15 of 15), and 1-, 2-, and 3-year overall survival rates were 100%, 93.3%, and 93.3%, respectively.

CONCLUSION

Percutaneous MWA is an effective and safe treatment option for stage T1a RCCs in solitary kidney patients; it can achieve high complete ablation rate in selected lesions of appropriate size and location.

Cryoablation for Secondary Renal Cell Carcinoma After Surgical Nephrectomy

PURPOSE

To retrospectively evaluate the clinical outcomes of cryoablation for secondary renal cell carcinoma for patients with a history of nephrectomy for initial renal cell carcinoma.

MATERIALS AND METHODS

Thirty patients with 40 renal tumors who had undergone a nephrectomy for initial renal cell carcinoma and cryoablation for renal cell carcinoma as a secondary treatment during the period from April 2014 to December 2018 at a single center institution were enrolled. The patients' overall survival, local control, relapse-free survival, change of renal function, and complications were evaluated. The clinical factors of relapse-free survival were also evaluated.

RESULTS

The 5 year overall survival rate was 94.5%, the 5 year local control rate was 89.3%, and the 5 year relapse-free survival rate (RFSR) was 56.3%. There was an average reduction in renal function of 8.5% after 1 year, and > grade 3 complications occurred in only one case. The RFSR in the patients whose initial stage was T3 was 0%, significantly lower than the 70.4% RFSR in the patients whose initial stage was T1 or T2.

CONCLUSION

Cryoablation for secondary renal cell carcinoma after nephrectomy was safe and provided good local control with preserved renal function. However, the indications for cryoablation should be carefully considered for patients with T3-stage initial renal cell carcinoma, because of the high risk of relapse.

LEVEL OF EVIDENCE

III.

Computed tomography-guided biopsy for small renal masses before or immediately after tumor ablation: factors affecting diagnostic yield

PURPOSE

To evaluate the diagnostic yield of percutaneous renal mass biopsy (RMB) before and after ablation.

MATERIALS AND METHODS

In total, 333 renal masses in 332 consecutive patients underwent computed tomography (CT)-guided biopsies and were included in this study. All biopsies were performed with 18-gauge core needles with CT fluoroscopic guidance before ablation (n  =  234) or immediately after radiofrequency ablation (RFA) (n  =  40) or cryoablation (CA) (n  =  59). The safety and diagnostic yield of RMB were evaluated. Both univariate and multivariate analyses were used to identify factors affecting diagnostic yield.

RESULTS

No major complication occurred. The 281 specimens (84%) were diagnostic. There were 257 renal cell carcinomas (77%), 21 benign masses (6%), and 3 metastases (1%). The remaining 52 specimens (16%) were nondiagnostic. The diagnostic yields before ablation, after RFA, and CA were 91% (212/234), 80% (32/40), and 63% (37/59), respectively. Small masses (P  =  0.050 and 0.006), cystic masses (P < 0.001 and < 0.001), and post-CA (P < 0.001 and < 0.001) were independent and significant factors affecting the nondiagnostic results in both univariate and multivariate analyses.

CONCLUSION

CT-guided RMB can be nondiagnostic when the tumor is small, cystic, or biopsied immediately after CA.

Urinothorax following percutaneous image-guided renal cryoablation

A 69-year-old lady with 2 renal cell carcinomas, one sited at the upper pole of her solitary right kidney, underwent percutaneous image-guided cryoablation and developed urinothorax as a complication. This was diagnosed from pleural fluid analysis and radiology imaging with computed tomography (CT). Management included image-guided chest drain and retrograde ureteric stent insertion to divert the urine from entering the pleural cavity. CT images demonstrated a fistula between the site of renal puncture and the pleural cavity, indicating that the cryoprobes traversed the diaphragm during the procedure. This case highlights urinothorax as an unusual complication of cryoablation of renal cell carcinoma. Prompt diagnosis by interventional radiologists is crucial to avert from this potentially life-threatening complication.

Invasive management of renal cell carcinoma in von Hippel-Lindau disease

Introduction

Patients affected by von Hippel-Lindau (VHL) disease experience an increased risk for bilateral, synchronous, and metachronous renal cell carcinoma (RCC). Oncologic and functional outcomes are the main goals in the management of renal masses. We present our protocol for patients with VHL disease-associated RCC alongside functional and oncologic results observed in our series.

Material and methods

We performed a retrospective analysis of our clinical database of patients with VHL disease-associated RCC referred to our department between June 2005 and December 2017. We offer surveillance for lesions <2 cm and active management with radiofrequency ablation (RFA) for lesions 2-3 cm, and nephron-sparing surgery (NSS), RFA or embolization techniques for lesions >3 cm or growth rate >1 cm/year.

Results

Our series comprises 14 patients, of whom 13 had undergone at least one invasive procedure for RCC, mean age at first intervention was 27 years (range 18-60). Overall, 30 interventions were performed in 21 kidneys: four radical nephrectomies, 13 RFAs, 12 NSSs, and one embolization. During follow-up (median time: 41 months, range: 6-149), eight patients (57%) presented with new lesions that required treatment, with a mean time between treatments of 32 ±18.5 months. No metastatic progression or need for dialysis was recorded; the success rate for RFA was 85%.

Conclusions

Management of VHL kidney disease by NSS is the standard of care with a cut-off at 3 cm, ablative procedures should be offered to lesions ranging 2-3 cm in size. Follow-up should be done strictly in referral centers that can provide all treatment options to renal function and control oncologic progression.

Usefulness of a Pretreatment CT-Based Modified RENAL Nephrometry Score in Predicting Renal Function After Cryotherapy for T1a Renal Mass

PURPOSE

We investigated the usefulness of the modified RENAL nephrometry (mRN) scoring system for predicting post-cryotherapy renal function in patients with T1a renal mass.

PATIENTS AND METHODS

A total of 75 patients with a T1a renal mass were enrolled. The mRN score was determined based on the tumor size, the tumor's exophytic/endophytic properties, the tumor's nearness to the collecting system, and the anterior/posterior location of the kidney. The change in the estimated glomerular filtration rate (ΔeGFR) was calculated as follows: ΔeGFR = 100 × ([pretreatment eGFR - eGFR at 6 months after cryotherapy]/pretreatment eGFR). Based on the ΔeGFR results, we classified the patients into two groups: a preserved renal function group (ΔeGFR < 10%) and an impaired renal function group (ΔeGFR ≥ 10%). We then analyzed the relationships between the mRN score and ΔeGFR and between the mRN score and the chronic kidney disease (CKD) stage.

RESULTS

The mean ΔeGFR for all patients was 5.5%. The mRN scores of the preserved renal function group (5.8 ± 0.3) were significantly lower than those of the impaired group (7.4 ± 0.3) (p < 0.001). When the mRN score cutoff value was set at 7 points, the mRN had 67.7% sensitivity, 72.7% specificity, 61.8% positive predictive value (PPV), 76.1% negative predictive value (NPV), and 70.7% accuracy for predicting impaired renal function. For predicting a deterioration of CKD stage, the mRN had 92.9% sensitivity, 67.2% specificity, 39.4% PPV, 97.6% NPV, and 72% accuracy.

CONCLUSION

Our newly proposed modified RENAL nephrometry score was suggested to be useful for predicting renal function after renal cryotherapy.

RETRACTED: Recommandations françaises du Comité de Cancérologie de l’AFU – Actualisation 2018–2020 : prise en charge du cancer du reinFrench ccAFU guidelines – Update 2018–2020: Management of kidney cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Cet article est retiré de la publication à la demande des auteurs car ils ont apporté des modifications significatives sur des points scientifiques après la publication de la première version des recommandations. Le nouvel article est disponible à cette adresse: DOI:10.1016/j.purol.2019.01.004. C’est cette nouvelle version qui doit être utilisée pour citer l’article. This article has been retracted at the request of the authors, as it is not based on the definitive version of the text because some scientific data has been corrected since the first issue was published. The replacement has been published at the DOI:10.1016/j.purol.2019.01.004. That newer version of the text should be used when citing the article.

Incidence of Post-ablation Syndrome Following Image-Guided Percutaneous Cryoablation of Renal Cell Carcinoma: A Prospective Study

PURPOSE

To prospectively evaluate the incidence of post-ablation syndrome (fever and flu-like symptoms) and impact on the quality of life in the first 10 days following percutaneous image-guided cryoablation for renal cell carcinoma (RCC).

MATERIALS AND METHODS

A prospective study of all cryoablation procedures with biopsy proven RCC was conducted with institutional review board approval between 08/2012 and 04/2016. Sixty-four patients (43 males and 21 females) underwent cryoablation. Mean age was 68 (range 24-86). A telephone questionnaire survey was conducted on days 1, 3, 5, 7 and 10 following cryoablation, and complications were recorded. Data collected included temperature, degree of flu-like symptoms, severity of pain, percentage of pain relief with analgesics, interference with general activity and with work (graded on a 0-10 Numeric Intensity Scale).

RESULTS

Following cryoablation, six patients (9%) out of 64 developed post-ablation syndrome. Thirty-three patients (52%) developed flu-like symptoms only, which completely resolved by day 10 in 25 patients (39%). One patient had pyrexia only, which was self- limiting by day 10. Twenty-four patients (38%) were asymptomatic. Pain (mean score = 2.1) and interference on general activities (mean score = 1.8) and work (mean score = 2) following cryoablation peaked on day 3 and improved subsequently. Forty-six patients (72%) had 90-100% pain relief by day 10. No major complications were observed.

CONCLUSION

The full spectrum of post-ablation syndrome following cryoablation occurs in approximately 9% of patients; however, 61% of patients experience flu-like symptoms in the first 10 days, which are self-limiting.

Outcomes After Cryoablation Versus Partial Nephrectomy for Sporadic Renal Tumors in a Solitary Kidney: A Propensity Score Analysis

BACKGROUND

While partial nephrectomy (PN) is considered the standard approach for a tumor in a solitary kidney, percutaneous cryoablation (PCA) is emerging as an alternative nephron-sparing option.

OBJECTIVE

To compare outcomes between PCA and PN for tumors in a solitary kidney.

DESIGN, SETTING, AND PARTICIPANTS

Patients who underwent PCA or PN between 2005 and 2015 for a single primary renal tumor in a solitary kidney were identified using Mayo Clinic Registries. Exclusion criteria were inherited tumor syndromes and salvage procedures.

INTERVENTION

PCA and PN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

To achieve balance in baseline characteristics, we used inverse probability of treatment weighting (IPTW) based on propensity to receive treatment. The risk of having a post-treatment complication and percent drop in estimated glomerular filtration rate (eGFR), as well as the risks of local/ipsilateral recurrence, distant metastasis, and cancer-specific mortality, were compared between groups using logistic, linear, and Fine-and-Gray competing risk regression models.

RESULTS AND LIMITATIONS

The cohort included 118 patients (PCA: 54; PN: 64) with a median follow-up of 47 mo (interquartile range 18, 74). In unadjusted analyses, PCA was associated with a lower risk of complications (15% vs 31%; odds ratio [OR]=0.38; 95% confidence interval [CI] 0.15, 0.96; p=0.04). However, upon accounting for baseline differences with IPTW adjustment, there was no longer a significant difference in the risk of complications (28% vs 29%; OR=0.95; 95% CI 0.53, 1.69; p=0.9). There were no significant differences between PCA and PN in percentage drop in eGFR at discharge (mean: 11% vs 16%; β=-5%; 95% CI -13, 3; p=0.2) or at 3 mo (12% vs 9%; β=3%; 95% CI -3, 10; p=0.3). Likewise, no significant differences were noted in local recurrence (HR=0.87; 95% CI 0.38, 1.98; p=0.7), distant metastases (HR=0.60; 95% CI 0.30, 1.20; p=0.2), or cancer-specific mortality (HR=1.13; 95% CI 0.32, 3.98; p=0.8). Limitations include the sample size, given the relative rarity of renal masses in solitary kidneys.

CONCLUSIONS

Our study found no significant difference in complications, renal function outcomes, and oncologic outcomes between PN and PCA for patients with a tumor in a solitary kidney. Validation in a larger multi-institutional analysis may be warranted.

PATIENT SUMMARY

Partial nephrectomy (surgery) and percutaneous cryoablation are both options for treating a kidney tumor while preserving the normal portion of the kidney. In patients with a tumor in their only kidney, we found no difference in the risk of complications, kidney function outcomes, or cancer control outcomes between these two approaches.

Cryotherapy of Renal Lesions: Enhancement on Contrast-Enhanced Sonography on Postoperative Day 1 Does Not Imply Viable Tissue Persistence

OBJECTIVES

To investigate whether persistent enhancement detected on contrast-enhanced sonography at postoperative day 1 (early contrast-enhanced sonography) after cryoablation of renal tumors implies the presence of residual viable tumor tissue, defined as residual enhancing tissue on reference imaging (computed tomography or magnetic resonance imaging) performed 6 months after the procedure.

METHODS

Seventy-four patients with percutaneous cryoablation of renal tumors had early contrast-enhanced sonography from November 2011 to August 2015. Two independent readers evaluated early contrast-enhanced sonographic findings and contrast-enhanced sonographic investigations performed 1 month after cryoablation of lesions that displayed enhancement on early contrast-enhanced sonography. They scored intralesional enhancement in 4 groups: no enhancement, few intralesional vessels, focal enhancing areas, and diffuse enhancement. Inter-reader agreement in evaluating lesion vascularity on early contrast-enhanced sonography was assessed with weighted κ statistics. Computed tomography or magnetic resonance imaging performed 6 months after the treatment was the reference procedure for assessing the absence or presence of residual disease.

RESULTS

Inter-reader agreement in assessing intratumoral vascularization on early contrast-enhanced sonography was very good (κ = 0.90). Enhancement was absent for both readers in 33 of 74 cases; only a few intralesional vessels were visible in 21; whereas diffuse or focal enhancement was present in 13. In the remaining 7 patients, there were differences. Four lesions with focal enhancement on early contrast-enhanced sonography and 1 that was considered avascular had residual tumors on reference imaging. Ablation was successful in the remaining 69 of 74 patients (93%).

CONCLUSIONS

After cryoablation, intratumoral enhancement on early contrast-enhanced sonography does not imply tumor cell viability.

Management of Small Renal Masses: American Society of Clinical Oncology Clinical Practice Guideline

Purpose To provide recommendations for the management options for patients with small renal masses (SRMs). Methods By using a literature search and prospectively defined study selection, we sought systematic reviews, meta-analyses, randomized clinical trials, prospective comparative observational studies, and retrospective studies published from 2000 through 2015. Outcomes included recurrence-free survival, disease-specific survival, and overall survival. Results Eighty-three studies, including 20 systematic reviews and 63 primary studies, met the eligibility criteria and form the evidentiary basis for the guideline recommendations. Recommendations On the basis of tumor-specific findings and competing risks of mortality, all patients with an SRM should be considered for a biopsy when the results may alter management. Active surveillance should be an initial management option for patients who have significant comorbidities and limited life expectancy. Partial nephrectomy (PN) for SRMs is the standard treatment that should be offered to all patients for whom an intervention is indicated and who possess a tumor that is amenable to this approach. Percutaneous thermal ablation should be considered an option if complete ablation can reliably be achieved. Radical nephrectomy for SRMs should only be reserved for patients who possess a tumor of significant complexity that is not amenable to PN or for whom PN may result in unacceptable morbidity even when performed at centers with expertise. Referral to a nephrologist should be considered if chronic kidney disease (estimated glomerular filtration rate < 45 mL/min/1.73 m²) or progressive chronic kidney disease occurs after treatment, especially if associated with proteinuria.

Percutaneous image-guided cryoablation of small renal masses

Renal cell carcinoma is a common malignancy with increasing incidence due to the incidental detection of non-symptomatic small renal masses on imaging. Management of these small tumors has evolved toward minimally invasive nephron-sparing techniques which include partial nephrectomy and image-guided ablation. Cryoablation and radiofrequency ablation are the most utilized ablation modalities with the former more suited for larger and central renal masses due to intra-procedural visualization of the ablation zone and reduced pelvicalyceal injury. In this article, we review the epidemiology and natural history of renal cell carcinoma, the role of biopsy, and the management options available-surgery, image-guided ablation, and active surveillance-with a focus on cryoablation. The clinical outcomes of the longer term maturing cryoablation data are discussed with reference to partial nephrectomy and radiofrequency ablation. Image-guided ablation has often been the management choice in patients deemed unfit for surgery; however, growing evidence from published series demonstrates image-guided ablation as a sound alternative treatment with equivalent oncological outcomes and minimal patient impact.

Percutaneous radiofrequency ablation of small renal tumours in patients with a single functioning kidney: long-term results

OBJECTIVES

To evaluate the long-term results of percutaneous radiofrequency ablation (RFA) of small renal tumours in patients with a single functioning kidney (SFK).

METHODS

This is a single-centre prospective study. Patients with an SFK and a tumour smaller than 3.5 cm, treated with RFA over a 7.5-year period, were included. Nineteen consecutive patients (12 male), aged between 33 and 83 years (mean 61.4), were treated for 23 lesions. Primary endpoints were technical success and tumour recurrence rate. Secondary endpoints were the deterioration of renal function and overall survival rate.

RESULTS

The mean follow-up was 56.1 months (range 36-102). Primary technical success was 100 %. There were no major peri-procedural complications. In two cases, minor complications occurred. There was no significant difference between the baseline glomerular filtration rate (GFR) and GFR at 3, 12 and 24 months post-procedure. In four lesions (17 %), recurrence was detected and an additional RFA session was performed. None of the patients developed renal failure during their lifetime. Three of the patients died because of other reasons.

CONCLUSIONS

Percutaneous RFA of small renal tumours in patients with an SFK offers very satisfactory long-term results regarding preservation of renal function, local tumour control and overall survival.

KEY POINTS

• Tumour in a single functioning kidney requires minimally invasive treatment. • Radiofrequency ablation plays an established role in managing small renal tumours. • Long-term results of radiofrequency ablation have shown satisfactory local tumour control. • Long-term results have also shown that renal function may be preserved.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease: indications, techniques, complications, and outcomes

Renal cell carcinoma (RCC) in patients with von Hippel Lindau (VHL) disease tends to be multifocal, bilateral, and recur or develop new tumors after removal. These characteristics make treating hereditary RCCs difficult for urologists or radiologists compared to treating a sporadic RCC. Radiofrequency ablation (RFA) is a minimally-invasive treatment for small hereditary RCCs associated with a low complication rate and a minimal decrease in renal function. No RFA guidelines have been established about what to treat and when and how to ablate RCCs in patients with VHL disease. Besides, reports on complications and treatment outcomes in this patient group are rare. The purpose of this review is to discuss the indications, techniques, complications, and outcomes of RFA in treating RCC in patients with VHL disease.

The effects of cryoablation on renal cell carcinoma perfusion and glomerular filtration rate measured using dynamic contrast-enhanced MRI: a feasibility study

AIM

To assess the effect of cryoablation on renal cell carcinoma (RCC) perfusion and single kidney (SK) glomerular filtration rate (GFR) using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Eighteen patients undergoing percutaneous cryoablation of a solitary RCC between August 2010 and November 2011 were evaluated with DCE-MRI immediately before and 1 month post-cryoablation. DCE-MRI data were acquired with 2 s temporal resolution in a coronal plane during the first pass of a 0.1 mmol/kg bolus dose of Gd-DOTA. Perfusion of the RCC (in ml/min/100 ml tissue) was estimated using a maximum slope technique. An index of SK GFR (SK-GFRi) was assessed using data acquired every 30 s for the following 3 min in the axial plane and analysed using Rutland-Patlak plots. This was compared to the GFR estimated by creatinine clearance (eGFR).

RESULTS

Perfusion in the zone of ablation decreased significantly (p<0.001) from a mean of 98.0 ± 37.5 ml/min/100 ml pre-cryoablation to 11.6 ± 4.1 ml/min/100 ml post-cryoablation; a mean decrease of 88.2%. Functional analysis was performed in seventeen patients. eGFR was underestimated by SK-GFRi which decreased significantly in tumour-bearing (-31.7%, p = 0.011), but not in contralateral kidneys (-4.4%, p = 0.14).

CONCLUSION

It is feasible to measure RCC perfusion pre- and post-cryoablation using DCE-MRI. The significant decrease within the zone of ablation suggests that this technique may be useful for assessment of treatment response. Further work is required to address the underestimation of eGFR by SK-GFRi and to validate the perfusion findings.

Thermal ablation in renal cell carcinoma: what affects renal function?

Because of its minimally invasive nature, thermal ablation is increasingly performed in patients with renal cell carcinoma (RCC) who are poor surgical candidates. Thermal ablation has been associated with excellent outcomes, and thus has been regarded as a viable alternative to nephron-sparing surgery. Many papers report minimal to no reduction in renal function after ablation therapies. However, in order to achieve good local control, normal renal tissue must be sacrificed, subsequently leading to reduced renal function. The amount of normal renal tissue to be ablated depends on the size, location, and number of RCCs, as well as the type of thermal ablation applied. However, there are few reports about what reduces renal function following thermal ablation therapies. The purpose of this review was to discuss factors that affect reduction in renal function and to assess the relationship between local tumour control and renal function.

Current management options for the small renal mass in a solitary kidney

The widespread use of cross-sectional imaging has resulted in an increase in the frequency of incidentally identified small renal masses (SRMs). With high cancer-specific survival rates following radical nephrectomy, there is an increasing patient cohort at risk of developing a metachronous contralateral tumour. Nephron-sparing surgery (NSS) has been shown to reduce progression of chronic kidney disease, being the impetus to utilize NSS for the management of SRMs in an anatomical or functional solitary kidney. At present, open partial nephrectomy is the gold standard treatment for an SRM in a solitary kidney; however, there are a number of other minimally invasive options, including laparoscopic partial nephrectomy, and in situ ablative procedures. In addition, variables such as warm and cold ischaemia and renal vascular clamping have been shown to affect outcomes. In this review, we summarize contemporary management options focusing specifically on oncological and functional outcomes.

[Cryoablation - back again?]

CLINICAL ISSUE

Primary and secondary liver tumors often limit patient outcome and only a minority of patients are eligible for potential curative surgery. Minimally invasive treatments, such as radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation are alternative treatment options in a curative and palliative setting. One major limitation of RFA and MWA is the limited size of tumor ablation. Furthermore during the procedure the ablation size can only be roughly estimated using RFA and MWA.

STANDARD TREATMENT

RFA is the standard modality of minimally invasive tumor therapy. In comparison cryoablation is rarely used despite its advantages.

TREATMENT INNOVATIONS

Argon-helium-based cryoablation systems of the newest generation combine the advantage of small diameter applicators comparable with those of RFA and MWA systems with intrinsic advantages.

ACHIEVEMENTS

Cryoablation is a minimally invasive treatment option with advantages, such as virtually unlimited ablation size, real-time visualization using computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound and intrinsic analgesic effects. On the other hand it is not very time-efficient in comparison to MWA. Especially in liver metastases RFA is the preferred treatment option.

PRACTICAL RECOMMENDATIONS

Cryoablation is a fascinating treatment option in minimally invasive tumor treatment. It demonstrates good results in hepatocellular carcinoma within the Milan criteria and T1a renal cell carcinoma. Furthermore it is a well-established treatment modality for palliative pain management in bone tumors.

Renal function outcomes in patients treated with partial nephrectomy versus percutaneous ablation for renal tumors in a solitary kidney

PURPOSE

Partial nephrectomy is the recommended management for small renal masses. Percutaneous ablation is safe and effective with comparable short-term cancer specific survival. Currently to our knowledge data are lacking on the impact of thermal ablation on renal function preservation. We examined the impact on renal function of partial nephrectomy vs percutaneous ablation in patients with a solitary kidney.

MATERIALS AND METHODS

We performed a retrospective review to identify patients with a solitary kidney who underwent partial nephrectomy or percutaneous ablation at Mayo Clinic Rochester between 2003 and 2009. Preoperative characteristics and 3-month posttreatment renal function were compared using the Wilcoxon rank sum, chi-square and Fisher exact tests.

RESULTS

During the study period 50 patients underwent percutaneous ablation and 62 underwent partial nephrectomy. At partial nephrectomy no ischemia was used in 30 cases (48%), a median of 28 minutes of cold ischemia was used in 26 (42%) and a median of 18 minutes of warm ischemia was used in 6 (10%). Patients who underwent partial nephrectomy were younger (median age 62.5 vs 68.5 years, p = 0.01) and harbored larger tumors (median 3.5 vs 2.5 cm, p = 0.005) with higher nephrometry scores (median 9 vs 7, p = 0.03). At 3-month posttreatment followup no differences were noted between the 2 groups in glomerular filtration rate (p = 0.91), change in glomerular filtration rate (p = 0.77) or change in chronic kidney disease stage (p = 0.87). Similar results were observed when adjusting for age, tumor size and nephrometry score on multivariate analysis.

CONCLUSIONS

With judicious use of ischemia partial nephrectomy, even for more complex tumors, has short-term renal function outcomes similar to those of percutaneous ablation.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease previously undergoing a radical nephrectomy or repeated nephron-sparing surgery

BACKGROUND

Radiofrequency ablation (RFA) is accepted as a minimally invasive treatment of renal cell carcinoma (RCC). However, RFA is not fully evaluated for treating RCC in patients with von Hippel Lindau (VHL) disease who cannot undergo surgery due to serious postoperative morbidity or mortality.

PURPOSE

To evaluate the role of RFA of RCC in patients with VHL disease previously undergoing renal surgery.

MATERIAL AND METHODS

Percutaneous RFA was performed for treating 14 RCCs in six patients who had undergone radical nephrectomy (n = 3) or repeated nephron-sparing surgery (n = 3). Treatment feasibility, complications, outcome, and the change of renal function were evaluated.

RESULTS

To completely ablate 14 RCCs, 23 ablations during 12 sessions were necessary. Of 14 RCCs, nine were in proximity (<5 mm) to one or more following organs: bowel (n = 4), ureteropelvic junction or pelvis (n = 2), psoas muscle (n = 2), vascular pedicle (n = 1), and pancreas (n = 1). Of 12 sessions, one major complication (pneumothorax) developed in one session (8%). No residual or recurrent tumors were identified at the ablation areas. However, new three solid tumors less than 1 cm in diameter developed during the follow-up period but ablation was withheld until these tumors had grown to more than 1 cm in size. The mean level of serum creatinine increased with 6.4% and the mean estimated glomerular filtration rate decreased by 12.8% after the last ablation compared to those before the initial ablation (P < 0.05).

CONCLUSION

Despite technical difficulties, percutaneous RFA is a promising treatment for VHL patients who cannot undergo surgery because of excellent treatment outcome and minimal change of renal function.

Image guided percutaneous probe ablation for renal tumors in 65 solitary kidneys: functional and oncological outcomes

PURPOSE

We evaluated the oncological and functional outcomes of computerized tomography guided percutaneous cryotherapy or radio frequency ablation of kidney tumors in patients with a solitary kidney.

MATERIALS AND METHODS

We reviewed the medical charts of patients with a solitary kidney who underwent percutaneous probe ablation for renal masses at our institution from April 2002 through March 2010. Followup consisted of computerized tomography or magnetic resonance imaging 1 day postoperatively, at 3, 6 and 12 months, and annually thereafter. Serum creatinine and estimated glomerular filtration rate were used to measure renal function. The cryotherapy and radio frequency ablation groups were compared for demographics, the 2-year actuarial survival rate and renal function.

RESULTS

Overall 65 patients were included in this retrospective analysis, of whom 29 (44.6%) underwent cryotherapy and 36 (55.4%) underwent radio frequency ablation. Median followup was 15.1 (IQR 4.4 to 32.9) and 38.8 months (13.8 to 50.7), respectively. The 2 groups were comparable in median age, body mass index, American Society of Anesthesiologists score, tumor size and preoperative estimated glomerular filtration rate. The 3 primary treatment failures, including 1 after cryotherapy and 2 after radio frequency ablation, were successfully re-treated with thermal ablation. There were 14 recurrences after radio frequency ablation and 3 after cryotherapy. Two-year actuarial overall, cancer specific, recurrence-free and metastasis-free survival rates for cryotherapy vs radio frequency ablation were 89% vs 93%, 100% vs 96%, 69% vs 58% and 86% vs 91%, respectively. For each group no significant decrease in renal functional parameters was found at the latest followup visit.

CONCLUSIONS

Computerized tomography guided percutaneous probe ablation represents a safe treatment option in surgical patients at high risk with a solitary kidney. It provides low morbidity, acceptable short-term cancer control and minimal clinical impact on postoperative renal function.