Single-Center Comparative Oncologic Outcomes of Surgical and Percutaneous Cryoablation for Treatment of Renal Tumors

Impact of Percutaneous Cryoablation on Renal Function in Patients with Stage I Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

PURPOSE

To assess the effect of cryoablation on renal function (measured by estimated glomerular filtration rate [eGFR] or serum creatinine) for treating Stage I renal cancer.

MATERIALS AND METHODS

The MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases were systematically searched from inception to May 1, 2023. Cohort studies that included data on change of eGFR and serum creatinine increase were included. Meta-analysis was performed by measuring the weighted mean difference and by fitting random-effect models.

RESULTS

Overall, 38 studies were included, comprising 3,202 participants. Percutaneous cryoablation was associated with an absolute eGFR reduction of -3.06 mL/min/1.73 m2 (95% CI, -4.12 to -2.01; P < .001) and serum creatinine increase of 0.05 mg/dL (95% CI, -0.02 to 0.11; P > .05). The weighted absolute mean difference of percutaneous cryoablation for treating Stage T1b renal cell carcinoma was estimated at -5.19 mL/min/1.73 m2 (95% CI, -11.1 to 0.72; P > .05). Lastly, when analyzing studies that included cohorts with solitary kidneys, the pooled weighted mean difference was estimated as -3.27 mL/min/1.73 m2 (95% CI, -6.79 to 0.25; P > .05).

CONCLUSIONS

Percutaneous cryoablation for Stage 1 renal cell carcinoma has minimal significant impact on renal function (measured by eGFR or serum creatinine). The same outcome was observed in patients with larger tumors (T1b) and those with solitary kidneys.

Assessing Trifecta Achievement after Percutaneous Cryoablation of Small Renal Masses: Results from a Multi-Institutional Collaboration

Background and Objectives: To assess efficacy and safety of Percutaneous Cryoablation (PCA) of small renal masses (SRMs) using Trifecta outcomes in a large cohort of patients who were not eligible for surgery. Materials and methods: All PCAs performed in four different centers between September 2009 and September 2019 were retrospectively evaluated. Patients were divided in two different groups depending on masses dimensional criteria: Group-A: diameter ≤ 25 mm and Group-B: diameter > 25 mm. Complications rates were reported and classified according to the Clavien−Dindo system. The estimate glomerular filtration rate (eGFR) was calculated before PCA and during follow-up schedule. Every patient received a Contrast Enhanced Ultrasound (CEUS) evaluation on the first postoperative day. Radiological follow-up was taken at 3, 6, and 12 months for the first year, then yearly. Radiological recurrence was defined as a contrast enhancement persistence and was reported in the study. Finally, Trifecta outcome, which included complications, RFS, and preservation of eGFR class, was calculated for every procedure at a median follow-up of 32 months. Results: The median age of the patients was 74 years. Group-A included 200 procedures while Group-B included 140. Seventy-eight patients were eligible for Trifecta evaluation. Trifecta was achieved in 69.6% of procedures in Group-A, 40.6% in Group-B (p = 0.02). We observed an increased rate of complication in Group-B (13.0% vs. 28.6; p < 0.001). However, 97.5% were <II Clavien−Dindo grade. No differences were found between the two groups regarding eGFR before and after treatment. Further, 24-months RFS rates were respectively 98.0% for Group-A and 92.1% in Group-B, while at 36 months were respectively 94.5% and 87.5% (p = 0.08). Conclusions: PCA seems to be a safe and effective treatment for SRM but in the need of more strict dimensional criteria to achieve a higher possible success rate.

Differential efficacy of ablation therapy versus partial nephrectomy between clinical T1a and T1b renal tumors: A systematic review and meta-analysis

PURPOSE

To assess the differential clinical outcomes of patients treated with partial nephrectomy (PN) vs. those treated with ablation therapy (AT) such as radiofrequency ablation, cryoablation and microwave ablation for cT1b compared to cT1a renal tumors.

MATERIALS AND METHODS

Multiple databases were searched for articles published before August 2021. Studies were deemed eligible if they compared clinical outcomes in patients who underwent PN with those who underwent AT for cT1a and/or cT1b renal tumors.

RESULTS

Overall, 27 studies comprising 13,996 patients were eligible for this meta-analysis. In both cT1a and cT1b renal tumors, there was no significant difference in the percent decline of estimated glomerular filtration rates or in the overall/severe complication rates between PN and AT. Compared to AT, PN was associated with a lower risk of local recurrence in both patients with cT1a and cT1b tumors (cT1a: pooled risk ratio [RR]; 0.43, 95% confidence intervals [CI]; 0.28-0.66, cT1b: pooled RR; 0.41, 95%CI; 0.23-0.75). Subgroup analyses regarding the technical approach revealed no statistical difference in local recurrence rates between percutaneous AT and PN in patients with cT1a tumors (pooled RR; 0.61, 95%CI; 0.32-1.15). In cT1b, however, PN was associated with a lower risk of local recurrence (pooled RR; 0.45, 95%CI; 0.23-0.88). There was no difference in distant metastasis or cancer mortality rates between PN and AT in patients with cT1a, or cT1b tumors.

CONCLUSIONS

AT has a substantially relevant disadvantage with regards to local recurrence compared to PN, particularly in cT1b renal tumors. Despite the limitations inherent to the nature of retrospective and unmatched primary cohorts, percutaneous AT could be used as a reasonable alternative treatment for well-selected patients with cT1a renal tumors.

Artificial intelligence in endourology: emerging technology for individualized care

PURPOSE OF REVIEW

Artificial intelligence in medicine has allowed for efficient processing of large datasets to perform cognitive tasks that facilitate clinical decision-making, and it is an emerging area of research. This review aims to highlight the most pertinent and recent research in artificial intelligence in endourology, where it has been used to optimize stone diagnosis, support decision-making regarding management, predict stone recurrence, and provide new tools for bioinformatics research within endourology.

RECENT FINDINGS

Artificial neural networks (ANN) and machine learning approaches have demonstrated high accuracy in predicting stone diagnoses, stone composition, and outcomes of spontaneous stone passage, shockwave lithotripsy (SWL), or percutaneous nephrolithotomy (PCNL); some of these models outperform more traditional predictive models and existing nomograms. In addition, these approaches have been used to predict stone recurrence, quality of life scores, and provide novel methods of mining the electronic medical record for research.

SUMMARY

Artificial intelligence can be used to enhance existing approaches to stone diagnosis, management, and prevention to provide a more individualized approach to endourologic care. Moreover, it may support an emerging area of bioinformatics research within endourology. However, despite high accuracy, many of the published algorithms lack external validity and require further study before they are more widely adopted.

Irreversible Electroporation for the Treatment of Small Renal Masses: 5-Year Outcomes

Introduction: Irreversible electroporation (IRE) is a nonthermal ablative technology that applies high-voltage short-pulse electrical current to create cellular membrane nanopores and ultimately results in apoptosis. This is thought to overcome thermal limitations of other ablative technologies. We report 5-year oncologic outcomes of percutaneous IRE for small renal masses. Patients and Methods: A single-institution retrospective review of cT1a renal masses treated with IRE from April 2013 to December 2019 was performed. Those with <1 month follow-up were excluded. IRE was performed with the NanoKnife^© System (Angiodynamics, Latham, NY). Renal mass biopsy was obtained before or during ablation in most circumstances; biopsy was excluded in some patients because of concern for IRE probe displacement. Postablation guideline-based surveillance imaging was performed. Initial treatment failure was defined as persistent tumor enhancement on first post-treatment imaging. Survival analysis was performed through the Kaplan-Meier method for effectively treated tumors (SPSS; IBM, Armonk, NY). Results: IRE was used to treat 48 tumors in 47 patients. Twenty-two per 48 tumors (45.8%) were biopsy-confirmed renal cell carcinoma (RCC). No complications ≥ Clavien Grade III occurred and 36 patients (76.6%) were discharged the same day. Initial treatment success rate was 91.7% (n = 44/48); three treatment failures were managed with salvage radiofrequency ablation and one with robotic partial nephrectomy. Median follow-up was 50.4 months (interquartile range 29.0-65.5). The 5-year local recurrence-free survival was 81.4% in biopsy-confirmed RCC patients and 81.0% in all patients. Five-year metastasis-free survival was 93.3% and 97.1%, respectively, and 5-year overall survival was 92.3% and 90.6%, respectively. Five-year cancer-specific survival was 100% for both biopsy-confirmed RCC and all patient groups. Conclusions: IRE has low morbidity, but suboptimal intermediate-term oncologic outcomes compared with conventional thermal ablation techniques for small low-complexity tumors. Use of IRE should be restricted to select cases.

Safety and Oncologic Outcomes of Magnetic Resonance Imaging-Guided Cryoablation of Renal Cell Carcinoma: A 10-Year Single-Center Experience

OBJECTIVES

Magnetic resonance imaging guidance has been sporadically reported for renal tumor cryoablation (CA); therefore, clinical experience with this modality is still limited.The aim of this study is to retrospectively analyze our 10-year experience with renal tumor CA performed on a 1.5 T magnetic resonance imaging unit with the intent of reporting procedural safety and oncologic outcomes.

MATERIALS AND METHODS

We included 143 patients (102 men; 41 women; median age, 73 years; range, 34-91 years) with 149 tumors (median size, 2.6 cm; range, 0.6-6.0 cm), treated between 2009 and 2019. Patient, tumor, procedure, and follow-up data were collected and analyzed. The Kaplan-Meier method was used to estimate local recurrence-free (LRFS), metastasis-free (MFS), disease-free (DFS), cancer-specific, and overall (OS) survival. Univariate and multivariate models were used to identify factors associated with complications, LRFS, MFS, DFS, and OS.

RESULTS

The overall complication rate was 10.7% (16/149 tumors), with 1 major (1/149 [0.7%]; 95% confidence interval, 0.0%-3.7%) hemorrhagic complication. Other minor complications (15/149 [10.1%]; 95% confidence interval, 0.6%-16.1%) did not include any cases of injury to nearby organs. There were no factors associated with complications.Five-year estimates of LRFS (primary/secondary), MFS, DFS, cancer-specific survival, and OS were 82.8%/91.5%, 91.1%, 75.1%, 98.2%, and 89.6%, respectively. Increasing tumor size (hazard radio [HR], 1.8; P = 0.02) and intraparenchymal tumor location (HR, 5.6; P < 0.01) were associated with lower LRFS; increasing patient's age (HR, 0.5; P = 0.01), high tumor grade (HR, 23.3; P < 0.01) and non-clear-cell/nonpapillary histology (HR, 20.1; P < 0.01) with metastatic disease; and high tumor grade (HR, 3.2; P = 0.04) with lower DFS.

CONCLUSION

Magnetic resonance imaging-guided CA of renal tumors is associated with acceptable morbidity and high survival estimates at 5-year follow-up. Given the absence of complications resulting from injuries to nearby organs, further studies are required to evaluate whether the potential reduced incidence of these adverse events justifies large-scale implementation of this interventional modality.

Percutaneous Renal Ablation

Incidental small renal cell cancers are increasingly being diagnosed on cross-sectional imaging. This review article describes the indications for percutaneous ablation of small renal cell cancers, choice of ablation technologies and imaging follow-up.

Outcomes of Renal Tumors Treated by Image-Guided Percutaneous Cryoablation: Immediate and 3- and 5-Year Outcomes at a Regional Center

OBJECTIVE. The purpose of this study was to evaluate the immediate and 3- and 5-year outcomes of patients with clinical stage T1 (cT1) biopsy-proven renal cell carcinoma (RCC) treated by image-guided percutaneous cryoablation at a regional interventional oncology center. MATERIALS AND METHODS. A prospectively maintained local interventional radiology database identified patients with cT1 RCC lesions that were treated by percutaneous cryoablation. Technical success, procedural complications (graded using the Clavien-Dindo classification system), and the residual unablated tumor rate were collated. Local tumor progression-free survival was estimated using Kaplan-Meier estimates. RESULTS. A total of 180 patients with 185 separate cT1 RCC lesions were identified. Mean patient age was 68.4 years (range, 34.1-88.9 years) and 52 patients (28.9%) were women. There were 168 (90.8%) and 17 (9.2%) cT1a and cT1b lesions, respectively, with a mean lesion size of 28.5 mm (range, 11-58 mm). Technical success was achieved in 183 of 185 (98.9%) patients. The major complication rate (Clavien-Dindo classification ≥ grade III) was 2.2% (four out of 185). Residual unablated tumor on the first follow-up scan was identified in four of 183 tumors (2.2%). Estimated local tumor progression-free survival at 3 and 5 years was 98.3% and 94.9%, respectively. No distant metastases or deaths attributable to RCC occurred. Mean estimated glomerular filtration rate (eGFR) before the procedure was 72.4 ± 18.5 (SD) mL/min/1.73 m² and this was not statistically significantly different after the procedure (69.7 ± 18.8 mL/min/1.73 m²), at 1 year (70.7 ± 16.4 mL/min/1.73 m²), or at 2 years (69.8 ± 18.9 mL/min/1.73 m²) (p > 0.05). CONCLUSION. These data add to the accumulating evidence that image-guided cryoablation is an efficacious treatment for selected cT1 RCC with a low complication rate and ro bust 3- and 5-year outcomes.

Percutaneous cryoablation vs. open partial nephrectomy in small kidney cancers: the Italian experience

INTRODUCTION

The aim of the present work was to analyze the economic impact of PCA (percutaneous cryoablation) vs. OPN (open partial nephrectomy), as it represents the most common standard of care for SRMs (small renal masses), namely T1a renal cancers (<4 cm), in Italy.

EVIDENCE ACQUISITION

A cost analysis was performed to compare the difference of the total perioperative costs between PCA and OPN, both from the perspective of the National Healthcare System and the hospital. Clinical and resources consumption inputs were retrieved by a non-systematic literature search on scientific databases, complemented by a grey literature research, and validated by expert opinion. Costs calculation for the NHS perspective were based on reference tariffs published by the National Ministry of Health, while for the hospital perspective, unit costs published in the grey literature were used to compare the two alternatives.

EVIDENCE SYNTHESIS

Assuming the NHS perspective, the cost analysis shows there is an economic advantage in using PCA vs. OPN (€4080 vs. €7541) for the treatment of SRMs. Hospitalization time is the driver of the total costs, while the costs of complications are quite negligible in both groups. From the hospital perspective the costs of PCA is slightly higher (+€737) than OPN, with cryoprobes contributing as the greatest cost component. However, this increase is quite restrained and is offset by an inferior use of healthcare resources (surgery room, healthcare personnel, length of stay in the hospital).

CONCLUSIONS

According to our analysis, PCA results an advantageous technique compared to OPN respectively in terms of costs and resource consumption from both the NHS and the hospital perspective.

[One-stage cryoablation of two renal tumors]

The progressive development of medical technologies allowed the introduction of alternative methods of treatment of localized renal cell carcinoma with a tendency to organ-sparing approach. Cryoablation, radiofrequency ablation, and some experimental methods of treatment (microwave and laser ablation, therapy with high-intensity focused ultrasound) are referred to minimally invasive treatment of renal cell carcinoma. Cryoablation is highly effective alternative method of treatment of renal cell carcinoma. The main advantages of this technique are tumor visualization and formation of 'ice ball' in real time, fewer complications compared with other methods, as well as the possibility of cryotherapy in critically ill patients. Compared to other ablative technologies, cryoablation is followed by low percentage of redo treatment and good intermediate oncological results. We described the experience of one-stage cryoablation of two kidney tumors in this report.

Patient-Reported Outcomes After Percutaneous Renal Ablation: Initial Experience

OBJECTIVE

The purpose of this study is to assess patient-reported outcomes after renal tumor ablation.

MATERIALS AND METHODS

A retrospective review of a pilot quality initiative from February 2016 to April 2016 in our renal ablation practice was performed to assess outcomes after treatment. This included a total of 38 patients (mean age, 63 years; range, 39-83 years) undergoing renal ablation procedures. This pilot included the quantification of recovery, pain, physical well-being, interference with social activities, and physical function as reported by the patient, including measures obtained from the National Institutes of Health's Patient-Reported Outcome Measurement Information System (PROMIS). Such measures were obtained within 24 hours before ablation and days 1-7 and 30 after ablation.

RESULTS

The mean numeric rating (0-10) pain scores at 1 and 2 days after treatment were 1.8 (SD, 2.3) and 2.6 (SD, 2.5). Similarly, mean scores for both overall physical well-being and social activities declined by less than 2 points in the days after ablation. PROMIS scales for physical function and social activities showed very little change from baseline. Nearly 50% of patients thought that they had completely recovered from the ablation on the day after treatment; this perception of recovery declined at days 3-5 and then increased to 89% at 30 days after ablation.

CONCLUSION

This pilot study shows the feasibility of capturing patient-reported outcomes after renal ablation. Such information, particularly when collected from a broader patient population, will be valuable in providing a means to measure quality in the ablation practice and in improving patient education regarding treatment.

The Role of Ablation and Minimally Invasive Techniques in the Management of Small Renal Masses

CONTEXT

Nephron-sparing approaches are increasingly recommended for incidental small renal masses. Herein, we review the current literature regarding the safety and efficacy of focal therapy, including percutaneous ablation, for small renal masses.

OBJECTIVE

To summarize the application of ablative therapy in the management of small renal masses.

EVIDENCE ACQUISITION

PubMed and Medline database search was performed to look for findings published since 2000 on focal therapy for small renal masses. After literature review, 64 articles were selected and discussed.

EVIDENCE SYNTHESIS

Radiofrequency ablation and cryotherapy are the most widely used procedures with intermediate-term oncological outcome comparable with surgical series. Cost effectiveness seems excellent and side effects appear acceptable. To date, no randomized trial comparing percutaneous focal therapy with standard surgical approach or active surveillance has been performed.

CONCLUSIONS

Focal ablative therapies are now accepted as effective treatment for small renal tumors. For tumors <3cm, oncological effectiveness of ablative therapies is comparable with that of partial nephrectomy. Percutaneous ablation has fewer complications and a better postoperative profile when compared with minimally invasive partial nephrectomy.

PATIENT SUMMARY

Focal ablative therapies are now accepted as effective treatment for small renal tumors. For tumors <3cm, oncological effectiveness of ablative therapies is comparable with that of partial nephrectomy.

Laparoscopic cryoablation vs. percutaneous cryoablation for treatment of small renal masses: a systematic review and meta-analysis

CONTEXT

Laparoscopic cryoablation (LCA) and percutaneous cryoablation(PCA) have been used on patients with small renal masses(SRMs) for many years. However, clinical studies assessing their feasibility and safety have reported contradictory outcomes. This systematic evaluation was performed to obtain comprehensive evidence with regard to the feasibility and safety of PCA compared with LCA.

METHODS

A systematic search of Embase, Pubmed, Medline, the Cochrane Library were performed to identify studies that compared LCA with PCA were published up to Mar 2016. Outcomes of interest included perioperative, pathologic variables, and complications.

RESULTS

Thirteen studies estimating LCA versus PCA were included for meta-analysis. Patients undergoing PCA were significantly older(WMD = -0.16 years; P = 0.01) and patients with posterior tumors were significantly prefer undergoing PCA than LCA(OR = 0.23; P = 0.0007), whereas patients with anterior tumors were significantly prefer undergoing LCA(OR = 3.82; P = 0.02). although PCA was associated with shorter hospital stay(WMD = 1.17 days; P < 0.0001) and higher incidence rate of perirenal hematoma(OR = 0.18; P < 0.0001). All the other analyzed parameters were similar, regardless of the surgical approach.

CONCLUSIONS

Patients undergoing PCA have shorter hospital stay and PCA was more frequently used in older patients and posterior tumors. Whereas LCA was associated with lower incidence rate of perirenal hematoma. Further multicenter, prospective and long-term follow-up RCTs are required to verify these findings.

Salvage Surgery After Renal Mass Ablation

Thermal ablative techniques represent treatment options for patients with small renal masses who are not candidates for surgery. The oncologic efficacy of ablation has not been compared in a randomized fashion with nephron-sparing surgery, and the urologist must be knowledgeable regarding the workup and treatment of patients with suspected residual or recurrent tumor following these therapies. Surveillance of patients with tumor recurrence after ablation may be indicated in select circumstances. When patients are deemed appropriate for salvage therapy, most undergo a repeat course of the same ablative modality. Salvage surgery is possible but often complicated by the prior ablative techniques.

Ablative Therapy for Small Renal Masses

The management of small renal masses has become an important public health topic. The increased use of cross-sectional imaging and ultrasound has led to a downward stage migration for the detection of small renal masses. Cancer-specific survival, however, has not reflected this trend accordingly. Although partial nephrectomy has been the mainstay of treatment of small renal masses less than 4 cm, there is growing interest in ablative therapies, such as cryoablation and radiofrequency ablation, due to decreased morbidity. Oncologic outcomes are limited by methodology and length of follow-up, but short-term recurrence rates are low.

Percutaneous image-guided cryoablation: current applications and results in the oncologic field

Percutaneous imaging-guided cryoablation (PICA) is a recently developed technique, which applies extreme hypothermia to destroy tumours under close imaging surveillance. It is minimally invasive, safe, repeatable, and does not interrupt or compromise other oncologic therapies. It presents several advantages over more established heat-based thermal ablation techniques (e.g. radiofrequency ablation; RFA) including intrinsic analgesic properties, superior monitoring capability on multi-modal imaging, ability to treat larger tumours, and preservation of tissue collagenous architecture. There has been a recent large increase in reports evaluating the utility of PICA in a wide range of patients and tumours, but systematic analysis of the literature is challenging due to the rapid pace of change and predominance of extensively heterogeneous level III studies. The precise onco-therapeutic role of PICA has not been established. This narrative review outlines the available evidence for PICA in a range of tumours. Current indications include curative therapy of small T1a renal tumours; curative/palliative therapy of small primary/secondary lung tumours where RFA is unsuitable; palliation of painful bone metastases; and urologic treatment of organ-confined prostate cancer. There is growing evidence to support its use for small hepatic tumours, and encouraging results have been obtained for breast tumours, extra-abdominal desmoid tumours, and management of higher-stage tumours and oligometastatic disease. However, the overall evidence base is weak, effectively restricting PICA to cases where standard therapy and RFA are unsuitable. As the technique and evidence continue to mature, the benefits of this emerging technique will hopefully become more widely available to cancer patients in the future.

Cryoablation of small kidney tumors

INTRODUCTION

Cryoablation (CA) has been broadly used mostly in the treatment of small renal masses (SRMs). The present review aims to define the current role of CA in the treatment of SRMs by assessing clinical indications and outcomes.

METHOD

A comprehensive review on patient selection, procedural details, perioperative complications, and short/long-term oncological and functional outcomes was conducted. For each section, a take-home message was formulated with level of evidence (LoE) according to Cochrane collaboration.

RESULTS

Age and comorbidity drive the choice of ablation in SRMs, although hospital setting also influences the decision. Technically in adequate CA or first post-CA control occurs in 3-5% of laparoscopic cryoablation (LCA) or percutaneous cryoablation (PCA) series. Meta-analysis does not evidence differences in the rate of residual tumor per person-year between the approaches (0.033 LCA vs. 0.046 PCA, p = 0.25). Perioperative complications (8-25%) are erratically reported. LCA has significantly lower likelihood of complications than minimally invasive partial nephrectomy (MIPN). Systematic reviews indicate 30-month local tumor progression rate of 8.5% for LCA in renal cell carcinoma but low metastatic progression (1-4.4%). Few LCA long-term follow-up series (mean/media 48-98 months) report recurrence-free survival (RFS) and cancer-specific survival (CSS) ranges of 80-100%. For PCA, Kaplan-Meier local disease-free survival (DFS) of 95.6% at 3-5 years [32] and 5-year overall survival and local RFS of 86.3% were reported. The decrease in renal function after CA is minimal, and the only risk factor associated is the basal estimated glomerular filtration rate (eGFR).

CONCLUSION

LoE 3a/b confirms lower CA perioperative complication rate and higher local progression rate than those for MIPN. CA preserves postoperative renal functional, without any evidence of differences in mid-/long-term follow-up compared to nephron sparing surgery.

Contemporary Status of Percutaneous Ablation for the Small Renal Mass

Renal cell carcinoma is the tenth most common malignancy in the USA, with upwards of 61,000 new cases and resulting in more than 14,000 deaths annually. Although partial nephrectomy remains the standard treatment, image-guided nephron-sparing ablative techniques including cryoablation, radiofrequency ablation, and microwave ablation have emerged as treatment options in certain patient populations. Ablative therapies have high technical successes, low tumor recurrence rates, and preserve renal parenchymal volume. The purpose of this article is to provide an update on ablation therapies for small renal masses.

Hemorrhagic Complications of Percutaneous Cryoablation for Renal Tumors: Results from a 7-year Prospective Study

PURPOSE

Cryoablation of renal tumors is assumed to have a higher risk of hemorrhagic complications compared to other ablative modalities. Our purpose was to establish the exact risk and to identify hemorrhagic risk factors.

MATERIALS AND METHODS

This IRB approved, 7-year prospective study included 261 renal cryoablations. Procedures were under conscious sedation and CT guidance. Pre- and postablation CT was obtained, and hemorrhagic complications were CTCAE tabulated. Age, gender, tumor size, histology, and probes number were tested based on averages or proportions using their exact permutation distribution. "High-risk" subgroups (those exceeding the thresholds of all variables) were tested for each variable alone, and for all combinations of variable threshold values. We compared the subgroup with the best PPV using one variable, with the subgroup with the best PPV using all variables (McNemmar test).

RESULTS

The hemorrhagic complication rate was 3.5 %. Four patients required transfusions, two required emergent angiograms, one required both a transfusion and angiogram, and two required bladder irrigation for outlet obstruction. Perirenal space hemorrhage was more clinically significant than elsewhere. Univariate risks were tumor size >2 cm, number of probes >2, and malignant histology (P = 0.005, 0.002, and 0.033, respectively). Multivariate analysis showed that patients >55 years with malignant tumors >2 cm requiring 2 or more probes yielded the highest PPV (7.5 %).

CONCLUSIONS

Although older patients (>55 years old) with larger (>2 cm), malignant tumors have an increased risk of hemorrhagic complications, the low PPV does not support the routine use of embolization. Percutaneous cryoablation has a 3.5 % risk of significant hemorrhage, similar to that reported for other types of renal ablative modalities.

Percutaneous microwave ablation of T1a and T1b renal cell carcinoma: short-term efficacy and complications with emphasis on tumor complexity and single session treatment

PURPOSE

To update the oncologic outcomes and safety for microwave (MW) ablation of T1a (≤4.0 cm) and T1b (4.1-7.0 cm) renal cell carcinoma (RCC) with emphasis on tumor complexity and single session treatment.

MATERIALS AND METHODS

Retrospective review of 29 consecutive patients (30 tumors) with localized (NOMO) RCC (23 T1a; 7 T1b) treated with percutaneous MW ablation between 3/2013 and 6/2014. Primary outcomes investigated were technical success, local tumor progression (LTP), and complications. Technical success was assessed with contrast-enhanced computed tomography (CECT) immediately after MW ablation. Presence of LTP was assessed with CECT or contrast-enhanced magnetic resonance at 6-month target intervals for the first two years and annually thereafter. Complications were categorized using the Clavien-Dindo classification system.

RESULTS

Median tumor diameter was 2.8 cm [IQR 2.1-3.3] for T1a and 4.7 cm [IQR 4.1-5.7] for T1b tumors. Median RENAL nephrometry score was 7 [IQR 4-8] for T1a tumors and 9 [IQR 6.25-9.75] for T1b tumors. Technical success was achieved for 22 T1a (96%) and 7 T1b (100%) tumors. There were no LTP during a median imaging follow-up of 12.0 months [IQR 6-18] for the 23 patients (24 tumors) with greater than 6 months of follow-up. There were three Clavien-Dindo grade I-II complication (10%) and no Clavien-Dindo grade III-V complications (0%). All but two patients (93%) are alive without metastatic disease; two patients died after 12-month follow-up of causes unrelated to the MW ablation.

CONCLUSION

Percutaneous MW ablation appears to be a safe and effective treatment option for low, moderate, and highly complex T1a and T1b RCC in early follow-up.

Indications for biopsy and the current status of focal therapy for renal tumours

The increased detection of small renal masses (SRMs) has focused attention on their uncertain natural history. The development of treatment alternatives and the discovery of biologically targeted drugs have also raised interest. Renal mass biopsies (RMBs) have a crucial role as they provide the pathological, molecular and genetic information needed to classify these lesions and guide clinical management. The improved accuracy has improved our knowledge of the behaviour of different tumour histologies and opened the potential for risk-adapted individualized treatment approaches. To date, studies have demonstrated that percutaneous ablation is an effective therapy with acceptable outcomes and low risk in the appropriate clinical setting. Although partial nephrectomy (PN) is still considered the standard treatment for SRM, percutaneous ablation is increasingly being performed and if long-term efficacy is sustained, it may have a wider application for SRMs after biopsy characterization.

Comparison of outcomes in patients undergoing percutaneous renal cryoablation with sedation vs general anesthesia

OBJECTIVE

To compare the efficacy and safety of local anesthesia with conscious sedation (LACS) with general anesthesia (GA) in patients undergoing percutaneous renal cryoablation (PRC) for renal cortical neoplasms.

METHODS

We performed a retrospective review of patients undergoing PRC between 2003 and 2013. Patient demographics, tumor characteristics, and perioperative and postoperative follow-up data were recorded and analyzed. We compared 3 principal outcomes across the GA and LACS groups: anesthesia-related outcomes, treatment failure, and complications.

RESULTS

A total of 235 patients with available data were included. Of these, 82 underwent PRC under GA and 153 patients under LACS. The 2 groups were similar with regard to age, gender, body mass index, American Society of Anesthesiologists score, tumor features, preoperative serum creatinine level, and hematocrit value. The GA and LACS groups had a similar percentage of patients with biopsy-proven renal cell carcinoma (68.5% and 64.2%, respectively; P = .62). The mean follow-up time for GA and LACS was 37 and 21 months, respectively (P <.0001). The mean procedure time for GA was significantly longer compared with LACS (133 vs 102 minutes; P <.001), and the mean hospital stay was shorter under LACS (1.08 vs 1.95 days; P <.0001). There was no difference in immediate failure (0% and 1.9%; P = .051) or recurrences (11% and 3.9%, respectively; P = .051) between GA and LACS groups. There was no difference in intraoperative and postoperative treatment-related complications between the 2 groups.

CONCLUSION

PRC for small renal masses under LACS is effective and safe. PRC with LACS has the advantage of decreased procedure time and a shorter hospital stay.

Cancer immunotherapy using tumor cryoablation

Cryoablation is increasingly being used as a primary treatment for localized cancers and as a salvage therapy for metastatic cancers. Anecdotal clinical reports and animal experiments have confirmed an induction of systemic antitumor immune response by tumor cryoablation. To capitalize on the stimulatory effects of cryoablation for cancer immunotherapy, this response must be intensified using other immunomodulatory agents. This article reviews the preclinical and clinical evidence and discusses the mechanism of the antitumor immune response generated by cryoablation. The rationale and evidence behind several immunotherapy approaches that can be combined with cryoablation to devise a cryoimmunotherapeutic strategy with a potential to impact the progression of metastatic disease are described.

Renal ablation update

Thermal ablative technologies have evolved considerably in the recent past and are now an important component of current clinical guidelines for the treatment of small renal masses. Both radiofrequency ablation and cryoablation have intermediate-term oncologic control that rivals surgical options, with favorable complication profiles. Studies comparing cryoablation and radiofrequency ablation show no significant difference in oncologic control or complication profile between the two modalities. Early data from small series with microwave ablation have shown similar promising results. Newer technologies including irreversible electroporation and high-intensity-focused ultrasound have theoretical advantages, but will require further research before becoming a routine part of the ablation armamentarium. The purpose of this review article is to discuss the current ablative technologies available, briefly review their mechanisms of action, discuss technical aspects of each, and provide current data supporting their use.

Destruction of cancer cells by laser-induced shock waves: recent developments in experimental treatments and multiscale computer simulations

In this emerging area article we review recent progress in the mechanical destruction of cancer cells using laser-induced shock waves. The pure mechanical damaging and destruction of cancer cells associated with this technique possibly opens up a new route to tumor treatments and the corresponding therapies. At the same time progress in multiscale simulation techniques makes it possible to simulate mechanical properties of soft biological matter such as membranes, cytoskeletal networks and even whole cells and tissue. In this way an interdisciplinary approach to understanding key mechanisms in shock wave interactions with biological matter has become accessible. Mechanical properties of biological materials are also critical for many physiological processes and cover length scales ranging from the atomistic to the macroscopic scale. We argue that the latest developments and progress in experimentation enable the investigation of the shock wave interaction with cancer cells on multiple time- and length-scales. In this way the integrated use of experiment and simulation can address key challenges in this field. The exploration of the biological effects of laser-generated shock waves on a fundamental level constitutes an emerging multidisciplinary research area combining scientific methods from the areas of physics, biology, medicine and computer science.