Role of intraarterial embolization before cryoablation of large renal tumors: a pilot study

Effect of iodized oil embolization on temperature change during cryoablation for renal cell carcinoma

INTRODUCTION

We aimed to evaluate the effect of transcatheter arterial embolization (TAE) with iodized oil (Lipiodol) on temperature change during cryoablation (CA) for renal cell carcinoma (RCC).

MATERIAL AND METHODS

We retrospectively reviewed patients receiving CA for RCC from February 2020 to July 2021, including those who received Lipiodol TAE prior to CA (TAE group) and those who underwent only CA with comparable clinical and tumor characteristics (non-TAE group). Clinical data and tumor characteristics of both groups were recorded. The temperature readings of each cryoprobe at every 15 s and 'time to -100 °C' were compared between the groups.

RESULTS

A total of 17 patients with 18 RCCs were recruited (seven in the TAE group and 11 in the non-TAE group). The 'time to -100 °C' was significantly longer in the TAE group than in the non-TAE group (64.5 ± 24.3 s vs. 48.8 ± 9.7 s, p = 0.018). Positive correlation between 'time to -100 °C' and tumor maximal diameter, RENAL nephrometry and PADUA score were observed in the non-TAE group, while no corresponding correlation was found in the TAE group.

CONCLUSIONS

Pre-embolization with iodized oil influences the temporal temperature changes during cryoablation by disrupting the positive correlation between the time to reach the target temperature and tumor characteristics.

Transarterial embolization of T1b and T2a renal cell carcinoma prior to percutaneous cryoablation: a retrospective comparative study

PURPOSE

To compare outcomes in patients with T1b and T2a renal cell carcinoma (RCC) treated with percutaneous cryoablation (PCA) who underwent transarterial embolization (TAE) of the RCC prior to PCA (TAE + PCA) to patients who were treated with PCA alone.

METHODS

Retrospective review of all adult patients with T1b (4.1-7 cm) and T2a (7.1-10 cm) RCC treated with PCA from 2008 to 2021. Data collected included age, sex, tumor diameter, RENAL nephrometry score, technical success, adverse events (AEs), changes in serum creatinine, local control, and recurrence rates. A p value of 0.05 was considered the threshold for statistical significance.

RESULTS

13 patients with 13 RCCs (mean age: 72.7 ± 10.4; 54% male) and 35 patients with 37 RCCs (mean age: 66.7 ± 10.6; 60% male) were included in the TAE + PCA and PCA groups, respectively. The TAE + PCA group had larger mean tumor diameter (5.7 ± 1.1 cm vs. 4.7 ± 0.6 cm; p < 0.0001) and higher mean RENAL nephrometry score (8.9 ± 1.1 vs. 7.8 ± 1.5; p = 0.02). There were no differences between the groups with respect to technical success of PCA (p = 0.46), local tumor control (p = 0.3), or mean number of procedures to achieve local tumor control (p = 0.85). Mean increase in serum creatinine was not significantly different between the two groups (p = .63). Major AEs were similar between the groups (p = 1); however, the TAE + PCA group had no major hemorrhagic AEs while the PCA alone group had three (8.3%).

CONCLUSION

TAE + PCA in patients with T1b or T2 RCC is technically feasible without significant added detriment to renal function. This combined approach may help to reduce hemorrhagic AEs but larger patient cohorts are needed.

Role of Fluorodeoxyglucose-PET in Interventional Radiology

Fluorodeoxyglucose (FDG)-PET has expanding applications in the field of interventional radiology. FDG-PET provides both qualitative and quantitative assessments of malignancy, infection, and inflammation. These assessments can assist interventional radiologists in selecting the most appropriate treatment options for their oncology patients. FDG-PET is also useful for evaluating the response to interventional treatments and in predicting the prognosis of oncology patients. Finally, FDG-PET can assist the interventional radiologist in diagnosing and monitoring response to treatment of infection and inflammation. Nevertheless, there is a need for additional prospective studies to further establish the role of FDG-PET in these applications.

Percutaneous Cryoablation of Large Tumors: Safety, Feasibility, and Technical Considerations

INTRODUCTION

Large tumors may prove unsuitable for surgical cure or other local therapies due to their size, involvement of critical structures, prior non-ablative treatment failure, or coexisting disease burden. This study was performed to assess the safety and feasibility of percutaneous cryoablation for treatment of large tumors exceeding 6 cm in size, and to highlight the key technical considerations inherent to such cases.

MATERIALS AND METHODS

This single-institution retrospective study identified 77 patients (42 male, 35 female; median age 55 years) who underwent 96 cryoablation procedures for treatment of 78 tumors (mean diameter 9.8 ± 3.6 cm) from 2008 through 2020. Technical success, procedure-related complications, mortality, oncologic outcomes, and procedural logistics were evaluated. Technical success was defined as ice ball extension at least 5 mm beyond the tumor margins.

RESULTS

Intentional subtotal ablations were performed in 32% of cases due to tumor encroachment on vulnerable structures or as part of staged/combined therapies. Of the 68% of cases that were planned for complete ablation, the technical success rate was 100%. Major complications occurred after 19/96 (20%) procedures, with hemorrhage and acute kidney injury each occurring in 6/96 (6%). Post-procedural myositis occurred in 24/96 (25%) cases and was not considered a major complication in the absence of acute kidney injury. Local recurrence occurred in 2/23 (8.7%) of patients undergoing ablation for cure or local control at a median follow-up duration of 13 months.

CONCLUSION

Percutaneous cryoablation may be used to treat large (> 6 cm) tumors with a high degree of technical success and an acceptable safety profile.

Long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring selective transarterial embolization

PURPOSE

To determine long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring transarterial embolization compared to patients who underwent uncomplicated renal cryoablation without major hemorrhage.

METHODS

Utilizing a matched cohort study design, retrospective review identified 23 patients who underwent percutaneous image-guided renal cryoablation complicated by major hemorrhage requiring ipsilateral transarterial embolization (TAE group) and a control group of 23 patients who underwent uncomplicated renal cryoablation matched 1:1 by age, gender and RENAL Nephrometry score at a single institution from 1/1/2005 to 12/31/2019. Primary outcome parameters included change in creatinine (mg/dl) and estimated glomerular filtration rate (ml/min/1.73 m²; eGFR) from baseline and were compared between TAE and control group using a paired t-test.

RESULTS

There was a significantly higher proportion of patients on pre-ablation anticoagulation in the TAE v. control group (30% v. 4%; p = 0.047), but all patients were off anticoagulation and with normal coagulation parameters at the time of cryoablation. Otherwise there were no significant differences in clinical, renal tumor, Charlson co-morbidity index, baseline renal function or cryoablation parameters between the TAE and control group. In the post-ablation period, there was trend toward greater increase in creatinine from baseline to worst post-ablation creatinine in the TAE v. the control group (+ 0.5 ± 0.7 mg/dl v. 0.2 ± 0.1 mg/dl; p = 0.056). However, at a mean follow-up of 42.7 ± 35.7 months, there was no significant difference between the TAE and control group in creatinine (p = 0.68), eGFR (p = 0.60) or change from baseline in creatinine (p = 0.28), eGFR (p = 0.80) or CKD stage (p = 0.74). No patient required initiation of hemodialysis.

CONCLUSION

Selective transarterial embolization for post-renal cryoablation hemorrhage does not significantly affect long-term renal function compared to cryoablation alone. Pre-ablation anticoagulation despite normal coagulation at time of ablation may be a risk factor for post-ablation hemorrhage, and warrants further evaluation when considering pre-ablation embolization.

Evaluation of Temperature Distribution Around the Probe in Cryoablation of Lipiodol-Mixed-Tissue Phantom

PURPOSE

To determine whether lipiodol, which has low thermal conductivity, influences ice ball formation during cryoablation of a lipiodol-mixed-tissue phantom.

MATERIALS AND METHODS

Lipiodol-mixed-tissue phantoms were created by injecting lipiodol (4-6 ml) into the renal arteries of ex vivo porcine kidneys (lipiodol group). A cryoprobe (CryoHit^™ Needle S) with a holder that was set with thermocouples at various positions around the cryoprobe was inserted. After freezing for 300 s, the followings were evaluated: ice ball size on CT, temperature distribution around the cryoprobe, and calculated distances at 0 °C and - 20 °C. Each variable was compared between lipiodol group (n = 6) those obtained in a control group without lipiodol injection (n = 6).

RESULTS

Mean ice ball diameter (width/length) on CT was 22.1 ± 2.3/22.9 ± 2.3 mm in the lipiodol group and 21.6 ± 0.7/22.2 ± 1.3 mm in the control group. Mean cryoprobe temperature was - 118 ± 3.0 °C in the lipiodol group and - 117 ± 2.6 °C in the control group. In both groups, temperature at the 3 mm thermocouple reached approximately - 50 °C and was < 0 °C within ~ 10 mm of the cryoprobe. Temperature of 0/- 20 °C occurred at a mean distance from the cryoprobe of 11.1 ± 0.5/6.9 ± 0.4 mm in the lipiodol group and 11.0 ± 0.2/6.9 ± 0.2 mm in the control group. There was no significant difference in any variable between the groups.

CONCLUSION

The inclusion of lipiodol in a tissue phantom had no negative effects on ice ball formation that were related to thermal conductivity.

Oncologic outcomes and safety of percutaneous cryoablation for biopsy-proven renal cell carcinoma up to 4 cm in diameter: a prospective observational study

BACKGROUND

Percutaneous cryoablation is widely used for the treatment of renal cell carcinoma. We prospectively evaluated the oncologic outcomes and safety of percutaneous cryoablation for the treatment of tumors ≤ 4 cm in diameter.

METHODS

We included patients aged ≥ 20 years, who had histologically proven renal cell carcinoma, tumor diameter ≤ 4 cm, a performance status of ≤ 1, acceptable laboratory parameters, were inoperable or refused to undergo surgery, and had signed a written informed consent. The primary endpoint was the cause-specific survival rate. The secondary endpoints were overall and progression-free survival, and adverse event frequency and grade. All procedures were percutaneously performed under computed tomography fluoroscopy guidance.

RESULTS

From October 2013 to October 2015, 33 patients (mean age: 68 ± 14 years; sex: six women, 27 men) were enrolled. The mean tumor diameter was 2.1 ± 0.6 (range 1.0-3.4) cm. The median follow-up period was 60.1 (range 18.4-76.6) months. One patient died of non-renal cell carcinoma-related disease 46 months after percutaneous cryoablation. The cause-specific and overall survival rates were 100% and 96.8% at 3 years, and 100% and 96.8% at 5 years, respectively. There was no local tumor progression or distant metastasis. The incidence of severe urological (urinary fistula and perinephric infection) and non-urological adverse events (increased creatine kinase and skin ulceration) was 6% each.

CONCLUSION

Percutaneous cryoablation for renal cell carcinoma ≤ 4 cm in diameter achieved good tumor control with a low complication frequency.

Ablation of Small Renal Masses

Renal cell carcinoma is most commonly diagnosed in the sixth or seventh decade of life. Historically, surgical extirpation was the gold standard treatment option for small renal masses. However, given the comorbidities in this elderly population, not all patients are candidates for surgery. The development of minimally invasive ablative therapies has solved the surgical dilemma in this patient population. Furthermore, the 2017 American Urological Association guidelines recommends consideration of percutaneous image guided thermal ablation as a treatment option for masses smaller than 3 cm even in healthy individuals. Percutaneous image guided thermal ablation is an attractive treatment option providing excellent local tumor control, fewer complications, better preservation of the renal functions, faster recovery and shorter hospital stay. Various ablative modalities are available in clinical practice. This includes radiofrequency ablation, cryoablation, microwave ablation, irreversible electroporation, high intensity focused ultrasound, and laser ablation. In this review, we focus on the most commonly used modalities including radiofrequency ablation and cryoablation and to a lesser extent microwave ablation and irreversible electroporation.

Protection from injury of organs adjacent to a renal tumor during percutaneous cryoablation

Renal cryoablation has become accepted as treatment for small renal tumors as an alternative to surgery. However, parallel with the increase in the use of this therapy, there also has been increases in the number of reports of complications related to renal cryoablation. One potential complication is injury to important non-renal structures adjacent to the ablated renal tumor, such as the colon, duodenum, ureter, psoas muscle and so on. To prevent injury of adjacent organs, separating organs from the tumor is desirable. Over the past 15 years, several techniques have been developed to protect against injury of organs adjacent to renal tumors that are targets of cryoablation. The most commonly used technique for this purpose has been hydrodissection. Others include dissection with gas, balloon dissection and probe traction. To avoid injury of a ureter running near the renal tumor, pyeloperfusion is known to be useful. The rate of cases necessitating avoidance of organ injury by using these techniques is relatively high. In some cases, more than two techniques are combined. In the present review, we provided an overview of techniques currently available to protect against organ injuries, and discussed the advantages and disadvantages of each technique.

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

BACKGROUND

Long-term data comparing partial nephrectomy (PN) and thermal ablation are lacking.

OBJECTIVE

To update our experience with PN, percutaneous radiofrequency ablation (RFA), and percutaneous cryoablation for cT1 renal masses.

DESIGN, SETTING, AND PARTICIPANTS

A total of 1798 patients with primary cT1N0M0 renal masses treated between 2000 and 2011 at Mayo Clinic were identified.

INTERVENTION

Percutaneous ablation versus PN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cancer-specific survival (CSS) was estimated using the Kaplan-Meier method. Local recurrence, metastases, and death from renal cell carcinoma (RCC) were compared with propensity-score-adjusted Cox models.

RESULTS AND LIMITATIONS

Among 1422 cT1a patients, 1055, 180, and 187 underwent PN, RFA, and cryoablation with median clinical follow-up of 9.4, 7.5, and 6.3yr, respectively. Comparisons of RFA with PN resulted in hazard ratios (HRs) of 1.49 (95% confidence interval [CI] 0.55-4.04, p=0.4), 1.46 (95% CI 0.41-5.19, p=0.6), and 1.99 (95% CI 0.29-13.56, p=0.5) for local recurrence, metastases, and death from RCC. Comparisons of cryoablation to PN resulted in HRs of 1.88 (95% CI 0.76-4.66, p=0.18), 0.23 (95% CI 0.03-1.72, p=0.15), and 0.29 (95% CI 0.01-6.11, p=0.4) for these same outcomes. Five-year CSS was 99%, 96%, and 100% for PN, RFA, and cryoablation, respectively. Among 376 cT1b patients, 324 and 52 underwent PN and cryoablation with median clinical follow-up of 8.7 and 6.0yr, respectively. Comparisons of cryoablation with PN resulted in HRs of 1.22 (95% CI 0.33-4.48, p=0.8), 0.95 (95% CI 0.21-4.38, p>0.9), and 1.94 (95% CI 0.42-8.96, p=0.4) for local recurrence, metastases, and death from RCC, respectively. Five-year CSS was 98% and 91% for PN and cryoablation, respectively. Limitations include retrospective review and selection bias.

CONCLUSIONS

With mature follow-up at a single institution, percutaneous ablation appears to have acceptable results for cT1 renal tumors and is appropriate for patients with a contraindication for surgery. For cT1a patients, clinically relevant differences between PN and ablation are unlikely, and treatment choice should involve shared decision making. For cT1b patients, death from RCC was more common with cryoablation, and large differences in this outcome cannot be ruled out. Further research is needed to confirm the oncologic effectiveness of cryoablation in the cT1b setting.

PATIENT SUMMARY

With appropriate patient triage, partial nephrectomy and percutaneous ablation can be used to treat cT1 renal masses, although additional follow-up and further study are still needed.

Sequential Interventional Management of Osseous Neoplasms via Embolization, Cryoablation, and Osteoplasty

The purpose of this study is to determine if sequential interventional therapy can become a mainstay option in providing palliation from fastidious osseous neoplasms in patients with pain refractory to oral analgesia and radiotherapy. This retrospective monocentric study was approved by our institutional review board. Between July 2012 and August 2014, we reviewed 15 patients (6 women, 9 men; age range of 36-81 years) who underwent embolization followed by cryoablation, with or without osteoplasty. Patient demographics and tumor characteristics, including primary histology and the location of metastasis, were included in our review. Pain intensity at baseline, after radiotherapy, and after sequential interventional therapy was reviewed using the hospital electronic medical record. The use of oral analgesia and procedural complications was also noted. Data was then assessed for normality and a two-tailed Student's t-test was performed on mean pain scores for difference phases of treatment. While radiotherapy offers pain relief with a mean pain score of 7.25 ±1.5 (p =<.0001), sequential interventional therapy results in better comfort as demonstrated by a mean pain score of 3.9 ± 2.6 (p=.0015). Moreover, all patients who reported oral analgesic use at presentation reported a decrease in their requirement after sequential interventional therapy. Embolization and cryoablation were performed in all patients, while osteoplasty was indicated in 6 cases. There was no difference in postprocedural pain intensity between patients who required osteoplasty and patients who did not (p = 0.7514). There were no complications observed during treatment. This retrospective study shows that sequential intervention with transarterial embolization, cryoablation, and osteoplasty is both safe and efficacious for bone pain refractory to the current standard of care. We demonstrated that this combination therapy has the potential to become an effective mainstay treatment paradigm in the palliative care of osseous neoplasm to improve quality of life.

Introduction of Microwave Ablation Into a Renal Ablation Practice: Valuable Lessons Learned

OBJECTIVE

The purpose of this study was to evaluate the early outcomes of percutaneous microwave ablation (MWA) for clinical stage T1 (cT1) renal masses when performed within a high-volume ablation practice with critical emphasis on procedural safety.

MATERIALS AND METHODS

A retrospective review of a percutaneous renal ablation registry identified 26 patients with a total of 27 cT1 renal masses treated with MWA between 2011 and 2017. Mean patient age was 63.8 years and 16 (61.5%) patients were male. Mean renal mass size ± SD was 2.3 ± 0.8 cm (range, 1.1-4.7 cm). The main outcome parameters investigated were technical success, local tumor progression, survival rates, and complications. Complications were categorized using the Clavien-Dindo classification system. Rates of local progression-free and cancer-specific survival (PFS and CSS, respectively) were estimated using the Kaplan-Meier method.

RESULTS

Technical success was 100% on contrast-enhanced CT or MRI performed immediately after renal MWA. Twenty-four patients (92%) with 25 tumors had follow-up imaging for 3 months or longer (mean, 20.6 ± 11.6 months), with no local tumor recurrences identified. Estimated 3-year local PFS and CSS were 96% and 94%, respectively. The overall complication rate was 19.2%; two patients (7.7%) experienced minor complications (grade I or II) and three patients (11.5%) experienced major bleeding or urinary-related complications (grade III or higher), including one death.

CONCLUSION

This study suggests that percutaneous MWA is a promising minimally invasive treatment option for cT1 renal masses. Nonetheless, major bleeding and urinary-related complications can occur, and further studies are needed to determine optimal patient and tumor selection for renal MWA.

A rare manifestation of clinical T1 renal tumor with parasitic arterial supply from the superior mesenteric artery

A 50-year-old man with von Hippel-Lindau syndrome who had undergone repeated tumor enucleation and transcatheter arterial embolization for multiple renal cell carcinomas (RCC) was referred to our hospital for percutaneous cryoablation (PCA) of an RCC of 42 mm in the midpole region of the right kidney. Transcatheter arterial embolization was planned prior to devascularize the RCC and selective angiography revealed parasitic arterial supply to the tumor by the ileocecal artery. Parasitic arterial supply to RCCs, particularly in patients with history of nephron-sparing treatment, can originate even from an intraperitoneal source and may lead to unexpected embolization.

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.

[Percutaneous renal ablation: Pre-, per-, post-interventional evaluation modalities and adapted management]

OBJECTIVES

Ablative treatment (AT) rise is foreseen, validation of steps to insure good proceedings is needed. By looking over the process of the patient, this study evaluates the requirements and choices needed in every step of the management.

METHODS

We searched MEDLINE^®, Embase^®, using (MeSH) words and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance.

RESULTS

Explanations of AT proposal rather than partial nephrectomy or surveillance have to be discussed in a consultation shared by urologist and interventional radiologist. Per-procedure choices depend on predictable ballistic difficulties. High volume, proximity of the hilum or of a risky organ are in favor of general anesthesia, cryotherapy and computed tomography/magnetic resonance imaging (CT/MRI). Percutaneous approach should be privileged, as it seems as effective as the laparoscopic approach. Early and delayed complications have to be treated both by urologist and radiologist. Surveillance by CT/MRI insure of the lack of contrast-enhanced in the treated area. Patients and tumors criteria, in case of incomplete treatment or recurrence, are the key of the appropriate treatment: surgery, second session of AT, surveillance.

CONCLUSION

AT treatments require patient's comprehension, excellent coordination of the partnership between urologist and radiologist and relevant choices during intervention.

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.

Renal artery embolization-indications, technical approaches and outcomes

Owing to improvements in catheters and embolic agents, renal artery embolization (RAE) is increasingly used to treat nephrological and urological disease. RAE has become a useful adjunct to medical resuscitation in severe penetrating, iatrogenic or blunt renal traumatisms with active bleeding, and might avoid surgical intervention, particularly among patients that are haemodynamically stable. The role of RAE in pre-operative or palliative management of advanced malignant renal tumours remains debated; however, RAE is recommended as a first-line therapy for bleeding angiomyolipomas and can be used as a preventative treatment for angiomyolipomas at risk of bleeding. RAE represents an alternative to nephrectomy in various medical conditions, including severe uncontrolled hypertension among patients with end-stage renal disease, renal graft intolerance syndrome or autosomal dominant polycystic kidney disease. RAE is increasingly used to treat renal artery aneurysms or symptomatic renal arteriovenous malformations, with a low complication rate as compared with surgical alternatives. This Review highlights the potential use of RAE as an adjunct in the management of renal disease. We first compare and contrast the technical approaches of RAE associated with the various available embolization agents and then discuss the complications associated with RAE and alternative procedures.

Complications of image-guided thermal ablation of liver and kidney neoplasms

Image-guided thermal ablation is a widely accepted tool in the treatment of a variety of solid organ neoplasms. Among the different techniques of ablation, radiofrequency ablation, cryoablation, and microwave ablation have been most commonly used and investigated in the treatment of liver and kidney neoplasms. This article will review complications following thermal ablation of tumors in the liver and kidney, and discuss the risks and clinical presentation of each complication as well as how to treat and potentially avoid complications.

Renal tumor ablation

Percutaneous, image-guided ablation for renal cell carcinoma (RCC) is an important treatment option for many patients. With more than 60,000 new cases every year and nearly three-fourths of those presenting as stage 1A, minimally invasive, nephron-sparing therapies have become the standard of care. Stage 1 A (<4cm, organ confined) disease presents the best scenario for percutaneous ablation. Various other factors influence the decision-making tree, such as patient age, life expectancy, comorbid condition, renal function, and the risk of metachronous lesions. Preparation aims at minimizing risks and has been discussed in detail. Computed tomography guidance remains the best option, and conscious sedation is adequate for most cases. Ultrasound and more recently magnetic resonance guidance are becoming viable alternatives. Whether radiofrequency or cryoablation are chosen, a margin of at least 5mm and up to 10mm is recommended. Various maneuvers required for optimum outcome, including hydrodissection and preoperative embolization are also discussed. Most renal ablations can be performed on an outpatient basis. Reasons to admit include complications, high-risk patients, and the need for symptom management. Follow-up aims at (1) ensuring complete ablation and (2) monitoring against a metachronous lesion. For the former, a 3-month contrast computed tomography or magnetic resonance imaging is required and for the latter an annual examination is recommended. Though partial nephrectomy remains the gold standard, image-guided, percutaneous ablation for RCC can result in very similar outcomes. Over the last 10 years, there have been numerous studies reporting the efficacy and safety of ablation, and more recently, long-term studies have confirmed those numbers. Overall, the efficacy for percutaneous ablation for RCC stands at 90%-95% with a complication rate of 6%-7%. The most important factors for positive outcome are patient or tumor selection and operator experience.

Percutaneous ablation for small renal masses-complications

Although percutaneous ablation of small renal masses is generally safe, interventional radiologists should be aware of the various complications that may arise from the procedure. Renal hemorrhage is the most common significant complication. Additional less common but serious complications include injury to or stenosis of the ureter or ureteropelvic junction, infection/abscess, sensory or motor nerve injury, pneumothorax, needle tract seeding, and skin burn. Most complications may be treated conservatively or with minimal therapy. Several techniques are available to minimize the risk of these complications, and patients should be appropriately monitored for early detection of complications. In the event of a serious complication, prompt treatment should be provided. This article reviews the most common and most important complications associated with percutaneous ablation of small renal masses.

Role of embolization in the treatment of renal masses

Renal arterial embolization (RAE) performed for the treatment of renal masses has been proven to be a safe and effective technique, with several decades of experience. RAE is well tolerated with few complications, particularly if the time interval from embolization to surgery is reduced to less than 48 hours. Review of the literature suggests that RAE is also extremely effective for palliation of symptoms in the setting of nonoperative advanced stage renal cell carcinoma. In addition, this technique plays a large role in the management of angiomyolipomas that are symptomatic or at risk of spontaneous rupture. To date, RAE has not been evaluated in a randomized controlled setting, which has contributed to its underutilization. All of these potential benefits warrant the need for prospective studies for further validation.

Renal artery embolization

Renal artery embolization (RAE) is an effective minimally invasive alternative procedure for the treatment of a variety of conditions. Since the 1970s when RAE was first developed, technical advances and growing experience have expanded the indications to not only include treatment of conditions such as symptomatic hematuria and palliation for metastatic renal cancer, but also preoperative infarction of renal tumors, treatment of angiomyolipomas, vascular malformations, medical renal disease, and complications following renal transplantation. With the drastically improved morbidity associated with this technique in part due to the introduction of more precise embolic agents and smaller delivery catheters, RAE continues to gain popularity for various urologic conditions. The indications and techniques for renal artery embolization are reviewed in the following sections.

Percutaneous cryoablation of solitary sporadic renal cell carcinomas

What's known on the subject? and What does the study add? Percutaneous renal cryoablation is a safe and effective treatment for patients with small renal masses, who are poor surgical candidates. Oncological outcomes from previous percutaneous ablation studies are difficult to interpret because of the large number of patients treated with a history of RCC (38% in our experience) and the large number of treated renal masses without a pathology-proven diagnosis. This cryoablation study addresses these issues by evaluating only solitary, sporadic biopsy-proven RCC. Oncological outcomes and complications were also evaluated by tumour T-stage, which allows some degree of comparison with previously published surgical results.

OBJECTIVE

• To evaluate retrospectively our single institution experience with percutaneous cryoablation of solitary, sporadic renal cell carcinomas (RCCs), and to compare the efficacy and safety of this technique for treatment of different T-stage RCC.

PATIENTS AND METHODS

• 116 patients were treated with percutaneous cryoablation for a solitary, sporadic biopsy-proven RCC in a single treatment session between November 2003 and November 2010. • The technical success of the ablation procedure, complications and evidence for local or metastatic tumour recurrence were evaluated for each patient.

RESULTS

• 83 patients (72%) were treated for a stage T1a RCC, 27 patients (23%) for a stage T1b RCC, and six patients (5%) for a stage T2 RCC. • Technical success was achieved in the treatment of 115 of 116 (99%) renal tumours. The single technical failure occurred in the treatment of a 4.3-cm RCC. • Local recurrent tumour was identified in one of 88 patients (1%) with follow-up computed tomography (CT) or magnetic resonance imaging available for review >3 months from the time of ablation. The median (range) imaging follow-up in these patients was 21 (3-73) months. The local tumour recurrence was identified on CT 11 months after the ablation procedure in a patient treated for a 2.7 cm RCC. • None of the patients developed metastatic RCC. • The major complication rate was 4% for patients with stage T1a tumours, 15% for those with stage T1b tumours, and 33% for those with stage T2 tumours. There were no procedural-related deaths.

CONCLUSIONS

• Percutaneous renal cryoablation of RCC can be performed with high technical success in patients with tumours up to, and beyond 7 cm in maximum diameter. • The tumour recurrence rate after percutaneous renal cryoablation was low, and recurrence was not related to tumour size in this group of patients. • Statistically significant higher complication rates were seen with treatment of larger (higher T-stage) RCCs.

Complications following 573 percutaneous renal radiofrequency and cryoablation procedures

PURPOSE

To review complications related to percutaneous renal tumor ablation.

MATERIALS AND METHODS

Prospectively collected data related to renal radiofrequency (RF) ablation and cryoablation procedures performed from May 2000 through November 2010 were reviewed. This included 573 renal ablation procedures performed in 533 patients to treat 633 tumors. A total of 254 RF ablation and 311 cryoablation procedures were performed; eight patients underwent simultaneous RF ablation and cryoablation. The mean age of patients at the time of the procedure was 70 years (range, 24-93 y), and 382 of 573 procedures (67%) were performed in male patients. Complications were recorded according to the Clavien-Dindo classification scheme. Duration of hospitalization was also documented.

RESULTS

Of the 573 procedures, 63 produced complications (11.0% overall complication rate). There were 66 reported complications, of which 38 (6.6% of total procedures) were Clavien-Dindo grade II-IV major complications; there were no deaths. Major complication rates did not differ statistically (P = .15) between cryoablation (7.7%; 24 of 311) and RF ablation (4.7%; 12 of 254). Of the complications related to cryoablation, bleeding and hematuria were most common. Bleeding during cryoablation was associated with advanced age, increased tumor size, increased number of cryoprobes, and central position (P < .05). Of those treated with RF ablation, nerve and urothelial injury were most common. Mean hospitalization duration was 1 day for RF ablation and cryoablation.

CONCLUSIONS

Complications related to percutaneous renal ablation are infrequent. Recognition of potential complications and associated risk factors can allow optimization of periprocedural care.