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.

Renal functional outcomes in patients undergoing percutaneous cryoablation or partial nephrectomy for a solitary renal mass.

OBJECTIVES: To compare renal functional changes after percutaneous cryoablation (PCA) or partial nephrectomy (PN). PATIENTS AND METHODS: Patients who underwent PCA or PN for a solitary renal mass at a single institution were identified (2003-2013). Estimated glomerular filtration rates (eGFRs) were calculated at baseline, discharge, and at the 3-month follow-up using the Chronic Kidney Disease Epidemiology Collaboration equation. Changes in renal function were compared between groups using 1:1 propensity score (PS) matching, adjustment for PS quintile, and inverse probability weighting (IPW). RESULTS: There were 2 040 procedures available for the PS analyses, including 448 PCA and 1 592 PN. After PS adjustments, there were no significant differences in baseline clinical features between PCA and PN patients. In the PS-matched analysis, the change in eGFR from baseline to discharge for PCA and PN patients was -3.1 and -1.1 mL/min/1.73 m2 , respectively (P = 0.038), with percentage changes of -4.5% and 0% respectively (P = 0.006). From baseline to the 3-month follow-up, the absolute change in eGFR for PCA and PN patients was -4.3 and -2.1 mL/min/1.73 m2 , respectively (P = 0.008), and the percentage change was -6.1% and -2.4% respectively (P = 0.005). Similar results were obtained after adjusting for PS quintiles and in the IPW analysis. Importantly, the rate of chronic kidney disease stage progression at the 3-month follow-up was similar between the groups (21% vs 18%). CONCLUSIONS: Our results confirm that both PCA and PN have a minor impact on renal function. While we observed a statistically greater decline in eGFR after PCA compared with PN, both approaches result in excellent preservation of renal function.

Retrospective Review of Percutaneous Image-Guided Ablation of Oligometastatic Prostate Cancer: A Single-Institution Experience.

PURPOSE: To retrospectively review and report the efficacy and safety of percutaneous image-guided ablation (cryoablation or radiofrequency ablation) in the treatment of oligometastatic prostate cancer. MATERIALS AND METHODS: An institutional registry was retrospectively reviewed and revealed 16 patients with oligometastatic prostate cancer (median age, 67 y; range, 50-86 y) who underwent percutaneous image-guided ablation to treat 18 metastatic sites. A subgroup of 7 patients with 8 metastases were androgen-deprivation therapy (ADT)-naïve and underwent ablation to delay initiation of ADT. Local tumor control, progression-free survival (PFS), ADT-free survival, and procedural complications were analyzed. RESULTS: Local tumor control was achieved in 15 of 18 metastases (83%) at a median follow-up of 27 months (range, 5-56 mo). Local tumor recurrence was found in 3 of 18 metastases (17%), with a median time to local recurrence of 3.5 months (range, 3-38 mo). Estimated PFS rates at 12 and 24 months were 56% (95% confidence interval [CI], 30%-76%) and 43% (95% CI, 19%-65%), respectively. In the 7 ADT-naïve patients, local tumor control was achieved in all metastases, and the median ADT-free survival period was 29 months. There were no major procedural complications. CONCLUSIONS: In this cohort of patients with oligometastatic prostate cancer, percutaneous image-guided ablation was feasible and well tolerated and achieved acceptable local tumor control rates. Percutaneous ablation may be of particular utility in patients who wish to delay initiation of ADT.

Percutaneous Cryoablation of Extraabdominal Desmoid Tumors: A 10-Year Experience.

OBJECTIVE: Extraabdominal desmoid (EAD) tumors pose a therapeutic challenge because they often recur locally and behave aggressively. Accepted management options include surgery, radiation, chemotherapy, and observation. The objective of this study was to assess the safety and efficacy of percutaneous cryoablation for the treatment of EAD tumors. MATERIALS AND METHODS: A retrospective search of our cryoablation database was performed to identify patients with EAD tumors treated with percutaneous cryoablation between June 15, 2004, and June 15, 2014. During this 10-year time period, we treated 18 patients with 26 discrete tumors during 31 treatment sessions. After cryoablation, contrast-enhanced MRI or CT was performed. Any enhancing soft tissue was considered viable EAD tumor and was measured in three planes. RESULTS: Of the 26 EAD tumors treated, follow-up imaging with IV contrast material was available for 23 tumors. The mean imaging follow-up was 16.2 ± 20.0 (SD) months. All 31 sessions were technically successful procedures. No residual viable EAD tumor was observed in nine of 23 tumors (39.1%). Some degree of volume reduction was evident in 22 of 23 tumors (95.7%). Progressive disease was observed in one of the 23 tumors (4.3%). Of the cases with residual or progressive disease, the recurrence occurred at the margin of the treated tumor in all cases. No major complications were observed, and none of the complications was more severe than Clavien-Dindo grade I. CONCLUSION: Percutaneous cryoablation is a safe, effective, and repeatable treatment for achieving local control of EAD tumors.

Percutaneous cryoablation of stage T1b renal cell carcinoma: technique considerations, safety, and local tumor control.

PURPOSE: To describe the technical methods, safety, and local tumor control rate associated with percutaneous cryoablation of stage T1b renal cell carcinoma (RCC). MATERIALS AND METHODS: A retrospective review of a percutaneous renal ablation registry was used to identify 46 patients with a total of 46 biopsy-proven RCC lesions measuring 4.1-7.0 cm treated with cryoablation between 2003 and 2011. The main outcome parameters investigated were adjunctive maneuvers, complications, and local tumor progression, and cancer-specific survival rates. Complication rates were categorized and recorded using the Clavien-Dindo classification system. Progression-free and cancer-specific survival rates were estimated using the Kaplan-Meier method. RESULTS: The mean treated RCC size was 4.8 cm (range, 4.1-6.4 cm). Prophylactic tumor embolization was performed in 7 patients (15%), ipsilateral ureteral stents were placed in 7 patients (15%), and hydrodisplacement of bowel was performed in the treatment of 16 tumors (35%). A single technical failure (2.2%) was observed at the time of ablation. Thirty-six tumors (78%) had follow-up imaging at 3 months or later following ablation, including a single recurrence at 9 months after ablation. The mean duration of follow-up for the 35 RCC tumors that did not recur was 2.0 years (range, 0.3-6.1 y). Estimated local progression-free survival rate at 3 years was 96.4%. Of the 46 cryoablation procedures, there were 7 complications (15.2%) of grade II or worse. CONCLUSIONS: The results suggest that cryoablation represents a valid treatment alternative for select patients with clinical stage T1b RCC. Complications are frequent enough that multidisciplinary patient management should be considered.

Predicting renal cryoablation complications: new risk score based on tumor size and location and patient history.

PURPOSE: To identify tumor and patient-related risk factors for major complications following renal cryoablation and to develop a model for predicting these adverse events. MATERIALS AND METHODS: Institutional review board approval and informed patient consent were obtained for this HIPAA-compliant retrospective study. All 398 renal cryoablation procedures performed from 2003 through 2011 were reviewed to identify tumor and patient-related risk factors associated with major complications (Clavien-Dindo classification, ≥ grade III). A scoring system for predicting these adverse events was then developed using risk factor weighting obtained from a multivariate logistic regression model. To internally validate this model, the scoring system was then applied to all 73 renal cryoablation procedures performed during 2012. RESULTS: Among tumor-related factors evaluated, Maximal tumor diameter (P = .0006) and Central tumor location (P = .02) were significantly associated with major complications. Among patient-related factors evaluated, prior Myocardial infarction (MI) (P = .002) and Complicated diabetes mellitus (P = .01) were significantly associated with major complications. This resulted in the (MC)2 risk scoring system, with (MC)2 risk score = 2.5 points (for tumors ≤ 2.5 cm in maximal diameter) or 0.1 points for each millimeter of maximal tumor diameter (for tumors > 2.5 cm) + 1.5 points (if central tumor location) + 2.5 points (if patient history of prior MI) + 3.0 points (if patient history of complicated diabetes). Mean (MC)2 risk score for all renal cryoablations was 4.7 (standard deviation, 1.9; range, 2.5-15.3). The observed major complication rates were 2.0% (95% confidence interval [CI]: 0.6%, 4.6%) in the low-risk group (score < 5.0), 12.8% (95% CI: 7.5%, 19.9%) in the moderate-risk group (score of 5.0-8.0), and 39.1% (95% CI: 19.7%, 61.5%) in the high-risk group (score > 8.0). Application of the (MC)2 scoring system to the validation group yielded a concordance index of 0.82 (95% CI: 0.62, 1.00). CONCLUSION: The results of this study suggest that the (MC)2 risk score is a valuable tool for predicting major complications in patients undergoing renal cryoablation. However, external validation is warranted.

Feasibility and oncologic control after percutaneous image guided ablation of metastatic renal cell carcinoma.

PURPOSE: We assessed the safety, local control and oncologic efficacy of percutaneous ablation in the treatment of metastatic renal cell carcinoma. MATERIALS AND METHODS: A retrospective review was performed of 61 patients who underwent 74 ablation procedures to treat 82 metastatic renal cell carcinoma lesions with the intent of local eradication. Technical success, local tumor control, complications and patient survival were analyzed according to standard criteria. RESULTS: Four (4.9%) technical failures were observed while 2 patients were lost to followup. Time to recurrence was assessed for the subset of 76 (93%) tumors that were followed after ablation. Six (of 76, 7.9%) tumors recurred at a mean of 1.6 years after ablation (median 1.4, range 0.6 to 2.9). Thus, known overall local tumor control was achieved in 70 of 80 (87.5%) tumors. Estimated local recurrence-free survival rates (95% CI, number still at risk) at 1, 2 and 3 years after ablation were 94% (88-100, 41), 94% (88-100, 32) and 83% (70-97, 17), respectively. Estimated overall survival rates (95% CI, number still at risk) at 1, 2 and 3 years after ablation were 87% (79-97, 42), 83% (73-94, 31) and 76% (63-90, 19), respectively. CONCLUSIONS: Image guided ablation of metastatic renal cell carcinoma is a relatively safe procedure with acceptable local control rates. Ablation may offer patients a minimally invasive option of local tumor eradication and warrants a role in the multimodal treatment approach for select patients.

Cryoablation of sternal metastases for pain palliation and local tumor control.

PURPOSE: To determine safety and effectiveness of cryoablation of sternal metastases for pain palliation and local tumor control. MATERIALS AND METHODS: A tumor ablation database was retrospectively reviewed for sternal cryoablation procedures performed between January 2005 and June 2013, which yielded 15 procedures to treat 12 sternal metastases in 12 patients (five men). Median patient age was 57 years (range, 38-80 y). Metastases arose from five primary sites (breast, lung, kidney, ampulla, and thyroid), and median tumor size was 3.8 cm (range, 2.2-7.5 cm). Seven patients (58%) underwent cryoablation for pain palliation, and five (42%) underwent cryoablation for local tumor control of oligometastatic disease. Clinical outcomes (including complications, local tumor control, and pain response) were evaluated retrospectively. RESULTS: Mean pain scores decreased from 7.0 ± 1.9 (median, 7; range, 4-10) at baseline to 1.8 ± 1.2 (median, 1.5; range, 0-4) following cryoablation (P = .00049). Two patients had durable pain palliation, and four had greater than 1 month of pain relief, with a median duration of 5.7 months (range, 1.5-14.7 mo). Two patients in whom recurrent pain developed underwent repeat cryoablation, with durable pain relief. Allowing for a single repeat treatment, local tumor control was achieved in four of five patients (80%) treated for this indication, with median follow-up of 8.4 months (range, 2.6-13.6 mo). In one patient (8%), an infectious complication developed that was successfully treated with antibiotics on an outpatient basis. CONCLUSIONS: Cryoablation is a safe and potentially effective treatment for patients with painful sternal metastases and can achieve local tumor control in select patients.

ABLATE: a renal ablation planning algorithm.

OBJECTIVE: The purpose of this article is to present the ABLATE renal ablation planning algorithm (Table 1), which is based on anatomic renal tumor characteristics critical to ablation. [Table: see text]. CONCLUSION: ABLATE provides a systematic method for reviewing cross-sectional imaging of renal masses for ablation planning purposes. The goal of this system is to help proceduralists anticipate and manage potential technical challenges of renal ablations to maximize oncologic outcomes and minimize complications.

Percutaneous renal cryoablation after partial nephrectomy: technical feasibility, complications and outcomes.

PURPOSE: Treatment of locally recurrent or de novo tumors in the ipsilateral kidney after partial nephrectomy represents a management dilemma. Percutaneous renal cryoablation offers a minimally invasive treatment option in such cases. We review our single institution experience with percutaneous cryoablation of renal tumors after partial nephrectomy for technical feasibility, complications and outcomes. MATERIALS AND METHODS: Between March 2003 and January 2012, 48 patients underwent percutaneous cryoablation for the treatment of 68 ipsilateral renal tumors after previous partial nephrectomy. Oncologic outcomes, complications (Clavien-Dindo classification system) and renal function were evaluated. RESULTS: Median maximal diameter of the treated renal tumors was 2.5 cm (range 1.2 to 5.4). All cryoablation procedures were considered technically successful. Of the 54 biopsy proven or suspected renal cell carcinomas with 3 or more months of computerized tomography/magnetic resonance imaging followup after cryoablation (median 19, range 3 to 61), 5 cases (9.3%) had local tumor recurrence. Major (grade 3 or greater) complications developed after 3 (5.7%) cryoablation procedures and there were no perioperative deaths. Median change in patient estimated glomerular filtration rate after renal cryoablation was -1.5 ml per minute. No patients required dialysis in the perioperative period, while 2 with stage 4 chronic kidney disease at the time of ablation became dialysis dependent at 5 and 23 months after treatment, respectively. CONCLUSIONS: Percutaneous renal cryoablation after ipsilateral partial nephrectomy is technically feasible, has a low rate of major complications, provides relative preservation of renal function and demonstrates acceptable short-term oncologic outcomes in this challenging population.

Usefulness of R.E.N.A.L. nephrometry scoring system for predicting outcomes and complications of percutaneous ablation of 751 renal tumors.

PURPOSE: We applied the R.E.N.A.L. (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior and location relative to polar lines) nephrometry scoring system to renal tumors treated with percutaneous ablation to determine whether this score is associated with oncological outcomes and complications. MATERIALS AND METHODS: A total of 751 renal tumors were treated at 679 percutaneous ablation sessions in 627 patients at our institution between 2000 and 2012. Of these renal masses 430 (57%) were treated with cryoablation and the remaining 321 were treated with radio frequency ablation. R.E.N.A.L. tumor scores were analyzed to determine the association of the score with ablation treatment outcomes and complications according to Clavien criteria. RESULTS: The mean ± SD R.E.N.A.L. nephrometry score of all ablated tumors was 6.7 ± 1.9. Those treated with cryoablation had higher scores than those treated with radio frequency ablation (mean 7.2 ± 1.9 vs 6.1 ± 1.8, p <0.001). We identified a total of 28 local treatment failures (3.7%) in the 751 tumors during a mean computerized tomography/magnetic resonance imaging followup of 27.9 ± 27.8 months. There was a significant association between R.E.N.A.L. nephrometry score and local treatment failure. Mean nephrometry score was 7.6 ± 2.2 vs 6.7 ± 1.9 for tumors with vs without local treatment failure (p <0.001). Of the 679 ablation treatments 38 (5.6%) major (grade 3 or greater) patient complications occurred. There was a significant association between R.E.N.A.L. nephrometry score and major complications. Patients with vs without a major complication had a mean nephrometry score of 8.1 ± 2.0 vs 6.8 ± 1.9 (p <0.001). CONCLUSIONS: The R.E.N.A.L. nephrometry scoring system predicts treatment efficacy and complications following percutaneous renal ablation.

Percutaneous cryoablation of musculoskeletal oligometastatic disease for complete remission.

PURPOSE: To assess the safety and effectiveness of percutaneous cryoablation to treat limited metastases to the musculoskeletal system, with the goal of complete disease remission. MATERIALS AND METHODS: In a single-institution retrospective study of data from December 2003 to October 2011, 43 consecutive patients underwent initial cryoablation of limited (five or fewer) musculoskeletal metastases with the goal of complete disease remission (ie, no clinical or radiographic evidence of disease). Three patients were lost to follow-up. As a result, the present report describes 40 patients who underwent 40 cryoablation procedures to treat 52 tumors. RESULTS: Local control was achieved in 45 of 52 tumors (87%; 95% confidence interval [CI], 75%-93%) at a median follow-up of 21 months (range, 4-62 mo). Thirteen of 19 treated bone metastases (68%) and 32 of 33 soft-tissue metastases (97%) showed local control (P = .007). One- and 2-year overall survival rates were 91% (95% CI, 75%-97%) and 84% (95% CI, 65%-93%), respectively. Median overall survival was 47 months (95% CI, 26-62 mo). One- and 2-year disease-free survival rates were 22% (95% CI, 11%-37%) and 7% (95% CI,<1% to 26%), respectively. Median disease-free survival was 7 months (95% CI, 5-10 mo). Two of 40 procedures (5%) were associated with major complications. CONCLUSIONS: Percutaneous cryoablation is a safe and effective treatment to achieve local tumor control and short-term complete disease remission in patients with limited metastatic disease to the musculoskeletal system.

Percutaneous ablation of renal masses measuring 3.0 cm and smaller: comparative local control and complications after radiofrequency ablation and cryoablation.

OBJECTIVE: The purpose of this article is to compare the efficacy and complication rates of percutaneous radiofrequency ablation (RFA) and cryoablation in the treatment of renal masses measuring 3.0 cm and smaller. MATERIALS AND METHODS: A retrospective review was performed of 385 patients with 445 tumors measuring 3.0 cm or smaller treated with thermal ablation from 2000 through 2010. Two hundred fifty-six tumors in 222 patients were treated with RFA (mean [± SD] tumor size, 1.9 ± 0.5 cm), and 189 tumors in 163 patients were treated with cryoablation (mean tumor size, 2.3 ± 0.5 cm). Major complications and efficacy as measured by technical success and local tumor recurrence rates were recorded. RESULTS: There were five (1.1%) technical failures, including one (0.4%) among tumors treated with RFA and four (2.1%) among tumors treated with cryoablation (p = 0.17). Of the 218 tumors treated with RFA and with follow-up beyond 3 months, seven (3.2%) developed local tumor recurrence, at a mean of 2.8 years after treatment (range, 1.2-4.1 years). Of the 145 tumors treated with cryoablation and with follow-up beyond 3 months, four (2.8%) developed local tumor recurrence at a mean of 0.9 years after treatment (range, 0.3-1.6 years). For biopsy-proven renal cell carcinoma, estimated local recurrence-free survival rates at 1, 3, and 5 years after RFA were 100%, 98.1%, and 98.1%, respectively, compared with 97.3%, 90.6%, and 90.6%, respectively, after cryoablation (p = 0.09). Major complications occurred after 4.3% (10/232) of RFAs and 4.5% (8/176) of cryoablation procedures (p = 0.91). CONCLUSION: RFA and cryoablation are both effective in the treatment of renal masses measuring 3 cm or smaller. Major complications with either procedure are infrequent.

Neuroanatomic considerations in percutaneous tumor ablation.

Percutaneous ablation is increasingly being used as focal therapy for tumors in the chest, abdomen, and pelvis, including tumors in proximity to neural structures. To ensure that tumor ablation is performed safely, knowledge of the regional neuroanatomy is particularly important because most relevant nerves are not visualized with the conventional imaging techniques used to guide ablation procedures. Familiarity with the expected course of nerves in commonly targeted areas is helpful in preventing inadvertent nerve injury and in accurately informing the patient of potential risks. In the chest and shoulder girdle, the brachial plexus as well as the phrenic, recurrent laryngeal, intercostal-subcostal, long thoracic, dorsal scapular, and suprascapular nerves may be encountered. Vulnerable neural structures in the abdomen and pelvis arise from the lumbar and sacral plexuses and include the femoral, obturator, sciatic, and pudendal nerves. Nerve protection and monitoring techniques should be used, when appropriate, to minimize the risk of neural injury during percutaneous tumor ablation and depend on the vulnerable nerve, the location of the targeted tumor, and the ablation device used for treatment. Nerves may be protected using displacement techniques, including instillation of air or fluid, insertion and insufflation of angioplastic or endoscopic balloons, and mechanical manipulation of the ablation device. Nerves may be monitored with cross-sectional imaging evaluation of the critical nerve or ablation zone, or with functional evaluation using electromyographic equipment or focused clinical examination. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg334125141/-/DC1.

A phase I oncolytic virus trial with vesicular stomatitis virus expressing human interferon beta and tyrosinase related protein 1 administered intratumorally and intravenously in uveal melanoma: safety, efficacy, and T cell responses.

Introduction: Metastatic uveal melanoma (MUM) has a poor prognosis and treatment options are limited. These patients do not typically experience durable responses to immune checkpoint inhibitors (ICIs). Oncolytic viruses (OV) represent a novel approach to immunotherapy for patients with MUM. Methods: We developed an OV with a Vesicular Stomatitis Virus (VSV) vector modified to express interferon-beta (IFN-ß) and Tyrosinase Related Protein 1 (TYRP1) (VSV-IFNß-TYRP1), and conducted a Phase 1 clinical trial with a 3 + 3 design in patients with MUM. VSV-IFNß-TYRP1 was injected into a liver metastasis, then administered on the same day as a single intravenous (IV) infusion. The primary objective was safety. Efficacy was a secondary objective. Results: 12 patients with previously treated MUM were enrolled. Median follow up was 19.1 months. 4 dose levels (DLs) were evaluated. One patient at DL4 experienced dose limiting toxicities (DLTs), including decreased platelet count (grade 3), increased aspartate aminotransferase (AST), and cytokine release syndrome (CRS). 4 patients had stable disease (SD) and 8 patients had progressive disease (PD). Interferon gamma (IFNγ) ELIspot data showed that more patients developed a T cell response to virus encoded TYRP1 at higher DLs, and a subset of patients also had a response to other melanoma antigens, including gp100, suggesting epitope spreading. 3 of the patients who responded to additional melanoma antigens were next treated with ICIs, and 2 of these patients experienced durable responses. Discussion: Our study found that VSV-IFNß -TYRP1 can be safely administered via intratumoral (IT) and IV routes in a previously treated population of patients with MUM. Although there were no clear objective radiographic responses to VSV-IFNß-TYRP1, dose-dependent immunogenicity to TYRP1 and other melanoma antigens was seen.

Percutaneous cryoablation of solitary sporadic renal cell carcinomas.

UNLABELLED: 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.

MR enterography in pediatric inflammatory bowel disease: retrospective assessment of patient tolerance, image quality, and initial performance estimates.

OBJECTIVE: The purpose of this article was to evaluate image quality, oral contrast administration and bowel distention, side effects, and performance estimates of MR enterography in a large cohort of pediatric patients with inflammatory bowel disease (IBD). MATERIALS AND METHODS: A retrospective analysis of the pediatric IBD clinic database (2007-2010) was performed. Eighty-five MR enterography studies in 70 patients were performed without sedation. All pediatric patients with the potential diagnosis of IBD were included, with the exception of studies performed on patients with ileoanal pouch anatomy. The quantity of ingested oral contrast material and number of adverse events were recorded. Retrospectively, image quality (including motion artifact and bowel distention) and enteric inflammation were assessed. Correlation between radiographic findings and endoscopic findings was tested by the Fisher exact test. RESULTS: Eighty-five MR enterography studies were performed without sedation in 70 patients (mean age, 15.6 years; age range, 9-18 years) over 30 months. The mean image quality for unenhanced images was significantly higher than for contrast-enhanced images (4.7 vs 4.1, p < 0.0001), with unacceptable image quality occurring on both unenhanced and contrast-enhanced sequences in one patient. The amount of oral contrast material ingested correlated with patient age (p = 0.009), with acceptable bowel distention occurring in 93% (78/85). Two patients had nausea or emesis and one experienced a syncopal episode after MR enterography. Sensitivity and specificity of MR enterography for active disease of the terminal ileum, right colon, and left colon were 80% and 85.2%, 79.1% and 77.8%, and 90.3% and 63.6%, respectively. CONCLUSION: MR enterography is feasible in patients 9 years old and older without sedation. Acceptable image quality can be achieved in nearly all patients, but a small minority will have suboptimal bowel distention or minor adverse events. Oral contrast ingestion regimes can be based on patient age. Performance estimates in children parallel reports in adults.

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 cryoablation of masses in a solitary kidney.

OBJECTIVE: The purpose of this study was to determine the effect of percutaneous cryoablation of tumors in a solitary kidney on renal function, treatment-related complications, and local tumor control. MATERIALS AND METHODS: A retrospective review of the cases of patients with a solitary kidney treated with percutaneous renal cryoablation from March 2003 through November 2008 was performed. Renal function was analyzed with serum creatinine concentration and glomerular filtration rate measured before ablation, on the first day after ablation, 3-6 months after ablation, and at the most recent evaluation on record at our institution. Index tumor size, ice ball size, and local tumor control were tabulated after review of preablation and postablation images. RESULTS: Thirty-one patients with 38 tumors (mean maximum diameter, 3.0 cm; range, 1.7-7.3 cm) were treated with 35 cryoablation procedures. After a mean follow-up period of 14 months (range, < 1-42 months), 29 patients had a 0.1-mg/dL median increase in creatinine concentration (p = 0.0089) and 4.7-mL/min/1.73 m(2) median decrease in glomerular filtration rate (p = 0.0335) from preablation levels. Fifteen of 25 patients with 3 months or more of renal function follow-up had a decrease in renal function. Ten of these 15 patients (67%) had a history of previous renal ablation or partial nephrectomy involving the same solitary kidney. No patient needed dialysis. Seven grade 3 or greater complications (Common Terminology Criteria for Adverse Events) occurred after the 35 procedures (20% complication rate). The median hospital stay was 1 day (range, 1-19 days). The local tumor control rate was 92%. CONCLUSION: Percutaneous cryoablation is effective in the management of renal tumors in patients with a solitary kidney, causing minimal loss of renal function. Patients who have previously undergone partial nephrectomy or ablation in a solitary kidney may be more susceptible to renal function loss than patients who have not undergone these procedures.