Adam J. Weisbrod

Comparison of partial nephrectomy and percutaneous ablation for cT1 renal masses.

BACKGROUND Partial nephrectomy (PN) is a preferred treatment for cT1 renal masses, whereas thermal ablation represents an alternative nephron-sparing option, albeit with higher reported rates of recurrence. OBJECTIVE To review our experience with PN, percutaneous radiofrequency ablation (RFA), and percutaneous cryoablation for cT1 renal masses. DESIGN, SETTING, AND PARTICIPANTS A total of 1803 patients with primary cT1N0M0 renal masses treated between 2000 and 2011 were identified from the prospectively maintained Mayo Clinic Renal Tumor Registry. INTERVENTION PN compared with percutaneous ablation. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Local recurrence-free, metastases-free, and overall survival rates were estimated using the Kaplan-Meier method and compared with log-rank tests. RESULTS AND LIMITATIONS Of the 1424 cT1a patients, 1057 underwent PN, 180 underwent RFA, and 187 underwent cryoablation. In this cohort, local recurrence-free survival was similar among the three treatments (p=0.49), whereas metastases-free survival was significantly better after PN (p=0.005) and cryoablation (p=0.021) when compared with RFA. Of the 379 cT1b patients, 326 patients underwent PN, and 53 patients were managed with cryoablation (8 RFA patients were excluded). In this cohort, local recurrence-free survival (p=0.81) and metastases-free survival (p=0.45) were similar between PN and cryoablation. In both the cT1a and cT1b groups, PN patients were significantly younger, with lower Charlson scores and had superior overall survival (p<0.001 for all). Limitations include retrospective review and selection bias. CONCLUSIONS In a large cohort of sporadic cT1 renal masses, we observed that recurrence-free survival was similar for PN and percutaneous ablation patients. Metastases-free survival was superior for PN and cryoablation patients when compared with RFA for cT1a patients. Overall survival was superior after PN, likely because of selection bias. If these results were validated, an update to clinical guidelines would be warranted. PATIENT SUMMARY Partial nephrectomy and percutaneous ablation for small (<7-cm) and localized renal masses are associated with similar rates of local recurrence.

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.

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 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.

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.

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 solitary sporadic renal cell carcinomas

Study Type – Therapy (case series)

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.

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.