Percutaneous Cryoablation of Plasmacytomas: Oncologic Effectiveness and Adverse Events.

PURPOSE: To evaluate the oncologic outcomes and adverse events associated with cryoablation of plasmacytomas. MATERIALS AND METHODS: Retrospective review of an institutional percutaneous ablation database showed that 43 patients underwent 46 percutaneous cryoablation procedures for treatment of 44 plasmacytomas between May 2004 and March 2021. The treatment of 25 (25 of 44, 56.8%) tumors was augmented with bone consolidation/cementoplasty. The median patient age was 64 years (interquartile range [IQR], 54-69), and 30 of 43 (69.8%) patients were men. The median maximum plasmacytoma diameter was 5.0 cm (IQR, 3.1-7.0). Thirty of 44 (68.2%) tumors were periacetabular, vertebral, or located in the iliac wing. Twenty-nine of 44 (65.9%) cryoablated plasmacytomas were recurrent tumors after prior external beam radiation therapy (EBRT). Survival analyses were performed using the Kaplan-Meier method. Adverse events were graded using Society of Interventional Radiology criteria. RESULTS: The 5-year estimated local tumor recurrence-free survival was 85.3% (95% CI, 74.1%-98.1%), the 5-year estimated new plasmacytoma-free survival was 49.9% (95% CI, 33.9%-73.4%), and the 5-year estimated overall survival was 70.4% (95% CI, 56.9%-87.1%). Nine of 46 (19.6%) major adverse events occurred in 8 patients, including 3 of 46 (6.5%) new or progressive pathologic fractures at the ablation site requiring surgical intervention, 3 of 46 (6.5%) nerve injuries, 1 of 46 (2.2%) avascular necrosis and femoral head collapse, 1 of 46 (2.2%) septic arthritis, and 1 of 46 (2.2%) acute renal failure caused by rhabdomyolysis. CONCLUSIONS: Percutaneous cryoablation is a viable treatment option for patients with plasmacytomas, including those with recurrent plasmacytomas after EBRT. Postcryoablation adverse events are relatively common.

Safety and Effectiveness of Transhepatic Access for Percutaneous Renal Mass Cryoablation: A Multicenter Cohort.

PURPOSE: To establish transhepatic percutaneous cryoablation of renal masses as a safe and effective approach. MATERIALS AND METHODS: A retrospective review of records from 3 separate medical centers was performed identifying 23 patients (median age, 63 years [range 41-84 years]; 12 female [52.2%]) who underwent percutaneous transhepatic cryoablation for right-sided renal masses (median diameter, 2.4 cm [1.5-4.6 cm]) between 2008 and 2021. The median radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines (RENAL) nephrometry score was 5 (4-10). Adverse events (AEs) were classified according to the Society of Interventional Radiology (SIR) and Clavien-Dindo (CD) classifications. Primary and secondary technical success of each procedure were recorded. RESULTS: Renal cell carcinoma (of any subtype) was found in 10 (71.5%) of the 14 masses that were biopsied. Tract cautery was used for transhepatic probes in 14 (63.6%) of 22 procedures. Three (13%) of 23 patients had postprocedural AEs. Two cases (8.6%) were hemorrhages related to transhepatic access (SIR moderate-2, CD 2; SIR severe-3, CD 1), and 1 case (4.4%) was related to bowel injury (SIR severe-3, CD 3a). There were no instances of pneumothorax. Tract cautery was used in the procedures that resulted in an AE. Primary technical success was achieved in 84.2% (16/19) of procedures, whereas secondary technical success was achieved in 2 additional patients. The secondary technical success rate was 94.7% (18/19). Four patients did not have imaging follow-up. CONCLUSIONS: The transhepatic approach to cryoablation of renal masses appears to have an acceptable safety profile and technical success rate. Larger studies, preferably comparative to nontranshepatic approach, are recommended.

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.

A Clinical Decision Aid to Support Personalized Treatment Selection for Patients with Clinical T1 Renal Masses: Results from a Multi-institutional Competing-risks Analysis.

BACKGROUND: Personalized treatment for clinical T1 renal cortical masses (RCMs) should take into account competing risks related to tumor and patient characteristics. OBJECTIVE: To develop treatment-specific prediction models for cancer-specific mortality (CSM), other-cause mortality (OCM), and 90-d Clavien grade ≥3 complications across radical nephrectomy (RN), partial nephrectomy (PN), thermal ablation (TA), and active surveillance (AS). DESIGN, SETTING, AND PARTICIPANTS: Pretreatment clinical and radiological features were collected for consecutive adult patients treated with initial RN, PN, TA, or AS for RCMs at four high-volume referral centers (2000-2019). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Prediction models used competing-risks regression for CSM and OCM and logistic regression for 90-d Clavien grade ≥3 complications. Performance was assessed using bootstrap validation. RESULTS AND LIMITATIONS: The cohort comprised 5300 patients treated with RN (n = 1277), PN (n = 2967), TA (n = 476), or AS (n = 580). Over median follow-up of 5.2 yr (interquartile range 2.5-8.7), there were 117 CSM, 607 OCM, and 198 complication events. The C index for the predictive models was 0.80 for CSM, 0.77 for OCM, and 0.64 for complications. Predictions from the fitted models are provided in an online calculator (https://small-renal-mass-risk-calculator.fredhutch.org). To illustrate, a hypothetical 74-yr-old male with a 4.5-cm RCM, body mass index of 32 kg/m2, estimated glomerular filtration rate of 50 ml/min, Eastern Cooperative Oncology Group performance status of 3, and Charlson comorbidity index of 3 has predicted 5-yr CSM of 2.9-5.6% across treatments, but 5-yr OCM of 29% and risk of 90-d Clavien grade 3-5 complications of 1.9% for RN, 5.8% for PN, and 3.6% for TA. Limitations include selection bias, heterogeneity in practice across treatment sites and the study time period, and lack of control for surgeon/hospital volume. CONCLUSIONS: We present a risk calculator incorporating pretreatment features to estimate treatment-specific competing risks of mortality and complications for use during shared decision-making and personalized treatment selection for RCMs. PATIENT SUMMARY: We present a risk calculator that generates personalized estimates of the risks of death from cancer or other causes and of complications for surgical, ablation, and surveillance treatment options for patients with stage 1 kidney tumors.

Safety and Efficacy of Percutaneous Image-Guided Mediastinal Mass Core-Needle Biopsy.

OBJECTIVE: To retrospectively evaluate the safety and efficacy of percutaneous image-guided mediastinal mass core-needle biopsy. PATIENTS AND METHODS: Retrospective review of an institutionally maintained biopsy registry identified 337 computed tomography- or ultrasound-guided percutaneous mediastinal mass core needle biopsies between October 2002 and August 2017 in a single quaternary referral center. Mean patient age was 51 (range, 18 to 93) years. Procedural techniques, anticoagulation/antiplatelet therapy, and tumor anatomical characteristics were reviewed. Classification and gradation of complications was based on the Clavien-Dindo system. Diagnostic yield was defined as the ratio of diagnostic biopsy to all biopsies performed. RESULTS: Mean tumor size was 59.2 (range, 10 to 180) mm with 89.9% (n=303) of lesions located in the prevascular (anterior) mediastinum. There was a single major complication (0.3%) of a symptomatic pneumothorax requiring intervention. There were seven (2.1%) minor complications, including three bleeding complications. A transpleural approach was the only variable associated with an increased complication rate (P<.01). Forty-one (12.2%) patients had a biopsy performed while taking an antiplatelet/anticoagulant agent within the therapeutic window, with a single case (0.3%) associated with a minor bleeding complication. Of 18 (5.3%) procedures performed without cessation of anticoagulant/antiplatelet therapy, there were no bleeding complications. Of all 337 biopsies, 322 (95.5%) were diagnostic. None of the analyzed variables were significantly associated with a nondiagnostic biopsy. CONCLUSION: Image-guided percutaneous core-needle biopsy of mediastinal masses is a safe procedure with high diagnostic yield. Further prospective studies are required to assess the complication profile in higher risk patients.

Safety and Efficacy of Retrograde Pyeloperfusion for Ureteral Protection during Renal Tumor Cryoablation.

PURPOSE: To determine safety and efficacy of retrograde pyeloperfusion for ureteral protection during cryoablation of adjacent renal tumors. MATERIALS AND METHODS: Retrospective review of 155 patients treated with renal cryoablation, including adjunctive retrograde pyeloperfusion, from 2005 to 2019 was performed. Ice contacted the ureter in 67 of the 155 patients who represented the study cohort. Median patient age was 68 years old (interquartile range [61, 74]), 52 patients (78%) were male, and 37 tumors (55%) were clear cell histology. Mean tumor size was 3.4 ± 1.3 cm, and 42 tumors (63%) were located at the lower pole. Treatment-related complication and oncologic outcomes were recorded based on a review of post-procedural images and chart review. RESULTS: Technical success of cryoablation was attained in 67 cases (100%), and technical success of pyeloperfusion was attained in 66 cases (99%). A total of 13 patients (19.4%) experienced SIR major C or D complications related to the procedure, including hemorrhage (n = 4), urine leak (n = 3), transient urinary obstruction (n = 2), pulmonary embolism (n = 1), hypertensive urgency (n = 1), acute respiratory failure (n = 1), and ureteropelvic junction (UPJ) stricture (n = 1). No complications were attributable to pyeloperfusion. Three of 45 patients with biopsy-proven renal cell carcinoma experienced local recurrence resulting in local recurrence-free survival of 92% (95% confidence interval, 81.5%-100%) 3 years after ablation. CONCLUSIONS: Retrograde pyeloperfusion of the renal collecting system is a relatively safe and efficacious option for ureteral protection during renal tumor cryoablation. This adjunctive procedure should be considered for patients in whom cryoablation of a renal mass could potentially involve the ureter.

Safety and Efficacy of Percutaneous Image-guided Cryoablation of Completely Endophytic Renal Masses.

OBJECTIVE: To evaluate the safety, efficacy, and oncologic control of percutaneous image-guided cryoablation in the treatment of completely endophytic renal masses. Percutaneous image-guided cryoablation is a minimally invasive and effective treatment for small renal masses. Image-guided cryoablation is an attractive treatment for completely endophytic tumors given the challenge in visualization of such lesions during surgical extirpation. MATERIALS AND METHODS: A retrospective study evaluating percutaneous cryoablation of completely endophytic renal masses with normal overlying renal cortex was performed. From January 2003 to December 2015, 200 endophytic renal masses (RENAL score 3 - endophytic/exophytic) were identified from an internal renal ablation database. After imaging review, 49 tumors with completely intact overlying renal cortex in 47 patients were included in the study. Outcomes, including complications and oncologic efficacy were evaluated according to standard nomenclature. RESULTS: Patients comprised 37 men and 10 women (mean age 64.0 years) who underwent 48 cryoablation procedures to treat 49 renal masses. Mean tumor size was 2.5 ± 0.5 cm. Major complications occurred following 5 of the 48 (10%) procedures. Forty of 46 (87%) tumors with imaging follow-up were recurrence-free at a mean of 56 months. Five of six local recurrences were successfully retreated with cryoablatoin. CONCLUSION: Percutaneous thermal ablation of completely endophytic renal masses is a relatively safe procedure associated with acceptable complication and local tumor control rates. Given the complexities associated with partial nephrectomy, percutaneous cryoablation may be considered an alternative treatment for these select patients. Long-term follow-up studies are necessary to determine the durable efficacy of this treatment.

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.

Frequency of Bleeding Complications After Percutaneous Core Needle Biopsy and the Association With Aspirin Usage and Length of Aspirin Discontinuation.

OBJECTIVE. The purpose of this study is to report the frequency of major bleeding after percutaneous image-guided core biopsy and its association with aspirin usage and duration of prebiopsy aspirin abstinence. MATERIALS AND METHODS. A retrospective review of percutaneous image-guided core biopsies performed at our institution between September 1, 2005, and September 1, 2016, was performed (n = 30,966). Patients were excluded if aspirin usage data were missing (n = 633). Bleeding complications were defined using the Common Terminology Criteria for Adverse Events and were considered significant if they were grade 3 or higher. Multivariate models were adjusted for age, sex, platelet count, international normalized ratio, and biopsy target. Three categorizations of aspirin use were examined: any use within 10 days before biopsy, duration of abstinence (> 10 days or no aspirin, 8-10 days, 4-7 days, and 0-3 days before biopsy), and use on the day of biopsy. Associations with bleeding complications were modeled using logistic regression models. A p < 0.05 was considered significant. RESULTS. The study included 30,333 biopsies in 21,938 subjects (57% male; median age, 60 years; interquartile range, 49-70 years). Of the biopsies, 7921 (26.1%) were performed in patients who received aspirin within 10 days of biopsy, and 3761 (47.5%) of those biopsies were performed in patients who took aspirin within 3 days. Ninety-eight (0.32%) significant bleeding complications occurred overall, including 34 (0.43%) in patients who used aspirin within 10 days before biopsy (odds ratio, 1.5; 95% CI, 0.96-2.3; p = 0.08). Duration of abstinence was associated with a significantly increased bleeding risk only between 0-3 days versus more than 10 days or no aspirin (odds ratio, 2.1; 95% CI, 1.3-3.6; p = 0.004). Aspirin use on the day of biopsy showed the greatest increase in risk (1.9%; odds ratio, 6.6; 95% CI, 3.8-11.5; p < 0.001). CONCLUSION. Significant bleeding complications after biopsy remain rare even among patients with recent aspirin usage, although shorter duration of prebiopsy abstinence increases bleeding risk, most significantly if aspirin is taken the day of biopsy.

Risk factors associated with significant bleeding events after ultrasound-guided percutaneous native renal biopsies: a review of 2204 cases.

OBJECTIVE: To review the incidence of significant bleeding complications after ultrasound-guided percutaneous core native renal biopsies at a single center using a standardized technique. MATERIALS AND METHODS: A retrospective review of ultrasound (US)-guided percutaneous native renal core biopsies done at our institution from September 2005 to December 2015 was performed. Demographic and clinical data were collected at the time of biopsy, with additional clinical information recorded 24 h and 3 months after the biopsy. Bleeding complications were defined using the Common Terminology Criteria for Adverse Events (CTCAE, version 4.0) created by the National Institutes of Health. RESULTS: 2204 US-guided native renal core biopsies were performed during the study period, with 37 hemorrhages (1.64%) that were CTCAE grade 3 or higher. The rate of inadequate sampling as reported by pathology was extremely low (1.1%). Factors demonstrating a significant association with bleeding risk included estimated glomerular filtration rate (eGFR), specifically when the eGFR was less than 60 (p = 0.025), platelet count (p = 0.002), including a statistically significant decreased risk of bleeding with a platelet count greater than 100 (109/L) (p = <0.001), and performing four or more needle passes (p = 0.012). While female gender was also associated with an increased bleeding risk (p = 0.05), there was a significant association between females with a BMI ≥ 25 and a decreased bleeding risk (0.034). No statistically significant association between post-biopsy hemorrhage and aspirin use within 10 days prior to biopsy or a prior diagnosis of amyloidosis was demonstrated. CONCLUSION: US-guided native renal biopsy is a safe procedure with a low rate of significant bleeding complications and a high tissue adequacy rate using an 18-gage spring-loaded biopsy device. Factors associated with increased bleeding risk include female gender, lower platelet counts, decreased eGFR and performing four or more needle passes, which has not been reported previously. Interestingly, females with a BMI ≥ to 25 demonstrated a decreased bleeding risk, and aspirin (81 mg or 325 mg) within 10 days of the procedure did not demonstrate a significant effect. While not shown in this current study, the relationship of very recent aspirin therapy with bleeding is yet to be defined. Similarly, the statistically significant decreased risk of bleeding complications in overweight or obese females requires further investigation.

Patient-Reported Outcomes After Percutaneous Renal Ablation: Initial Experience.

OBJECTIVE: The purpose of this study is to assess patient-reported outcomes after renal tumor ablation. MATERIALS AND METHODS: A retrospective review of a pilot quality initiative from February 2016 to April 2016 in our renal ablation practice was performed to assess outcomes after treatment. This included a total of 38 patients (mean age, 63 years; range, 39-83 years) undergoing renal ablation procedures. This pilot included the quantification of recovery, pain, physical well-being, interference with social activities, and physical function as reported by the patient, including measures obtained from the National Institutes of Health's Patient-Reported Outcome Measurement Information System (PROMIS). Such measures were obtained within 24 hours before ablation and days 1-7 and 30 after ablation. RESULTS: The mean numeric rating (0-10) pain scores at 1 and 2 days after treatment were 1.8 (SD, 2.3) and 2.6 (SD, 2.5). Similarly, mean scores for both overall physical well-being and social activities declined by less than 2 points in the days after ablation. PROMIS scales for physical function and social activities showed very little change from baseline. Nearly 50% of patients thought that they had completely recovered from the ablation on the day after treatment; this perception of recovery declined at days 3-5 and then increased to 89% at 30 days after ablation. CONCLUSION: This pilot study shows the feasibility of capturing patient-reported outcomes after renal ablation. Such information, particularly when collected from a broader patient population, will be valuable in providing a means to measure quality in the ablation practice and in improving patient education regarding treatment.

Effectiveness and Safety of Percutaneous CT-Guided Rib Biopsy.

PURPOSE: To retrospectively evaluate effectiveness and safety of percutaneous CT-guided rib biopsy. MATERIALS AND METHODS: CT-guided core rib biopsies were performed in 249 consecutive patients between January 2002 and June 2016. Mean patient age was 64.8 years ± 13.8. Additional patient demographics, rib lesion characteristics, and procedural techniques were reviewed. Diagnostic yield was assessed, and complications were classified using SIR criteria. RESULTS: Mean maximal diameter of 249 rib lesions was 2.7 cm ± 1.8, and 107 (43%) rib lesions had an associated extraosseous soft tissue component. Of rib lesions, 172 (69%) were lytic, 75 (30%) were sclerotic, and 2 (1%) were identifiable only with positron emission tomography/CT correlation. Specimens from 241 (96.8%) biopsies were adequate for pathologic diagnosis, whereas 8 (3.2%) were nondiagnostic. Of diagnostic biopsies, 168 (69.7%) were positive for malignancy; 73 (30.3%) revealed benign etiologies. There was a significant difference in diagnostic biopsy rate depending on size of the rib lesion (mean 2.8 cm ± 1.8 for diagnostic biopsies vs mean 1.3 cm ± 0.5 for nondiagnostic biopsies; P = .007). Of rib lesions, 170 (99%) lytic lesions and 69 (92%) sclerotic lesions yielded diagnostic biopsies; diagnostic biopsy rate was significantly higher for lytic lesions than sclerotic lesions (P = .01). There were 14 (5.6%) minor complications and no major complications. CONCLUSIONS: Percutaneous CT-guided core rib biopsy resulted in high diagnostic yield and low complications. Diagnostic biopsy rates were higher with larger lesion size and lytic rib lesions.

Impact of a 3D printed model on patients' understanding of renal cryoablation: a prospective pilot study.

PURPOSE: To determine whether a 3D printed model improves patients' understanding of renal cryoablation and the involved anatomy. METHODS: This prospective study included 25 control patients, who received standard of care renal cryoablation education (verbal explanation accompanied by review of relevant 2D imaging) and 25 experimental patients, who received education using a 3D printed renal cryoablation model in addition to standard of care. Subsequent patient surveys included 5 anatomy and 5 procedural knowledge questions. The experimental cohort also subjectively graded the importance of the 3D model for understanding the renal cryoablation procedure and associated anatomy. RESULTS: Mean percent of anatomy questions answered correctly was significantly higher in the experimental cohort than that in the control group (87.2% vs. 72.8%; p = 0.007). After adjusting for the physician providing the education, however, the 3D model was no longer significantly associated with patient anatomy knowledge (p = 0.22). Mean percent of procedure-related questions answered correctly was higher in the experimental cohort (93.6%) than that in the control group (89.6%) (p = 0.16). The experimental cohort graded the importance of the 3D model for understanding their renal tumor anatomy and upcoming procedure to be very high (mean 9.4 and 9.5, respectively, on a 0-10 point scale). Twenty-three (92%) patients "definitely recommended" continued use of the 3D model as a patient educational tool. CONCLUSIONS: Although patients' objective anatomy and procedural knowledge was not significantly improved with the 3D renal cryoablation model in this small pilot study, patients' high perceived value of the model supports investigation in a larger study.

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.

Palliative Percutaneous Cryoablation and Cementoplasty of Acetabular Metastases: Factors Affecting Pain Control and Fracture Risk.

PURPOSE: To characterize the response of patients with acetabular metastases following combined cryoablation and cementoplasty (CCC) for pain palliation and fracture risk reduction, based on completeness of ablation and the presence of pre-existing pathologic fracture. MATERIALS AND METHODS: Thirty-nine consecutive acetabular CCC procedures were performed in 37 patients (24 M:13F, age 66 ± 8 years). Pain was assessed using a 0-10 numeric rating scale. Development of new or progression of pre-existing fractures and local tumor progression (LTP) were determined on follow-up imaging. Pain score reduction and fracture development rates were compared by ablation completeness and the presence of pre-existing fractures. RESULTS: Twenty-three of 27 (85%) patients with evaluable pain scores had reduced pain, decreasing from 7.5 ± 2.1 to 3.6 ± 2.6 (p < 0.0001). Of 39 tumors, 28 (72%) were completely ablated with no significant difference in pain reduction after complete versus incomplete ablations (p = 0.9387). Six of 30 (20%) patients with follow-up imaging demonstrated new/progressive acetabular fractures. Four of 5 (80%) patients with LTP developed new/progressive fractures compared to 2 of 25 (8%) without tumor progression (p = 0.0003). Pre-existing fracture was not associated with subsequent fracture/fracture progression (p = 0.2986). However, patients with prior acetabular radiation therapy or surgery had increased fractures following treatment (p = 0.0380). CONCLUSION: Complete acetabular tumor ablation during CCC was not associated with superior pain relief compared to subtotal ablation but did result in improved fracture stabilization. Pre-treatment pathologic fractures were not associated with fracture progression, but new/progressive fractures were more frequent in patients with prior radiation therapy or surgery.

Percutaneous Cryoablation of Solitary, Sporadic Renal Cell Carcinoma: Outcome Analysis Based on Clear-Cell versus Papillary Subtypes.

PURPOSE: To evaluate treatment outcomes with percutaneous cryoablation (PCA) based on renal cell carcinoma (RCC) histology. METHODS AND MATERIALS: Patients treated with PCA for a solitary, sporadic stage T1a RCC from 2003 to 2016 were identified from a single institution's renal ablation registry. Patients with multiple tumors, history of RCC, or genetic syndromes associated with RCC (n = 60); no specific RCC subtype determined from core biopsy (n = 66); RCC subtype other than clear-cell or papillary (n = 7); or less than 3 mo of follow-up imaging (n = 5) were excluded. In total, 173 patients met study inclusion criteria. Oncologic outcomes, clinical outcomes, and complications were evaluated based on tumor subtype. RESULTS: Of the 173 patients who underwent PCA for a stage T1a RCC, 130 (75%) had clear-cell RCC (ccRCC) and 43 (25%) had papillary RCC (pRCC). Median tumor size was 2.9 cm (range, 1.3-4.0 cm). Technically successful cryoablation was achieved in all 173 patients. Local tumor recurrence developed in 6 patients with ccRCC (4.6%), new renal tumors developed in 1 patient (0.8%), and metastatic RCC developed in 1 patient (0.8%) who also had local tumor recurrence. No patients with pRCC showed local tumor recurrence, new renal tumors, or metastatic disease. The 5-year disease-free survival rate in patients with ccRCC was 88%, compared with 100% in patients with pRCC (P = .48). Nine patients (5.2%), all with ccRCC, experienced major complications (P = .11). CONCLUSIONS: Percutaneous ablation is a viable treatment option for patients with clinical stage T1a pRCC and ccRCC. Percutaneous ablation may be a very favorable treatment strategy particularly for pRCC.

Thermal ablation of intrahepatic cholangiocarcinoma: Safety, efficacy, and factors affecting local tumor progression.

PURPOSE: To evaluate the safety and oncologic efficacy of percutaneous thermal ablation of intrahepatic cholangiocarcinoma (ICC) and identify risk factors for local tumor progression (LTP). MATERIALS AND METHODS: Retrospective review of an institutional tumor ablation registry demonstrated that 20 patients (9 males, 11 females; mean age 62.5 ± 15.8 years) with 50 ICCs (mean size 1.8 ± 1.3 cm) were treated with percutaneous radiofrequency ablation (RFA) or microwave ablation (MWA) between 2006 and 2015. Thirty-eight of the treated ICCs (76%) were metastases that developed after surgical resection of the primary tumor. Patient demographics, procedure technical parameters, and clinical outcomes were reviewed. A Cox proportional hazards model was used to examine the risk of LTP by ablation modality. Survival analyses were performed using the Kaplan-Meier method. RESULTS: Mean imaging follow-up time was 41.5 ± 42.7 months. Forty-four (88%) ICCs were treated with RFA, and 6 (12%) with MWA. Eleven (22%) cases of LTP developed in 5 (25%) patients. The median time to LTP among these 11 tumors was 7.1 months (range, 2.3-22.9 months). Risk of LTP was not significantly different for ICCs treated with MWA compared to RFA (HR 2.72; 95% CI 0.58-12.84; p = 03.21). Median disease-free survival was 8.2 months (1.1-70.4 months), and median overall survival was 23.6 months (7.4-122.5 months). No major complication occurred. CONCLUSIONS: Percutaneous thermal ablation is a safe and effective treatment for patients with ICCs and may be particularly valuable in unresectable patients, or those who have already undergone hepatic surgery. Tumor size and ablation modality were not associated with LTP, whereas primary tumors and superficially located tumors were more likely to subsequently recur.

Synchronous nephron-sparing approaches for bilateral renal masses: peri-operative and renal functional outcomes.

OBJECTIVES: To evaluate the peri-operative and renal functional outcomes of patients undergoing synchronous bilateral partial nephrectomy (PN) or percutaneous cryoablation (PCA). PATIENTS AND METHODS: We retrospectively reviewed our institutional nephrectomy and renal mass ablation registries to identify all patients with synchronous bilateral renal masses who underwent simultaneous bilateral PN (n = 76) or PCA (n = 13) between 1974 and 2013. Changes in estimated glomerular filtration rate (eGFR) as well as peri-operative complications are descriptively reported for each procedure. RESULTS: The number of treated renal masses in the 76 patients in the PN group and the 13 patients in the PCA group was 249 and 28, respectively. The median (interquartile range [IQR]) age at treatment was 62 (50, 71) years for the PN group and 67 (56, 72) for the PCA group. The median (IQR) maximum tumour sizes were 4.6 (3.4, 6.5) cm and 2.6 (2.4, 3.2) cm for the PN and PCA groups, respectively. The median (IQR) length of hospital stay was 7 (5, 8) days for the PN group and 1 (1, 10) days for the PCA group. The median (IQR) change in eGFR from baseline to discharge was -32 (-46, -15)% for the PN group and -17% (-33, -3) for the PCA group. By 3 months, median (IQR) renal function improved, with changes of -9 (-19, 0)% and -8 (-11, 15)%, respectively, compared with baseline. No patient in either group required renal replacement therapy in the peri-operative period. Early postoperative complications (within 30 days) occurred in 16 patients (21.6%) in the PN and four patients in the PCA group. In particular, angioembolization for bleeding was required in the postoperative period in two patients (2.7%) in the PN and one patient in the PCA group. CONCLUSIONS: Our experience suggests that synchronous bilateral PN or PCA are feasible treatment options for select patients presenting with bilateral renal masses. In select cases, both approaches appear to have reasonable rates of peri-operative complications and effects on renal function.

Imaging following renal ablation: what can we learn from recurrent tumors?

PURPOSE: The purpose of the study was to evaluate the post-contrast appearance of local tumor progression (LTP) following renal ablation to better understand patterns of tumor recurrence and to optimize follow-up imaging protocols. METHODS: From 2002 to 2015, 913 patients underwent 988 renal ablation procedures for treatment of 1064 tumors. LTP was identified in 24 (2.6%) patients during median imaging follow-up of 30 months (range 0-139). One patient with LTP was followed with non-contrast MRI only and was excluded from evaluation. Three body radiologists reviewed the contrast-enhanced CT and/or MRI follow-up imaging in the remaining 23 patients to determine the timing and imaging appearance of the recurrent tumor. RESULTS: Local tumor progression was identified on contrast-enhanced CT or MRI at median 11 months (range 1 and 68) after renal ablation. Corticomedullary phase imaging was performed in 16/23 (70%) patients. LTP was identified on the corticomedullary phase in all cases, and was most conspicuous on the corticomedullary phase compared to any other phase of imaging in 15/16 (94%) patients. No cases of LTP were best visualized on non-contrast or excretory phase images. CONCLUSIONS: Delayed recurrence following renal ablation is possible; therefore, extended follow-up is indicated in ablation patients. Almost all cases of LTP were best visualized on the corticomedullary phase of imaging, which should be included in any post-ablation imaging protocol. Excretory phase images were not required to diagnose LTP in any case and could be excluded from routine post-ablation follow-up.

A Comparison of Bleeding Complications in Patients Undergoing Percutaneous Renal Cryoablation Using Cryoprobes with and without Heat-Based Track Ablation.

PURPOSE: To determine if the use of heat-based track ablation with new-generation cryoprobes is associated with decreased renal cryoablation bleeding complications. MATERIALS AND METHODS: Eighty-nine patients who underwent percutaneous cryoablation for treatment of a solitary renal mass with the use of cryoprobes with track ablation (CwTA) from October 29, 2015, to May 18, 2017, were compared with a propensity score-matched control group of 178 patients who underwent treatment with the use of cryoprobes without track ablation (Cw/oTA) from January 5, 2012, to October 28, 2015. Bleeding complications were assessed with the use of the Clavien-Dindo classification system and compared between the matched patient groups by means of conditional logistic regression, both univariately and in a multivariate model to adjust for imbalanced covariates. Change in patient hemoglobin was evaluated as a secondary measure of periprocedural bleeding. RESULTS: Seven of the 89 patients (7.9%) who underwent percutaneous renal cryoablation with the use of CwTA developed major (grade ≥3) bleeding complications, versus 13 of the 178 patients (7.3%) treated with the use of Cw/oTA. Conditional logistic regression analysis adjusted for potential confounders showed that major, minor, and overall bleeding complications were not associated with the type of cryoprobes used for treatment (P values .727, .370, and .733, respectively). There was also no significant difference in postprocedural change in hemoglobin for patients treated with the use of CwTA compared with Cw/oTA (P = .909). Furthermore, total duration of track ablation in patients with bleeding complications (mean 169 seconds, SD 68, range 60-240) was not significantly different than in patients without bleeding complications (mean 171 seconds, SD 86, range 30-360; P = .940). CONCLUSIONS: The use of cryoprobes with heat-based track ablation did not decrease the incidence of bleeding complications after renal cryoablation compared with procedures performed without track ablation.