Safety of percutaneous renal cryoablation: an international multicentre experience from the EuRECA retrospective percutaneous database

Cryoablation-induced modulation of Treg cells and the TGF-β pathway in lung adenocarcinoma: implications for increased antitumor immunity

BACKGROUND

Cryoablation plays a key role in the comprehensive management of lung adenocarcinoma, characterized by its ability to activate antitumor immunity. This study aimed to explore the impact of cryoablation on the local immune microenvironment, focusing on regulatory T cells (Tregs) and the TGF-β pathway.

METHODS

Single-cell sequencing was employed to identify differences in immune cell populations and related pathway expression between lung adenocarcinoma tissues and adjacent noncancerous tissues. Prospective observations of changes in Tregs in the peripheral blood pre- and post-cryoablation for lung adenocarcinoma were conducted at Dongfang Hospital, Beijing University of Chinese Medicine. Bulk RNA-seq analysis of mouse tumor tissues was performed to predict the potential mechanisms underlying cryoablation-induced antitumor immunity. Finally, these predictions were validated through in vitro and in vivo experiments employing cell cryoablation and mouse subcutaneous tumor transplantation models.

RESULTS

Single-cell RNA sequencing analysis revealed intricate interactions between Tregs subpopulations and the regulation of the immune response in lung adenocarcinoma, highlighting the involvement of the TGF-β pathway. A significant decrease in the level of Tregs was noted at 30 days post-cryoablation compared to pre-surgical and 3-day post-surgery levels. The cellular and murine cryoablation models validated the inhibitory effect of cryoablation on Tregs and its potential to stimulate antitumor immunity. Additionally, the results of bulk RNA-seq demonstrated the role of cryoablation in regulating postoperative immunity via the TGF-β pathway. Cryoablation decreased the expression levels of TGF-β1, suppressed the phosphorylation of Smad2 and Smad3, and downregulated the expression of FOXP3, thereby inhibiting the conversion of CD4 + T cell precursors into Tregs. Moreover, cryoablation enhanced the expression of interferon-gamma (IFN-γ), thereby promoting its antitumor activity.

CONCLUSIONS

This study revealed the effective modification of the lung adenocarcinoma microenvironment by cryoablation through the suppression of Tregs and activation of antitumor immunity via the TGF-β pathway. These findings hold implications for optimizing cryoablation-based therapies and guiding future clinical trials on lung adenocarcinoma treatment.

TRIAL REGISTRATION

This trial was registered with the Chinese Clinical Trial Registry (Chictr.org.cn, ChiCTR2000038580, Sep 24, 2020).

Including the Hollow Viscera (Stomach or Bowel) within the Ice Ball during Cryoablation: A Review of Adverse Events

PURPOSE

To evaluate the safety of including hollow viscus (stomach or bowel) in the ice ball during cryoablation.

MATERIALS AND METHODS

Forty-three patients who underwent 50 cryoablations between January 1, 2012, and February 1, 2023, were retrospectively reviewed and compared with a control cohort of those who underwent cryoablation without hollow visceral involvement (n = 86). Adverse events (AEs) were stratified by the Society of Interventional Radiology (SIR) AE classification system, 2017. AEs occurring within 12 months and factors that may affect the AE rate, such as degree of hollow visceral involvement and segment of gastrointestinal tract involved, were reviewed.

RESULTS

Fourteen AEs occurred in 13 patients (13/43, 30.2%). This included 7 Grade 1 (7/43, 16.3%), 3 Grade 2 (3/43, 7.0%), and 4 Grade 3 (4/43, 9.3%) AEs. Of them, 1 Grade 3 AE was judged to be related to bowel involvement (1/43, 2.3%). When comparing AEs by degree of visceral wall involvement, there were more injuries with the full-thickness visceral wall cases (6/9, 66.7%) than with partial-thickness visceral wall cases, but the findings were not statistically significant (P = .140). When investigating AEs by segment of the gastrointestinal tract involved, 7 (7/14, 50%), 10 (10/17, 58.8%), and 4 (4/19, 21.1%, P = .055) were found when the stomach, small bowel, and large bowel were involved, respectively. No significant differences in AEs (13/43, 30.2%, vs 31/86, 36%; P = .511) or severe AEs (4/43, 9.3%, vs 9/86, 10.5%; P = .836) were found between the study and control cohorts.

CONCLUSIONS

Findings from this single-center retrospective experience suggest that hollow visceral wall involvement by the ice ball during cryoablation resulted in a lower-than-expected rate of AEs for bowel-related injuries.

Profile and methodology of ancillary protective measures employed during percutaneous renal cryoablation in a single high-volume centre

OBJECTIVES

To evaluate the at-risk organs that require protection during percutaneous cryoablation (PCA) of renal tumours and the correlation with patient and target lesion characteristics, type of protective measure used and postoperative outcomes.

MATERIALS AND METHODS

Single-centre retrospective review of patients with renal tumours who underwent PCA between 2008 and 2020. Final analysis included 374 tumours. Patient, tumour, and procedure technical details were extracted and analysed. At-risk organs were classified according to tumour location relative to kidney side, pyelic axis, and polar lines.

RESULTS

There were 171 (46.0%) tumours in the left kidney, and 194 (52.0%) in the right. Cryoprotection was required for 272 (272/374; 73.0%) tumours, with hydrodissection (216/374; 58.0%) being the most common technique. Protective measures were used for 82 (82/93; 88.0%) tumours in under/normal-weight patients and 143 (143/196; 73.0%) in overweight/obese ones (P = 0.004). In the left kidney, colon was the most common at-risk organ (63/171; 37.0%), followed by spleen (21/171; 12.3%), small bowel (21/171; 12.3%), ureter (19/171; 11.1%), abdominal wall (15/171; 8.8%), psoas muscle (10/171; 5.8%), and pancreas (9/171; 5.3%). In the right kidney, common at-risk organs were the colon (67/194; 35.0%), liver (50/194; 25.7%), ureter (15/194; 15.5%), diaphragm (16/194; 8.2%), abdominal wall (14/194; 7.2%), and duodenum (12/194; 6.1%). No cryoinjuries to at-risk organs occurred.

CONCLUSION

Hydrodissection is the most common cryoprotective measure used for renal tumour PCA. Under/normal-weight patients are more likely to require cryoprotection. The colon is the most common adjacent at-risk organ requiring protection for both right- and left-sided tumours.

Single-Probe Percutaneous Cryoablation with Liquid Nitrogen for the Treatment of T1a Renal Tumors

Kidney cancer accounts for 3% of adult malignancies and is increasingly detected through advanced imaging techniques, highlighting the need for effective treatment strategies. This retrospective study assessed the safety and efficacy of a new single-probe percutaneous cryoablation system using liquid nitrogen for treating T1a renal cancers. From May 2019 to May 2022, 25 consecutive patients from two academic hospitals, with a median age of 64.8 years [IQR 59; 75.5], underwent cryoablation for 26 T1a renal tumors. These tumors had a median size of 25.3 mm [20; 30.7] and a median RENAL nephrometry score, indicating tumor complexity, of 7 [5; 9]. No major complications arose, but three non-clinically relevant perirenal hematomas were detected on post-procedure CT scans. With a median follow-up of 795 days [573; 1020], the primary local control rate at one month stood was 80.8% (21 out of 26). The five recurrent lesions, which exhibited a higher renal score (p = 0.016), were treated again using cryoablation, achieving a secondary local control rate of 100%. No patient died, and the disease-free survival rate was 92% (23 out of 25). In conclusion, single-probe percutaneous cryoablation emerges as a promising modality for managing small renal masses. Notably, recurrence rates appear influenced by RENAL nephrometry scores, suggesting a need for further research to refine the technique.

MRI- Versus CT-Guided Renal Tumor Cryoablation: Is There a Difference?

PURPOSE

To compare procedure-related variables, safety, renal function, and oncologic outcomes in patients undergoing percutaneous cryoablation (CA) of renal tumors with MRI- or CT-guidance.

MATERIALS AND METHODS

Patient, tumour, procedure, and follow-up data were collected and analysed. MRI and CT groups were matched using a coarsened exact approach according to patient's gender and age, tumour grade, size and location. P < 0.05 was considered statistically significant.

RESULTS

Two-hundred fifty-three patients (266 tumors) were retrospectively selected. Following the coarsened exact matching 46 patients (46 tumors) in the MRI group and 42 patients (42 tumors) in the CT group were matched. There were no significant baseline differences between the two populations except for the duration of follow-up (P = 0.002) and renal function (P = 0.002). On average MRI-guided CA lasted 21 min longer than CT-guided ones (P = 0.005). Following CA, complication rates (6.5% for MRI vs 14.3% for CT; P = 0.30) and GFR decline (mean - 13.1 ± 15.8%; range - 64.5-15.0 for MRI; mean - 8.1 ± 14.8%; range - 52.5-20.4; for CT; P = 0.13) were similar in both groups. The 5-year local progression-free, cancer-specific and overall survivals in the MRI and CT groups were 94.0% (95% CI 86.3%-100.0%) and 90.8% (95% CI 81.3%-100.0%; P = 0.55), 100.0% (95% CI 100.0%-100.0%) and 100.0% (95% CI 100.0%-100.0%; P = 1), and 83.7% (95% CI 64.0%-100.0%) and 76.2% (95% CI 62.0%-93.6%; P = 0.41), respectively.

CONCLUSIONS

Apart from increased procedural times associated with MRI-guided CA of renal tumors compared to CT-guidance, both modalities demonstrate similar safety, GFR decline and oncologic outcomes.

Feasibility and Safety of Single-Probe Cryoablation with Liquid Nitrogen: An Initial Experience in 24 Various Tumor Lesions

Simple Summary

Percutaneous cryoablation was developed to minimally perform multi-organ tumor ablations. The most widely known cryotherapy systems use argon gas (high-pressure) and multiple needles to achieve sufficient ablations. The aim of our retrospective study was to assess the feasibility of a new cryotherapy system using single-probe liquid nitrogen for tumor lesions of various sizes and locations, and to evaluate the safety of cryoablation with this technique. Correlations between ice ball sizes and ablation zone sizes with two needle sizes (10G or 13G) and with the freezing duration were evaluated, as well as the sphericity of the ice ball and ablation zones. We showed that this technique is safe in all organs tested. We showed a correlation between the freezing duration and the ice ball size, but not with the ablation zone, which is useful for planning the procedure and treatment conducted by the oncology team.

Abstract

Background: Percutaneous cryoablation with liquid nitrogen is a new technique being used in the treatment of some malignant tumors. Our objective was to assess its feasibility in the ablation of tumor lesions of various sizes and locations. Methods: This retrospective, monocentric study included all consecutive patients who underwent percutaneous cryoablation with liquid nitrogen between December 2019 and March 2021. Cryoablation was performed using 10G or 13G cryoprobes. The ablation volume was measured on post-treatment CT or MRI. Results: 22 patients (24 lesions) were included, 16 of whom were men (73%), while median age was 66 years. The lesions were located in the bone (42%), kidney (29%), soft tissue (17%), lung (8%), or liver (4%). It was feasible in all tumor locations and produced median ablation zones 25 mm in width and 35 mm in length, with a 23 min median freezing time. Freezing duration was correlated with the ice volume (p Spearman = 0.02), but not with the ablation volume (p = 0.11). The average difference between the ablation zone and ice ball sizes were −6.4 mm in width and −7.7 mm in length. Both ice and ablation volumes were larger when using the 10G probe as compared to when the 13G was used. No complications were reported. Discussion: We showed that this technique was safe and feasible in all organs tested. The freezing duration was correlated with the ice ball size, but not with the ablation zone.

Percutaneous cryoablation for desmoid fibromatosis: initial experience at a UK centre

AIM

To report the first UK experience of cryoablation in desmoid fibromatosis (DF) with particular focus on technique, safety, and efficacy.

MATERIALS AND METHODS

Patients were selected at multidisciplinary tumour board meetings at a specialist cancer hospital. Radiation dose, procedure duration, and number of cryoprobes were compared for small versus large tumours (>10 cm long axis). Response at magnetic resonance imaging (MRI) was evaluated using different criteria, and percentage agreement with clinical response as assessed in oncology clinic calculated.

RESULTS

Thirteen procedures were performed in 10 patients (eight women, median age 51 years, IQR 42-69 years) between February 2019 and August 2021. Procedures for large tumours had higher radiation dose (2,012 ± 1,012 versus 1,076 ± 519 mGy·cm, p=0.048) used more cryoprobes (13 ± 7 versus 4 ± 2, p=0.009), and were more likely to have residual unablated tumour (38 ± 37% versus 7.5 ± 10%, p=0.045). Adverse events were minor apart from one transient radial nerve palsy. Eight of 10 patients had symptomatic benefit at clinical follow-up (median 353 days, IQR 86-796 days), and three started systemic therapy mean 393 days later. All patients who had complete ablation demonstrated symptomatic response, with no instances of repeat treatment, recurrence, or need for systemic therapy during the study period. All progression occurred outside ablation zones.

CONCLUSION

Cryoablation for symptomatic DF is a reproducible technique with low, transient toxicity, where one or two treatments can achieve a meaningful response. Where possible, the ablation ice ball should fully cover DF tumours.

Safety and Oncologic Outcomes of Percutaneous Cryoablation of Renal Cell Carcinoma Recurrences in the Ipsilateral Kidney Following Partial Nephrectomy

PURPOSE

To retrospectively investigate the safety and oncological outcomes of cryoablation performed on residual/recurring renal cell carcinoma (RCC) in the ipsilateral kidney following partial nephrectomy (PN).

MATERIALS AND METHODS

Data dealing with patients', RCC, procedure (including the length of the hospital stay), and follow-up (technical efficacy [TE], local tumor progression-free survival [LTPFS], disease-free survival [DFS], metastasis-free survival [MFS], cancer-specific survival (CSS), and overall survival [OS]) were retrospectively collected and analyzed.

RESULTS

Between January 2008 and November 2020, 21 consecutive patients (17 [81%] men; 4 [19%] women; median age 68 years; range 43-82) underwent cryoablation due to residual/recurring RCC in the PN site (15 patients) or de-novo RCC (6 patients) in the ipsilateral kidney. Median tumor size was 2.2 cm (mean 2.3 cm; range 0.8-4; interquartile range [IQR] 1.9-3). There were two (2/21; 10%) minor self-limiting hemorrhagic complications, both occurring in the group of patients with RCC in the PN site. Median hospital stay was 2 days (mean 2.1; range 1-5; IQR 2-2). TE was 100% (21/21 patients), and 10-year estimates of LTPFS, MFS and DFS were 74.1% (95% confidence intervals [CI] 56.8-96.7%), 36.4% (95% CI 14.2-93.8%), and 43.5% (95% CI 21.9-86.4%), respectively. CSS and OS were 100% at the last available follow-up (median 56 months; mean 67.4; range: 12-147; IQR:34-95).

CONCLUSION

Cryoablation in patients with residual/recurring RCC following PN is safe and results in high 10-year estimates of LTPFS.

Selective Arterial Embolization with N-Butyl Cyanoacrylate Prior to CT-Guided Percutaneous Cryoablation of Kidney Malignancies: A Single-Center Experience

The study’s purpose was to assess the safety, feasibility and efficiency of selective arterial embolization (SAE) using N-butyl cyanoacrylate (NBCA) glue before percutaneous cryoablation (PCA) of renal malignancies in patients whose tumor characteristics and/or comorbidities resulted in an unacceptable risk of bleeding. In this single-center retrospective study of 19 consecutive high-risk patients (median age, 74 years) with renal malignancies managed in 2017–2020 by SAE with NBCA followed by PCA, data about patients, tumor and procedures characteristics, complications, renal function and hemoglobin concentration before and after treatment, as well as recurrence were collected. Charlson comorbidity index was ≥4 in 89.5% of patients. Ten patients were treated by antiplatelet and/or anticoagulant therapy. Median tumor largest diameter was 3.75 cm (range, 1–6.5 cm) and R.E.N.A.L. nephrometry score was ≥7 in 80%, indicating substantial tumor complexity. No major complications were recorded and minor complications occurred in 7 patients. No residual tumor was found at 6-week imaging follow-up in 18/19 patients. Tumor recurrence was visible in 1/16 patients at 6-month imaging follow-up. No significant difference was found for renal function after treatment (p = 0.07), whereas significant decrease in hemoglobin concentration was noted (p = 0.00004), although it was relevant for only one patient who required only blood transfusion and no further intervention. SAE prior to PCA is safe and effective for managing renal malignancies in high-risk patients.

Cryoablation of renal tumors: long-term follow-up from a multicenter experience

Purpose

To retrospectively investigate long-term outcomes of renal cryoablation from a multicenter database.

Methods

338 patients with 363 renal tumors underwent cryoablation in 4 centers in North-Eastern Italy. 340/363 tumors (93.7%) were percutaneously treated with CT guidance. 234 (68.8%) were treated after conscious sedation, 76 (22.3%) under local lidocaine anesthesia only and 30 (8.8%) under general anesthesia. Treatment efficacy and complication rate considered all procedures. Oncologic outcomes considered a subset of 159 patients with 159 biopsy proven renal cell carcinoma.

Results

Mean tumor size was 2.53 cm. Technical success was achieved in 355/363 (97.8%) treatments. Treatment efficacy after the first treatment was achieved in 348/363 (95.9%) tumors. Statistical analysis revealed a significant lower treatment efficacy for ASA score >3, Padua score >8, tumor size >2.5 cm, use of >2 cryoprobes, presence of one single kidney. In the subset of 159 patients, recurrence-free survival rates were 90.5% (95% CI 83.0%, 94.9%) at 3 years and 82.4% (95% CI 72.0%, 89.4%) at 5 years; overall survival rates were 96.0% (95% CI 90.6%, 98.3%) at 3 years and 91.0% (95% CI 81.7%, 95.7%) at 5 years; no patient in this subset developed metastatic disease. Clavien-Dindo >1 complications were recorded in 14/369 procedures (3.8%) and were related to age >70 years, tumor size >4 cm and use of >2 cryoprobes.

Conclusion

Cryoablation performed across four different centers in a large cohort of predominantly small renal tumors showed that this technique provides good recurrence-free survival rates and overall survival rates at three- and five-year with very low major complications rate.

Electronic supplementary material

The online version of this article (10.1007/s00261-021-03082-z) contains supplementary material, which is available to authorized users.

Pain relief and local tumour control following percutaneous image-guided cryoablation for spine metastasis: a 12-year single-centre experience

AIM

To assess pain relief and local tumour control retrospectively in spinal metastases undergoing cryoablation.

MATERIALS AND METHODS

Between May 2008 and September 2020, 46 metastases in 41 consecutive patients (mean age 59.7±4.4 [SD] years; range 27-84) were treated with cryoablation in 42 interventional sessions. Patient demographics, procedural data, complications, pain, and local tumour control were analysed retrospectively.

RESULTS

Thirty-one patients (36 spine metastases; 32 sessions) were treated for pain relief and 10 (10 metastases; 10 sessions) for local tumour control. Clinical success was reached in 30/32 (93.8%) interventional palliative sessions. Mean pre-procedural numerical pain rate scale was 6.2±1.7 (SD), and dropped significantly to 3.5±1.8 (SD), 1.9±1.7 (SD), and 1.9±1.8 (SD) at 24-h, 1-month and at the last available follow-up (median 16.5±23.2 [SD] months), respectively. For patients requiring local tumour control, primary clinical success was reached in 6/10 (60%) spinal metastases at median 25-months follow-up. The overall complication rate was 8%, with no secondary fractures or iatrogenic thermal-mediated nerve injuries reported.

CONCLUSION

Percutaneous image-guided cryoablation of spinal metastases is safe and effective in achieving pain relief and local tumour control.

Percutaneous CT-Guided Renal Cryoablation: Technical Aspects, Safety, and Long-Term Oncological Outcomes in a Single Center

Background and objectives: Cryoablation is emerging as a safe and effective therapeutic option for treating renal cell carcinoma. This study analyzed the safety and long-term oncological outcomes of cryoablation in our center. Materials and methods: Patients who underwent computed tomography (CT)-guided percutaneous cryoablation between February 2011 and June 2020 for one or more clinically localized renal tumors were identified. Technical success and treatment efficacy were assessed. Post-procedural complications were classified according to the Clavien-Dindo system. Recurrence-free survival was determined for biopsy-proven malignant renal tumors. Results: A total of 174 renal tumors, 78 of which were biopsy-proven malignant carcinomas, were treated in 138 patients (97 males and 41 females, mean age: 73 years, range: 43-89 years). Mean tumor size was 2.25 cm and 54.6% of the lesions required a complex approach. Technical success was achieved in 171 out of 174 tumors (98.3%). Primary treatment efficacy was 95.3% and increased to 98.2% when retreats were taken into account. The overall complication rate was 29.8%. No complications of Clavien-Dindo grade III or more were encountered. Median follow-up was 21.92 months (range: 0.02-99.87). Recurrence-free survival was 100% at 1 year, 95.3% (95% CI: 82.1%-98.8%) at 3 years, and 88.6% (95% CI: 71.8%-95.7%) at 5 years. Conclusions: Cryoablation is a safe and effective technique for the treatment of small renal lesions, with no major complications when performed by expert interventional radiologists. The multidisciplinary discussion is essential, especially considering the high number of histologically undetermined lesions. Our long-term oncological outcomes are encouraging and in line with the literature.

Percutaneous hydrodissection for thermoprotection during cryoablation of periureteric and pyeloureteric junction renal cell carcinomas

OBJECTIVE

To report our experience of percutaneous image-guided cryoablation of renal tumors located within 10 mm of the pyeloureteric junction (PUJ) and/or ureter, with hydrodissection as a stand-alone thermoprotective technique.

MATERIALS AND METHODS

All patients who were offered combined hydrodissection and cryoablation of the PUJ/ureter to treat stage-1 renal cell carcinoma were retrospectively reviewed. Data regarding patients, lesions, and outcomes were collected.

RESULTS

Twenty tumors in 20 patients (13 males:7 females) with a mean age of 74.4 ± 7.5 were included. Mean tumor size was 27.6 ± 6.4 mm. Nearby vulnerable structure(s) were identified as the ureter in 5/20 cases, the PUJ in 8/20 cases and both the PUJ and the ureter in the remaining 7/20 cases (35%) cases. Mean minimal distance between the tumor and the vulnerable organ(s) was 4.8 ± 2.6 mm (range 0-10). A mean of 1.7 ± 0.6 spinal needles were used per intervention with a mean time to complete hydrodissection of 18.6 ± 13.4 min. Primary and secondary technical efficacy rates were 90% and 95%, respectively. Mean follow-up was 23.1 ± 9.2 months. There were no immediate or delayed complications, in particular no urothelial strictures. Two tumor recurrences occurred during follow-up, with a time to disease progression of 13 and 31 months, respectively.

CONCLUSION

hydrodissection of the PUJ/ureter to prevent thermal injury during cryoablation is an effective technique and does not seem to compromise the efficacy of ablation at short or mid-term follow-up.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Asian Conference on Tumor Ablation guidelines for renal cell carcinoma

Thermal ablation has been established as an alternative treatment for renal cell carcinoma (RCC) in patients who are poor candidates for surgery. However, while American and European guidelines have been established for American and European patients, respectively, no ablation guidelines for Asian patients with RCCs have been established many years after the Asian Conference on Tumor Ablation (ACTA) had been held. Given that Western guidelines are difficult to apply to Asian patients due to differences in body habitus, economic status, and insurance systems, the current review sought to establish the first version of the ACTA guidelines for treating a RCC with thermal ablation.

Gangrene of the Kidney Following Percutaneous Renal Cryoablation of a Small Tumor

Background: In selected cases cryoablation is a valid treatment option for small renal masses. The procedure is generally considered oncologically efficient with a low rate of severe complications. We report here a case of a 62-year-old man who after percutaneous cryoablation develops severe gangrene in the treated kidney. Case Presentation: A 62-year-old man was incidentally diagnosed with a 45-mm renal cell carcinoma. The tumor was found on a CT scan performed on the suspicion of diverticulitis. An abscess in relation to the sigmoid was found and he was treated with aspiration and antibiotics. The tumor was treated with percutaneous cryoablation 20 days later. On the third postoperative day, he was readmitted with urosepsis. A CT scan revealed gangrene at the ablation site, and a nephrectomy was performed. Clinical progress was slow, and a new CT scan showed reformation of the abscess at the sigmoid and a suspicion of a colonic tumor was raised. This was confirmed by coloscopy and biopsy. The patient had a right hemicolectomy, and the pathology report described a T4 adenocarcinoma with positive margins. After 4 months follow-up, metastases to the lungs was found and the patient was referred to further oncologic treatment. Conclusion: Renal cryoablation is generally a very safe procedure, but severe complications may occur. This case report highlights that attention should be given to recent abdominal infections and that delayed intervention might be in place in selected cases.

Urinothorax following percutaneous image-guided renal cryoablation

A 69-year-old lady with 2 renal cell carcinomas, one sited at the upper pole of her solitary right kidney, underwent percutaneous image-guided cryoablation and developed urinothorax as a complication. This was diagnosed from pleural fluid analysis and radiology imaging with computed tomography (CT). Management included image-guided chest drain and retrograde ureteric stent insertion to divert the urine from entering the pleural cavity. CT images demonstrated a fistula between the site of renal puncture and the pleural cavity, indicating that the cryoprobes traversed the diaphragm during the procedure. This case highlights urinothorax as an unusual complication of cryoablation of renal cell carcinoma. Prompt diagnosis by interventional radiologists is crucial to avert from this potentially life-threatening complication.

Percutaneous CT- and MRI-guided Cryoablation of cT1 Renal Cell Carcinoma: Intermediate- to Long-term Outcomes in 307 Patients

Background Percutaneous ablation for cT1 renal cell carcinoma (RCC) remains underused, partially because of heterogeneous and limited long-term outcomes data assessing recent cryoablation methods. Purpose To report intermediate- to long-term outcomes of image-guided percutaneous cryoablation of cT1 RCC and to compare outcomes for CT versus MRI guidance. Materials and Methods This HIPAA-compliant retrospective single-institution study assessed patients who underwent percutaneous cryoablation for solitary pathology-proven cT1 RCC between August 2000 and July 2017. Tumors (cT1a, n = 282; cT1b, n = 25; size range, 0.6-6.5 cm; median size, 2.5 cm) underwent cryoablation with CT (n = 155) or MRI (n = 152) guidance. Primary end points of overall survival (OS), disease-specific survival (DSS), imaging-confirmed disease-free survival (DFS), and local progression-free survival (LPFS) were calculated by using Kaplan-Meier analysis. Secondary end points of technique efficacy and adverse event rate were also calculated. Primary and secondary end points for CT and MRI guidance were compared by using univariable regression analysis. Results A total of 307 patients (mean age, 68 years ± 11 [standard deviation]; 192 men) were evaluated. Median clinical follow-up lasted 95 months (range, 8-219 months), and median imaging follow-up lasted 41 months (range, 0-189 months). Survival metrics at 3, 5, 10, and 15 years, respectively, included OS of 91% (95% confidence interval [CI]: 88%, 94%), 86% (95% CI: 82%, 90%), 78% (95% CI: 73%, 84%), and 76% (95% CI: 69%, 83%); DSS of 99.6% (95% CI: 99%, 100%), 99% (95% CI: 98%, 100%), 99% (95% CI: 98%, 100%), and 99% (95% CI: 98%, 100%); DFS of 94% (95% CI: 92%, 97%), 91% (95% CI: 88%, 96%), 88% (95% CI: 83%, 93%), and 88% (95% CI: 83%, 93%); and LPFS of 97% (95% CI: 94%, 99%), 95% (95% CI: 93%, 98%), 95% (95% CI: 93%, 98%), and 95% (95% CI: 93%, 98%). Survival did not significantly differ between CT and MRI guidance, with univariable Cox regression analysis hazard ratios of 0.97 (95% CI: 0.57, 1.67; P = .92) for OS, 0.63 (95% CI: 0.26, 1.52; P = .30) for DFS, and 0.83 (95% CI: 0.26, 2.74; P = .77) for LPFS. Primary and secondary technique efficacy were 96% and 99%, respectively. Overall adverse event rate was 14% (43 of 307), including 11 grade 3 events and three grade 4 events according to the Common Terminology Criteria for Adverse Events. Conclusion Percutaneous CT- and MRI-guided cryoablation of cT1 renal cell carcinoma had similar excellent intermediate- and long-term outcomes. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Georgiades in this issue.

Is percutaneous image-guided renal tumour ablation ready for prime time?

In the last few decades, thermal ablation (TA) techniques have been increasingly applied to treat small localised renal cell carcinomas. Despite this trend, there is still an underuse of TA compared to surgery and a substantial lack of high-quality evidence derived from large, prospective, randomised controlled trials comparing the long-term oncologic outcomes of TA and surgery. Therefore, in this narrative review, we assess published guidelines and recent literature concerning the diagnosis and management of kidney-confined renal cell carcinoma to understand whether percutaneous image-guided TA is ready to be proposed as a first-line treatment.

Percutaneous Cryoablation of Symptomatic Intramuscular Venous Malformation

PURPOSE

To evaluate the efficacy and safety of cryoablation for venous malformations.

MATERIALS AND METHODS

A total of 12 patients with symptomatic intramuscular venous malformations who underwent percutaneous cryoablation between February 2015 and December 2018 were retrospectively studied. The mean age was 42 y (range, 19-58 y). Pain was reported by 11 patients (92%) and swelling by 1 (8%). Pain was assessed with a visual analog scale (VAS) before and after cryoablation. Lesion size was followed with magnetic resonance (MR) imaging at baseline and at 3-mo follow-up. Median initial VAS score was 7 (range, 0-8), and median initial lesion size was 32.5 mm (range, 11-150 mm).

RESULTS

The median VAS score at 3 mo was 0 (range, 0-4), and the median lesion size at 3 mo was 0 mm (range, 0-142 mm). Eleven of 12 patients reported an improvement in their pain. MR imaging control showed a treatment scar with no residual lesion in 5 patients and decreased lesion size in 4. No major complications were reported. One minor hematoma and 1 small myositis were noted as defined by Society of Interventional Radiology criteria.

CONCLUSIONS

Percutaneous cryoablation is effective and safe for treatment of symptomatic intramuscular venous malformations, with improvement of symptoms.