Percutaneous Cryoablation of Stage T1b Renal Cell Carcinoma: Safety, Technical Results, and Clinical Outcomes. Cardiovasc Intervent Radiol. 2019;42:970-978. [PMID: 31044292 DOI: 10.1007/s00270-019-02226-5]

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.

Protection from injury to organs adjacent to a renal tumor during Imaging-guided thermal ablation with hydrodissection and pyeloperfusion

PURPOSE

The treatment of renal tumors is dictated by the results acquired from renal imaging, which play a crucial role in determining the appropriate strategy and surgical plan. Radiofrequency ablation, microwave ablation, and cryoablation are established percutaneous thermal ablation procedures that have widespread recognition. The objective of this scholarly article is to present a comprehensive summary of the application of the primary thermal protection strategies of the structures adjacent to renal tumors, in particular the effectiveness in terms of safety of hydrodissection and pyeloperfusion, in the context of percutaneous thermal ablation for renal tumors.

METHODS

A literature search was conducted in PubMed in April 2023 using the keywords "hydrodissection", "hydrodisplacement", "renal", "kidney", "percutaneous ablation", "cryoablation", "microwave", "radiofrequency", and "pyeloperfusion". No language restriction was applied.

RESULTS

Our study yielded a total of 676 cases describing the use of either hydrodissection or pyeloperfusion in conjunction with percutaneous thermal ablation. The fluids employed for displacing the neighboring structures encompassed saline solution, a mixture of saline solution and iodinated contrast, 5% dextrose in water, iodinated contrast in dextrose solution, lactated singer solution, and iodinated contrast.

CONCLUSIONS

By using these procedures effectively, a greater number of ablations could be performed on anterior or lower polar renal tumors, sometimes excluded from these treatments due to the high risk of causing damage to adjacent anatomical structures.

Combining Transarterial Embolization and Percutaneous Cryoablation for Early-Stage Renal Cell Carcinoma: Embolization Materials and Impacts of Tumor Size

BACKGROUND/OBJECTIVES

Our aim was to compare the complication rates of different embolization materials (absolute ethanol and gelatin sponges) used for combined transarterial embolization (TAE) and to investigate the impact of tumor size on operative time and cryoneedle use during percutaneous cryoablation (PCA).

METHODS

We treated 27 patients (9 women and 18 men; mean age, 74 years) with 28 early-stage (T1a) renal cell carcinoma (RCC) lesions using combined TAE and PCA between September 2018 and January 2021. During TAE, 15 lesions in 14 patients were embolized using mixed absolute ethanol and iodized oil. The remaining 13 lesions (in 13 patients) were embolized using a gelatin sponge followed by iodized oil. The PCA was performed within 3 to 21 days of the TAE. We compared complications between the TAE subgroups (i.e., absolute ethanol and gelatin sponge) and assessed potential correlations between tumor size and the operative time of the PCA.

RESULTS

All patients were successfully treated by combined TAE-PCA. Local control was achieved for all patients (monitoring period, 1-48 months; median, 28 months). Although the effect of TAE did not differ between subgroups, a significantly higher number of patients in the absolute ethanol group experienced intraprocedural pain than in the gelatin sponge group (p < 0.05). The operative time of the PCA was significantly correlated with the size of the RCC lesion (p < 0.01). The number of cryoneedles used for the PCA was also correlated with the size of the RCC lesion (p < 0.0001).

CONCLUSIONS

For TAE prior to PCA for early-stage RCC, gelatin sponges can replace absolute ethanol to reduce intraprocedural pain. Tumor size correlates with operative time and the number of cryoneedles needed for PCA, which suggests the total medical cost for PCA therefore varies based on the tumor's size.

Liquid nitrogen-based cryoablation: complication rates for lung, bone, and soft tissue tumors cryoablation

OBJECTIVE

This study aimed to assess the complication rate during and 24 hours after cryoablation in lung, bone, and soft tissue tumors.

METHODS

We reviewed complications in a total of 85 consecutive patients who underwent cryoablation using a liquid nitrogen-based system in various lesions between April 2017 and October 2022. There were no liver and renal lesions. Complications were categorized using the Society of Interventional Radiology classification.

RESULTS

Eighty-five patients were treated for 96 lesions in the bone (36.4%; 35 of 96), lung (18.8%; 18 of 96), and soft tissue (44.8%; 43 of 96). The primary technical success rate was 97.7% (83 of 85). The total grade 2 and 1 complication rates were 5.2% (5/96) and 20.8% (20/96), respectively. Two patients had asymptomatic pulmonary embolisms incidentally noted at the 24-hour follow-up computed tomography (grade 2). The most frequent complications were simple and hemorrhagic pleural effusions (18.7%; 18 of 96). Lung procedures had the highest complication rate, where 13 patients (72.2%; 13 of 18) reported complications, including 2 cases of symptomatic hydropneumothorax requiring drainage (grade 2) and an additional 2 days of hospital stay. Eight patients (24.2%; 8 of 33) with bone lesions and 4 (9.3%; 4 of 43) with soft tissue lesions experienced complications.

CONCLUSION

Cryoablation using a liquid nitrogen-based system is safe, with only minor complications observed.

ADVANCES IN KNOWLEDGE

This study provides data on the safety of liquid nitrogen-based percutaneous cryoablation in tumors located in lung, in bones and in soft tissues. Despite using larger diameter cryoprobes than those typically reported with argon-based system, our experience shows that complications are mostly low and comparable in frequency and severity.

Cryoprobe Placement Using Electromagnetic Navigation System (IMACTIS® CT-Navigation™) for Cryoablation Treatment of Upper Kidney Pole Lesions and Adrenal Metastases: Experience from a Single-Center, 4-Year Study

The aim of this study is to evaluate the safety and efficacy of the use of the IMACTIS® CT-Navigation™-electromagnetic navigation system (EMNS) in cryoablation CT-guided procedures under local anesthesia for the treatment of upper kidney pole and adrenal lesions. We conducted a retrospective analysis of patients with upper kidney pole lesions and adrenal metastases who underwent cryoablation using the IMACTIS-CT®-EMNS between January 2019 and April 2023. The EMNS was used to guide the placement of the cryoprobes with CT guidance under local anesthesia. The primary outcome was technical success, defined as the successful placement of the cryoprobes in the target lesion. A total of 31 patients were studied, of whom, 25 patients were treated with cryoablation for upper pole kidney masses, and 6 patients underwent the cryoablation of adrenal metastases during the study period. The mean age was 60 years (range, 36-82 years), and 21 patients were male. All the upper kidney pole lesions were renal cell carcinomas, and regarding adrenal metastases, the primary cancer sites were the lungs (n = 3), breast (n = 2), and the colon (n = 1). The median size of the lesions was 3,8 cm (range, 1.5-5 cm). All procedures were technically successful, with the cryoprobes accurately placed in the target lesions under CT guidance using the EMNS, avoiding the penetration of any other organs using an oblique trajectory. No major complications were reported, and local tumor control was achieved in all cases. Our initial experience using the EMNS for cryoprobe placement during CT-guided interventional procedures under local anesthesia for the cryoablation treatment of upper pole kidney lesions and adrenal metastases showed that it is safe and effective.

Impact of Percutaneous Cryoablation on Renal Function in Patients with Stage I Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

PURPOSE

To assess the effect of cryoablation on renal function (measured by estimated glomerular filtration rate [eGFR] or serum creatinine) for treating Stage I renal cancer.

MATERIALS AND METHODS

The MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases were systematically searched from inception to May 1, 2023. Cohort studies that included data on change of eGFR and serum creatinine increase were included. Meta-analysis was performed by measuring the weighted mean difference and by fitting random-effect models.

RESULTS

Overall, 38 studies were included, comprising 3,202 participants. Percutaneous cryoablation was associated with an absolute eGFR reduction of -3.06 mL/min/1.73 m2 (95% CI, -4.12 to -2.01; P < .001) and serum creatinine increase of 0.05 mg/dL (95% CI, -0.02 to 0.11; P > .05). The weighted absolute mean difference of percutaneous cryoablation for treating Stage T1b renal cell carcinoma was estimated at -5.19 mL/min/1.73 m2 (95% CI, -11.1 to 0.72; P > .05). Lastly, when analyzing studies that included cohorts with solitary kidneys, the pooled weighted mean difference was estimated as -3.27 mL/min/1.73 m2 (95% CI, -6.79 to 0.25; P > .05).

CONCLUSIONS

Percutaneous cryoablation for Stage 1 renal cell carcinoma has minimal significant impact on renal function (measured by eGFR or serum creatinine). The same outcome was observed in patients with larger tumors (T1b) and those with solitary kidneys.

Percutaneous Ablation of T1b Renal Cell Carcinoma: An Overview

PURPOSE OF REVIEW

There is increasing incidence of renal cell carcinoma (RCC) with multiple treatment options currently available. The purpose of this review is to outline patient selection and technical approaches and present the current literature for percutaneous ablation of T1b (4.1-7 cm) RCC.

RECENT FINDINGS

An increasing number of retrospective studies and meta-analyses have evaluated the use of percutaneous ablation for T1b RCC. Overall, these studies tend to show that percutaneous ablation in this patient population is feasible. However, rates of major adverse events and local recurrence after percutaneous ablation for T1b RCC are both higher than when ablation is used for smaller tumors. As such, a multi-disciplinary, patient-centered approach is required. Due to the increasing literature in this area, the most recent National Comprehensive Cancer Network (NCCN) guidelines include percutaneous ablation as an option for non-surgical patients with T1b RCC.

Percutaneous cryoablation of 100 anterior renal tumors: safety and technical success

PURPOSE

To assess the safety, technical success, and clinical outcomes of percutaneous cryoablation (PCA) in patients with anterior renal tumors.

METHODS

A retrospective analysis of patients with anterior renal tumors, defined as tumors at or anterior to the level of the renal pelvis, treated with CT-guided PCA from 2008 to 2022. Summary statistics included demographics and baseline tumor attributes. Treatment and follow-up metrics included primary and secondary technical success, adverse events (AEs) according to the SIR classification, local recurrence, overall survival (OS), and cancer-specific survival (CSS)). 100 patients (60 males; mean age: 63, mean BMI: 33, mean Charlson comorbidity index:6) with 100 anterior renal tumors were included.

RESULTS

78% of tumors were T1a and 22% T1b with mean maximal tumoral dimension of 29 mm (range: 6-62 mm) and mean distance to nearest critical structure 9 mm (range: 0-40 mm). Mean follow-up was 20.9 months (range: 3-103). 28% of PCAs required hydrodissection. Technical success was achieved in 92% of patients; with six remaining patients undergoing successful repeat PCA (secondary technical success: 98%). The remaining two patients without primary technical success were either surveilled or had a benign pathology on resulted concomitant biopsy. Four patients (4%) had major AEs (hemorrhage requiring prolonged admission, transfusion, or embolization (n = 3), perinephric abscess requiring drainage (n = 1)) and 27% had minor AEs. Eight patients (8%) had recurrence with a one-year OS of 94% and CSS of 100%. All recurrences underwent repeat ablation without additional recurrence and 3/8 (38%) were T1b and 5/8 (63%) were T1a tumors.

CONCLUSION

PCA of anterior renal tumors can be performed safely with high rates of technical and oncologic success.

Efficacy and safety of cryoablation for localized renal tumor as an alternative approach to partial nephrectomy

Introduction

Renal cryoablation displays a profile of high tolerance, including in a frail population. Cryoablation appears as a validated alternative treatment to surgery for renal tumors smaller than 4 cm. However, evidence is lacking for larger tumors, despite encouraging data for tumors up to 7 cm.

Material and methods

This retrospective descriptive study of a population with a stage T1b renal tumor treated by cryoablation was conducted at the Nantes University Hospital between January 2009 and July 2021. Primary endpoint was 3-year rate of local recurrence. Secondary endpoints included technical efficacy, overall and cancer-specific survivals, and safety assessment.

Results

A total of 63 patients were analyzed. Three-year rate of local recurrence was 11.1%. Primary and secondary technical efficacies were achieved in 88.9% and 96.8% of patients, respectively, and 3-year overall and cancer-specific survival were 87.3% and 95.2%, respectively. Most patients (73%) experienced no complications, 13% of patients had minor (CIRSE grades 1 or 2) adverse effects, and 13% had severe but non-lethal (CIRSE grade 3) adverse effects. One patient died following cryoablation due to colic perforation. The most common AE (all grades) was hemorrhage (9.5%).

Discussion

This study showed a good efficacy and safety of cryoablation for renal tumors up to 7 cm (T1b). Our results were consistent with a rather sparse literature and contributed to guide future recommendations about cryoablation as an alternative to surgery for T1b renal tumors.

Percutaneous tumor ablation versus image guided robotic-assisted partial nephrectomy for cT1b renal cell carcinoma: a comparative matched-pair analysis (UroCCR 80)

BACKGROUND

Partial nephrectomy (PN) is the gold standard treatment for cT1b renal tumors. Percutaneous guided thermal ablation (TA) has proven oncologic efficacy with low morbidity for the treatment of small renal masses (<3 cm). Recently, 3D image-guided robot-assisted PN (3D-IGRAPN) has been described, and decreased perioperative morbidity compared to standard RAPN has been reported. Our objective was to compare two minimally invasive image-guided nephron-sparing procedures (TA vs. 3D-IGRAPN) for the treatment of cT1b renal cell carcinomas (4.1-7 cm).

METHODS

Patients treated with TA and 3D-IGRAPN for cT1b renal cell carcinoma, prospectively included in the UroCCR database (NCT03293563), were pair-matched for tumor size, pathology, and RENAL score. The primary endpoint was the local recurrence rate between the two groups. Secondary endpoints included metastatic evolution, perioperative complications, decrease in renal function, and length of hospitalization.

RESULTS

A total of 198 patients were included and matched into two groups of 72 patients. The local recurrence rate was significantly higher in the TA group than that in the 3D-IGRAPN group (4.2% vs. 15.2%, P=0.04). Metastatic evolution and perioperative outcomes such as major complications, eGFR decrease, and length of hospitalization did not differ significantly between the two groups.

CONCLUSIONS

3D-IGRAPN resulted in a significantly lower local recurrence rate and comparable rates of complications and metastatic evolution compared with thermal ablation.

Long-term follow-up of CT-guided percutaneous radiofrequency ablation of T1 renal cell carcinoma

Background

Radiofrequency ablation (RFA) has an established role in effective treatment of renal cell carcinomas (RCCs), as most of RCCs are diagnosed incidentally in early stages. Long-term follow-up is however important to consolidate the technique. Most of the literature contains series of short-term follow-ups of periods shorter than 2 years. This study in hand demonstrates the results of longer-term follow-up than the previously published series.

Results

Data analysis of 31 patient records involved in this study demonstrated the high clinical efficacy of RFA for long term, 12-year follow-up, by following the absence of tumor recurrences, as shown on regular interval contrast enhanced computed tomography (CT) and or magnetic resonance imaging (MRI).

Conclusions

RFA continues to prove its competent role in treating RCCs on longer-term follow-ups; the smaller the size of a tumor and the more peripheral the tumor is, the more effective the therapy. Even in larger early stages tumors, repeating the ablative sessions results in complete ablation without the need for more invasive surgical interventions.

A multicenter comparative matched-pair analysis of percutaneous tumor ablation and robotic-assisted partial nephrectomy of T1b renal cell carcinoma (AblatT1b study-UroCCR 80)

OBJECTIVE

Renal cell carcinomas represent the sixth- and tenth-most frequently diagnosed cancer in men and women. Recently, percutaneous-guided thermal ablations have proved to be as effective as partial nephrectomy and safer for treating small renal masses (i.e.,  < 3 cm). This study compared the perioperative and recurrence outcomes of percutaneous thermal ablation (TA) and robotic-assisted partial nephrectomy (RAPN) for the treatment of T1b renal cell carcinomas (4.1-7 cm).

METHODS

Retrospective data from 11 centers on the national database, between 2010 and 2020, included 81 patients treated with thermal ablation (TA) and 308 patients treated with RAPN for T1b renal cell carcinoma, collected retrospectively and matched for tumor size, histology results, and the RENAL score. TA included cryoablation and microwave ablation. Endpoints compared the rate between the two groups: local recurrence, metastases, complications, renal function decrease, and length of hospitalization.

RESULTS

After matching, 75 patients were included in each group; mean age was 76.6 (± 9) in the TA group and 61.1 (± 12) in the RAPN group, including 69.3% and 76% men respectively. The local recurrence (LR) rate was significantly higher in the TA group than in the PN group (14.6% vs 4%; p = 0.02). The LR rate was 20% (1/5) after microwave ablation, 11.1% (1/9) after radiofrequency ablation, and 14.7% (9/61) after cryoablation. The major complication rate (Clavien-Dindo  ≥ 3) was higher following PN than after TA (5.3% vs 0%; p < 0.001). Metastases, eGFR decrease, and length of hospitalization did not differ significantly between the two groups.

CONCLUSIONS

The local recurrence rate was significantly higher after thermal ablation; however, thermal ablation resulted in significantly lower rates of complications. Thermal ablation and robotic-assisted partial nephrectomy are effective treatments for T1b renal cancer; however, the local recurrence rate was higher after thermal ablation.

KEY POINTS

• The local recurrence rate was significantly higher in the thermal ablation group than in the partial nephrectomy group. • The major complication rate (Clavien-Dindo ≥ 3) was higher following PN than after TA (5.3% vs. 0%; p < 0.001).

Percutaneous cryoablation versus partial nephrectomy for cT1b renal tumors: An inverse probability weight analysis

PURPOSE

To investigate differential clinical outcomes in patients treated with partial nephrectomy (PN) vs. percutaneous cryoablation (PCA) for cT1b renal tumors.

MATERIALS AND METHODS

We retrospectively analyzed the records of 119 patients who had undergone PN (n = 90) or PCA (n = 29) for cT1b renal tumors. Inverse probability weighting (IPW) was used for balancing patient demographics, including renal function and tumor complexity. Perioperative complications, renal function preservation rates, and oncological outcomes such as local recurrence-free, metastasis-free, cancer-specific, and overall survival were compared using IPW-adjusted restricted mean survival times (RMSTs).

RESULTS

PCA was more likely to be selected for octogenarians (odds ratio: 11.4, 95% confidence interval [CI]: 3.33-45.1). During the median follow-up of 43 months in the PCA group and 36.5 months in the PN group, unablated local residue or local recurrence was noted in 6 patients in the PCA group and local recurrence was noted in 4 patients in the PN groups. Of the 6 patients in the PCA group, 4 underwent salvage PCA, and local control had been achieved at the last visit. In the IPW-adjusted population, PCA had significantly worse local recurrence-free survival compared with PN (IPW-adjusted RMST difference: -22.7 months, 95% CI: -45.3 to -0.4, P = 0.046). IPW-adjusted RMST for metastasis-free survival (P = 0.23), cancer-specific survival (P = 0.77), and overall survival (P = 0.11) did not differ between PCA and PN. In addition, PN was not a predictor for local control failure at the last visit (odds ratio: 0.30, 95%CI: 0.05-1.29). There were no statistically significant differences between PN and PCA in renal function preservation or overall/severe complication rates.

CONCLUSIONS

In patients with cT1b renal tumor, although the local recurrence rate is higher for PCA than for PN, PCA provides comparable distant oncologic outcomes. PCA can be an alternative treatment option for elderly, comorbid patients, even those with cT1b renal tumors.

Thermal ablation for small renal masses: Identifying the most appropriate tumor size cut-off for predicting perioperative and oncological outcomes

OBJECTIVES

To test TRIFECTA achievement [1) absence of CLAVIEN-DINDO ≥3 complications; 2) complete ablation; 3) absence of ≥30% decrease in eGFR] and local recurrence rates, according to tumor size, in patients treated with thermal ablation (TA: radiofrequency [RFA] and microwave ablation [MWA]) for small renal masses.

METHODS

Retrospective analysis (2008-2020) of 432 patients treated with TA (RFA: 162 vs. MWA: 270). Tumor size was evaluated as: 1) continuously coded variable (cm); 2) tumor size strata (0.1-2 vs. 2.1-3 vs. 3.1-4 vs. >4 cm). Multivariable logistic regression models and a minimum P-value approach were used for testing TRIFECTA achievement. Kaplan-Meier plots depicted local recurrence rates over time.

RESULTS

Overall, 162 (37.5%) vs. 140 (32.4%) vs. 82 (19.0%) vs. 48 (11.1%) patients harboured, respectively, 0.1 to 2 vs. 2.1 to 3 vs. 3.1 to 4 vs. >4 cm tumors. In multivariable logistic regression models, increasing tumor size was associated with higher rates of no TRIFECTA achievement (OR:1.11; P< 0.001). Using a minimum P-value approach, an optimal tumor size cut-off of 3.2 cm was identified (P< 0.001). In multivariable logistic regression models, 3.1 to 4 cm tumors (OR:1.27; P< 0.001) and >4 cm tumors (OR:1.49; P< 0.001), but not 2.1 to 3 cm tumors (OR:1.05; P= 0.3) were associated with higher rates of no TRIFECTA achievement, relative to 0.1 to 2 cm tumors. The same results were observed in separate analyses of RFA vs. MWA patients. After a median (IQR) follow-up time of 22 (12-44) months, 8 (4.9%), 8 (5.7%), 11 (13.4%), and 5 (10.4%) local recurrences were observed in tumors sized 0.1 to 2 vs. 2.1 to 3 vs. 3.1 to 4 vs. >4 cm, respectively (P= 0.01).

CONCLUSION

A tumor size cut-off value of ≤3 cm is associated with higher rates of TRIFECTA achievement and lower rates of local recurrence over time in patients treated with TA for small renal masses.

The Role of Focal Therapy and Active Surveillance for Small Renal Mass Therapy

Small and low-grade renal cell carcinomas have little potential for metastasis and disease-related mortality. As a consequence, the main problem remains the use of appropriately tailored treatment for each individual patient. Surgery still remains the gold standard, but many clinicians are questioning this approach and present the advantages of focal therapy. The choice of treatment regimen remains a matter of debate. This article summarizes the current treatment options in the management of small renal masses.

Differential efficacy of ablation therapy versus partial nephrectomy between clinical T1a and T1b renal tumors: A systematic review and meta-analysis

PURPOSE

To assess the differential clinical outcomes of patients treated with partial nephrectomy (PN) vs. those treated with ablation therapy (AT) such as radiofrequency ablation, cryoablation and microwave ablation for cT1b compared to cT1a renal tumors.

MATERIALS AND METHODS

Multiple databases were searched for articles published before August 2021. Studies were deemed eligible if they compared clinical outcomes in patients who underwent PN with those who underwent AT for cT1a and/or cT1b renal tumors.

RESULTS

Overall, 27 studies comprising 13,996 patients were eligible for this meta-analysis. In both cT1a and cT1b renal tumors, there was no significant difference in the percent decline of estimated glomerular filtration rates or in the overall/severe complication rates between PN and AT. Compared to AT, PN was associated with a lower risk of local recurrence in both patients with cT1a and cT1b tumors (cT1a: pooled risk ratio [RR]; 0.43, 95% confidence intervals [CI]; 0.28-0.66, cT1b: pooled RR; 0.41, 95%CI; 0.23-0.75). Subgroup analyses regarding the technical approach revealed no statistical difference in local recurrence rates between percutaneous AT and PN in patients with cT1a tumors (pooled RR; 0.61, 95%CI; 0.32-1.15). In cT1b, however, PN was associated with a lower risk of local recurrence (pooled RR; 0.45, 95%CI; 0.23-0.88). There was no difference in distant metastasis or cancer mortality rates between PN and AT in patients with cT1a, or cT1b tumors.

CONCLUSIONS

AT has a substantially relevant disadvantage with regards to local recurrence compared to PN, particularly in cT1b renal tumors. Despite the limitations inherent to the nature of retrospective and unmatched primary cohorts, percutaneous AT could be used as a reasonable alternative treatment for well-selected patients with cT1a renal tumors.

Percutaneous Cryoablation of Renal Tumors: Initial Indian Experience

Objective The purpose of this study was to report short-term outcomes of cryoablation of early-stage renal tumors (T1a and T1b) at a tertiary hospital in India.

Methods This was a retrospective study of consecutive patients who underwent cryoablation for renal cell carcinoma (RCC) from November 2018 to June 2020. Cryoablation was performed under combined ultrasound and computed tomography guidance using a helium-argon cryoablation system. Tumor number, size, location, nephrometry score, relationship of the tumor with pelvicalyceal system, and adjacent organs were tabulated, and technical and clinical success evaluated. Early and late recurrence and complications were also assessed.

Results Eleven patients (median age: 62 years) with 11 tumors underwent cryoablation. The mean tumor size was 2.58 cm (range: 1.62–5.62 cm) with 10 lesions being T1a and one lesion T1b. Tissue sampling was done in 9/11 patients, 3 were papillary RCC and the rest, clear cell RCC. In two patients, the tumor was completely endophytic, three patients had partially endophytic tumors while 6 patients had exophytic lesions. The median nephrometry score was 6 (range: 4–11, Mode 4). Technical success was achieved in all patients. Complete response was achieved in 81% (9/11) of the patients at 1-month follow-up. Median follow-up period was 6 months. Two patients showed residual disease on follow-up imaging at 1 and 3 months, respectively.

Conclusion Cryoablation is a promising, relatively new minimally invasive therapy for treating small renal tumors in India. It is safe, technically feasible, and shows excellent short-term efficacy.

Patients' radiation dose in computed tomography-fluoroscopy-guided percutaneous cryoablation for small renal tumors

PURPOSE

This study aimed to evaluate patients' radiation dose in computed tomography (CT)-fluoroscopy-guided cryoablation for small renal tumors and assess the possible factors affecting it.

METHODS

In our institution, cryoablation was performed in 152 patients between 2013 and 2020. Procedures that were not for renal tumors and did not have radiation dose records and detailed information were excluded from the analysis. The size-specific dose estimates (SSDE), volume CT dose index (CTDI_vol), dose-length product (DLP), and entrance skin dose (ESD) were evaluated for both spiral scan and CT-fluoroscopy. The effects of the number of cryoneedle punctures; combined use of hydro- and/or pneumodissection procedures; patients' characteristics, such as body-mass index (BMI); and the tumor-related factors, such as tumor location, were determined by the univariate and multivariate analyses.

RESULTS

In the 72 included procedures, the median SSDE was 658 mGy and the median CTDI_vol was 456 mGy. The median percentage dose of CT-fluoroscopy to the total procedure dose was estimated as 89.8% (591/658 mGy) with SSDE and 41.4% (611/1,475 mGy cm) with DLP. The combined use of hydro- and/or pneumodissection and number of cryoneedle punctures were significantly associated with the total ESD, and the maximum total ESD was 863 mGy in our cases.

CONCLUSIONS

Using SSDE as an index, 89.8% of patients' radiation dose was attributed to CT-fluoroscopy, and ESD for the total procedure did not exceed 1 Gy. The increased number of cryoneedle punctures and combined use of hydro- and/or pneumodissection increased the total ESD.

Computed Tomography-Guided Percutaneous Microwave Ablation for Renal Cell Carcinoma: Impact of Tumor Size on the Progression Survival Rates

The aim of the present study was to evaluate the safety and efficacy of computed tomography (CT)-guided percutaneous microwave ablation (MWA) of renal cell carcinoma (RCC) along with identifying prognostic factors affecting the progression survival rate. Institutional database retrospective research identified 69 patients with a biopsy proven solitary T1a (82.6%) or TIb (17.4%) RCC who have underwent percutaneous CT-guided MWA. Kaplan–Meier survival estimates for events were graphed and Cox regression analysis was conducted. Mean patient age was 70.4 ± 11.5 years. Mean size of the lesions was 3 ± 1.3 cm. Mean follow up time was 35.6 months (SD = 21.1). The mean progression free survival time from last ablation was 84.2 months. For T1a tumors, the cumulative progression free survival rate for 1, 6, 12 and 36 months were 100% (SE = 0%), 91.2% (SE = 3.7%), 91.2% (SE = 3.7%) and 87.5% (SE = 4.4%); the recurrence free survival rate for T1a RCC was 94.9%. For T1b tumors, the cumulative progression free survival rate for 1, 6, 12 and 36 months were 100% (SE = 0%), 63.6% (SE = 14.5%), 63.6% (SE = 14.5%) and 63.6% (SE = 14.5%). Grade 1 complications were recorded in 5 (7.2%) patients. Significantly greater hazard for progression was found in cases with a tumor size > 4 cm (HR = 9.09, p = 0.048). No statistically important difference regarding tumor progression was recorded between T1a tumors with a diameter ≤3 cm and >3 cm. In summary, the results of the present study show that CT guided percutaneous MWA is an effective technique for treatment of T1a renal cell carcinomas, irrespective of tumor size. T1b tumors were associated with higher progression rates.

Local recurrence and other oncologic outcomes after percutaneous image-guided tumor ablations on stageT1b renal cell carcinoma: a systematic review and network meta-analysis

OBJECTIVE

A systematic review of clinical trials on thermal ablation of T1b RCC was conducted to assess oncologic outcomes of those procedures. The primary endpoint was the rate of local recurrence. Secondary endpoints included technical efficacy, progression to metastatic disease, cancer-specific mortality, complications and renal function decrease.

METHODS

PubMed (MEDLINE) and Embase databases were searched in June 2020 for eligible trials following the PRISMA selection process. Prevalence of local recurrence and per procedural major adverse effects were calculated using double arcsine transformation and a random-effects model.

RESULTS

Nine clinical trials (all retrospective) involving 288 patients with T1b renal clear cell carcinoma treated with either percutaneous microwave ablation, cryoablation or radiofrequency ablation were analyzed. Using a random-effects model, the overall prevalence of local recurrence following percutaneous ablation was 0.08 (0.04-0.14; p = 0.05). Primary technical efficacy was 226/263 (86%) patients and secondary technical efficacy was 247/263 (94%). Overall, 10/176 (6%) patients presented metastatic locations following the ablation. Major adverse effects prevalence was 0.09 (0.06-0.14; p = 0.05).

CONCLUSIONS

Thermal ablations are feasible, safe, and effective to treat T1b renal clear cell carcinoma. More trials are necessary to determine the rate of the evidence of the benefit.HighlightsThermal ablations are feasible and safe to treat T1b renal clear cell carcinoma.Oncologic outcomes appear to be very good on both local control and distant progression.Due to small number and heterogeneity of studies more trials are necessary to determine the rate of the evidence of the benefit.

Role of Imaging in Renal Cell Carcinoma: A Multidisciplinary Perspective

With the expansion in cross-sectional imaging over the past few decades, there has been an increase in the number of incidentally detected renal masses and an increase in the incidence of renal cell carcinomas (RCCs). The complete characterization of an indeterminate renal mass on CT or MR images is challenging, and the authors provide a critical review of the best imaging methods and essential, important, and optional reporting elements used to describe the indeterminate renal mass. While surgical staging remains the standard of care for RCC, the role of renal mass CT or MRI in staging RCC is reviewed, specifically with reference to areas that may be overlooked at imaging such as detection of invasion through the renal capsule or perirenal (Gerota) fascia. Treatment options for localized RCC are expanding, and a multidisciplinary group of experts presents an overview of the role of advanced medical imaging in surgery, percutaneous ablation, transarterial embolization, active surveillance, and stereotactic body radiation therapy. Finally, the arsenal of treatments for advanced renal cancer continues to grow to improve response to therapy while limiting treatment side effects. Imaging findings are important in deciding the best treatment options and to monitor response to therapy. However, evaluating response has increased in complexity. The unique imaging findings associated with antiangiogenic targeted therapy and immunotherapy are discussed. An invited commentary by Remer is available online. Online supplemental material is available for this article. ^©RSNA, 2021.

Image-guided percutaneous cryoablation of T1b renal cell carcinomas in patients with comorbidities

PURPOSE

To investigate the influence of comorbidities and tumor characteristics on outcomes following percutaneous cryoablation (PCA) of T1b renal cell carcinoma (RCC).

MATERIALS AND METHODS

Age-adjusted Charlson comorbidity index (ACCI); standardized system for quantitating renal tumor size, location, and depth (RENAL nephrometry score [RNS]); and local tumor control and survival were retrospectively investigated in 28 patients who underwent PCA for stage T1b RCC. Risk factors for elevated serum creatinine levels were also investigated.

RESULTS

Complete ablation was obtained in 27 of 28 patients. Two cases of metastasis were observed; one patient died 12 months after PCA. Overall survival at 5 years was 79.1%, with a mean follow-up of 42.0 ± 16.0 months. Local tumor control was not correlated with the ACCI and RNS. Worsening renal function 3 months after PCA was observed in ten patients, and it correlated with the presence of single kidneys (7/28 patients; p = 0.023). Significant worsening of renal function continued until 1 year after PCA (p = 0.013). Having a single kidney was a risk factor for worsened renal function after PCA (odds ratio, 8.00; 95% confidence interval 1.170-54.724).

CONCLUSION

PCA for T1b RCC confers positive local tumor control regardless of comorbidities and tumor characteristics.

Long-term outcomes of CT-guided percutaneous cryoablation of T1a and T1b renal cell carcinoma

PURPOSE

We aimed to evaluate the long-term outcomes of computed tomography-guided percutaneous cryoablation (PCA) for biopsy-confirmed renal cell carcinoma (RCC).

METHODS

This was a single-center, retrospective study investigating all patients treated with PCA between January 2010 and February 2019 for RCC tumors. Primary outcome measures included overall survival (OS), disease-free survival (DFS), progression-free survival (PFS) and cancer-specific survival (CSS). Secondary outcome measures included kidney function, complications, technical success, hospital stay, procedural time, and the identification of factors affecting the primary outcomes.

RESULTS

Fifty-three consecutive patients with 54 lesions (T1a: 49/54; T1b: 5/54) were included. Mean tumor diameter was 28.0±8.5 mm and mean R.E.N.A.L. score was 7.2±2.0. Technical success was 100% (54/54 lesions) after two reinterventions for incomplete ablation. Mean follow-up time was 46.7±28.6 months (range, 3-122 months). Local recurrence was noted in 5 patients (9.2%). According to Kaplan-Meyer analysis, OS was 98.2%, 94.2%, 71.2%, and 58.2% at 1, 3, 5, and 8 years. One patient (1.9%) died of cancer and CSS was 95.8% at 8 years. DFS was 100.0%, 95.5%, and 88.6%, and PFS was 100%, 94.3%, and 91.0%, at 1, 2, and 5 years. Clavien-Dindo grade II complication rate was 7.8% (5/64 procedures). There were no complications classified as grade III or greater. Mean creatinine increase was 7.1±6.3 μm/L (p = 0.31). No patient advanced to dialysis during follow up. Mean procedural time was 163±45 min. Median hospital stay was 2.0 days (IQR, 1-2.5 days). Diabetes was the only independent predictor of decreased OS (hazard ratio 4.3, 95% CI 0.043-0.914; p = 0.038).

CONCLUSION

PCA for stage T1a and T1b RCC provides favorable long-term oncological and renal function preservation outcomes, with acceptable complication rates.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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 There a Role for Combination, Single-Session Selective Transarterial Embolization and Microwave Ablation for Large Renal Masses?

PURPOSE

Thermal ablation of small renal tumors is safe and efficacious. Thermoablation of tumors greater than 3 cm has decreased efficacy and a greater risk of complications. Combined embolization and radiofrequency ablation has shown encouraging results. We report on the use of combined single-session transarterial embolization and microwave ablation to treat large renal masses.

MATERIALS AND METHODS

After obtaining IRB approval, a review of the medical record between October 2016 and January 2020 was performed. Patients with renal tumors who underwent combined transarterial embolization and microwave ablation were assessed retrospectively. Patient demographic information, intraoperative, postoperative, and follow-up data were recorded.

RESULTS

Eleven patients were identified meeting inclusion criteria. The mean age was 73 years, with 64% male, an average BMI of 26.5, and average Charleston Comorbidity Index of 6.7. Nine tumors were identified as clear cell carcinoma, one as papillary carcinoma and one as an oncocytic neoplasm. Average tumor size was 4.5 cm (2.7-8.3), with an average RENAL score of 8.5. Successful ablation with a 5 mm margin was achieved in all patients, and in all cases, ablation and embolization were performed on the same day. The only related post-procedure complication was a single groin hematoma. Surveillance was performed with CT or MRI. Average follow-up was 419.5 days (range 27-747), with no patients showing evidence of recurrence to date.

CONCLUSIONS

Combined single-session transarterial embolization and microwave ablation is technically feasible, safe, and efficacious in treating large renal tumors in a series of 11 patients with no recurrence to date.

LEVEL OF EVIDENCE

Level 4, case series.

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.

Computed tomography-guided percutaneous cryoablation of T1b renal tumors: safety, functional and oncological outcomes

Purpose: To evaluate the safety, functional and oncological outcomes associated with percutaneous cryoablation of stage T1b renal cell carcinoma (RCC). Materials and methods: Institutional database was reviewed to identify patients treated by percutaneous CT-guidance cryoablation between 2013 and 2018 for biopsy-proven RCC tumors measuring 4.1-7.0 cm. The main outcome parameters analyzed were primary and secondary technique efficacy, progression-free survival (PFS), cancer-specific survival (CSS), loss of estimated glomerular filtration rate (eGFR) and complications. PFS and CSS were estimated by the Kaplan-Meier method. Complications were graded by the Clavien-Dindo system. Results: Twenty-three consecutive patients were included (mean tumor diameter: 45.6 ± 6.2 mm; mean RENAL score: 8.1 ± 1.8). The technical success rate was 95.7%. Primary and secondary technique efficacy rates were 86.3 and 100%, respectively. Three patients found to have incomplete ablations at 3 months were successfully treated by repeat cryoablation. Median duration follow-up was 11 months (range: 3-33). Imaging showed PFS to be 85.7% at 6 months, 66.7% at 12 months and 66.7% at 24 months. One patient with a local recurrence at 12 months was treated by radical nephrectomy. One patient died from progression of disease within 12 months. One patient reported a complication grade ≥ II (4.3%). Mean eGFR loss was 4.4 ± 8.5 ml/min/1.73m², which was significantly higher among those treated for central tumors (p < .05). Conclusion: Cryoablation for stage T1b renal tumors is technically feasible, with favorable oncological and perioperative outcomes. Longer-term studies are needed to verify our findings.

Percutaneous Microwave Ablation of Histologically Proven T1 Renal Cell Carcinoma

Objectives

To assess the safety and efficacy of percutaneous microwave ablation (MWA) of histologically proven T1 renal cell carcinoma (RCC).

Methods

We analysed patients with a histologically proven RCC (≤ 7 cm) treated by MWA from April 2012–April 2018. Primary and secondary efficacy, local tumour recurrence (LTR), morbidity and mortality were reported. Efficacy was defined as no residual tumour enhancement on follow-up imaging 1 month after the first ablation (primary efficacy) and after re-ablation(s) for residual disease (secondary efficacy). Adverse events (AE) were registered by the Clavien–Dindo classification and the common terminology criteria for AE. Univariable and multivariable logistic regression analyses were performed to investigate a relation among pre-treatment factors incomplete ablation and complications.

Results

In 100 patients, a total of 108 RCCs (85 T1a and 23 T1b) were treated by MWA. Median size was 3.2 cm (IQR 2.4–4.0). Primary efficacy was 89% (95%CI 0.81–0.94) for T1a lesions and 52% (95%CI 0.31–0.73) for T1b lesions (p < 0.001). Fifteen lesions (7 T1a) were re-ablated for residual disease by MWA in one (n = 13) and two (n = 2, both T1b) sessions resulting in secondary efficacy rates of 99% (T1a) and 95% (T1b, p = 0.352). LTR occurred in four tumours (2 T1a, 2 T1b) after 10–60 months. Six (4%) AEs grade > 3–5 were observed (2 T1a, 4 T1b, p = 0.045). Multivariable analysis showed that mR.E.N.A.L. nephrometry was independently associated with incomplete ablation (p = 0.012).

Conclusion

Microwave ablation is safe and effective for T1a and T1b RCC lesions with a significantly lower primary efficacy for T1b lesions.

Cryoablation for liver metastasis from solid pseudopapillary tumor of the pancreas: A case report

BACKGROUND

Solid pseudopapillary tumor (SPT) of the pancreas is a rare pancreatic tumor and 10% to 15% of cases are associated with metastasis. Cryoablation is a new method that can induce tumor necrosis, and treatment of tumors by cryoablation can cause anti-tumor immune responses.

CASE SUMMARY

A 16-year-old woman with SPT of the pancreas developed liver metastases 5.3 years after complete resection of the primary pancreatic tumor. She was admitted with chief complaints of abdominal pain in the upper abdomen and a weight loss of approximately 5 kg over 4 mo. Carbohydrate antigen (CA) 125, carcinoembryonic antigen, and CA 199 were normal. An abdominal computed tomography scan found multiple nodules in the right lobe of the liver that measured approximately 13.5 cm × 10.8 cm × 21.4 cm. Immunohistochemical staining results showed that CD10 and CD56 were positive, and the patient was diagnosed with SPT of the pancreas with liver metastasis. The patient underwent percutaneous cryoablation and interventional embolization. During the 5-year follow-up, the patient remained disease-free after cryoablation, with relatively normal immune function.

CONCLUSION

Herein, we for the first time report the treatment of liver metastasis from SPT of the pancreas using cryoablation plus interventional embolization, which could be a promising alternative therapy for pancreatic SPT liver metastasis.