Cryoablation versus Partial Nephrectomy for Clinical Stage T1 Renal Masses: A Systematic Review and Meta-Analysis

Percutaneous ablation versus robotic‑assisted partial nephrectomy for cT1 renal cell carcinoma: an evidence-based analysis of comparative outcomes

This investigation sought to conduct a comprehensive meta-analysis to assess the comparative effectiveness and safety of percutaneous ablation (PCA) versus robotic-assisted partial nephrectomy (RAPN) among individuals diagnosed with cT1 renal tumors. This study rigorously followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to conduct a systematic review and meta-analysis. A systematic search was carried out in the PubMed, Embase, Web of Science, and Cochrane Library databases, focusing on studies published in English through February 2024. We focused on evaluating primary outcomes, specifically perioperative outcomes, functional outcomes, and oncological outcomes. In this analysis, data from 1534 patients across 13 studies were evaluated. PCA was found to have advantageous outcomes in comparison to RAPN regarding hospital stay durations, with a Weighted Mean Difference (WMD) of - 2.03 days (95% Confidence Interval [CI]: -3.78 to - 0.27; p = 0.02), operative times (WMD: -106.75 min; 95% CI: - 170.78 to - 42.72; p = 0.001), and overall complication rates (Odds Ratio [OR]: 0.61; 95% CI: 0.42 to 0.89; p = 0.01). Conversely, PCA showed a higher incidence of local recurrence compared to RAPN, with an OR of 3.20 (95% CI: 1.91 to 5.35; p < 0.00001). Moreover, there were no statistically significant differences between the two treatments in terms of major complications, declines in estimated glomerular filtration rates (eGFR), variations in creatinine levels, overall survival rates, and recurrence-free survival. While PCA exhibits higher local recurrence rates than RAPN, it also presents significant advantages, such as shorter hospital stays, decreased operative durations, and lower complication rates. This juxtaposition underscores the urgent need for further, more rigorous research to substantiate these findings.

Renal Function After CT-Guided Cryoablation of Small Renal Tumours in Patients with Solitary Kidney: An Analysis of European Multinational Prospective EuRECA Registry

PURPOSE

Treatment of renal cell carcinoma (RCC) in patients with solitary kidneys remains challenging. The purpose of this multicentre cohort study was to explore how renal function is affected by percutaneous image-guided cryoablation in patients with solitary kidneys.

MATERIAL AND METHODS

Data from the European Registry for Renal Cryoablation database were extracted on patients with RCC in solitary kidneys treated with image-guided, percutaneous cryoablation. Patients were excluded if they had multiple tumours, had received previous treatment of the tumour, or were treated with more than one cryoablation procedure. Pre- and post-treatment eGFR (within 3 months of the procedure) were compared.

RESULTS

Of 222 patients with solitary kidneys entered into the database, a total of 70 patients met inclusion criteria. The mean baseline eGFR was 55.8 ± 16.8 mL/min/1.73 m2, and the mean 3-month post-operative eGFR was 49.6 ± 16.5 mL/min/1.73 m2. Mean eGFR reduction was - 6.2 mL/min/1.73 m2 corresponding to 11.1% (p = 0.01). No patients changed chronic kidney disease group to severe or end-stage chronic kidney disease (stage IV or V). No patients required post-procedure dialysis.

CONCLUSION

Image-guided renal cryoablation appears to be safe and effective for renal function preservation in patients with RCC in a solitary kidney. Following cryoablation, all patients had preservation of renal function without the need for dialysis or progression in chronic kidney disease stage despite the statistically significant reduction in eGFR. LEVEL OF EVIDENCE 3: Observational study.

Feasibility test of a sapphire cryoprobe with optical monitoring of tissue freezing

This article describes a sapphire cryoprobe as a promising solution to the significant problem of modern cryosurgery that is the monitoring of tissue freezing. This probe consists of a sapphire rod manufactured by the edge-defined film-fed growth technique from Al₂ O₃ melt and optical fibers accommodated inside the rod and connected to the source and the detector. The probe's design enables detection of spatially resolved diffuse reflected intensities of tissue optical response, which are used for the estimation of tissue freezing depth. The current type of the 12.5-mm diameter sapphire probe cooled down by the liquid nitrogen assumes a superficial cryoablation. The experimental test made by using a gelatin-intralipid tissue phantom shows the feasibility of such concept, revealing the capabilities of monitoring the freezing depth up to 10 mm by the particular instrumentation realization of the probe. This justifies a potential of sapphire-based instruments aided by optical diagnosis in modern cryosurgery.

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.

Progress in the cryoablation and cryoimmunotherapy for tumor

With the rapid advancement of imaging equipment and minimally invasive technology, cryoablation technology is being used more frequently in minimally invasive treatment of tumors, primarily for patients with early tumors who voluntarily consent to ablation as well as those with advanced tumors that cannot be surgically removed or cannot be tolerated. Cryoablation is more effective and secure for target lesions than other thermal ablation methods like microwave and radiofrequency ablation (RFA). The study also discovered that cryoablation, in addition to causing tumor tissue necrosis and apoptosis, can facilitate the release of tumor-derived autoantigens into the bloodstream and activate the host immune system to elicit beneficial anti-tumor immunological responses against primary. This may result in regression of the primary tumor and distant metastasis. The additional effect called " Accompanying effects ". It is the basis of combined ablation and immunotherapy for tumor. At present, there is a lot of research on the mechanism of immune response induced by cryoablation. Trying to solve the question: how positively induce immune response. In this review, we focus on: 1. the immune effects induced by cryoablation. 2. the effect and mechanism of tumor immunotherapy combined with cryoablation. 3.The clinical research of this combination therapy in the treatment of tumors.

Cryoablation for the Treatment of Kidney Cancer: Comparison With Other Treatment Modalities and Review of Current Treatment

With cancer among the leading causes of death worldwide and kidney cancer among the more common cancers in the United States, it has become increasingly important to ensure that first-line treatments remain validated and supported in recent literature. Surgical intervention has long remained the gold standard for intervention but with newer techniques and technology on the horizon, there must be a constant review of other options that may provide improved outcomes and reduction of associated risks. Ablative techniques have gained traction and are becoming a valuable intervention for multiple different types of cancers, kidney cancer included. Cryoablation, a newer ablative technique taking advantage of extreme cold to freeze and destroy abnormal tissue, provides a promising option for treatment. Currently, no review article, to our knowledge, compares all the different treatment options for kidney cancer. Additionally, while some literature has addressed cryoablation in comparison to other methods of management, there has not been an extensive review to combine our current understanding of these comparisons. In this review article, we provide an overview of each of the commonly used treatments for kidney cancer and summarize the current literature regarding the advantages and disadvantages of each intervention. Finally, we seek to compare cryoablation, a newer option for treatment, to each of the approaches with the goal of evaluating the best methods for management and determining cryoablation's role alongside these current interventions.

Assessing Trifecta Achievement after Percutaneous Cryoablation of Small Renal Masses: Results from a Multi-Institutional Collaboration

Background and Objectives: To assess efficacy and safety of Percutaneous Cryoablation (PCA) of small renal masses (SRMs) using Trifecta outcomes in a large cohort of patients who were not eligible for surgery. Materials and methods: All PCAs performed in four different centers between September 2009 and September 2019 were retrospectively evaluated. Patients were divided in two different groups depending on masses dimensional criteria: Group-A: diameter ≤ 25 mm and Group-B: diameter > 25 mm. Complications rates were reported and classified according to the Clavien−Dindo system. The estimate glomerular filtration rate (eGFR) was calculated before PCA and during follow-up schedule. Every patient received a Contrast Enhanced Ultrasound (CEUS) evaluation on the first postoperative day. Radiological follow-up was taken at 3, 6, and 12 months for the first year, then yearly. Radiological recurrence was defined as a contrast enhancement persistence and was reported in the study. Finally, Trifecta outcome, which included complications, RFS, and preservation of eGFR class, was calculated for every procedure at a median follow-up of 32 months. Results: The median age of the patients was 74 years. Group-A included 200 procedures while Group-B included 140. Seventy-eight patients were eligible for Trifecta evaluation. Trifecta was achieved in 69.6% of procedures in Group-A, 40.6% in Group-B (p = 0.02). We observed an increased rate of complication in Group-B (13.0% vs. 28.6; p < 0.001). However, 97.5% were <II Clavien−Dindo grade. No differences were found between the two groups regarding eGFR before and after treatment. Further, 24-months RFS rates were respectively 98.0% for Group-A and 92.1% in Group-B, while at 36 months were respectively 94.5% and 87.5% (p = 0.08). Conclusions: PCA seems to be a safe and effective treatment for SRM but in the need of more strict dimensional criteria to achieve a higher possible success rate.

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.

Radiation dose reduction in CT-guided cryoablation of renal tumors

PURPOSE

We aimed to evaluate the effect on the radiation dose to the patient by reducing the tube current during the placement of the ablation needles (reduced dose group) compared with the patient doses delivered when scanning at the standard fully diagnostic level (full dose group) in computed tomography (CT)-guided percutaneous cryoablation.

METHODS

We conducted a retrospective study of 103 patients undergoing cryoablation in a tertiary cancer center. Overall, 62 patients were scanned with standard exposure parameters (full dose group) set on a 64-slice multidetector CT scanner, while 41 patients were scanned on a reduced dose protocol. Dose levels were retrieved from the hospital picture and archiving communication system including the volumetric CT dose index (CTDIvol), total dose length product (DLP), length of cryoablation procedure, number of cryoablation needles and patient size. Wilcoxon Mann-Whitney (rank-sum) tests were used to compare the median DLP, CTDIvol and skin dose between the two groups.

RESULTS

Median total DLP for the full dose group was 6025 mGy•cm (1909-13353 mGy•cm) compared with 3391 mGy•cm (1683-6820 mGy•cm) for the reduced dose group. The reduced dose group had a 44% reduction in total DLP and 42% reduction in total CTDIvol (p < 0.001). The estimated skin doses were 384 mGy for the full dose group and 224 mGy for the reduced dose group (42% reduction) (p < 0.001). At 12-month follow-up, the technical success for the full dose (n=62) was 97% with 2 patients requiring a further cryoablation treatment for residual tumor. The technical success for the reduced dose group (n=41) was 100%.

CONCLUSION

CT dose reduction technique during image-guided cryoablation treatment of renal tumors can achieve significant radiation dose reduction whilst maintaining sufficient image quality.

Functional and oncological outcome of percutaneous cryoablation versus laparoscopic partial nephrectomy for clinical T1 renal tumors: A propensity score-matched analysis

PURPOSE

To evaluate the clinical trifecta of percutaneous cryoablation (PCA) vs. laparoscopic partial nephrectomy (LPN) for cT1 renal tumors.

PATIENTS AND METHODS

We retrospectively analyzed the records of patients who had undergone 2 types of nephron sparing surgeries (NSS) PCA or LPN for cT1 renal tumors between November 2011 and December 2019. The cohorts were matched by one-to-one propensity scores based on patient demographics, renal function, and tumor complexity. Perioperative and oncological outcomes and preservation of renal function following surgery were compared.

RESULTS

After matching, a total of 180 patients who had undergone NSS for de novo renal tumors were evaluable: 90 for PCA and 90 for LPN. No statistically significant differences were noted among the measured baseline characteristics in the propensity score-matched cohorts. Overall perioperative complication rates were 5.5% in the PCA and 11.1% in the LPN groups (P = 0.28). The rate of eGFR preservation 1 to 3 months after surgery was significantly higher for PCA than for LPN (92.8 ± 11.5% vs. 88.5 ± 14.6%, P = 0.03). Median follow-up was 33 months for PCA and 18 months for LPN (P < 0.001). Three residual and 4 recurrent tumors were later diagnosed in the PCA group and 1 recurrent tumor in the LPN group. The 5-year local recurrence-free survival was lower for PCA than LPN (90.2% vs. 98.5%, P = 0.36). The 5-year metastasis-free survival rate was similar in both groups (98.4% vs. 100%, P = 0.38). The 5-year overall and cancer-specific survival rates were comparable in both groups (91.7% vs. 98.9%, P = 0.53, and 95% vs. 100%, P = 0.55, respectively).

CONCLUSIONS

Clinical T1 RCC patients are better treated with LPN if technically possible. Though PCA had a higher local recurrence rate, medium-term local control was not inferior to LPN. Additionally, PCA patients tended to retain renal function without severe complications. PCA appears to be a reasonable option for patients with high comorbidity at presentation.

Validation of a Web-Based Planning Tool for Percutaneous Cryoablation of Renal Tumors

Purpose

To validate a simulation environment for virtual planning of percutaneous cryoablation of renal tumors.

Materials and Methods

Prospectively collected data from 19 MR-guided procedures were used for validation of the simulation model. Volumetric overlap of the simulated ablation zone volume (Σ) and the segmented ablation zone volume (S; assessed on 1-month follow-up scan) was quantified. Validation metrics were DICE Similarity Coefficient (DSC; the ratio between twice the overlapping volume of both ablation zones divided by the sum of both ablation zone volumes), target overlap (the ratio between the overlapping volume of both ablation zones to the volume of S; low ratio means S is underestimated), and positive predictive value (the ratio between the overlapping volume of both ablation zones to the volume of Σ; low ratio means S is overestimated). Values were between 0 (no alignment) and 1 (perfect alignment), a value > 0.7 is considered good.

Results

Mean volumes of S and Σ were 14.8 cm³ (± 9.9) and 26.7 cm³ (± 15.0), respectively. Mean DSC value was 0.63 (± 0.2), and ≥ 0.7 in 9 cases (47%). Mean target overlap and positive predictive value were 0.88 (± 0.11) and 0.53 (± 0.24), respectively. In 17 cases (89%), target overlap was ≥ 0.7; positive predictive value was ≥ 0.7 in 4 cases (21%) and < 0.6 in 13 cases (68%). This indicates S is overestimated in the majority of cases.

Conclusion

The validation results showed a tendency of the simulation model to overestimate the ablation effect. Model adjustments are necessary to make it suitable for clinical use.

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.

Three-dimensional reconstruction facilitates off-clamp laparoscopic partial nephrectomy for stage cT1b renal tumors

Background

This study aimed to evaluate the role of three-dimensional (3D) reconstruction of T1b renal tumors in the off-clamp laparoscopic partial nephrectomy (LPN).

Methods

A total of 40 consecutive patients undergoing LPN for stage cT1b renal tumor between January 2018 and July 2018 were included. Twenty received off-clamp LPN under the guidance of 3D reconstruction (3D group), and remaining 20 underwent off-clamp LPN under the guidance of conventional computer tomography arteriography (CTA group). The demographics, perioperative characteristics and renal function were compared between groups.

Results

All the procedures were performed successfully without conversion to main renal artery clamping. There were no significant differences in the age, gender, body mass index (BMI), tumor size, and RENAL score between two groups. The mean operation time (OT) was significantly shorter and estimated blood loss markedly less in the 3D group than in the CTA group. Incidence of postoperative complications was 5% in the 3D group and 10% in the CTA group (P>0.05). 3D reconstruction of renal tumors resulted in more accurate dissection of the tumor artery (90.9%) as compared to conventional CTA (81.5%). All the patients had negative surgical margins. There was no significant difference in the estimated glomerular filtration rate (eGFR) before and after surgery between two groups.

Conclusions

3D reconstruction is beneficial for the resection of cT1b renal tumor and tumor-specific feeding arteries in the off-clamp LPN.

Percutaneous Image-guided Thermal Ablation for Renal Cell Carcinoma

Nephrectomy is the gold standard for the treatment of renal cell carcinoma (RCC). However, some patients are not suitable candidates for nephrectomy because of high surgical risk, reduced renal function, or the presence of multiple renal tumors. Percutaneous image-guided thermal ablation, including cryoablation and radiofrequency ablation, is a minimally invasive and highly effective treatment and can be used to treat RCC in patients who are not good candidates for surgery. This article will review percutaneous image-guided thermal ablation for RCC, covering treatment indications, ablation modalities and techniques, oncologic outcomes, and possible complications. In addition, the characteristics of each ablation modality and its comparison with nephrectomy are also presented.