Cryoablation of small kidney tumors

Correlation between bilateral GFR in patients with localized renal cancer after partial nephrectomy

OBJECTIVE

To explore the relationship between the residual glomerular filtration rate (GFR) on the operated side and the GFR on the contralateral side following partial nephrectomy (PN) in patients with localized renal cell carcinoma (RCC).

MATERIALS AND METHODS

Following institutional review board approval, we conducted a retrospective analysis of clinical records from May 2018 to July 2023, involving 118 patients who underwent partial nephrectomy for unilateral localized kidney tumors (T1-T2). Glomerular filtration rate data were assessed using single photon emission computed tomography (SPECT)/computed tomography imaging [using 9mTc-DTPA (diethylenetriaminepentaacetic acid) renal dynamic imaging]. The independent determinants of postoperative renal function or renal function change were determined using linear regression analysis. In addition, the patient's demographic, clinical, and nephrometry characteristics were collected.

RESULTS

A total of 58 patients were finally enrolled. The preoperative and postoperative GFR of bilateral kidneys showed a significant positive correlation. Postoperative GFR of the operated kidney was the independent predictor of GFR of contralateral kidney (p = 0.001). Tumor diameter (p = 0.036), age (p = 0.005), and postoperative GFR of the contralateral kidney (p = 0.001) were all independent predictors of postoperative GFR of the operated kidney. ΔGFR1 was the independent predictor of ΔGFR2. Results showed that a more pronounced postoperative decline in GFR on the operated side corresponded to a weaker compensatory capacity of the contralateral-side kidney.

CONCLUSIONS

During the course of the surgical procedure, the active endeavor to safeguard the renal function of the operated kidney side holds paramount importance, which yields positive outcomes for postoperative kidney function on the contralateral side, consequently contributing to the overall preservation of renal function.

Ablative Treatments for Small Renal Masses and Management of Recurrences: A Comprehensive Review

This review focuses on ablative techniques for small renal masses (SRMs), including radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), and irreversible electroporation (IRE), and discusses recurrence management. Through an extensive literature review, we outline the procedures, outcomes, and follow-up strategies associated with each ablative method. The review provides a detailed examination of these techniques-RFA, CA, MWA, and IRE-elucidating their respective outcomes. Recurrence rates vary among them, with RFA and CA showing comparable rates, MWA demonstrating favorable short-term results, and IRE exhibiting promise in experimental stages. For managing recurrences, various strategies are considered, including active surveillance, re-ablation, or salvage surgery. Surveillance is preferred post-RFA and post-CA, due to slow SRM growth, while re-ablation, particularly with RFA and CA, is deemed feasible without additional complications. Salvage surgery emerges as a viable option for larger or resistant tumors. While ablative techniques offer short-term results comparable to surgery, further research is essential to understand their long-term effects fully. Decisions concerning recurrence management should consider individual and tumor-specific factors. Imaging, notably contrast-enhanced ultrasounds, plays a pivotal role in assessing treatment success, emphasizing the necessity of a multidisciplinary approach for optimal outcomes. The lack of randomized trials highlights the need for further research.

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.

Intraoperative MRI-derived volumetric ablation margins and initial correlation with local outcome after MRI-guided cryoablation of renal tumors

PURPOSE

To assess volumetric ablation margins derived from intraoperative pre- and post-ablation MRI after magnetic resonance imaging (MRI)-guided percutaneous cryoablation of renal tumors and explore its correlation with local treatment success.

METHODS

Retrospective analysis was performed on 30 patients (mean age 69y) who underwent percutaneous MRI-guided cryoablation between May 2014 and May 2020 for 32 renal tumors (size: 1.6-5.1 cm). Tumor and ice-ball volumes were segmented on intraprocedural pre- and post-ablation MR images using Software Assistant for Interventional Radiology (SAFIR) software. After MRI-MRI co-registration, the software automatically quantified the minimal treatment margin (MTM),defined as the smallest 3D distance between the tumor and ice-ball surface. Local tumor progression (LTP) after cryoablation was assessed on follow-up imaging.

RESULTS

Median follow-up was 16 months (range: 1-58). Local control after cryoablation was achieved in 26 cases (81%) while LTP occurred in 6 (19%). The intended MTM of ≥5 mm was achieved in 3/32 (9%) cases. Median MTM was significantly smaller for cases with (- 7 mm; IQR:-10 to - 5) vs. without LTP (3 mm; IQR:2 to 4) (P < .001). All cases of LTP had a negative MTM. All negative treatment margins occurred in tumors > 3 cm.

CONCLUSIONS

Determination of volumetric ablation margins from intraoperative MRI was feasible and may be useful in predicting local outcome after MRI-guided renal cryoablation. In our preliminary data, an intraoperative MRI-derived minimal margin extending at least 1 mm beyond the MRI-visible tumor led to local control and this was more difficult to achieve in tumors > 3 cm. Ultimately, online margin analysis may be a valuable tool to intraoperatively assess therapy success, but larger prospective studies are needed to establish a reliable threshold for clinical use.

Contemporary standards in UK nephrectomy practice: Analysis of the British Association of Urological Surgeons Complex Operations Reports, 2016–2018

Objective:

To analyse the 2016–2018 British Association of Urological Surgeons (BAUS) Complex Operations Reports nephrectomy database, providing a comprehensive description of modern nephrectomy practice.

Patients and Methods:

Analysis of 2016–2018 data held on the BAUS Complex Operations Reports nephrectomy database was performed for 21,366 patients in England. Data are reported on patient, disease, operation and outcome variables.

Results:

Using Hospital Episode Statistics (HES) as a comparator, the database captured an estimated 88% of nephrectomies. Benign nephrectomies (BNs) accounted for 11%, 51% were radical nephrectomies (RNs), 14% were nephroureterectomies (NUs) and 22% were partial nephrectomies (PNs). Of the 2399 BNs, 10% were performed for stone disease, 9% for allograft donation and 9% for infective pathology. Aetiology was not specified further than non-functioning kidney in 51% of cases; 80% of cases adopted minimally invasive surgery (MIS). Histology was benign in 96% of cases. Of 10,843 RNs performed, 77% were performed using MIS. Final histology was renal cell carcinoma in 87% of cases and benign histology confirmed in 9% of cases. Of 3038 NUs performed, 88% were performed using MIS. Histology confirmed malignancy in 94% of cases with transitional cell carcinoma accounting for 82% of cases overall. Of 4708 PNs performed, 74% were performed using MIS; 85% of cases were performed for T1 disease; 16% of cases overall returned benign histology. Across the cohort, 30-day mortality was 0.36%. Transfusion rates were 3.3%, 6.1%, 3.3% and 2.0% for BNs, RNs, NUs and PNs, respectively. In malignant disease, positive surgical margins were present in 0.7% of RNs, 1.2% of NUs and 7.3% of PNs.

Conclusions:

The BAUS nephrectomy dataset provides a real-world description of nephrectomy practice across England, enabling surgeons to compare their practice against a national average. This dataset allows surgeons to share data with patients enhancing informed consent and facilitating shared-decision making. Overall, MIS is widespread, and early mortality after nephrectomy is low.

Level of evidence:

2B

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.

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.

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.

Image-guided thermal ablation of central renal tumors with retrograde cold pyeloperfusion technique: a monocentric experience

Purpose: To evaluate feasibility, safety and efficacy of image-guided thermal ablations associated with retrograde pyeloperfusion in patients with centrally located renal tumors.Materials and methods: 48 patients (15 women, 33 men, mean age 69.1 ± 11.8) were treated with image-guided thermal ablation associated with pyeloperfusion for 58 centrally located renal tumors (mean diameter 32.3 ± 7.32 mm). 7 patients had a single kidney. Microwave and radiofrequency ablation were used. All treatments were performed with ultrasound, CT, or fusion imaging guidance under general anesthesia and simultaneous retrograde cold pyeloperfusion technique.Results: Procedure was feasible in all cases. Technical success and primary technical efficacy were reached in 51/58 (88%) and 45/54 tumors (83%). With a second ablation performed in 5 tumors, secondary technical efficacy was achieved in 50/50 (100%) tumors. Minor and major complications occurred in 8/58 (13%) and 5/58 (8%) tumors. No significative change in renal function occurred after treatment.During follow-up, 5 recurrences occurred, that were retreated with a second ablation. At last follow up (mean 32.2 ± 22.0 months), 41/48 (85%) treated patients were free from disease. The median TTP and PFS were 27.0 (range, 2.3-80.0) and 26.5 months (range, 2.3-80.0), respectively.Conclusion: Image-guided thermal ablation associated with protective pyeloperfusion is a feasible, safe, and effective treatment option for patients with central renal tumors with a minimal impact on renal function and relevant potential to avoid nephrectomy.

Safety and effectiveness of percutaneous renal cryoablation with conscious sedation

OBJECTIVE

To investigate complications and treatment failure rates of percutaneous renal cryoablation (PRC) for small renal masses under local anaesthesia and conscious sedation (LACS), to assess the safety and effectiveness of this approach, as PRC is typically performed under general anaesthesia (GA).

PATIENTS AND METHODS

We retrospectively reviewed PRC under LACS from 2003 to 2017. We analysed perioperative parameters between patients who successfully underwent PRC under LACS and patients with post-procedural complications or treatment failure (renal mass enhancement after successful intraoperative tumour ablation). Two-sided non-parametric and Fisher's exact tests were performed to compare uncomplicated or disease-free PRC with the complication or treatment failure group, respectively.

RESULTS

A total of 100 PRCs under LACS were performed during the study period. Of these patients, six patients had at least one postoperative complication (6%), and treatment failure was diagnosed in nine patients (9%) after PRC [mean (SD) follow-up of 42.7 (26.6) months]. The procedural failure rate was 1%. No ablations were converted to GA. The mean tumour size was smaller in patients who had no complications during PRC compared to those who did, at a mean (SD) of 2.2 (0.6) cm vs 3.0 (1.0) cm (P = 0.039). The use of more intraoperative probes during the PRC was also associated with complications, at a mean (SD) 3.0 (1.4) vs 1.8 (0.8) (P = 0.021).

CONCLUSIONS

PRC under LACS is an effective and safe procedural approach for managing small renal masses with low complication, treatment failure, and procedural failure rates. Larger renal masses and intraoperative use of multiple probes is associated with an increased risk of PRC complications.

ABBREVIATIONS

BMI: body mass index; CCI: Charlson Comorbidity Index; GA: general anaesthesia; LACS: local anaesthesia and conscious sedation; PRC: percutaneous renal cryoablation; R.E.N.A.L.: Radius, Exophytic/Endophytic, Nearness, Anterior/Posterior, Location.

Active surveillance and focal ablation for small renal masses: a better solution for comorbid patients

The natural history of small renal masses (SRM) is still not well understood and they are frequently incidentally diagnosed in elderly patients. Therefore, there is a need for less invasive options sparing the patient from the side-effects related to conventional surgical treatment. PubMed and Medline database search was performed to look for new findings on active surveillance and focal therapy for SRM. Sixty-one articles published between 2002 and 2018 were selected for the purpose of the review. There is growing evidence confirming the safety of active surveillance in patients at surgical risk and there appears to be a satisfactory intermediate-term outcome of focal treatment of SRM. In the group of elderly patients with a decreased life expectancy active surveillance appears to be the most appropriate approach. The future of minimally invasive therapy appears bright, especially with the improvement of new imaging modalities.

Acute gouty arthritis following percutaneous cryoablation of renal cell carcinoma

We report a case of acute gouty monoarthritis of the left ankle in a 58-year-old female with chronic renal insufficiency after cryoablation of a 3.8 cm left renal cell carcinoma. The patient's symptoms resolved after intravenous Solumedrol and did not recur at her 1-month follow-up visit. To the best of our knowledge, this is the first reported case of acute gouty monoarthritis after cryoablation of a renal cell carcinoma lesion in a patient with underlying chronic renal insufficiency. Clinicians should be vigilant of the potential for this complication in at-risk patient populations.

Current opinion in urology 2017: focal therapy of small renal lesions

PURPOSE OF REVIEW

With the increasing incidence of small renal masses (SRMs), ablative technologies are becoming more commonly utilized. With any nascent treatment modality, outcomes literature needs to be constantly re-evaluated. The purpose of this review is to revisit the most updated literature regarding the safety and efficacy of ablative treatments of renal lesions.

RECENT FINDINGS

Recent literature demonstrates that small renal tumor ablation is safe and effective. Although it does not have the same oncological efficacy of surgical extirpation, local recurrence-free survival has consistently shown to be around 90%. Cryoablation and radiofrequency ablation have longer-term data demonstrating durable responses. Microwave ablation and irreversible electroporation are promising modalities with longer-term data coming. Complication rates and procedural morbidity of ablation are consistently lower than for partial nephrectomy.

SUMMARY

Image-guided focal ablation is a valuable tool in the management of SRMs. Although it does not have the same efficacy of surgical extirpation, with the ability to perform repeat procedures and salvage surgery if necessary, oncologic outcomes are comparable to those of upfront surgery. Ultimately, longer-term studies and prospective trials are needed to further elucidate these modalities.

Percutaneous cryoablation for renal cell carcinoma using ultrasound-guided targeting and computed tomography-guided ice-ball monitoring: radiation dose and short-term outcomes

BACKGROUND

Usefulness of ultrasound (US)-guided mass targeting and computed tomography (CT)-guided ice-ball monitoring in percutaneous cryoablation (PCA) for renal cell carcinoma (RCC) is still uncertain.

PURPOSE

To assess radiation dose and short-term outcomes of PCA for RCC using US-guided targeting and CT-guided ice-ball monitoring.

MATERIAL AND METHODS

Thirty-nine consecutive patients who underwent PCA for biopsy-proven RCC were included. Mass targeting was performed with US and ice-ball was monitored with CT guidance. Effective radiation dose of CT during PCA was recorded. Follow-up was conducted with contrast-enhanced CT or magnetic resonance imaging (MRI) (mean follow-up time = 10.1 ± 7.0 months). Local tumor progression was defined by the presence of focal enhancing areas at the ablation zone (CT, ≥ 20 HU; MRI, presence of focal enhancement on subtraction contrast-enhanced image). Technical success, major complication rate (e.g. Clavien-Dindo classification ≥ 3), and one-year local tumor progression-free survival (PFS) rate were analyzed.

RESULTS

Mean effective radiation dose in association with PCA was 12.1 ± 4.5 mSv (range = 7.0-25.2 mSv). Technical success was achieved in 100%. Local tumor progression occurred in a single patient (2.6%, 1/39), and one-year local tumor PFS rate was 95.7%. No major complication was found.

CONCLUSION

PCA using US-guided targeting and CT-guided ice-ball monitoring may allow acceptable local tumor control for RCC, as a radiation-reducing strategy.

Percutaneous image-guided cryoablation: current applications and results in the oncologic field

Percutaneous imaging-guided cryoablation (PICA) is a recently developed technique, which applies extreme hypothermia to destroy tumours under close imaging surveillance. It is minimally invasive, safe, repeatable, and does not interrupt or compromise other oncologic therapies. It presents several advantages over more established heat-based thermal ablation techniques (e.g. radiofrequency ablation; RFA) including intrinsic analgesic properties, superior monitoring capability on multi-modal imaging, ability to treat larger tumours, and preservation of tissue collagenous architecture. There has been a recent large increase in reports evaluating the utility of PICA in a wide range of patients and tumours, but systematic analysis of the literature is challenging due to the rapid pace of change and predominance of extensively heterogeneous level III studies. The precise onco-therapeutic role of PICA has not been established. This narrative review outlines the available evidence for PICA in a range of tumours. Current indications include curative therapy of small T1a renal tumours; curative/palliative therapy of small primary/secondary lung tumours where RFA is unsuitable; palliation of painful bone metastases; and urologic treatment of organ-confined prostate cancer. There is growing evidence to support its use for small hepatic tumours, and encouraging results have been obtained for breast tumours, extra-abdominal desmoid tumours, and management of higher-stage tumours and oligometastatic disease. However, the overall evidence base is weak, effectively restricting PICA to cases where standard therapy and RFA are unsuitable. As the technique and evidence continue to mature, the benefits of this emerging technique will hopefully become more widely available to cancer patients in the future.