Microwave Thermal Ablation versus Open Partial Nephrectomy for the Treatment of Small Renal Tumors in Patients Over 70 Years Old

Comparative efficacy and safety of ablative therapies in the management of primary localised renal cell carcinoma: a systematic review and meta-analysis

BACKGROUND

Non-invasive and minimally invasive ablative treatments, including stereotactic body radiotherapy (SBRT), radiofrequency ablation, microwave ablation, and cryoablation, have emerged as key treatment options for managing renal cell carcinoma, especially for patients who are unsuitable for surgery. We aimed to compare the clinical efficacy and safety of these emerging treatment methods in patients with localised renal cell carcinoma.

METHODS

In this systematic review and meta-analysis, we searched PubMed (MEDLINE), Embase, and the Cochrane Library for publications between Jan 1, 2000, and March 1, 2024. Eligible articles were observational studies and randomised controlled trials including at least five adult patients (age ≥18 years) with primary and localised renal cell carcinoma treated with SBRT, radiofrequency ablation, microwave ablation, or cryoablation and that reported on local control outcomes. Two reviewers independently screened titles and abstracts and then full texts of eligible studies were independently evaluated by the same reviewers, with disagreements resolved via discussion or consultation with a third reviewer. Summary estimates were extracted from published reports manually using a standardised data extraction form. The primary endpoint was local control rate at 1 year, 2 years, and 5 years after start of treatment. A meta-analysis was conducted using a DerSimonian and Laird model to summarise local control rates. Publication bias was evaluated using funnel plots and Egger's test. We also recorded the frequency and severity of adverse events after treatment on the basis of the Common Terminology Criteria for Adverse Events (version 5.0) and Clavien-Dindo complication index. The study protocol was prospectively registered with PROSPERO, CRD42024511840.

FINDINGS

We identified 6668 records, of which 330 were assessed via full-text review, and 133 were included in our systematic review and meta-analysis. The eligible studies included data for 8910 patients (mean age 67·9 years [SD 7·3], 2518 [31·4%] of 8018 patients with available data were female and 5500 [68·6%] were male). Local control rates for SBRT were 99% (95% CI 97-100; I2=6%) at 1 year, 97% (95-99; I2=0%) at 2 years, and 95% (89-98; I2=42%) at 5 years; for radiofrequency ablation were 96% (94-98; I2=73%) at 1 year, 95% (92-98; I2=77%) at 2 years, and 92% (88-96; I2=78%) at 5 years; for microwave ablation were 97% (95-99; I2=74%) at 1 year, 95% (92-98; I2=77%) at 2 years, and 86% (75-94; I2=66%) at 5 years; and for cryoablation were 95% (93-96; I2=61%) at 1 year, 94% (91-96; I2=69%) at 2 years, and 90% (87-93; I2=74%) at 5 years. The proportion of patients who reported grade 3-4 adverse events was 3% (121 of 3726) after cryoablation, 2% (39 of 2503) after radiofrequency ablation, 1% (22 of 2069) after microwave ablation, and 2% (11 of 612) after SBRT. Risk of bias was moderate in most studies (70 [53%] of 133) and no publication bias was observed.

INTERPRETATION

All investigated ablative methods continue to represent effective treatment choices in renal cell carcinoma, and these findings support multi-disciplinary discussions of these treatment methods, along with surgery and surveillance, to individualise treatment decisions in these patients. Future research should aim to conduct randomised controlled trials across larger patient populations to further elucidate the long-term oncological and survival outcomes associated with these treatments.

FUNDING

None.

Percutaneous Image-Guided Ablation of Renal Cancer: Traditional and Emerging Indications, Energy Sources, Techniques, and Future Developments

Percutaneous image-guided ablation (IGA) has emerged as an established alternative to surgical management for small renal masses. This comprehensive review examines traditional and emerging indications, energy sources, techniques, and future developments in IGA for renal cancer treatment. Traditionally, IGA has been indicated for frail or comorbid patients, those with solitary kidneys or chronic kidney disease, and those with histologically proven renal cell carcinomas less than 4 cm in size. Recent evidence supports expanding these indications to include T1b or T2 tumours and hereditary or recurrent renal cell carcinomas. The use of IGA combined with pre-ablation transarterial embolisation is discussed herein. This review then explores traditional energy sources including radiofrequency ablation, cryoablation, and microwave ablation, highlighting their respective advantages and limitations. Emerging technologies such as irreversible electroporation and histotripsy, as promising alternatives, are then presented, highlighting their advantage of being able to treat tumours near critical structures. Future research priorities highlight the need to establish high-quality evidence through innovative trial designs, as well as taking patient-reported outcome measures into account. Health economic considerations are key to ensuring that ablation therapies are cost-effective. The integration of artificial intelligence and radiomics shows vast potential for improving patient selection and treatment outcomes. Additionally, the immunomodulatory effects of ablative therapies suggest possible synergistic benefits when combined with immunotherapy which also require exploration in future research. Technological advancement and research developments will continue to broaden the role of IGA in clinical practice.

Partial nephrectomy in elderly patients: a systematic review and analysis of comparative outcomes

PURPOSE

The management of renal masses in the elderly population is particularly challenging, as these patients are often more frail and potentially more susceptible to surgical morbidity. This review aims to provide a comprehensive analysis of the outcomes of partial nephrectomy (PN) for treating renal masses in elderly individuals.

METHODS

A systematic electronic literature search was conducted in May 2024 using the Medline (via PubMed) database by searching publications up to April 2024. The population, intervention, comparator, and outcome (PICO) model defined study eligibility. Studies were deemed eligible if assessing elderly patients (aged 70 years or older) (P) undergoing PN (I) with or without comparison between a different population (non-elderly) or a different treatment option (radical nephrectomy, ablation or active surveillance) (C) evaluating surgical, functional, and oncological outcomes (O).

RESULTS

A total of 23 retrospective studies investigating the role of PN in elderly patients were finally included. PN emerged as a safe procedure also for older patients, demonstrating good outcomes. Preoperative evaluation of frailty status emerged to be paramount. Age alone was discredited as the sole reason to reject the use of PN. The main limitation is the retrospective nature of included studies and the lack of the assessment of elderly patients' frailty.

CONCLUSIONS

The surgical treatment of renal masses in older patients is a challenging scenario. PN should be chosen over RN whenever possible since it can better preserve renal function. The use of minimally invasive techniques should be favored in this extremely fragile group of patients.

Advances in Molecular Mechanisms of Kidney Disease: Integrating Renal Tumorigenesis of Hereditary Cancer Syndrome

Renal cell carcinoma (RCC) comprises various histologically distinct subtypes, each characterized by specific genetic alterations, necessitating individualized management and treatment strategies for each subtype. An exhaustive search of the PubMed database was conducted without any filters or restrictions. Inclusion criteria encompassed original English articles focusing on molecular mechanisms of kidney cancer. On the other hand, all non-original articles and articles published in any language other than English were excluded. Hereditary kidney cancer represents 5-8% of all kidney cancer cases and is associated with syndromes such as von Hippel-Lindau syndrome, Birt-Hogg-Dubè syndrome, succinate dehydrogenase-deficient renal cell cancer syndrome, tuberous sclerosis complex, hereditary papillary renal cell carcinoma, fumarate hydratase deficiency syndrome, BAP1 tumor predisposition syndrome, and other uncommon hereditary cancer syndromes. These conditions are characterized by distinct genetic mutations and related extra-renal symptoms. The majority of renal cell carcinoma predispositions stem from loss-of-function mutations in tumor suppressor genes. These mutations promote malignant advancement through the somatic inactivation of the remaining allele. This review aims to elucidate the main molecular mechanisms underlying the pathophysiology of major syndromes associated with renal cell carcinoma. By providing a comprehensive overview, it aims to facilitate early diagnosis and to highlight the principal therapeutic options available.

Perioperative, functional and oncologic outcomes of percutaneous ablation versus minimally invasive partial nephrectomy for clinical T1 renal tumors: outcomes from a pooled analysis

The objective of this study was to perform a comprehensive pooled analysis aimed at comparing the efficacy and safety of percutaneous ablation (PCA) versus minimally invasive partial nephrectomy (MIPN), including robotic and laparoscopic approaches, in patients diagnosed with cT1 renal tumors. We conducted a comprehensive search across four major electronic databases: PubMed, Embase, Web of Science, and the Cochrane Library, targeting studies published in English up to April 2024. The primary outcomes evaluated in this analysis included perioperative outcomes, functional outcomes, and oncological outcomes. A total of 2449 patients across 17 studies were included in the analysis. PCA demonstrated superior outcomes compared to MIPN in terms of shorter hospital stays (WMD: - 2.13 days; 95% Confidence Interval [CI]: - 3.29, - 0.97; p = 0.0003), reduced operative times (WMD: - 109.99 min; 95% CI: - 141.40, - 78.59; p < 0.00001), and lower overall complication rates (OR: 0.54; 95% CI: 0.40, 0.74; p = 0.0001). However, PCA was associated with a higher rate of local recurrence when compared to MIPN (OR: 3.81; 95% CI: 2.45, 5.92; p < 0.00001). Additionally, no significant differences were observed in major complications, estimated glomerular filtration rate decline, creatinine variation, overall survival, recurrence-free survival, and disease-free survival between the two treatment modalities. PCA presents a notable disadvantage regarding local recurrence rates in comparison to MIPN. However, PCA offers several advantages over MIPN, including shorter durations of hospital stay, reduced operative times, and lower complication rates, while achieving similar outcomes in other oncologic metrics.

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.

Image-Guided Ablation of Renal Masses: Challenges to Produce High-Quality Evidence and Future Directions

Image-guided ablation (IGA) is a rapidly developing field in interventional oncology. There is some evidence suggesting IGA's non-inferiority compared with partial or radical nephrectomy for the treatment of small renal masses (SRM). However, these are mostly limited to retrospective cohort studies. This review article outlines the evidence comparing IGA to partial nephrectomy by collating the different survival measures and evaluates the challenges of producing clinical trials and high-quality evidence. The main challenges are due to the heterogeneity of SRM, patient selection bias, unstandardized endpoint and outcomes, and the lack of global practice standards. Despite the evidence thus far demonstrating that IGA stands as a non-inferior treatment modality for SRMs, exhibiting favorable short- and long-term outcomes, further robust research is needed to integrate ablation techniques into routine clinical practice with a multidisciplinary approach. There is emerging evidence that suggests randomized controlled trial in SRMs is possible, and technologies such as histotripsy as well as artificial intelligence are used in IGA.

Minimally invasive nephron-sparing treatments for T1 renal cell cancer in patients over 75 years: a comparison of outcomes after robot-assisted partial nephrectomy and percutaneous ablation

PURPOSE

To compare the oncological and perioperative outcomes of robot-assisted partial nephrectomy (RPN) and percutaneous thermal ablation (PTA) for treatment of T1 renal cell cancer (RCC) in patients older than 75 years.

MATERIALS AND METHODS

Retrospective national multicenter study included all patients older than 75 years treated for a T1 RCC by RPN or PTA between January 2010 and January 2021. Patients' characteristics, tumor data, and perioperative and oncological outcomes were compared.

RESULTS

A total of 205 patients for 209 procedures (143 RPN and 66 PTA) were included. In the PTA group, patients were older (80.4 ± 3.7 vs. 79 ± 3.7 years (p = 0.01)); frailer (ASA score (2.43 ± 0.6 vs. 2.17 ± 0.6 (p < 0.01)); and more frequently had a history of kidney surgery (16.7% [11/66] vs. 5.6% [8/143] (p = 0.01)) than in the RPN group. Tumors were larger in the RPN group (2.7 ± 0.7 vs. 3.2 ± 0.9 cm (p < 0.01)). Operation time, length of hospital stay, and increase of creatinine serum level were higher in RPN (respectively 92.1 ± 42.7 vs. 150.7 ± 61.3 min (p < 0.01); 1.7 ± 1.4 vs. 4.2 ± 3.4 days (p < 0.01); 1.9 ± 19.3% vs. 10.1 ± 23.7 (p = 0.03)). Disease-free survival and time to progression were similar (respectively, HR 2.2; 95% CI 0.88-5.5; p = 0.09; HR 2.1; 95% CI 0.86-5.2; p = 0.1). Overall survival was shorter for PTA that disappeared after Cox adjusting model (HR 3.3; 95% CI 0.87-12.72; p = 0.08).

CONCLUSION

Similar oncological outcomes are observed after PTA and RPN for T1 RCC in elderly patients.

CLINICAL RELEVANCE STATEMENT

Robot-assisted partial nephrectomy and percutaneous thermal ablation have similar oncological outcomes for T1a kidney cancer in patients over 75 years; however, operative time, decrease in renal function, and length of hospital stay were lower with ablation.

KEY POINTS

• After adjusting model for age and ASA score, similar oncological outcomes are observed after percutaneous thermal ablation and robot-assisted partial nephrectomy for T1 renal cell cancer in elderly patients. • Operation time, length of hospital stay, and increase of creatinine serum level were higher in the robot-assisted partial nephrectomy group.

Comparison of microwave ablation and partial nephrectomy for T1a small renal masses

OBJECTIVE

To compare the oncological and renal function outcomes of microwave ablation (MWA) compared to partial nephrectomy (PN) in two small renal mass (SRM) tumor size cohorts, <3 cm and 3-4 cm.

MATERIALS AND METHODS

This study included retrospective data from 2009 to 2015 and prospective data since 2015 from a single-institution database. Patient demographics, renal mass characteristics, and treatment outcomes were collected. Survival curves and hazard analysis were used to assess oncological outcomes. Changes in eGFR and CKD stage following surgery were used to assess renal function outcomes.

RESULTS

A total of 80 PN and 126 MWA patients were analyzed. Median age and Charlson Comorbidity Index (CCI) of MWA patients were greater than PN for each tumor size cohort. Cumulative progression free survival at 36-months was 91% for MWA and 90% for PN. Preoperative renal function was significantly lower in patients undergoing MWA for both tumor sizes, however there was no significant difference in the postoperative change in renal function between MWA and PN for tumors up to 4 cm.

CONCLUSIONS

Oncological outcomes and renal preservation were comparable between MWA and PN cohorts for SRMs <3cm and 3-4cm despite the MWA cohort being older and having more comorbidities. Our findings suggest that MWA can be used as a safe and effective alternative to PN for T1a renal tumors up to 4 cm.

Cost-effectiveness analysis: percutaneous microwave ablation vs robotic-assisted partial nephrectomy for small renal masses

PURPOSE

The majority of newly diagnosed renal tumors are masses < 4 cm in size with treatment options, including active surveillance, partial nephrectomy, and ablative therapies. The cost-effectiveness literature on the management of small renal masses (SRMs) does not account for recent advances in technology and improvements in technical expertise. We aim to perform a cost-effectiveness analysis for percutaneous microwave ablation (MWA) and robotic-assisted partial nephrectomy (RA-PN) for the treatment of SRMs.

METHODS

We created a decision analytic Markov model depicting management of the SRM incorporating costs, health utilities, and probabilities of complications and recurrence as model inputs using TreeAge. A willingness to pay (WTP) threshold of $100,000 and a lifetime horizon were used. Probabilistic and one-way sensitivity analyses were performed.

RESULTS

Percutaneous MWA was the preferred treatment modality. MWA dominated RA-PN, meaning it resulted in more quality-adjusted life years (QALYs) at a lower cost. Cost-effectiveness analysis revealed a negative Incremental Cost-Effectiveness Ratio (ICER), indicating dominance of MWA. The model revealed MWA had a mean cost of $8,507 and 12.51 QALYs. RA-PN had a mean cost of $21,521 and 12.43 QALYs. Relative preference of MWA was robust to sensitivity analysis of all other variables. Patient starting age and cost of RA-PN had the most dramatic impact on ICER.

CONCLUSION

MWA is more cost-effective for the treatment of SRM when compared with RA-PN and accounting for complication and recurrence risk.

Ablative therapies versus partial nephrectomy for small renal masses - A systematic review and meta-analysis

BACKGROUND

High quality studies and reviews on the management of small renal masses (SRM) are lacking. This review aims to compare oncological outcomes in patients undergoing ablative therapies (AT) or partial nephrectomy (PN) for T1a or T1b SRM.

MATERIAL AND METHODS

Medline, EMBASE, Cochrane CENTRAL and conference proceedings were searched on the 15th July 2020 for comparative studies respective to our research question. The ROBINS-I tool and the GRADE approach were used to assess any risk of biases and certainty of evidence in the included studies. The review is registered on PROSPERO.

RESULTS

1,748 records were retrieved. 32 observational studies and 1 RCT integrating 74,946 patients were included. Patients undergoing AT patients are significantly older than PN patients (MD 5.70, 95%CI 3.83-7.58). In T1a patients, AT patients have significantly worse overall survival (HR 1.64, 95%CI 1.39-1.95). Local recurrence-free survival is similar with PN in patients with longer than five-years follow up (HR 1.54, 95%CI 0.88-2.71). AT patients also have similar cancer-specific survival (CSS), metastasis-free survival, disease-free survival, significantly fewer post-operative complications (RR 0.72, 95%CI 0.55-0.94), and a smaller decline in estimated glomerular filtration rate post-operatively (MD: -7.42, 95%CI -13.1 to -1.70) compared to those undergoing PN. Evidence contradicts in T1b patients for oncological outcomes.

CONCLUSIONS

AT have similar long-term oncological durability; lower rates of complications and superior kidney function preservation compared to PN. Given the low quality of evidence, AT is a reasonable alternative to PN in frail and co-morbid patients. Long-term high-quality studies are needed to confirm the potential benefits of AT, especially in T1b patients.

PROSPERO REGISTRATION

CRD42020199099.

Use of percutaneous microwave ablation in the treatment of retroperitoneal neoplasia in three dogs

CASE DESCRIPTION

3 dogs with retroperitoneal masses (2 renal and 1 located near the diaphragm) were treated by percutaneous microwave ablation (MWA).

CLINICAL FINDINGS

Dogs between 11 and 13 years of age weighing between 13.7 and 43.8 kg had either a renal mass (n = 2) or a mass located in the caudodorsal aspect of the retroperitoneal space near the right side of the diaphragm (1). Cytology revealed that one of the renal masses and the mass located near the diaphragm were malignant neoplasias. Findings on cytologic evaluation of a sample of the other renal mass was nondiagnostic. Maximum mass diameters ranged between 1.4 and 2.5 cm.

TREATMENT AND OUTCOME

All dogs were treated by percutaneous MWA. Probes were directed into tumors by use of ultrasound and CT guidance, and microwave energy was applied to each mass. Findings on imaging of each mass following MWA was consistent with successful treatment. No intraprocedural or major postprocedural complications occurred, and all dogs were discharged from the hospital within 3 days of treatment. Two dogs died at 3 and 21 months after MWA with no known local recurrence; 1 dog was still alive 64 months after treatment.

CLINICAL RELEVANCE

Although the indications for MWA in the treatment of neoplasia in companion animals are limited, the outcomes of dogs in the present report provided preliminary evidence that percutaneous MWA can be safely used to effectively treat retroperitoneal neoplasia. This procedure was successfully performed with image guidance in all 3 dogs.

A review of antenna designs for percutaneous microwave ablation

Microwave (MW) antenna is a key element in microwave ablation (MWA) treatments as the means that energy is delivered in a focused manner to the tumor and its surrounding area. The energy delivered results in a rise in temperature to a lethal level, resulting in cell death in the ablation zone. The delivery of energy and hence the success of MWA is closely dependent on the structure of the antennas. Therefore, three design criteria, such as expected ablation zone pattern, efficiency of energy delivery, and minimization of the diameter of the antennas have been the focus along the evolution of the MW antenna. To further improve the performance of MWA in the treatment of various tumors through inventing novel antennas, this article reviews the state-of-the-art and summarizes the development of MW antenna designs regarding the three design criteria.

The Importance of Reporting Clinical and Epidemiological Data in Urology: Local Experiences and Insights from the International Literature

Pathologies of the genito-urinary tract are responsible for a considerable disease burden worldwide, leading to significant losses of income, lost working days, increased expenditures for national healthcare systems, and decreased quality of life (QoL) in the affected patients. Among these diseases, infections and malignancies in this anatomical region are some of the most important illnesses in human medicine; nevertheless, benign prostate hyperplasia (BPH), erectile dysfunction, hypospadias, urinary incontinence, and vesicoureteral reflux are also relevant disorders affecting millions. The publication of various microbiological and clinical studies in urology from different geographical regions has important ramifications from the standpoint of epidemiology: on one hand, reported data may influence the development of therapeutic guidelines for urinary tract infections (UTIs) (empiric antibiotic-therapy) and malignancies (including classical cytotoxic drug protocols and next-generation anticancer therapies) both locally and internationally; on the other hand, the relevant stakeholders and government representatives often base their decisions on published evidence. Therefore, novel studies in the field of urology are strongly encouraged to maintain and improve the high standard of patient care internationally and to ensure continuous information supply for international datasets on the causative agents of UTIs and cancer registries. The present Editorial aims to highlight some relevant studies published from the field of urology in Medicina over the last several years.