Safety and efficacy of RFA versus MWA for T1a renal cell carcinoma: a propensity score analysis

Current use of percutaneous ablation in renal tumors: an analysis of the registry of the German Society for Interventional Radiology and Minimally Invasive Therapy

OBJECTIVE

To evaluate the success and complications of thermal ablation (TA) based on the voluntary, prospective registry of the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) with 303 participating centers from Germany, Austria, and Switzerland.

MATERIALS AND METHODS

Registry data from 2018 until 2023 of 1102 patients with small renal tumors (age: 72.5 ± 11.6 years; female: 33.6%, 370/1102) were analyzed. Hospitals with ≥ 20 TAs were considered high-volume centers. Technical success and complication rates between different parameters were compared using the chi-square or Fisher's exact test, p < 0.05 was considered statistically significant.

RESULTS

Patients were most frequently treated with radiofrequency ablation (RFA, 43.6%, 481/1102), then microwave ablation (MWA, 41.9%, 462/1102) or cryoablation (13.3%, 147/1102). Technical success for heat-based TA (RFA&MWA) was 94.3% (893/947), for cryoablation 97.3% (143/147). RFA&MWA was significantly more successful in lesions ≤ 3 cm (96.1%, 567/590) compared to 3-4 cm lesions (89.8%, 97/108; p = 0.005). In patients treated with cryoablation, no significant differences between sizes could be found (≤ 3 cm: 97.9%, 94/96; 3-4 cm: 85.7%, 12/14; p = 0.078). Complication rate was significantly higher in RFA&MWA of lesions 3-4 cm compared to ≤ 3 cm (≤ 3 cm: 3.9%, 23/590; 3-4 cm: 11.1%, 12/108, p = 0.002), while no significant differences were seen regarding cryoablation (≤ 3 cm: 1.0%, 1/96; 3-4 cm: 0.0%, 0/14; p = 1.000).

CONCLUSIONS

In this exploratory analysis of the DeGIR registry, percutaneous TA of small renal masses is technically feasible with low complication rates. Heat-based TAs seem to have lower success rates and higher complication rates in larger tumors. Cryoablation could potentially be a safe alternative for 3- to 4-cm-sized tumors.

KEY POINTS

Question How effective is renal thermal ablation (TA) in terms of treatment success and complication rates? Findings In contrast to cryoablation, heat-based thermal ablation has lower success and higher complication rates in tumors measuring 3-4 cm compared to tumors < 3 cm. Clinical relevance Thermal ablation is not influenced by the need for additional techniques such as cooling, protective organ displacement, or temporary vessel occlusion. For small renal tumors, TA is an effective and safe treatment option. Cryoablation could be beneficial in larger tumors.

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.

Microwave vs radiofrequency ablation for small renal masses: perioperative and oncological outcomes

OBJECTIVE

To conduct a comprehensive comparison of microwave ablation (MWA) vs radiofrequency ablation (RFA) outcomes in the treatment of small renal masses (SRMs), specifically: TRIFECTA ([i] complete ablation, [ii] absence of Clavien-Dindo Grade ≥III complications, and [iii] absence of ≥30% decrease in estimated glomerular filtration rate) achievement, operative time (OT), and local recurrence rate (LRR).

PATIENTS AND METHODS

We retrospectively analysed 531 patients with SRMs (clinical T1a-b) treated with MWA or RFA at a single centre (2008-2022). First, multivariable logistic regression models were used for testing TRIFECTA achievement. Second, multivariable Poisson regression models were used to evaluate variables associated with longer OT. Finally, Kaplan-Meier plots depicted LRR over time. All analyses were repeated after 1:1 propensity score matching (PSM).

RESULTS

Of 531 patients with SRMs, 373/531 (70.2%) underwent MWA and 158/531 (29.8%) RFA. MWA demonstrated superior TRIFECTA achievement (314/373 [84.2%]) compared to RFA (114/158 [72.2%], P = 0.001). These differences were driven by higher rates of complete ablation in MWA- vs RFA-treated patients (348/373 [93.3%] vs 137/158 [86.7%], P < 0.001). In multivariable logistic regression models, MWA was associated with higher TRIFECTA achievement, compared to RFA, before (odds ratio [OR] 1.92, P = 0.008) and after PSM (OR 1.99, P = 0.023). Finally, the median OT was shorter for MWA vs RFA (105 vs 115 min; P = 0.002). At Poisson regression analyses, MWA predicted shorter OT before (incidence rate ratio [IRR] 0.86, P < 0.001) and after PSM (IRR 0.85, P < 0.001). Local recurrence occurred in 17/373 (4.6%) MWA-treated patients and 21/158 (13.3%) RFA-treated patients (P = 0.29) after a median (interquartile range) follow-up of 24 (8-46) months. There were no differences in the LRR in Kaplan-Meier plots before (P = 0.29) and after PSM (P = 0.42).

CONCLUSION

Microwave ablation provides higher TRIFECTA achievement, and shorter OT than RFA. No significant differences were found regarding the LRR.

Percutaneous irreversible electroporation of renal cell carcinomas in an acquired solitary kidney: A primary study

OBJECTIVE

To evaluate the postoperative complications and prognosis of renal cell carcinoma (RCC) in a solitary kidney after irreversible electroporation (IRE).

MATERIALS AND METHODS

A total of 8 patients with 9 RCCs in a solitary kidney treated with computed tomography (CT)-guided IRE from February 2017 to September 2020 were retrospectively analyzed. Follow-up included contrast-enhanced CT or magnetic resonance imaging examinations at 1 day, 1 week, 1 month, 3 months, 6 months, 12 months, and each year after IRE and the evaluation of the incidence of postoperative complications, renal function changes, local tumor recurrence, and metastasis.

RESULTS

Technical success was achieved in all 8 patients treated with IRE. No serious complications were observed. Recurrence or metastasis occurred in two patients. The renal function and hemoglobin values of the 8 patients before treatment and at the last follow-up showed no significant difference.

CONCLUSION

IRE is a relatively effective, safe, and feasible treatment for RCCs in a solitary kidney, which improved the effective survival and quality of life of these patients.

Effective strategies to enhance the diagnosis and treatment of RCC: The application of biocompatible materials

Renal cell carcinoma (RCC) is recognized as one of the three primary malignant tumors affecting the urinary system, posing a significant risk to human health and life. Despite advancements in understanding RCC, challenges persist in its diagnosis and treatment, particularly in early detection and diagnosis due to issues of low specificity and sensitivity. Consequently, there is an urgent need for the development of effective strategies to enhance diagnostic accuracy and treatment outcomes for RCC. In recent years, with the extensive research on materials for applications in the biomedical field, some materials have been identified as promising for clinical applications, e.g., in the diagnosis and treatment of many tumors, including RCC. Herein, we summarize the latest materials that are being studied and have been applied in the early diagnosis and treatment of RCC. While focusing on their adjuvant effects, we also discuss their technical principles and safety, thus highlighting the value and potential of their application. In addition, we also discuss the limitations of the application of these materials and possible future directions, providing new insights for improving RCC diagnosis and treatment.

Percutaneous microwave ablation of T1a renal cell carcinomas: A 10-year single-center retrospective review

INTRODUCTION

Partial nephrectomy is currently the preferred treatment option for T1a renal cell carcinomas (RCC), with nephron-sparing techniques, including microwave ablation, becoming more common in select patients. Primary aims are to document outcomes of microwave ablation for T1a RCCs in an Australian tertiary centre to add to the evidence for its safety and efficacy.

METHODS

The prospectively maintained Sir Charles Gairdner Hospital Interventional Radiology database was retrospectively searched for all Renal Microwave ablations completed between June 2012 and February 2022. This database and a combination of hospital programmes including Agfa Impax PACS, Bossnet digital medical record and iSoft Clinical Manager were used to extract the relevant data which was anonymized and entered into an Excel spreadsheet for analysis.

RESULTS

Forty-eight patients underwent microwave ablation for 50 tumours. Of these, there were two local and two distant recurrences. A fifth patient had metastases on presentation. Higher local recurrence rates were associated with larger tumour size (P = 0.043). Tumour proximity to the collecting system <4 mm was associated with higher rates of complications (P = 0.020). RENAL scores did not show statistically significant correlation with complications (P = 0.092) or local or distant recurrence. Notably, the study follow-up time was longer than many comparative studies (mean = 2796, ~7.66 years censoring for death and mean = 832 days, ~2.28 years not censoring for death).

CONCLUSION

Consistent with the literature, this study further demonstrates that microwave ablation is a safe and efficacious option for treatment of T1a RCC.

Efficacy and safety of radiofrequency ablation in the treatment of inoperable patients with pulmonary malignant nodules

BACKGROUND

Radiofrequency ablation (RFA) has been recently applied as an alternative treatment in the patients with pulmonary malignancies. The aim of our study was to assess the incidence of complications and survival rate of RFA for malignant lung nodules, and evaluate the efficacy and safety of RFA in the treatment of inoperable patients with pulmonary malignant nodules.

METHODS

The clinical data of 50 patients with primary and metastatic lung malignant nodules treated with RFA from June 2015 and July 2017 in Hebei General Hospital were considered, and the characteristics and clinical data of these patients were analysed. Complications, progression-free survival and overall survival at 1, 2 and 5 years of these patients were evaluated.

RESULTS

Following the procedure. There were no major complications and deaths during the operation. 26 (52%) patients presented mild-to-moderate chest pain that was easily controlled by analgesic drugs. 8 (16%) patients with pneumothorax, 4 (8%) haemoptysis, 6 (12%) pneumonia, 7 (14%) pleural effusion and 1 (2%) postoperative bronchopleural fistula. Needle-track implantation was observed in 2 (4%) patients. Median progression-free survival (PFS) was 24.6 months. The PFS at 1, 2, 5 years was 76%, 52% and 20%, respectively. Median overall survival (OS) was 35.5 months. The OS at 1, 2 and 5 years was 80%, 58% and 32%, respectively.

CONCLUSION

RFA is a safe and effective alternative treatment for the inoperable patients with primary or metastatic pulmonary malignant nodules. The clinical impact and long-term results of RFA need to be further confirmed in a larger series of patients, and RFA should ideally be compared with surgery.

Synergistic effect of OK-432 in combination with an anti-PD-1 antibody for residual tumors after radiofrequency ablation of hepatocellular carcinoma

BACKGROUND AND AIMS

Radiofrequency ablation (RFA) often results in incomplete ablation for medium-to-large and irregular tumors. To solve this clinical problem, we proposed a new treatment strategy of OK-432 in combination with an anti-programmed cell death protein 1 (αPD-1) antibody for residual tumors after incomplete RFA (iRFA) of hepatocellular carcinoma (HCC).

APPROACH AND RESULTS

The effect of OK-432 on immature dendritic cells (iDCs) was evaluated in vitro. A CCK-8 kit and ELISPOT were used to assess the killing effect of OK-432-induced CD8+ T cells in combination with an αPD-1 antibody on Hepa1-6 cells. We found that OK-432 significantly increased the maturation level of DCs, and OK-432-induced CD8+ T cells in combination with αPD-1 antibody significantly enhanced the function of CD8+ T cells. In the in vivo experiment, HCC model mice were treated with (1) pseudo iRFA + phosphate-buffered saline (PBS); (2) iRFA + PBS; (3) iRFA + OK-432; (4) iRFA + αPD-1; or (5) iRFA + OK-432 + αPD-1. We found that the combined therapy of OK-432 with αPD-1 antibody significantly increased the infiltration and function of CD8+ T cells and significantly decreased the number of FoxP3+ regulatory T cells in residual tumors after iRFA of HCC. Moreover, the smallest tumor volumes and the longest survival were observed in the triple combination treatment (iRFA+OK-432 +αPD-1 antibody) group compared with the other four groups.

CONCLUSIONS

The combined therapy of OK-432 with αPD-1 antibody induced a strong antitumor immune response, which significantly inhibited the residual tumors after iRFA of HCC. This concept may provide a new treatment strategy to increase the curative efficacy of RFA for medium-to-large and irregular HCCs.

AVAILABILITY OF DATA AND MATERIAL

The data of this study are available from the corresponding author on reasonable request.

Efficacy and safety of MWA versus RFA and CA for renal tumors: A systematic review and meta-analysis of comparison studies

PURPOSE

Thermal ablation procedures represent an alternative treatment option for patients with T1a renal tumors. Radiofrequency ablation (RFA) and cryoablation (CA) are the most used and studied techniques, while microwave ablation (MWA) has progressively emerged in recent years. Our aim was to assess the effectiveness and safety of MWA in comparison to RFA and CA for the treatment of primary renal tumors.

METHOD

Pubmed, CENTRAL, Web of Science and Scopus were searched until March 2023 to identify studies aimed at comparing the efficacy and safety of MWA with those of RFA and CA for the treatment of patients with primary renal tumors. We compared MWA and RFA/CA primary technique efficacy, local recurrences, overall and cancer-specific survival, major and overall complications, and eGFR changes. Moreover, subgroup analyses were conducted (MWA vs RFA; MWA vs CA; MWA vs RFA/CA in T1a renal tumors).

RESULTS

Ten retrospective studies with 2258 thermal ablations were included (508 MWA and 1750 RFA /CA). MWA had fewer local recurrences (OR = 0.31; 95% CI, 0.16, 0.62; p = 0.0008) than RFA/CA; the other outcomes were not significantly different. In subgroup analyses, MWA resulted to have fewer overall complications than RFA (OR = 0.60; 95% CI, 0.38, 0.97; p = 0.04) and CA (OR = 0.49; 95% CI, 0.28, 0.85; p = 0.01); moreover, MWA was associated with fewer recurrences than CA (OR = 0.30; 95% CI, 0.11, 0.84; p = 0.02). In T1a renal tumors subgroup analysis, the outcomes were not significantly different.

CONCLUSIONS

MWA is an ablative procedure as effective and safe as RFA or CA for the treatment of renal tumors.