Efficacy and Safety of Microwave Ablation for Malignant Renal Tumors: An Updated Systematic Review and Meta-Analysis of the Literature Since 2012

Abstract

ObjectiveTo systematically determine the treatment outcomes of percutaneous microwave ablation (MWA) in patients with malignant renal tumor.Materials and MethodsOriginal studies that reported the clinical outcomes of MWA in patients with malignant renal tumors were identified in MEDLINE and EMBASE from 2012 to June 30, 2017. Inverse variance and random-effects models were used to evaluate and acquire meta-analytic summary estimates of various clinical outcomes, including technical outcomes (technical success rate [TSR] and technical efficacy rate [TER]), oncologic outcomes (local tumor recurrence rate [LRR], cancer-specific survival rate [CSSR], and overall survival rate [OSR]), and complications.ResultsAmong the 145 articles screened, 13 articles including 567 patients carrying 616 malignant renal tumors were included in the meta-analysis. The meta-analytic pooled TSR and TER were 97.3% (95% confidence interval, 94.3–99.4%; I2 = 0.0%) and 97.6% (95.0–99.4%, I2 = 48.5%), respectively. The meta-analytic pooled LRR was 2.1% (0.3–4.7%, I2 = 54.1%). At 1-, 2-, 3-, and 5-year follow-up time points, the meta-analytic pooled CSSRs were 99.1% (97.2–100.0%; I2 = 0.0%), 98.4% (95.1–100.0%; I2 = 31.2%), 97.6% (93.4–99.9%; I2 = 52.3%), and 96.9% (93.3–99.2%; I2 = 0.0%) respectively, while the OSRs were 98.3% (96.1–99.8%; I2 = 0.0%), 94.9% (91.7–97.5%; I2 = 0.0%), 86.8% (81.9–91.1%; I2 = 22.1%), and 81.9% (75.4–87.6%; I2 = 0.0%). In terms of major complications, a 1.8% (0.6–3.3%; I2 = 0.0%) rate of meta-analytic pooled incidence was found.ConclusionMicrowave ablation showed favorable technical and oncologic outcomes with a low incidence of major complications. Hence, image-guided percutaneous MWA can be considered as a safe and effective treatment for malignant renal tumors.

Percutaneous Microwave Ablation of Histologically Proven T1 Renal Cell Carcinoma

“…The overall AE rate of 19% was relatively high compared to previous percutaneous ablation and surgical studies [9,32]. However, most AEs were low grade (15%) with minimal consequences for the patient.…”

“…Besides the tumour size, our cohort contained difficult tumours with a close relation to the collecting system. Reports of percutaneous ablation of T1b RCCs by MWA are rare, and series are small [3,9]. Primary efficacy rates between 75 and 100% were reported in 12 and 7 T1b tumours, respectively [12,33].…”

“…[4,20] With RFA and MWA, the evolvement of the ablation zone during the procedure is less visible compared to CA [16]. Reports about the efficacy and safety of large cohorts of MWA remain limited, especially for T1b tumours [9,10].…”

Percutaneous ablation techniques for renal cell carcinoma: current status and future trends

“…Another recent retrospective analysis performed on a large patient cohort with long-term follow up confirmed 3-, 5-and 9-year specific and nonspecific cancer survival rates not to be statistically significant among thermal ablation, partial and total nephrectomy [28]. These recent insights, along with detailed economic analysis supporting the convenience of minimally invasive procedures have been confirmed in numerous studies, including recent meta-analysis [22,23,[29][30][31]. Within the T1a classification, tumors larger than 3 cm have been associated with higher incidence of recurrence, with a disease-free survival of 68% compared to 97% of tumors 3 cm [32].…”

“…Rates of acute renal failure were found to be lower for percutaneous ablation (3% vs. 7-11%) [27,45]. Meta-analytic pooled incidences concerning major and minor complications of MW ablation reported rates of 1.8% and 17.5%, respectively [30].…”