Effectiveness of ultrasound-guided radiofrequency ablation in the treatment of 36 renal cell carcinoma tumours compared with published results of using computed tomography guidance

Protection from injury to organs adjacent to a renal tumor during Imaging-guided thermal ablation with hydrodissection and pyeloperfusion

PURPOSE

The treatment of renal tumors is dictated by the results acquired from renal imaging, which play a crucial role in determining the appropriate strategy and surgical plan. Radiofrequency ablation, microwave ablation, and cryoablation are established percutaneous thermal ablation procedures that have widespread recognition. The objective of this scholarly article is to present a comprehensive summary of the application of the primary thermal protection strategies of the structures adjacent to renal tumors, in particular the effectiveness in terms of safety of hydrodissection and pyeloperfusion, in the context of percutaneous thermal ablation for renal tumors.

METHODS

A literature search was conducted in PubMed in April 2023 using the keywords "hydrodissection", "hydrodisplacement", "renal", "kidney", "percutaneous ablation", "cryoablation", "microwave", "radiofrequency", and "pyeloperfusion". No language restriction was applied.

RESULTS

Our study yielded a total of 676 cases describing the use of either hydrodissection or pyeloperfusion in conjunction with percutaneous thermal ablation. The fluids employed for displacing the neighboring structures encompassed saline solution, a mixture of saline solution and iodinated contrast, 5% dextrose in water, iodinated contrast in dextrose solution, lactated singer solution, and iodinated contrast.

CONCLUSIONS

By using these procedures effectively, a greater number of ablations could be performed on anterior or lower polar renal tumors, sometimes excluded from these treatments due to the high risk of causing damage to adjacent anatomical structures.

Factors that Affect Outcome of Ultrasound-Guided Radiofrequency Ablation of Renal Masses

The purpose of this study was to examine the factors influencing the efficacy and safety of the ultrasound-guided radiofrequency ablation of renal tumors. Between January 2010 and December 2018, 159 patients with renal tumors treated with ultrasound-guided percutaneous radiofrequency ablation at our institution were included in this study. Biopsies were performed for histopathological analysis prior to each ablation. Patients underwent computed tomography follow-ups at 3, 6, and 12 months and were subsequently observed on an annual basis. The primary efficacy rate (i.e., residual tumor), local tumor progression, morbidity and mortality, and possible outcome predictors (age, body mass index, gender, tumor size, tumor location, tumor characteristics, ablation temperature, and reported technical problems) were analyzed using binary logistic regression. At the first follow-up, 3 months after ablation, the primary efficacy rate was 79%. Two percent of the tumors showed local tumor progression during the whole follow-up. Tumor proximity to the collecting system and the final temperature in the ablation region were associated with the occurrence of residual tumor (OR = 2.85, p = 0.019 and OR = 4.23, p = 0.006, respectively). A similar trend was shown for tumors larger than 3 cm (p = 0.066). A short distance to the collecting system and the ablation temperature were significantly related to the occurrence of residual tumors after the radiofrequency ablation of small renal masses. The ultrasound guidance used in our study has a lower primary efficacy rate than the computed tomography guidance used in comparable studies.

Radiofrequency Ablation, Cryoablation, and Microwave Ablation for the Treatment of Small Renal Masses: Efficacy and Complications

Over the last two decades the detection rate of small renal masses has increased, due to improving diagnostic accuracy, and nephron-sparing treatments have become the first-choice curative option for small renal masses. As a minimally invasive alternative, thermal ablation has increased in popularity, offering a good clinical outcome and low recurrence rate. Radiofrequency ablation, Cryoablation, and Microwave ablation are the main ablative techniques. All of them are mostly overlapping in term of cancer specific free survival and outcomes. These techniques require imaging study to assess lesions features and to plan the procedure: US, CT, and both of them together are the leading guidance alternatives. Imaging findings guide the interventional radiologist in assessing the risk of complication and possible residual disease after procedure. The purpose of this review is to compare different ablative modalities and different imaging guides, underlining the effectiveness, outcomes, and complications related to each of them, in order to assist the interventional radiologist in choosing the best option for the patient.

Radiofrequency ablation using real-time ultrasonography–computed tomography fusion imaging improves treatment outcomes for T1a renal cell carcinoma: Comparison with laparoscopic partial nephrectomy

Purpose

To determine whether real-time ultrasonography–computed tomography (US-CT) fusion imaging can improve technical feasibility versus B-mode US and provide comparable outcomes of radiofrequency ablation (RFA) for T1a renal cell carcinoma (RCC) compared with laparoscopic partial nephrectomy (LPN).

Materials and Methods

Between June 2013 and August 2016, biopsy- or pathologically confirmed stage T1a RCCs were retrospectively reviewed. Of these, 39 cases were included in the RFA group, and 46 cases were included in the LPN group. In the RFA group, we evaluated tumor visibility and technical feasibility before RFA on a four-point scale on B-mode US and US-CT fusion images. After RFA, hospital days, creatinine value, complications, and disease-free survival rate were compared between the two groups. All results were analyzed by use of the Mann–Whitney U-test and Kaplan–Meier method.

Results

Compared with B-mode US alone, real-time US-CT fusion significantly improved the tumor visibility score and overall mean technical feasibility grade (p<0.001). The 5-year disease-free survival rate was 97.4% and 97.8% in the RFA and LPN groups, respectively, and there was no statistically significant difference between groups (p=0.1). Mean periprocedural creatinine levels were significantly lower in the RFA group than in the LPN group. The number of hospital days was shorter in the RFA group. Minor complications were present in 5.1% of the RFA group and 13.0% of the LPN group, with no major complications.

Conclusions

US-CT fusion-image-guided RFA improved tumor visibility scores and overall mean technical validity and resulted in a comparable disease-free survival rate to LPN.

Assessment of Diagnostic Yield of Cystoscopy and Computed Tomographic Urography for Urinary Tract Cancers in Patients Evaluated for Microhematuria: A Systematic Review and Meta-analysis

IMPORTANCE

Microhematuria (MH) is a common finding that often leads to further evaluation for urinary tract cancers. There is ongoing debate about the extent to which patients with MH should be evaluated for cancer.

OBJECTIVE

To assess the diagnostic yield for detection of urinary tract cancers, specifically bladder cancer, upper tract urothelial carcinoma (UTUC), and kidney cell carcinoma, among patients evaluated for MH using cystoscopy and computed tomographic (CT) urography.

DATA SOURCES

MEDLINE, Scopus, and Embase were systematically searched for eligible studies published between January 1, 2009, and December 31, 2019.

STUDY SELECTION

Original prospective and retrospective studies reporting the prevalence of cancer among patients evaluated for MH were eligible. Two authors independently screened the titles and abstracts to select studies that met the eligibility criteria and reached consensus about which studies to include. Among 5802 records identified, 5802 articles were screened using titles and abstracts. After exclusions, 55 full-text articles were assessed for eligibility, with 39 studies selected for systematic review.

DATA EXTRACTION AND SYNTHESIS

This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Studies were quantitatively synthesized using a random-intercept logistic regression model.

MAIN OUTCOMES AND MEASURES

The primary outcome was diagnostic yield, defined as the proportion of patients with a diagnosis of urinary tract cancer (bladder cancer, UTUC, or kidney cell carcinoma) after presentation with MH. Studies were stratified by the percentage of cystoscopy and CT urography use and by high-risk cohorts. The diagnostic yields of CT urography and cystoscopy were calculated for each cancer type.

RESULTS

A total of 30 studies comprising 24 366 patients evaluated for MH were included in the meta-analysis. The pooled diagnostic yield among all patients was 2.00% (95% CI, 1.30%-3.09%) for bladder cancer, 0.02% (95% CI, 0.0%-0.15%) for UTUC, and 0.18% (95% CI, 0.09%-0.36%) for kidney cell carcinoma. Stratification of studies that used cystoscopy and/or CT urography for 95% or more of the cohort produced diagnostic yields of 2.74% (95% CI, 1.81%-4.12%) for bladder cancer, 0.09% (95% CI, 0.01%-0.75%) for UTUC, and 0.10% (95% CI, 0.04%-0.23%) for kidney cell carcinoma. In high-risk cohorts, the diagnostic yields increased to 4.61% (95% CI, 2.34%-8.90%) for bladder cancer and 0.45% (95% CI, 0.22%-0.95%) for UTUC.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that, given the low diagnostic yield of CT urography and the associated risks and costs, limiting its use to high-risk patients older than 50 years is warranted. Risk stratification, as recommended by the recent American Urology Association guidelines on MH, may be a better approach to tailor further evaluation.

[Percutaneous renal ablation: Pre-, per-, post-interventional evaluation modalities and adapted management]

OBJECTIVES

Ablative treatment (AT) rise is foreseen, validation of steps to insure good proceedings is needed. By looking over the process of the patient, this study evaluates the requirements and choices needed in every step of the management.

METHODS

We searched MEDLINE^®, Embase^®, using (MeSH) words and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance.

RESULTS

Explanations of AT proposal rather than partial nephrectomy or surveillance have to be discussed in a consultation shared by urologist and interventional radiologist. Per-procedure choices depend on predictable ballistic difficulties. High volume, proximity of the hilum or of a risky organ are in favor of general anesthesia, cryotherapy and computed tomography/magnetic resonance imaging (CT/MRI). Percutaneous approach should be privileged, as it seems as effective as the laparoscopic approach. Early and delayed complications have to be treated both by urologist and radiologist. Surveillance by CT/MRI insure of the lack of contrast-enhanced in the treated area. Patients and tumors criteria, in case of incomplete treatment or recurrence, are the key of the appropriate treatment: surgery, second session of AT, surveillance.

CONCLUSION

AT treatments require patient's comprehension, excellent coordination of the partnership between urologist and radiologist and relevant choices during intervention.

Improved outcome with combined US/CT guidance as compared to US guidance in percutaneous radiofrequency ablation of small renal masses

BACKGROUND

When performing percutaneous radiofrequency ablation (RFA) of small renal masses (SRM), use of optimized periprocedural image guidance is essential to secure curative outcome of the treatment.

PURPOSE

To retrospectively compare the short-term radiological and clinical outcomes of RFA under combined ultrasound (US) and computed tomography (CT) guidance with that of a previously performed US-guided series at the same institution.

MATERIAL AND METHODS

From November 2009 to November 2013, 60 patients (mean age, 70.1 years; range, 34-86 years) with renal masses measuring in the range of 13-50 mm in maximal diameter (mean diameter, 25.4 ± 6.8 mm) underwent percutaneous RFA with combined US/CT guidance. The technical success rate, recurrence-free survival, rate of complications, and the percentage change in the estimated glomerular filtration rate (eGFR) were compared with that of a previously published series of 41 patients with SRM treated with US-guided RFA between November 2002 and December 2008.

RESULTS

The tumor and patient characteristics were similar between the two treatment groups. The primary and secondary technical success rate was significantly higher in the group treated with combined US/CT guidance compared with the group treated with US guidance alone (100% and 100% vs. 82% and 91%, respectively). The local recurrence-free survival was significantly better in the combined US/CT-guided group than in the US-guided group (P = 0.016). There was no significant difference in the rate of overall complications (13% vs. 17%) or the mean percentage decrease in the eGFR after the respective treatment (1.1 ± 18.3% vs. 5.0 ± 11.7%).

CONCLUSION

The use of combined US/CT guidance when performing renal RFA resulted in superior primary and short-term outcome compared to the use of US guidance alone in patients treated at the same institution.

Radiation exposure from CT-guided ablation of renal masses: effects on life expectancy

OBJECTIVE. The purpose of this article is to project the effects of radiation exposure on life expectancy (LE) in patients who opt for CT-guided radiofrequency ablation (RFA) instead of surgery for renal cell carcinoma (RCC). MATERIALS AND METHODS. We developed a decision-analytic Markov model to compare LE losses attributable to radiation exposure in hypothetical 65-year-old patients who undergo CT-guided RFA versus surgery for small (≤ 4 cm) RCC. We incorporated mortality risks from RCC, radiation-induced cancers (for procedural and follow-up CT scans), and all other causes; institutional data informed the RFA procedural effective dose. Radiation-induced cancer risks were generated using an organ-specific approach. Effects of varying model parameters and of dose-reduction strategies were evaluated in sensitivity analysis. RESULTS. Cumulative RFA exposures (up to 305.2 mSv for one session plus surveillance) exceeded those from surgery (up to 87.2 mSv). In 65-year-old men, excess LE loss from radiation-induced cancers, comparing RFA to surgery, was 11.7 days (14.6 days for RFA vs 2.9 days for surgery). Results varied with sex and age; this difference increased to 14.6 days in 65-year-old women and to 21.5 days in 55-year-old men. Dose-reduction strategies that addressed follow-up rather than procedural exposure had a greater impact. In 65-year-old men, this difference decreased to 3.8 days if post-RFA follow-up scans were restricted to a single phase; even elimination of RFA procedural exposure could not achieve equivalent benefits. CONCLUSION. CT-guided RFA remains a safe alternative to surgery, but with decreasing age, the higher burden of radiation exposure merits explicit consideration. Dose-reduction strategies that target follow-up rather than procedural exposure will have a greater impact.

Update on thermal ablation of renal cell carcinoma: oncologic control, technique comparison, renal function preservation, and new modalities

Recent studies report mid- and long-term oncologic control with thermal ablation for small renal tumors to be equivalent to surgery. Comparisons of cryoablation, radiofrequency ablation (RFA), and laparoscopic approaches to percutaneous approaches report equivalent results. Studies report little or no decrease in renal function after ablation of renal tumors. These studies support the use of percutaneous thermal ablation for treatment of small renal malignancies. Studies also report that percutaneous ablation is a safe and durable treatment of the primary tumor in stage IV patients, ultrasound guidance for percutaneous ablation can be effective, and chyluria is relatively common after RFA. Results were disappointing for newer ablation techniques, including microwave, irreversible electroporation, and high-intensity focused ultrasound. These techniques require improvements before their use in place of RFA and cryoablation. The rates of diagnostic and subtype-specific renal tumor biopsies can be improved by using both aspirate and core techniques.

Radiofrequency ablation of small renal masses as an alternative to nephron-sparing surgery: preliminary results

Introduction

Radical endoscopic minimal-invasive treatment methods, such as thermal ablation, are sought as an alternative to standard radical surgical treatment of kidney neoplasms. We analysed patients who could be qualified for radical treatment due to T1a renal tumour.

Material and methods

Twenty-three patients out of 129 who underwent radiofrequency thermal ablation of kidney tumours in the years 2003-2010 were analysed. The inclusion criteria were age below 70 years, lack of major comorbidities (ASA score 1, 2), and competent contralateral kidney. In all cases tumour size was below 4 cm. All patients were followed up with computed tomography (CT) and ultrasonography (USG) every 6 months for 3 years.

Results

In 20 patients kidney tumour was biopsied before radiofrequency ablation (RFA) and 10 of these biopsies were positive and revealed cancer. Six patients required additional treatment due to recurrence visible in CT – 3 with a positive biopsy result, 1 with negative and 2 without biopsy. Three of them were treated with a second session of RFA, 1 with radical nephrectomy and 2 with partial nephrectomy. No disease dissemination was observed and all patients who received additional treatment remain disease free.

Conclusions

The RFA can be safely used in selected patients with T1a tumour as an alternative to partial nephrectomy. Careful follow-up is required after thermal ablation and allows early detection and successful treatment of recurrences.