Percutaneous radiofrequency ablation of renal cell carcinomas in patients with solitary kidney: 6 years experience

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.

Partial nephrectomy versus radiofrequency ablation in patients with cT1a renal cell carcinoma: A surveillance, epidemiology, end results (SEER) analysis

Radiofrequency ablation (RFA) has been proposed for T1a renal cell carcinoma (RCC). The present study compared partial nephrectomy (PN) with RFA for T1a RCC stratified by tumor sizes. We selected patients with RCC and underwent PN or RFA through the surveillance, epidemiology, end results (SEER) database. The Kaplan-Meier method and Cox proportional hazards regression model were conducted. Inverse probability of treatment weights was conducted for sensitivity analysis. We enrolled 15,692 patients in the unmatched cohort, 15,392 (98.1%) underwent PN, and 300 (1.9%) underwent RFA. For tumor ≦ 2 cm, PN was equal to RFA in terms of overall survival (OS) (P > .05) and cancer-specific survival (CSS) (P > .05). For tumor size 2 to 3 cm, PN is likely to have a better OS (P < .05)and comparable CSS (P > .05). For > 3 cm tumor, PN might be associated with higher OS (P < .05) and CSS (P < .05) compared with RFA. In conclusion, PN had a similar OS and CSS compared with RFA in tumor size ≦ 2 cm, RFA could be offered for elderly or patients with comorbidity. For > 2 cm tumors, RFA is not recommended. However, further randomized controlled trials are further required to validate our results.

Radiofrequency ablation for renal tumours: A retrospective study from a tertiary centre

Objective

This study aimed to evaluate the safety and efficacy outcomes of percutaneous radiofrequency ablation (RFA) for localised renal cell carcinoma (RCC) in a tertiary hospital patient who remained unfit for surgical intervention.

Methods

We retrospectively analysed survival outcomes for patients with biopsy proven RCC treated by RFA at Royal Perth Hospital between September 2009 and May 2018. Complication data were gathered for all patients that underwent renal RFA along with 2- and 5-year recurrence-free survival (RFS) rate and compared the outcomes with data from previous studies.

Results

A total of 69 patients (73 procedures) were eligible for the study, and those patients had biopsy-proven RCC with a minimum of 2-year follow-up. The complication rate was 8.2% (6/73) and local recurrence rate 9.6% (7/73). Two-year RFS is 95.7% and 5-year RFS is 78.8% on a median 3.82-year follow-up (interquartile range 1.90-5.75 years).

Conclusion

RFA performed at our centre was found to be safe and effective with low complication rates and durable RFS in line with expectations from existing research. Our study demonstrated that RFA is an alternative modality of treatment for small renal tumours in patients unfit for surgical approach.

Long term follow-up results of ablation treatment for patients with small renal mass

OBJECTIVE

The aim of this study is to evaluate the outcome of ablation therapy in our clinic for the treatment of patients with a small renal mass Materials and Methods: We retrospectively evaluated the technic and follow-up data of 30 patients with 36 tumours who underwent Radiofrequency Ablation (RFA) and Microwave Ablation (MWA) in our clinic. Demographic data, ablation type, tumour characteristics, peroperative and postoperative complications and treatment success of the patients were evaluated.

RESULTS

A total of 36 tumours who underwent ablation treatments, 23 were treated with RFA, 13 with MWA. The mean tumour size was 28.9 ± 6.92 mm in RFA and 29.3 ± 7.70 mm in MWA. The mean follow-up period was 49.6 ± 24.7 months in patients with RFA and mean follow-up was 16 ± 8.05 months in MWA treatments. The overall success in MWA administration was calculated as 76.9%, while the overall success in RFA was 80%.

CONCLUSION

Long-term oncologic efficacy of RFA appears to be successful in the treatment of T1a renal carcinomas. Further studies can be conducted to elucidate the influence of MWA on long-term oncological outcomes.

The role of imaging in the management of renal masses

The wide availability of cross-sectional imaging is responsible for the increased detection of small, usually asymptomatic renal masses. More than 50 % of renal cell carcinomas (RCCs) represent incidental findings on noninvasive imaging. Multimodality imaging, including conventional US, contrast-enhanced US (CEUS), CT and multiparametric MRI (mpMRI) is pivotal in diagnosing and characterizing a renal mass, but also provides information regarding its prognosis, therapeutic management, and follow-up. In this review, imaging data for renal masses that urologists need for accurate treatment planning will be discussed. The role of US, CEUS, CT and mpMRI in the detection and characterization of renal masses, RCC staging and follow-up of surgically treated or untreated localized RCC will be presented. The role of percutaneous image-guided ablation in the management of RCC will be also reviewed.

Safety and oncological outcome following radiofrequency ablation of small renal masses in a single center

OBJECTIVE

To evaluate the safety and efficacy of percutaneous CT-guided radiofrequency ablation (RFA) for small renal masses (SRMs) at a large single-institution center during a period of 12 years.

MATERIALS AND METHODS

A total of 118 patients underwent RFA for SRM between July 2006 and July 2018 at our institution. We included demographic information, comorbidity, procedural details, and oncological outcome in the analysis. Survival analysis was performed using competing risk.

RESULTS

87 males and 31 females with median age 66 years underwent RFA. Median tumor size was 23 mm. Tumor biopsy was performed in 94% of cases, of which 56% were confirmed renal cell carcinoma (RCCs). Twenty-eight patients had benign tumors or underwent treatment for recurrence of prior RCC. Median follow-up of 5 years. Median Charlson Comorbidity Index was 5. Major complications occurred in 1.7%. No change in kidney function was observed. The initial treatment response was 98%. Among patients treated for newly diagnosed radiological suspected RCC without Von Hippel-Lindau or benign biopsy (90 pts), the cumulative incidence of radiological recurrence after 5 and 10 years was 6.6% (95% CI: 0.8-12%) and 16% (95% CI: 4.2-28%), respectively. Three patients died of RCC during follow-up. The cumulative incidence of kidney cancer death was 4.5% (95% CI: 4.3-13%) after 10 years. The incidence of other-cause mortality was 50% (95% CI: 34-67%).

CONCLUSION

CT-guided RFA is a safe and effective treatment option for patients unsuitable for surgery. RFA is a good alternative to partial or radical nephrectomy for SRMs, although randomized trials comparing surgery to minimally invasive thermal ablation techniques are missing.

Percutaneous image-guided renal ablations: Current evidences for long-term oncologic efficacy

The rise in incidentally discovered small renal neoplasms has focused attention on nephron-sparing treatment strategies including partial nephrectomy and percutaneous ablation as well as active surveillance. As all treatment modality, renal ablation has matured technically. Radiofrequency ablation, microwave ablation or cryoablation are now performed in many institutions under imaging guidance. The long-term results allow them to be now recommended as a therapeutic option whatever the patients' condition if complete ablation can reliably be achieved.

Predictive factors for complete renal tumor ablation using RFA

BACKGROUND

Radiofrequency ablation (RFA) can be used to treat renal masses in patients where surgery is preferably avoided. As tumor size and location can affect ablation results, procedural planning needs to identify these factors to limit treatment to a single session and increase ablation success.

PURPOSE

To identify factors that may affect the primary efficacy of complete renal tumor ablation with radiofrequency after a single session.

MATERIAL AND METHODS

Percutaneous RFA (using an impedance based system) was performed using computed tomography (CT) guidance. Fifty-two renal tumors (in 44 patients) were retrospectively studied (median follow-up, 7 months). Data collection included patient demographics, tumor data (modified Renal Nephrometry Score, histopathological diagnosis), RFA treatment data (electrode placement), and follow-up results (tumor relapse). Data were analyzed through generalized estimating equations.

RESULTS

Primary efficacy rate was 83%. Predictors for complete ablation were optimal electrode placement (P = 0.002, OR = 16.67) and increasing distance to the collecting system (P = 0.02, OR = 1.18). Tumor size was not a predictor for complete ablation (median size, 24 mm; P = 0.069, OR = 0.47), but all tumors ≤2 cm were completely ablated. All papillary tumors and oncocytomas were completely ablated in a single session; the most common incompletely ablated tumor type was clear cell carcinoma (6 of 9).

CONCLUSION

Optimal electrode placement and a long distance from the collecting system are associated with an increased primary efficacy of renal tumor RFA. These variables need to be considered to increase primary ablation success. Further studies are needed to evaluate the effect of RFA on histopathologically different renal tumors.

Analysis of radiofrequency ablation of small renal tumors in patients at high anesthetic and surgical risk: urologist experience with follow-up results in the initial six months

BACKGROUND

To evaluate the results of various types of radiofrequency ablation (RFA) treatment of renal tumors in patients with excessive anesthetic and surgical risk.

MATERIALS AND METHODS

Data for RFA performed in in high risk patients were retrospectively evaluated. Other RFA applications in patients with no anesthetic and/or surgical risk were excluded. RFA was by ultrasound or CT guided percutaneous (USG/CT-PRFA) and retroperitoneally or transperitoneally laparoscopic (R/T-LRFA) techniques under general or local anethesia. Follow-up data of enhanced CT or MRI after 1, 3 and 6 months were analysed for twelve RFA applications.

RESULTS

The RFA applications included 4 (40%) left-sided, 5 (50%) right-sided and 1 (10%) bilaterally RFA (simultaneously 1 right and 2 left). The localizations of tumors were 2 (16.6%) upper, 5 (41.6%) mid and 5 (41.6%) lower pole. The RFA applications included 9 (75%) USG-PRFA, 1 (8.3%) CT-PRFA, 1 (8.3%) T-LRFA and 1 (8.3%) R-LRFA. The mean age was 65.3 ± 8.5 (52-76) years. The mean tumor size was 29.6 ± 6.08 (15-40) mm. No complications related to the RFA were encountered in any of the cases. Failure (residual tumour) was determined in 8.3% (1/12) of USG-RFA application. The success rate was thus 91.7% (11/12). Other 1st, 3rd and 6th months follow-up data revealed no residua and recurrence.

CONCLUSIONS

RFA application appears to be safe as a less invasive and effective treatment modality in selected cases of small renal tumors in individuals with excessive anesthetic and also surgical risk.

Comparison of laparoscopic radiofrequency ablation and open partial nephrectomy in patients with a small renal mass

Purpose

We have performed both open partial nephrectomy (OPN) and laparoscopic radiofrequency ablation (RFA) on selected patients since January 2007 and have been following these patients through serial laboratory assessments and computed tomography (CT). The purpose of the present study was to evaluate long-term oncologic outcomes and renal function status for laparoscopic RFA versus OPN at a minimum follow-up of 3 years.

Materials and Methods

A total of 55 patients with exophytic, single small renal masses were treated with either OPN (n=14) or laparoscopic RFA (n=41) by a single surgeon. The indications for laparoscopic RFA were as follows: 1) cases with the greatest dimension of the renal mass <3 cm, and 2) cases in which the collecting system, renal calyx, and great vessels were free from the tumor margins by 1 cm.

Results

The estimated blood loss (EBL), the operation time, and the mean number of hospital days was significantly lower in the laparoscopic RFA group than in the OPN group. Oncologic data did not differ significantly between the two groups. Creatine clearance levels did not differ significantly compared with those before the operation in either group.

Conclusions

Our data suggest excellent therapeutic outcomes with laparoscopic RFA with achievement of effective operative times, hospital stays, and EBL compared with OPN. According to our indications for laparoscopic RFA, laparoscopic RFA is an effective minimally invasive therapy for the treatment of small renal masses, yielding oncologic outcomes and renal function equivalent to those of OPN.

Percutaneous radiofrequency ablation of small renal tumours in patients with a single functioning kidney: long-term results

OBJECTIVES

To evaluate the long-term results of percutaneous radiofrequency ablation (RFA) of small renal tumours in patients with a single functioning kidney (SFK).

METHODS

This is a single-centre prospective study. Patients with an SFK and a tumour smaller than 3.5 cm, treated with RFA over a 7.5-year period, were included. Nineteen consecutive patients (12 male), aged between 33 and 83 years (mean 61.4), were treated for 23 lesions. Primary endpoints were technical success and tumour recurrence rate. Secondary endpoints were the deterioration of renal function and overall survival rate.

RESULTS

The mean follow-up was 56.1 months (range 36-102). Primary technical success was 100 %. There were no major peri-procedural complications. In two cases, minor complications occurred. There was no significant difference between the baseline glomerular filtration rate (GFR) and GFR at 3, 12 and 24 months post-procedure. In four lesions (17 %), recurrence was detected and an additional RFA session was performed. None of the patients developed renal failure during their lifetime. Three of the patients died because of other reasons.

CONCLUSIONS

Percutaneous RFA of small renal tumours in patients with an SFK offers very satisfactory long-term results regarding preservation of renal function, local tumour control and overall survival.

KEY POINTS

• Tumour in a single functioning kidney requires minimally invasive treatment. • Radiofrequency ablation plays an established role in managing small renal tumours. • Long-term results of radiofrequency ablation have shown satisfactory local tumour control. • Long-term results have also shown that renal function may be preserved.

Radiofrequency ablation of renal tumors: four-year follow-up results in 47 patients

Objective

To retrospectively evaluate the intermediate results of radiofrequency ablation (RFA) of small renal masses (SRMs).

Materials and Methods

Percutaneous or laparoscopic RFA was performed on 48 renal tumors in 47 patients. The follow-up studies included a physical examination, chest radiography, creatinine level, and contrast-enhanced CT or MRI. To confirm the pathologic criteria of complete ablation, 35 patients underwent a follow-up biopsy. Recurrence was defined as contrast enhancement on imaging studies after 3 months, lesion growth at subsequent imaging, or viable cancer cells on follow-up biopsy.

Results

Technical success was achieved in 43 (89.6%) of 48 renal tumors. The mean tumor size was 2.3 cm and the mean follow-up period was 49.6 months. Repeated RFA was necessary in 5 tumors due to incomplete ablation. The overall complication rate was 35.8%, of which 96.2% were mild complications. Serum creatinine levels at 12 months after RFA did not differ from those before RFA (1.28 vs. 1.36 mg/dL). Four patients were found to have recurrence at various follow-up intervals, and distant metastasis was not found in any cases.

Conclusion

RFA appears to be a useful treatment for selected patients with SRMs. Our 4-year follow-up results disclose an excellent therapeutic outcome with RFA, while achieving effective local tumor control.

Radiofrequency ablation of renal tumors: our experience

Purpose

To report our results of nephron-sparing radiofrequency ablation (RFA) of renal tumors.

Materials and Methods

Since August 2004, 49 patients with renal tumors were treated with either percutaneous or laparoscopic RFA. All patients underwent preoperative imaging with contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) and were suspected to have renal cell carcinoma. The follow-up for each patient included a physical examination, chest radiography, liver function tests, and a contrast-enhanced CT or MRI. To confirm the pathologic criteria of complete ablation, 30 patients underwent 6-month or 1-year follow-up biopsy. Recurrence was defined as growth of the tumor or any new enhancing portions at 3 months after confirmed nonenhancement of the initial RFA lesion.

Results

Technical success was achieved in 46/49 cases (94%). The mean tumor size was 2.4 cm and the mean follow-up period was 31.7 months (range, 6-68 months). Of 49 patients, repeated RFA was necessary in 7 patients (14%). Three patients were found to have recurrence at various follow-up intervals. Twenty-three patients (47%) experienced complications, and all but one necessitated intervention. No distant metastasis was found in any cases, and all patients are alive and are being serially followed up.

Conclusions

Percutaneous or laparoscopic RFA is considered to be a useful treatment for selected patients with small renal masses and for nephron-sparing. With a mean follow-up of 31.7 months, our intermediate data suggest excellent therapeutic outcome with RFA with effective local tumor control and preservation of renal function. The ultimate role of this modality will continue to evolve and warrants further studies.

The importance of nephron-sparing focal therapy: renal function preservation

Historically, renal cancer has been treated with radical nephrectomy. Consequently, many patients developed renal insufficiency and the health problems associated with this. With the increasing diagnosis of small renal masses, nephron-sparing treatments have been developed to treat these masses adequately, while maximizing renal function. Focal ablative therapy is a means to treat small renal masses in a minimally invasive manner. Yet, there are few studies that have focused on their ability to preserve renal function. In this article, we review the existing literature on the renal function outcomes of patients treated with either radio frequency ablation or cryoablation.

Radiofrequency ablation for renal tumors: our experience

OBJECTIVES

To report our results of percutaneous radiofrequency ablation (RFA) for renal tumors and to assess predictors of therapeutic efficacy.

METHODS

Forty patients (median age 73 years) with renal tumors were treated with RFA under local or epidural anesthesia. All of them had high surgical risk or refused radical surgery. Tumors were punctured percutaneously using the Radionics Cool-tip RF System under computed tomography or ultrasonographic guidance. Median tumor diameter was 24 mm. After RFA, contrast-enhanced computed tomography or magnetic resonance imaging was performed within 1 month. Complete response (CR) was defined as no enhancement inside the tumor. Factors related to the outcome and to renal function were assessed.

RESULTS

Median follow up was 16 months. CR was observed in 34 cases (85.0%). A significant difference in CR rate was observed between tumors < or =30 mm and those >30 mm. Outcomes tended to be better for tumors in the mid to lower kidney, and those away from the renal hilum. Recurrence was observed in one case (2.9%), but a CR was obtained again by additional RFA. Out of a total of 77 RFA procedures, complications occurred in only three cases (3.9%), and conservative treatment was possible in all cases. Serum creatinine levels 3 months after RFA did not differ from those before RFA.

CONCLUSIONS

Percutaneous RFA is a safe and effective treatment for small renal tumors in patients with high surgical risk or who refuse radical surgery.

Computed tomography and magnetic resonance imaging appearance of renal neoplasms after radiofrequency ablation and cryoablation

Thermal ablation procedures including radiofrequency ablation and cryoablation have been increasingly used for treatment for small renal cell carcinoma. Currently, computed tomography and magnetic resonance imaging are usually used to assess residual or recurrent disease after thermal ablation of renal tumor. After thermal ablation, the zone of ablation is usually seen as an area of hypoattenuation on computed tomography and is generally hypointense at T2-weighted magnetic resonance imaging and iso- to hyperintense at T1-weighted imaging relative to renal parenchyma. The ablation zone frequently involutes over time. Residual tumor after thermal ablation is most common at the margin of the ablation zone and often seen as nodular or crescent-shaped areas of contrast enhancement. Accurate assessment of ablated tumors at postprocedural imaging is essential for evaluating the adequacy of treatment and guiding further management. Complications are uncommon and usually minor but should be detected on postprocedural imaging studies.