Renal cell carcinoma in patients with a solitary kidney after nephrectomy treated with radiofrequency ablation: Mid term results

Efficacy and safety of CT-guided microwave ablation for stage T1a renal cell carcinoma in patients with a solitary kidney

OBJECTIVE

To retrospectively evaluate early clinical outcomes of percutaneous microwave ablation (MWA) for stage T1a renal cell carcinomas (RCCs) in solitary kidney patients.

MATERIALS AND METHODS

15 solitary kidney patients with 16 stage T1a N0M0 biopsy-proved RCCs underwent CT-guided percutaneous microwave ablation between October 2016 and July 2020. The patients were followed up with contrast-enhanced computed tomography or magnetic resonance imaging at 1, 3, and 6 months and every 6 months thereafter. Serum creatinine levels of each patient pre MWA, 1 day after MWA and the most recent record were collected. Technical effectiveness, local recurrence, survival rates and complications were accessed.

RESULTS

Complete ablation was achieved in all 16 tumors (100%) including 13 clear cell carcinomas and 3 papillary carcinomas. Within the follow-up time (median: 24 months) no tumor recurrence or major complication was detected. No significant change in serum creatinine level was noted. The cancer-specific survival rate was 100% (15 of 15), and 1-, 2-, and 3-year overall survival rates were 100%, 93.3%, and 93.3%, respectively.

CONCLUSION

Percutaneous MWA is an effective and safe treatment option for stage T1a RCCs in solitary kidney patients; it can achieve high complete ablation rate in selected lesions of appropriate size and location.

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.

Ablation of Small Renal Masses

Renal cell carcinoma is most commonly diagnosed in the sixth or seventh decade of life. Historically, surgical extirpation was the gold standard treatment option for small renal masses. However, given the comorbidities in this elderly population, not all patients are candidates for surgery. The development of minimally invasive ablative therapies has solved the surgical dilemma in this patient population. Furthermore, the 2017 American Urological Association guidelines recommends consideration of percutaneous image guided thermal ablation as a treatment option for masses smaller than 3 cm even in healthy individuals. Percutaneous image guided thermal ablation is an attractive treatment option providing excellent local tumor control, fewer complications, better preservation of the renal functions, faster recovery and shorter hospital stay. Various ablative modalities are available in clinical practice. This includes radiofrequency ablation, cryoablation, microwave ablation, irreversible electroporation, high intensity focused ultrasound, and laser ablation. In this review, we focus on the most commonly used modalities including radiofrequency ablation and cryoablation and to a lesser extent microwave ablation and irreversible electroporation.

Management of small renal masses: An interventional radiologist's perspective

Renal cell carcinoma is relatively common malignancy. Its imaging features are often non-specific and can present a diagnostic dilemma for clinicians. Historically, all patients with a renal mass underwent radical nephrectomy. Advances in technology have allowed for an increase in partial nephrectomies and percutaneous ablations. This essay briefly describes some of the imaging findings of renal cell carcinoma and several of its mimics followed by an in-depth review of procedural management with a particular focus on recent advancements.

Image-Guided Percutaneous Radiofrequency Ablation of Central Renal Cell Carcinoma: Assessment of Clinical Efficacy and Safety in 31 Tumors

PURPOSE

To assess clinical efficacy and safety of image-guided percutaneous radiofrequency (RF) ablation of central renal cell carcinoma with adjunctive pyeloperfusion.

MATERIALS AND METHODS

Patients with central renal tumors who underwent percutaneous RF ablation between 2005 and 2010 were retrospectively evaluated. Thirty patients with 31 central renal tumors underwent 39 RF ablation sessions. Mean tumor diameter was 3.7 cm (range, 2-7 cm). Median distance between tumor and renal pelvis was 5 mm (range, 0-15 mm). Pyeloperfusion was performed in 27 patients (27/30; 90%). Contrast-enhanced CT or MR imaging was performed to evaluate treatment response.

RESULTS

Technical success of RF ablation was achieved in 38/39 (97.4%) ablation sessions. Primary efficacy was 83.9% (26/31) on first follow-up imaging. One (3.2%) case of local tumor progression was detected 6 months after initial ablation. Secondary efficacy was 96.8% (30/31) after repeat RF ablation for residual tumor or local tumor progression. Median follow-up was 88 months (mean 82.6 mo ± 30.7; range, 9-121 mo). Major complications occurred in 5/39 (12.8%) RF ablation sessions. Complications were significantly higher for tumors located within 5 mm of the renal pelvis or 0 mm of a major calyx (28.6% vs 4.0%; P < .05). Overall survival was 96.0% (95% CI, 88.4%-100.0%), and progression-free survival at 5 years was 80.9% (95% CI, 65.8%-95.9%).

CONCLUSION

Image-guided percutaneous RF ablation combined with pyeloperfusion has satisfactory clinical efficacy in treating central renal tumors. Although clinically effective, RF ablation of central tumors may also be associated with significant major complications.

Clinical outcomes of percutaneous radiofrequency ablation for small renal cancer

Partial nephrectomy is the treatment of choice for small renal cell carcinoma (RCC) from the perspective of cancer management and renal function. However, when patients with RCC are of advanced age, exhibit severe comorbidities, including cardiovascular and pulmonary diseases, or have hereditary RCC, ablative therapies, including radiofrequency ablation (RFA) and cryoablation are useful treatment options. In the present study, the clinical outcomes of percutaneous RFA for treating small RCC were evaluated. Between December 2005 and March 2015, 40 patients (41 renal tumors in total) underwent RFA and a total of 50 sessions of RFA were performed. The average tumor size was 2.5 cm. A total of 18 tumors were exophytic and 23 were parenchymal. Of the 41 tumors, 85.4% were completely ablated by initial RFA and the rate of complete ablation following reablation for residual viable lesions was 95.1%. Local recurrence-free survival following complete ablation was 84.2% at 3 years. A patient with a 4.7 cm RCC tumor rapidly progressed following four RFA treatments until complete ablation was achieved. The metastasis-free survival rate following initial RFA was 95.7% at 3 years. The RCC-specific survival was 100% (mean follow-up, 38 months). Adverse events occurred in five sessions (10%); however, only 1 patient with arteriovenous fistula required intervention (transarterial embolization). The mean hospital stay following RFA was 3.2 days. The mean decrease in estimated glomerular filtration rate following RFA was 2.7%. The results of the present study indicate that percutaneous RFA was an effective treatment for small RCCs with respect to management of cancer, minimal invasiveness and minimal loss of renal function, particularly in patients for whom surgery would be a high risk and those at increased risk of deterioration of renal function.

Ultrasound-guided radiofrequency ablation for cT1a renal masses in poor surgical candidates: mid-term, single-center outcomes

OBJECTIVES

Surgical management of small renal masses can be challenging in frail patients and thus modalities such as radiofrequency ablation (RFA) have emerged as valid alternative options. The aim of the current study was to present mid-term oncological and functional results on a series of patients with cT1a renal cell carcinomas (RCCs) who were unfit for surgery and underwent RFA using ultrasound guidance under local anesthesia.

METHODS

Data from patients fulfilling the study selection criteria were retrospectively collected. RENAL nephrometry score was used for tumor description. Parametric tests were used for data analysis and survival curves were estimated using the Kaplan-Meier method.

RESULTS

Overall, 32 patients (mean±standard deviation age, 72.4 ± 7.6 years) with biopsy-proven RCCs (tumor size, 23.75 ± 10.44 mm and RENAL score, 5.28 ± 1.33) underwent 32 RFA sessions. Twenty-seven patients (84.4%) had low complexity masses and five patients had masses of intermediate complexity (15.6%) according to RENAL score categorization. Over a follow-up period of 22.1 ± 13.7 months, one case of primary treatment failure was recognized (primary technical success 97.0%), and overall, three patients were diagnosed with residual disease (primary technique effectiveness 90.6%). No major complications occurred during the postprocedure 90-day follow up, while no difference was found in serum creatinine and estimated glomerular filtration rate pre and post procedure. Patients with intermediate-complexity renal lesions had shorter time to recurrence in comparison to low-complexity masses (p = 0.002). All patients were alive at the time of study data analysis without diagnosed metastases.

CONCLUSIONS

Percutaneous RFA of small RCCs using ultrasound-based guidance under local anesthesia can be an effective alternative method for managing patients who are unfit for surgery.

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.

Renal volumetric analysis: a new paradigm in renal mass treatment assessment

Abstract Background and Purpose: Multiple renal volumetric assessment studies have correlated parenchymal volume with the glomerular filtration rate. The objective of this study was to compare renal volumes before and after treatment of renal masses with either partial nephrectomy or radiofrequency ablation (RFA).

PATIENTS AND METHODS

We reviewed our prospectively collected database of patients with renal masses who were treated between November 2001 and January 2011 with robot-assisted laparoscopic partial nephrectomy (RALPN), laparoscopic RFA (LRFA), or CT-guided percutaneous RFA (CTRFA). Digital Imaging and Communications in Medicine CT imaging data were analyzed in an open-source viewer. Volumetric calculations were used to measure the normal, enhancing bilateral renal parenchyma and tumor volumes. Normal parenchymal volume loss was compared among treatments.

RESULTS

There were 96 patients (68 men) with an average age of 68.0 (36-84) years who met our inclusion criteria. The average tumor diameter, tumor volume, and nephrometry score (NS) was 3.5 cm, 32.0 cm(3), and 7.1 in RALPN (n=26), 2.6 cm, 9.8 cm(3), and 7.1 in CTRFA (n=47), and 2.9 cm, 14.3 cm(3), and 7.2 in LRFA (n=23) groups. The percent change in the operated kidney volume was similar in RALPN (-12%±15), CTRFA (-13%±16), and LRFA (-17%±18) groups. NS was the only variable in a multivariate linear regression model that correlated with the amount of volume lost in the ipsilateral kidney.

CONCLUSIONS

Our retrospective volumetric analysis of renal parenchyma before and after partial nephrectomy or RFA of renal masses revealed that all treatments produce similar volume of collateral damage.

Current management options for the small renal mass in a solitary kidney

The widespread use of cross-sectional imaging has resulted in an increase in the frequency of incidentally identified small renal masses (SRMs). With high cancer-specific survival rates following radical nephrectomy, there is an increasing patient cohort at risk of developing a metachronous contralateral tumour. Nephron-sparing surgery (NSS) has been shown to reduce progression of chronic kidney disease, being the impetus to utilize NSS for the management of SRMs in an anatomical or functional solitary kidney. At present, open partial nephrectomy is the gold standard treatment for an SRM in a solitary kidney; however, there are a number of other minimally invasive options, including laparoscopic partial nephrectomy, and in situ ablative procedures. In addition, variables such as warm and cold ischaemia and renal vascular clamping have been shown to affect outcomes. In this review, we summarize contemporary management options focusing specifically on oncological and functional outcomes.

Ablative therapies for renal tumors

Owing to an increased use of diagnostic imaging for evaluating patients with other abdominal conditions, incidentally discovered kidney masses now account for a majority of renal tumors. Renal ablative therapy is assuming a more important role in patients with borderline renal impairment. Renal ablation uses heat or cold to bring about cell death. Radiofrequency ablation and cryoablation are two such procedures, and 5-year results are now emerging from both modalities. Renal biopsy at the time of ablation is extremely important in order to establish tissue diagnosis. Real-time temperature monitoring at the time of radiofrequency ablation is very useful to ensure adequacy of ablation.

Probe ablation as salvage therapy for renal tumors in von Hippel-Lindau patients: the Cleveland Clinic experience with 3 years follow-up

BACKGROUND

To evaluate the efficacy and safety of probe ablative therapy as salvage treatment for renal tumor in von Hippel-Lindau (VHL) patients after previous partial nephrectomy (PN).

METHODS

Medical records of VHL patients undergoing probe ablative treatment for renal tumors from March 2003 to January 2010 at our institution were retrospectively analyzed.

RESULTS

Fourteen VHL patients who were submitted to salvage probe ablative therapy were included in the analysis. Twelve patients (85%) had a solitary kidney. Overall, 33 tumors were ablated by either percutaneous cryoablation (P-Cryo) (n of procedures = 13), radiofrequency ablation (RFA) (n = 14), and laparoscopic cryoablation (L-Cryo) (n = 3). Average maximal renal tumor diameter was 2.6 ± 1 cm. Average ablation time was 18.3 ± 2.1 minutes for P-Cryo, 36.7 ± 17 minutes for RFA, and 17.3 ± 4 minutes for L-Cryo. All procedures were successfully completed without transfusions and intraoperative complications. No early postoperative complications were recorded. Postoperative decline in renal function was minimal and not clinically significant. With a mean follow-up of 37.6 months (range 12-82), 4 patients had a suspicious recurrence on computed tomography/magnetic resonance imaging (CT/MRI) scan and in 3 of them a re-ablation was performed. Actuarial overall and cancer-specific survivals were 92% and 100%, respectively.

CONCLUSIONS

Probe ablative therapy seems to represent a suitable treatment option for VHL patients with a previous history of PN as it offers a repeatable operation, with a high technical success rate and causing minor changes in renal function.

Radiofrequency ablation: a minimally invasive approach in kidney tumor management

The management and diagnosis of renal tumors have changed significantly over the last decade. Due to advances in imaging techniques, more than 50% of kidney tumors are discovered incidentally and many of them represent an early stage lesion. This has stimulated the development of nephron-sparing surgery and of the minimally invasive treatment options including ablative techniques, i.e., radiofrequency ablation (RFA) and cryoablation. The objective of the minimally invasive approach is to preserve the renal function and to lower the perioperative morbidity. RFA involves inducing the coagulative necrosis of tumor tissue. Being probably one of the least invasive procedures in kidney tumor management, RFA may be performed percutaneously under ultrasound (US), computed tomography (CT) or magnetic resonance (MR) guidance. Most of the studies show that the RFA procedure is efficient, safe and has a low complication rate. Due to the still limited data on the oncological outcome of RFA, the indication for this intervention remains limited to selected patients with small organ-confined renal tumors and contraindication to surgery or who have a solitary kidney. The aim of our study is to review the literature on RFA of kidney tumors.

Thermal ablation of renal cell carcinoma: triage, treatment, and follow-up

The incidence of renal cell carcinoma (RCC) is increasing. With the increasing emphasis on minimally invasive nephron-sparing surgery, thermal ablation is playing a larger role in the management of patients with this disease. This review outlines imaging management, intraoperative and percutaneous ablation, and postprocedural follow-up of RCC.

Results of radiofrequency kidney tumor ablation: renal function preservation and oncologic efficacy

OBJECTIVES

Radiofrequency ablation (RFA) is increasingly finding a place in the treatment of small renal masses (SRM). RFA may be able to provide better renal preservation, while achieving appropriate cancer control. This investigation takes a critical look at pertinent aspects of RFA principles and reviews oncological and renal function outcomes.

METHODS

A review of the most current English literature using a PubMed search was done. Oncological and renal function outcomes were reviewed from selected articles published between 2003 and 2009. Oncological outcome was determined by "single treatment" success rate at first follow-up and "After single treatment" success rate after first follow-up. Renal function outcome was determined by either change in creatinine, creatinine clearance, or GFR after RFA.

RESULTS

The mean tumor size was 2.5 cm for 16/17 studies. Average mean and median follow-up was 23.3 months in 13/17 studies and 19.8 months for 4/17 studies. "Single Treatment" success rates of 90-100% (average = 97.2%) were noted in 13 studies. Average increase in serum creatinine was +0.14 mg/dL in four studies. Serum creatinine and creatinine clearance change in one solitary kidney study was +11 mmol/L and -8 mL/min., respectively.

CONCLUSIONS

RFA is fast emerging as a safe and efficacious treatment for small renal masses. Compared to extirpative treatment options, RFA seems to provide the lowest rate of renal impairment, while providing acceptable rates of tumor ablation. As long-term results emerge, this may become one of the treatment modalities for renal tumors in patients with solitary kidneys and renal impairment.

Management for patients with de novo or recurrent tumors in the residual kidney after surgery for nonfamilial bilateral renal cell carcinoma

The tumor de novo in the residual kidney after surgery for nonfamilial bilateral renal cell carcinoma (RCC) is problematic. We reviewed 5 patients who experienced such a situation. Three patients had had metachronous bilateral RCC, treated with radical nephrectomy in one kidney and nephron-sparing surgery (NSS) in the other. Two patients had had synchronous disease; one patient had received radical nephrectomy and NSS, and the other bilateral NSS. The 5 patients had another solid mass/de novo tumor in the residual kidney 16-88 (mean 46.8) months after surgery. For the tumor de novo in earlier years (1992-1999), one patient underwent surgery and hemodialysis, and the other selected a conservative observation. In recent years (2000-2007), one patient was conservatively observed; the remaining 2 received computerized-tomography-guided radiofrequency ablation, and the local tumors were well controlled postoperatively for 20 and 12 months with their renal function unimpaired. Ablative techniques can potentially strike a balance between oncological and nephrological outcomes in patients with sporadic multiple RCC, successful management of which was difficult previously.