Differences in Patterns of Care: Reablation and Nephrectomy Rates After Needle Ablative Therapy for Renal Masses Stratified by Medical Specialty

Ablative Treatments for Small Renal Masses and Management of Recurrences: A Comprehensive Review

This review focuses on ablative techniques for small renal masses (SRMs), including radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), and irreversible electroporation (IRE), and discusses recurrence management. Through an extensive literature review, we outline the procedures, outcomes, and follow-up strategies associated with each ablative method. The review provides a detailed examination of these techniques-RFA, CA, MWA, and IRE-elucidating their respective outcomes. Recurrence rates vary among them, with RFA and CA showing comparable rates, MWA demonstrating favorable short-term results, and IRE exhibiting promise in experimental stages. For managing recurrences, various strategies are considered, including active surveillance, re-ablation, or salvage surgery. Surveillance is preferred post-RFA and post-CA, due to slow SRM growth, while re-ablation, particularly with RFA and CA, is deemed feasible without additional complications. Salvage surgery emerges as a viable option for larger or resistant tumors. While ablative techniques offer short-term results comparable to surgery, further research is essential to understand their long-term effects fully. Decisions concerning recurrence management should consider individual and tumor-specific factors. Imaging, notably contrast-enhanced ultrasounds, plays a pivotal role in assessing treatment success, emphasizing the necessity of a multidisciplinary approach for optimal outcomes. The lack of randomized trials highlights the need for further research.

Retreatment after focal therapy for failure: a bridge too far?

PURPOSE OF REVIEW

To summarize the current knowledge about the evaluation of disease persistence and recurrence after focal therapy ablation (FTA) for small renal masses and to assess the outcomes and complications of related treatment options.

RECENT FINDINGS

FTA procedures continuously increased over the last 20 years, being now performed in more than one on 10 patients with T1a renal cell carcinoma. Disease recurrence seems to occur more often following radiofrequency ablation (RFA) compared with cryoablation. Evidence about the management of disease recurrence is scarce. Treatment options are similar to those available for de novo renal cell carcinomas, and include reablation, partial or radical nephrectomy and observation. Reablation is feasible, safe and can be easily done in the majority of cases. Oncological outcomes of repeated ablation, although encouraging, remain mostly uninvestigated and unreported.

SUMMARY

In case of disease persistence or recurrence after FTA, observation may be an acceptable approach, reserving repeated ablation or surgery only in those exhibiting significant tumor growth. In these patients repeated ablation with RFA is safe and noninvasive. Surgery after FTA presents technical difficulties related to perinephric scarring, especially with regards to nephron-sparing surgery. This should be taken into consideration in patients' counseling as well as in decision-making process.

Focal ablation therapy for renal cancer in the era of active surveillance and minimally invasive partial nephrectomy

Partial nephrectomy is the optimal surgical approach in the management of small renal masses (SRMs). Focal ablation therapy has an established role in the modern management of SRMs, especially in elderly patients and those with comorbidities. Percutaneous ablation avoids general anaesthesia and laparoscopic ablation can avoid excessive dissection; hence, these techniques can be suitable for patients who are not ideal surgical candidates. Several ablation modalities exist, of which radiofrequency ablation and cryoablation are most widely applied and for which safety and oncological efficacy approach equivalency to partial nephrectomy. Data supporting efficacy and safety of ablation techniques continue to mature, but they originate in institutional case series that are confounded by cohort heterogeneity, selection bias, and lack of long-term follow-up periods. Image guidance and surveillance protocols after ablation vary and no consensus has been established. The importance of SRM biopsy, its optimal timing, the type of biopsy used, and its role in treatment selection continue to be debated. As safety data for active surveillance and experience with minimally invasive partial nephrectomy are expanding, the role of focal ablation therapy in the treatment of patients with SRMs requires continued evaluation.

Salvage Surgery After Renal Mass Ablation

Thermal ablative techniques represent treatment options for patients with small renal masses who are not candidates for surgery. The oncologic efficacy of ablation has not been compared in a randomized fashion with nephron-sparing surgery, and the urologist must be knowledgeable regarding the workup and treatment of patients with suspected residual or recurrent tumor following these therapies. Surveillance of patients with tumor recurrence after ablation may be indicated in select circumstances. When patients are deemed appropriate for salvage therapy, most undergo a repeat course of the same ablative modality. Salvage surgery is possible but often complicated by the prior ablative techniques.

Thermal ablative therapies for treatment of localised renal cell carcinoma: a systematic review of the literature

BACKGROUND AND AIMS

Small renal masses are commonly diagnosed incidentally. The majority are malignant and require intervention. The gold standard treatment is partial nephrectomy unless the patient has significant co-morbidities when surveillance or ablative therapies are utilised. The latter are relatively novel and their long-term efficacy and safety remain generally poorly understood. We performed a literature review to establish the current evidence on the oncological outcome of thermal ablative techniques in small renal masses treatment.

METHODS AND RESULTS

A systematic literature search was performed using PubMed, supplemented with additional references. Articles were reviewed for data on indications, tumour characteristics, ablative techniques, oncological outcome, impact on renal function and complications. The vast majority of articles identified were observational studies. There has not been any direct comparison against partial nephrectomy. Radiofrequency ablation and cryoablation are the techniques that are more commonly used. They have favourable oncological results on intermediate follow-up and indications that successful outcome is sustained long term. The morbidity and impact on renal function appear to be minimal.

CONCLUSION

Thermal ablative therapies are valid alternatives to partial nephrectomy for the treatment of small renal masses in patients unfit for surgery. Prospective long-term data will be needed before the indications for their use expand further.

Salvage Percutaneous Cryoablation for Locally Recurrent Renal-Cell Carcinoma After Primary Cryoablation

BACKGROUND

The management of locally recurrent renal-cell carcinoma (RCC) following cryoablation remains a clinical dilemma. There is limited data regarding the management of locally recurrent disease in the setting of patients who have failed initial percutaneous cryoablation (PCA). We evaluate and report our experience with salvage PCA for local recurrence following renal cryoablation failure.

PATIENTS AND METHODS

We reviewed our experience with patients who underwent salvage PCA for local biopsy proven RCC recurrence following primary cryoablation procedures. Complications and oncologic outcomes were evaluated. Recurrence-free survival after primary and repeat cryoablation was plotted using the Kaplan-Meier curves.

RESULTS

A total 250 patients underwent primary cryoablation for RCC and 20 (8%) patients were identified who underwent repeat PCA for 21 locally recurrent tumors. The mean tumor size was 2.4 cm. Biopsy revealed clear cell in 14 patients, three papillary and four chromophobe RCC. All repeat cryoablation procedures were completed successfully, with no treatment failures on postprocedure imaging. There were no complications or deaths. With the median follow-up of 30 months (range 7-63), 3 (15%) patients experienced local recurrence. One patient had an enhancing lesion at 13 months following repeat PCA and underwent a third PCA. Two patients had recurrence at 6 and 35 months respectively and underwent successful laparoscopic partial nephrectomy. Local recurrence-free, metastasis-free and cancer-specific survival rates were 85%, 100%, and 100% respectively. Limitations include retrospective design and small number of patients.

CONCLUSIONS

Repeat PCA after primary cryoablation failure is feasible, has a low complication rate, and acceptable short-term oncologic outcomes. Further studies with durable follow-up are required.

Radio-frequency ablation helps preserve nephrons in salvage of failed microwave ablation for a renal cancer in a solitary kidney

Recurrent tumors after renal ablative therapy present a challenge for clinicians. New ablative modalities, including microwave ablation (MWA), have very limited experience in methods of retreating ablation failures. Additionally, in MWA, no long-term outcomes have been reported. In patients having local tumor recurrence, options for surveillance or surgical salvage must be assessed. We present a case to help assess radio-frequency ablation (RFA) for salvage of failed MWA. We report a 63-year-old male with a 4.33-cm renal mass in a solitary kidney undergoing laparoscopic MWA with simultaneous peripheral fiber-optic thermometry (Lumasense, Santa Clara, CA, USA) as primary treatment. Follow-up contrast-enhanced computed tomography (CT) scan was performed at 1 and 4.3 months post-op with failure occurring at 4.3 months as evidenced by persistent enhancement. Subsequently, a laparoscopic RFA (LRFA) with simultaneous peripheral fiber-optic thermometry was performed as salvage therapy. Clinical and radiological follow-up with a contrast-enhanced CT scan at 1 and 11 months post-RFA showed no evidence of disease or enhancement. Creatinine values pre-MWA, post-MWA, and post-RFA were 1.01, 1.14, and 1.17 mg/ml, respectively. This represents a 15% decrease in estimated glomerular filtration rate (eGFR) (79 to 67 ml/min) post-MWA and no change in eGFR post-RFA. Local kidney tumor recurrence often requires additional therapy and a careful decisionmaking process. It is desirable not only to preserve kidney function in patients with a solitary kidney or chronic renal insufficiency, but also to achieve cancer control. We show the feasibility of RFA for salvage treatment of local recurrence of a T1b tumor in a solitary kidney post-MWA.

Treatment of localised renal cell carcinoma

CONTEXT

The increasing incidence of localised renal cell carcinoma (RCC) over the last 3 decades and controversy over mortality rates have prompted reassessment of current treatment.

OBJECTIVE

To critically review the recent data on the management of localised RCC to arrive at a general consensus.

EVIDENCE ACQUISITION

A Medline search was performed from January 1, 2004, to May 3, 2011, using renal cell carcinoma, nephrectomy (Medical Subject Heading [MeSH] major topic), surgical procedures, minimally invasive (MeSH major topic), nephron-sparing surgery, cryoablation, radiofrequency ablation, surveillance, and watchful waiting.

EVIDENCE SYNTHESIS

Initial active surveillance (AS) should be a first treatment option for small renal masses (SRMs) <4 cm in unfit patients or those with limited life expectancy. SRMs that show fast growth or reach 4 cm in diameter while on AS should be considered for treatment. Partial nephrectomy (PN) is the established treatment for T1a tumours (<4 cm) and an emerging standard treatment for T1b tumours (4-7 cm) provided that the operation is technically feasible and the tumour can be completely removed. Radical nephrectomy (RN) should be limited to those cases where the tumour is not amenable to nephron-sparing surgery (NSS). Laparoscopic radical nephrectomy (LRN) has benefits over open RN in terms of morbidity and should be the standard of care for T1 and T2 tumours, provided that it is performed in an advanced laparoscopic centre and NSS is not applicable. Open PN, not LRN, should be performed if minimally invasive expertise is not available. At this time, there is insufficient long-term data available to adequately compare ablative techniques with surgical options. Therefore ablative therapies should be reserved for carefully selected high surgical risk patients with SRMs <4 cm.

CONCLUSIONS

The choice of treatment for the patient with localised RCC needs to be individualised. Preservation of renal function without compromising the oncologic outcome should be the most important goal in the decision-making process.

Minimally invasive surgery using ablative modalities for the localized renal mass

Due to a number of evolving devices and modalities to treat the small, localized renal mass, the physician and patient have the opportunity to choose an appropriate therapy from several treatment options. Minimally invasive surgery to ablate a localized renal tumor is an alternative strategy to nephron-sparing surgery for the small renal mass. Even though partial nephrectomy has been established as an optimal technique for nephron-sparing surgery, patients who have comorbidities and renal insufficiency would potentially benefit from less invasive treatment. With respect to those concerns, several articles are discussed here regarding thermal ablative therapy for the small renal mass along with oncological outcomes and complications among these modalities compared to conventional procedures. In this review, a comprehensive PubMed search was conducted. For the purposes of reviewing the current status of thermal ablative modalities for the small renal mass, only articles written in English published from 1992 to 2009 were considered. Cryoablation and radiofrequency ablation are the most utilized and potentially promising therapies that are evolving as nephron-sparing minimally invasive surgery for patients with a localized renal tumor. High-intensity focused ultrasound, a relatively new modality to treat the renal mass, needs further study. All modalities require long-term follow up with unified reporting methods in terms of patient selection, pre- and post-treatment evaluation, treatment description, and analysis of outcome.