Minimally invasive treatment of small renal tumors: trends in renal cancer diagnosis and management

Contrast-enhanced ultrasound after successful cryoablation of benign and malignant renal tumours: how long does tumour enhancement persist?

INTRODUCTION

To investigate how long successfully ablated tumours take to become completely avascular at CEUS after cryoablation.

METHODS

Ninety-five patients had percutaneous cryoablation of 103 renal tumours investigated at CEUS on post-operative day one. If the lesion was avascular, a contrast-CT/MR was scheduled six months after the procedure, while CEUS was repeated if the lesion still displayed enhancement, until the disappearance of intralesional vascularity. Technical success was defined when the tumour was covered completely by the ablation zone. Technique efficacy was assessed at six months of follow-up.

RESULTS

Technical efficacy was obtained for 101/103 cryoablations, 56% of which (57/101) were avascular on post-operative day one. After one week, two weeks, one month 83%, 91% and 100% of these 101 lesions, respectively, were avascular. Two tumours were unsuccessfully treated. They displayed persistent intralesional vascularity at CEUS one month after the procedure.

CONCLUSIONS

After cryoablation, obtaining CEUS before one month may be misleading. When technical efficacy is obtained, disappearance of intralesional enhancement is observed within two weeks in the majority of cases (91%), but can persist until one month. Identification of tumour enhancement after one month may be concerning for residual viable tumour.

Local recurrence of renal cell carcinoma successfully treated with fusion imaging-guided percutaneous thermal ablation

Image-guided thermal ablations are increasingly applied in the treatment of renal cancers, under the guidance of ultrasound (US) or computed tomography (CT). Fusion imaging allows exploitation of the strengths of all imaging modalities simultaneously, eliminating or minimising the weaknesses of every single modality. We present a case of a 68-year-old patient treated using US/CT fusion imaging to guide radiofrequency ablation for local recurrence of renal cell carcinoma undetectable by ultrasound.

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

Percutaneous ablation is an increasingly applied technique for the treatment of localized renal tumors, especially for elderly or co-morbid patients, where co-morbidities increase the risk of traditional nephrectomy. Ablative techniques are technically suited for the treatment of tumors generally not exceeding 4 cm, which has been set as general consensus cutoff and is described as the upper threshold of T1a kidney tumors. This threshold cutoff is being challenged, but with still limited evidence. Percutaneous ablation techniques for the treatment of renal cell carcinoma (RCC) include radiofrequency ablation, cryoablation, laser or microwave ablation; the main advantage of all these techniques over surgery is less invasiveness, lower complication rates and better patient tolerability. Currently, international guidelines recommend percutaneous ablation either as intervention for frail patients or as a first line tool, provided that the tumor can be radically ablated. The purpose of this article is to describe the basic concepts of percutaneous ablation in the treatment of RCC. Controversies concerning techniques and products and the need for patient-centered tailored approaches during selection among the different techniques available will be discussed.

[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.

Percutaneous image-guided cryoablation of small renal masses

Renal cell carcinoma is a common malignancy with increasing incidence due to the incidental detection of non-symptomatic small renal masses on imaging. Management of these small tumors has evolved toward minimally invasive nephron-sparing techniques which include partial nephrectomy and image-guided ablation. Cryoablation and radiofrequency ablation are the most utilized ablation modalities with the former more suited for larger and central renal masses due to intra-procedural visualization of the ablation zone and reduced pelvicalyceal injury. In this article, we review the epidemiology and natural history of renal cell carcinoma, the role of biopsy, and the management options available-surgery, image-guided ablation, and active surveillance-with a focus on cryoablation. The clinical outcomes of the longer term maturing cryoablation data are discussed with reference to partial nephrectomy and radiofrequency ablation. Image-guided ablation has often been the management choice in patients deemed unfit for surgery; however, growing evidence from published series demonstrates image-guided ablation as a sound alternative treatment with equivalent oncological outcomes and minimal patient impact.

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.

Local Recurrence of Renal Cancer After Surgery: Prime Time for Percutaneous Thermal Ablation?

PURPOSE

The purpose of the study was to retrospectively assess the safety and efficacy of radiofrequency thermal ablation (RFA) for retroperitoneal relapse following surgery for renal cell carcinoma (RCC).

PATIENTS AND METHODS

After open radical nephrectomy or nephron-sparing surgery, eight patients with no evidence of distant metastases were treated for retroperitoneal relapse of RCC with RFA. A total of 16 lesions were ablated. Technical success, tumor response, follow-up duration, and complications were retrospectively analyzed.

RESULTS

Disease progression after surgery occurred within a mean time of 57 months (range 9-120). Recurrent tumor size varied from 5 to 34 mm. Five patients previously underwent surgical resection of retroperitoneal recurrent lesions. Six patients were treated with percutaneous approach, while two with recurrent nodes located on the anterior pancreatic surface underwent laparotomic RFA approach. All lesions were completely ablated and patients were followed up with CT at 30 days, after 3 and every 6 months. There was no residual enhancement after a mean follow-up of 12 months (range 7-17). Both patients treated with laparotomic approach had a grade 2 complication according to the Clavien-Dindo classification.

CONCLUSIONS

In our small series, RFA after relapse of surgically removed RCC was safe and effective. Percutaneous and laparotomic thermal ablation should be assessed as first line loco-regional treatment on a larger patient group.

Image-guided ablation of primary liver and renal tumours

Image-guided ablation (IGA) techniques have evolved considerably over the past 20 years and are increasingly used to definitively treat small primary cancers of the liver and kidney. IGA is recommended by most guidelines as the best therapeutic choice for patients with early stage hepatocellular carcinoma (HCC)-defined as either a single tumour smaller than 5 cm or up to three nodules smaller than 3 cm-when surgical options are precluded, and has potential as first-line therapy, in lieu of surgery, for patients with very early stage tumours smaller than 2 cm. With regard to renal cell carcinoma, despite the absence of any randomized trial comparing the outcomes of IGA with those of standard partial nephrectomy, a growing amount of data demonstrate robust oncological outcomes for this minimally invasive approach and testify to its potential as a standard-of-care treatment. Herein, we review the various ablation techniques, the supporting evidence, and clinical application of IGA in the treatment of primary liver and kidney cancers.

Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: systematic review of compliance with reporting standards

OBJECTIVE

To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports.

MATERIALS AND METHODS

Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated.

RESULTS

Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology.

CONCLUSION

The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology.

Interpretation of needle biopsies of the kidney for investigation of renal masses

The development of new therapeutic options for renal tumors has lead to the need of a pretherapeutic diagnosis for an increasing proportion of patients presenting with a renal mass. This need is particularly important for a small, incidentally discovered renal mass (less than 4 cm) as it can be a benign lesion in a significant percentage of cases. Recent studies have shown that needle biopsy is an accurate and safe method allowing for a precise histopathological diagnosis of the mass in most cases. The aims of the biopsy are (1) to assess the benign or malignant nature of the lesion, (2) to assess the primary or secondary nature of the lesion, and (3), in case of a primary malignancy, to determine histological prognostic factors, such as the tumor type. This review, based on the most recent literature and our own experience, is intended to provide a practical approach to the diagnosis, relying on appropriate morphologic assessment and the use of immunohistochemistry.

Urinary tract effects after multifocal nonthermal irreversible electroporation of the kidney: acute and chronic monitoring by magnetic resonance imaging, intravenous urography and urinary cytology

PURPOSE

The nonthermal irreversible electroporation (NTIRE) is a novel potential ablation modality for renal masses. The aim of this study was the first evaluation of NTIRE's effects on the renal urine-collecting system using intravenous urography (IVU) and urinary cytology in addition to histology and magnetic resonance imaging (MRI).

METHODS

Eight percutaneous NTIRE ablations of the renal parenchyma, including the calyxes or pelvis, were performed in three male swine. MRI, IVU, histology, and urinary cytology follow-ups were performed within the first 28 days after treatment.

RESULTS

MRI and histological analysis demonstrated a localized necrosis 7 days and a localized scarification of the renal parenchyma with complete destruction 28 days after NTIRE. The urine-collecting system was preserved and showed urothelial regeneration. IVU and MRI showed an unaltered normal morphology of the renal calyxes, pelvis, and ureter. A new urinary cytology phenomenon featured a temporary degeneration by individual vacuolization of detached transitional epithelium cells within the first 3 days after NTIRE.

CONCLUSIONS

This first urographical, urine-cytological, and MRI evaluation after porcine kidney NTIRE shows multifocal parenchyma destruction while protecting the involved urine-collecting system with regenerated urothelial tissue. NTIRE could be used as a targeted ablation method of centrally located renal masses.