Management of Residual or Recurrent Disease Following Thermal Ablation of Renal Cortical Tumors

Management of residual or recurrent disease following thermal ablation of renal cortical tumors includes surveillance, repeat ablation, or surgical extirpation. We present a multicenter experience with regard to the management of this clinical scenario. Prospectively maintained databases were reviewed to identify 1265 patients who underwent cryoablation (CA) or radiofrequency ablation (RFA) for enhancing renal masses. Disease persistence or recurrence was classified into one of the three categories: (i) residual disease in ablation zone; (ii) recurrence in the ipsilateral renal unit; and (iii) metastatic/extra-renal disease. Seventy seven patients (6.1%) had radiographic evidence of disease persistence or recurrence at a median interval of 13.7 months (range, 1–65 months) post-ablation. Distribution of disease included 47 patients with residual disease in ablation zone, 29 with ipsilateral renal unit recurrences (all in ablation zone), and one with metastatic disease. Fourteen patients (18%) elected for surveillance, and the remaining underwent salvage ablation (n = 50), partial nephrectomy (n = 5), or radical nephrectomy (n = 8). Salvage ablation was successful in 38/50 (76%) patients, with 12 failures managed by observation (3), tertiary ablation (6), and radical nephrectomy (3). At a median follow-up of 28 months, the actuarial cancer-specific survival and overall survival in this select cohort of patients was 94.8 and 89.6%, respectively

Factors Associated with Diagnostic Accuracy When Performing a Preablation Renal Biopsy

Introduction Long-term management of patients undergoing definitive treatment of a small renal mass depends largely on the final pathology. Pre-ablation renal biopsy (PABx) is often the only source of pathology in patients undergoing thermal ablation of a small renal mass. We sought to evaluate patient and tumor characteristics which may play a role in determining the accuracy of a PABx obtained during radiofrequency ablation (RFA). Materials and methods This retrospective study included a review of our prospectively collected database of all laparoscopic and computer tomography guided RFA (LRFA;CTRFA) performed in our center November 2001- July 2013. Three 18-gauge core biopsies were obtained per tumor. Pathology samples were stratified into diagnostic (group 1) and non-diagnostic (ND) (group 2). We used univariate and multivariate analysis to identify potential biopsy result-modifying factors including patient characteristics (age, BMI), biopsy approach (CTRFA versus LRFA), tumor size, orientation, depth and polarity Results A total of 463 treatments in 411 patients were evaluated. Of these, 66% were CTRFA while 34% were LRFA. Mean patient age was 67.4 years (31-88), mean BMI was 28.3 kg/m2 (16.6-47.2) and mean tumor size was 2.6 cm (0.3-5.5). There were a total of 73 (15.8%) ND biopsies. On multivariate analysis CTRFA and medial tumors treated with either CTRFA or LRFA were found to be associated with an increased likelihood of a ND biopsy. Conclusion PABx obtained in patients undergoing CTRFA and from medial tumors treated with either CTRFA or LRFA were more likely to be ND. Future RFA patients should be counseled appropriately. Additional biopsy cores may be required in these subgroups. Further prospective studies are warranted to confirm these findings

Emerging needle ablation technology in urology

Thermal ablation of urologic tumors in the form of freezing (cryoablation) and heating (radiofrequency ablation) have been utilized successfully to treat and ablate soft tissue tumors for over 15 years. Multiple studies have demonstrated efficacy nearing that of extirpative surgery for certain urologic conditions. There are technical limitations to their speed and safety profile because of the physical limits of thermal diffusion. Recently, there has been a desire to investigate other forms of energy in an effort to circumvent the limitations of cryoblation and radiofrequency ablation. This review will focus on three relatively new energy applications as they pertain to tissue ablation: microwave, irreversible electroporation, and water vapor. High-intensity-focused ultrasound nor interstitial lasers are discussed, as there have been no recently published updates. Needle and probe-based ablative treatments will continue to play an important role. As three-dimensional imaging workstations move from the advanced radiologic interventional suite to the operating room, surgeons will likely still play a pivotal role in the +-application of these probe ablative devices. It is essential that the surgeon understands the fundamentals of these devices in order to optimize their application

Initial experience using microwave ablation therapy for renal tumor treatment: 18-month follow-up

To assess efficacy and morbidity of microwave ablation (MWA) for small renal tumors in an initial cohort of patients. MWA is a recently introduced thermal needle ablation treatment modality with theoretical advantages compared with radiofrequency ablation, such as greater intratumoral temperatures, lack of a grounding pad, and superior convection profile. However, experience has been limited in the human kidney. Ten patients with a single, solid-enhancing renal tumor from June 2008 to November 2008 received laparoscopic or computed tomography-guided percutaneous MWA at a tertiary referral center with ≥14 months of follow-up. MWA was performed using the Valleylab Evident, 915-MHz MWA system at 45 W with intraoperative biopsy before ablation, and peripheral fiberoptic thermometry to determine the treatment endpoints. The patients were followed up with contrast-enhanced computed tomography at 1 month, 6 months to 1 year, and annually to monitor for tumor recurrence. The follow-up duration for the 6 male and 4 female patients (mean tumor size 3.65 cm, range 2.0-5.5; mean age 69.8 years) was 17.9 months. The recurrence rate, defined by persistent enhancement, was 38% (3 of 8). The intraoperative and postoperative complication rate was 20% and 40%, respectively. MWA resulted in poor oncologic outcomes with a significant complication rate at an intermediate level of follow-up. However, MWA has promising theoretical advantages and should not be discarded. Additional studies should be considered to better understand the microwave-tissue interaction and treatment endpoints for different size renal masses before widespread use

Renal Mass Biopsy Indications, Risks, Technical Aspects and Future Trends

This text presents a comprehensive and state-of-the-art approach to renal mass biopsy, and reviews current techniques for obtaining samples, proper tissues processing, indications for biopsy, and treatment outcomes. Sections address preliminary issues faced by urologists, pathologists, interventional radiologists, oncologists, and nephrologists who may be initially reconsidering the role for RMB including clinical decision making, financial considerations, misconceptions, sampling errors, and understanding limitations. Basic techniques and set-up, navigational tools, and tips and tricks to maximize sampling and avoid complications is also included. Sections also address patient selection, pre-biopsy considerations, technical aspects of the most common techniques and equipment, and image guidance systems. Pathological considerations include role of fine needle aspirations, touch preparation, core biopsies, immunohistochemistry, and classification schemata. The text concludes with chapters on future directions and improvements in diagnostic imaging, future developments in optical biopsies (confocal microscopy), and ancillary studies on renal masses. Written by experts in the field of urology and pathology, Renal Mass Biopsy is your go to resource for techniques and outcomes for the treatment of renal masses.

Radiofrequency ablation for treatment of renal tumors: technological principles and outcomes

Radiofrequency ablation (RFA) is a minimally invasive, energy-based, needle-ablative treatment modality that is currently being used to treat small renal masses (SRMs) and offers advantages over extirpative techniques. RFA treats SRM with heat induced by the tissue impedance to radiofrequency current emitted from a needle probe within the SRM. Currently available RFA systems use either an impedance- or temperature-based treatment algorithm to reach treatment end point while minimizing risk of carbonization. Physical limitations, such as electrical property heterogeneity and convective heat loss due to blood flow, and technical considerations should be addressed when performing RFA. Nonetheless, investigations with intermediate follow-up have demonstrated single-treatment radiographic recurrence-free rates of >90%. Future trends include the use of noninvasive imaging thermometry, electromagnetic targeting and adjuvant techniques

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