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.

Oncologic outcomes for ablative therapy of kidney cancer.

Needle ablative therapies for small incidental renal masses are emerging as alternatives to traditional extirpative surgery. Reasons include their associated decreased morbidity, shorter convalescence, and the ability to avert the higher risk of extirpative surgery in an aging patient population. Cryoablation (CA) and radiofrequency ablation are the two most thoroughly studied needle ablative methods used for renal cancer. High-intensity focused ultrasound has also been studied but with limited published human experience at this time. For both radiofrequency ablation and CA, in vitro experiments, animal studies, and (increasingly) human experience have been published, allowing us to define appropriate candidates for such therapies, their oncologic outcomes, and the potential pitfalls. While long-term data is being collected, the current literature suggests that CA and radiofrequency ablation can be safely performed and can effectively eradicate small renal cancers with cancer-specific survival rates similar to those of traditional surgical options.

Imaging associated with percutaneous and intraoperative management of renal tumors.

As new minimally invasive treatment options for small renal tumors such as laparoscopic partial nephrectomy (LPN), radiofrequency ablation (RFA), and cryoablation(CA) have been developed, the reliance upon imaging technologies, both intraoperatively and postoperatively, has expanded greatly. CT, MRI, and ultrasonography (US)have proven themselves extremely useful in this regard, but their utility requires a thorough understanding of each modality's limitations, proper intraoperative use, and expected postoperative findings. This article discusses intraoperative use of US for LPN,RFA, and CA. The expected postoperative MRI and CT findings after CA and RFA also are covered, highlighting the different radiographic evolutionary patterns encountered after use of these technologies. Because the success of these new treatments for small re-nal tumors (especially RFA and CA) depends not only on the technology itself but also on the advantages and limitations of the associated radiographic techniques, urologists of the 21st century must be facile at interpreting and manipulating these imaging modalities to appropriately care for their renal tumor patients.

Expression of HIF-1 and ubiquitin in conventional renal cell carcinoma: relationship to mutations of the von Hippel-Lindau tumor suppressor gene.

Conventional clear cell renal cell carcinomas (cRCC) have mutations of the von Hippel-Lindau (VHL) tumor suppressor gene at 3p25 in approximately 50% of cases. The VHL gene normally regulates ubiquitin-mediated proteolysis of hypoxia-inducible factor 1alpha (HIF-1alpha); in cell lines, VHL inactivation blocks HIF-1alpha proteolysis, resulting in increased HIF-1 expression. This study was undertaken to investigate the relationship between VHL mutations and the expression of ubiquitin and HIF-1alpha in cRCC. Eleven cRCC were studied with microsatellite analysis for 3p deletions and with sequencing for VHL mutations. Immunohistochemistry was performed for HIF-1alpha and ubiquitin. Deletions at 3p25 were found in 10 tumors, and VHL mutations were identified in 6 of these cases. There was staining for ubiquitin and HIF-1alpha in all tumors with VHL mutations. Among the five cases without VHL mutations, staining for ubiquitin or HIF-1alpha was not present in three cases but was present in two tumors, both of which had 3p deletions. The findings support a role for VHL mutations promoting cRCC development by an impairment of HIF-1alpha proteolysis. The findings also suggest that a 3p tumor suppressor gene other than VHL may also influence HIF-1alpha degradation and that there is an additional tumorigenic pathway for cRCC that does not involve VHL or HIF-1.

Effects of cryoablation on short-term development of urinary fistulas in the porcine kidney.

PURPOSE: To determine the effect of cryoablation on the collecting system in the porcine kidney and the possible development of pelvic injury or fistula. MATERIALS AND METHODS: Six kidneys from three domestic swine were utilized. Under MRI guidance, a 3-mm cryoprobe was placed percutaneously and advanced to a point adjacent to the collecting system. The tissue then was frozen to -40 degrees C for 4 to 6 minutes to create a 2-cm iceball. At 1 week postprocedure, the kidneys were harvested and underwent gross and microscopic examination for evidence of fistula formation or renal pelvis injury. RESULTS: The procedures were performed without complications, although during placement of the probe in one pig, the collecting system was inadvertently entered. The diameter of the iceballs ranged from 2.0 to 2.5 cm. On pathologic examination, five of six of the kidneys, excluding the one noted above, were found to have no gross evidence of injury or fistula formation from the collecting system. Microscopic examination of the collecting system demonstrated necrosis extending up to the mucosa but no injury to the collecting system itself. CONCLUSIONS: In this animal model, no evidence of damage to the renal collecting system secondary to freezing was found. Treatment of renal tumors that are close to the collecting system may be possible without damage to the collecting system.

Clinical, pathologic, and functional outcomes after nephron-sparing surgery in patients with a solitary kidney: a multicenter experience.

BACKGROUND AND PURPOSE: Surgical management of a renal neoplasm in a solitary kidney is a balance between oncologic control and preservation of renal function. We analyzed patients with a renal mass in a solitary kidney undergoing nephron-sparing procedures to determine perioperative, oncologic, and renal functional outcomes. PATIENTS AND METHODS: A multicenter study was performed from 12 institutions. All patients with a functional or anatomic solitary kidney who underwent nephron-sparing surgery for one or more renal masses were included. Tumor size, complications, and recurrence rates were recorded. Renal function was assessed with serum creatinine level and estimated glomerular filtration rate. RESULTS: Ninety-eight patients underwent 105 ablations, and 100 patients underwent partial nephrectomy (PN). Preoperative estimated glomerular filtration rate (eGFR) was similar between the groups. Tumors managed with PN were significantly larger than those managed with ablation (P<0.001). Ablations were associated with a lower overall complication rate (9.5% vs 24%, P=0.01) and higher local recurrence rate (6.7% vs 3%, P=0.04). Eighty-four patients had a preoperative eGFR ≥60 mL/min/1.73 m(2). Among these patients, 19 (23%) fell below this threshold after 3 months and 15 (18%) at 12 months. Postoperatively, there was no significant difference in eGFR between the groups. CONCLUSIONS: Extirpation and ablation are both reasonable options for treatment. Ablation is more minimally invasive, albeit with higher recurrence rates compared with PN. Postoperative renal function is similar in both groups and is not affected by surgical approach.

Percutaneous renal cryoablation of angiomyolipomas in patients with solitary kidneys.

OBJECTIVES: To determine the feasibility and safety of performing percutaneous cryoablation of angiomyolipomas (AMLs) in patients with solitary kidneys. METHODS: Three patients with AMLs involving a solitary kidney underwent computed tomography-guided percutaneous cryoablation. All lesions were located in the lateral/posterior part of the kidney, allowing for safe access from the skin for cryoprobe insertion. Intravenous sedation and local anesthesia were used for each patient. Follow-up computed tomography or magnetic resonance imaging and physical examination, urinalysis, and serum blood urea nitrogen/creatinine measurement were performed to evaluate for lesion recurrence and to evaluate the safety profile. RESULTS: Three tumors (1.2-2.5 cm) were treated. The patients experienced minimal to no pain during percutaneous cryoablation, and all were discharged the same day. No procedural or postoperative complications were noted. During the follow-up period (5-36 months), the first 2 patients had no radiographic evidence of recurrence. Initial follow-up imaging of the third patient displayed persistent AMLs. CONCLUSIONS: A review of the published data suggested the necessity to prophylactically treat AMLs of solitary kidneys. In this series, percutaneous cryoablation proved a safe and effective method for treating these lesions. This ultimately provides a minimally invasive option for similar patients, potentially avoiding an open surgical procedure or the risk of hemorrhage.

Renal cell carcinoma and end stage renal disease.

PURPOSE: Patients with ESRD secondary to acquired renal cystic disease have been reported to have a higher incidence of RCC than the general population. We examined the clinical and pathological significance of incidental renal masses in patients with ESRD. MATERIALS AND METHODS: From January 1994 to July 2000, 852 consecutive patients with ESRD who were being considered for renal transplantation at University of Mississippi Medical Center were evaluated with renal ultrasound as part of assessment for possible kidney transplantation. Those patients with ultrasound suspicious for a malignant renal lesion were further evaluated with CT of the abdomen with and without intravenous contrast medium. Any patient with CT findings suspicious for RCC was recommended to undergo radical nephrectomy before kidney transplantation. RESULTS: A total of 19 patients had CT criteria for a possible malignant renal lesion. Seven patients had Bosniak class 3 renal cysts and 12 patients had solid, enhancing renal masses. Of the patients 17 underwent radical nephrectomy. On pathological examination 14 patients had RCC with a 1.64% prevalence in the population screened. Mean Fuhrman nuclear grade in our patients was 2.45. CONCLUSIONS: RCC in patients with ESRD are of clinical significance, considering the size, grade, histology and pathological stage of these tumors. The higher prevalence of clinically significant RCC in patients with ESRD as well as the risk of cancer progression while patients are on immunosuppressive medications justifies screening for RCC in patients with ESRD who are awaiting renal transplantation.

Percutaneous renal cryoablation of renal tumors in patients with von Hippel-Lindau disease.

PURPOSE: We determine the feasibility and safety of performing percutaneous cryoablation of renal tumors in patients with von Hippel-Lindau disease. MATERIALS AND METHODS: We selected 2 men and 2 women with von Hippel-Lindau disease and radiographic determined solid renal tumors were selected to undergo percutaneous cryoablation. All patients underwent standard preoperative evaluation. An interventional magnetic resonance imaging unit was used for probe guidance and ice ball monitoring. The cryoablation procedure was performed with a 2 or 3 mm. cryoprobe using a pressurized argon gas system for ice ball formation. The patients were hospitalized overnight for observation and discharged home the following day. A followup computerized tomogram or magnetic resonance imaging scan was performed at 1 week, 1, 3, 6 and 12 months and every 6 months thereafter, along with physical examination, urinalysis, serum blood urea nitrogen and creatinine. RESULTS: A total of 5 tumors were treated ranging from 2.8 to 5.0 cm. in diameter. All patients underwent the procedure without difficulty with 2 requiring re-treatment due to residual tumor for a total of 7 treatments. At followup from 2 to 23 months there has been no radiographic evidence of recurrence at the cryoablated areas. CONCLUSIONS: Percutaneous cryoablation of renal tumors in patients with von Hippel-Lindau disease proved to be successful in this initial series. Although 2 patients had residual tumor after the initial cryoablation procedure re-treatment was performed with no adverse sequela. This minimally invasive therapy may allow patients with von Hippel-Lindau disease to avoid the necessity of multiple open surgical procedures.

Three-year follow-up of laser prostatectomy versus transurethral resection of the prostate in men with benign prostatic hyperplasia.

OBJECTIVES: To present our 3-year data comparing laser prostatectomy and transurethral resection of the prostate (TURP) for benign prostatic hyperplasia (BPH). Laser prostatectomy was one of the first new minimally invasive treatment modalities for BPH, and few reports of the long-term results of this treatment regimen have been published. METHODS: One hundred men with BPH in whom medical therapy had failed were randomized to undergo either laser prostatectomy or TURP. Preoperative measurements included American Urologic Association symptom score, prostate-specific antigen, uroflowmetry, and transrectal ultrasonography (TRUS). Laser prostatectomy was performed using the potassium titanyl-phosphate/neodynium:yttrium aluminum-garnet laser. TURP was performed in a standard manner with video monitoring. Patients were seen in follow-up at 1, 3, 6, and 12 months and every 12 months thereafter, with the following data obtained: symptom score, peak urinary flow rate, prostate-specific antigen level, and TRUS volume. RESULTS: A total of 100 patients were entered into the study, with 50 patients in each treatment group. The mean age was 68.2 years (range 45 to 90) for the laser patients and 67.4 years (range 54 to 82) for the TURP group. The mean symptom score decreased from 22.0 to 9.9 at 36 months of follow-up for the laser patients compared with 21.2 to 7.7 for the TURP patients. The mean peak flow rate increased from 8.2 to 12.3 mL/s at 36 months for the laser group with a similar increase from 7.3 to 12.8 mL/s for the TURP patients. The mean TRUS volume for the laser patients decreased from 33.9 to 32.9 cm3 at 36 months compared with a mean TRUS volume of 29.6 cm3 preoperatively for the TURP patients that decreased to 26.3 cm3 at 36 months. CONCLUSIONS: At 36 to 72 months of follow-up, the durability of results achieved by the patients in the laser cohort was similar to that for patients undergoing TURP.

Interventional magnetic resonance image-guided percutaneous cryoablation of renal tumors.

We describe the first two cases of percutaneous cryoablation under magnetic resonance imaging guidance. To date, this minimally invasive procedure has been used for the treatment of renal cell tumors in patients who cannot tolerate or refuse surgical nephrectomy. The two patients described showed no evidence of recurrence or complications 35 and 36 months after the procedure.

Defining the complications of cryoablation and radio frequency ablation of small renal tumors: a multi-institutional review.

PURPOSE: Ablative treatments (cryoablation or radio frequency ablation) for renal cell carcinoma aim to decrease morbidity by treating renal tumors in situ, eliminating the need for extirpation. These technologies have potential for complications previously unassociated with renal tumor treatment. We identified complications associated with percutaneous and laparoscopic ablative treatment of renal tumors. MATERIALS AND METHODS: Groups at medical centers with reported experience with ablation of renal tumors were invited to participate in this study. Each group submitted retrospective data regarding overall ablative treatment experience and associated complications. For each incident the nature of the complication, its associated morbidity, the necessity and nature of any subsequent interventions, and the final patient outcome were evaluated. Complications were divided into minor and major categories. Data were collected from groups at 4 institutions with a combined experience of 271 cases. Of these cases 139 were cryoablation and 133 were radio frequency ablation. There were 181 procedures performed percutaneously and 90 performed laparoscopically. RESULTS: A total of 30 complications occurred (11.1%) with 5 major (1.8%) and 25 minor (9.2%) complications, and 1 death (0.4%). Overall 26 of the 30 complications (86.7%) were directly attributable to the ablation procedure. The most common complication was pain or paraesthesia at the probe insertion site. CONCLUSIONS: Ablation technologies appear to have a low complication profile when used to treat small renal tumors. The majority of complications are minor and require observation only. Further study and followup are necessary to determine long-term oncological efficacy.