Active surveillance of renal cortical neoplasms: a contemporary review

INTRODUCTION

Over the past 2 decades, there has been a significant increase in the number of incidentally found small renal cortical neoplasms (RCNs). As more RCNs are being discovered in the elderly and infirmed patient populations, there has been a growing interest in the role of active surveillance (AS). Active surveillance is recommended for high surgical-risk patients and those with a reduced life expectancy. It is also an option for patients wishing to avoid surgery. We review the current literature on AS and highlight the natural history of disease, the important factors to evaluate during AS, and the contemporary role of biopsy.

METHODS AND MATERIALS

The MEDLINE database was searched using PubMed. Search terms included active surveillance, renal mass, natural history, and renal mass histology. From 1966 to present, 17 AS series were identified, all of which have been included in this summary. A summary was performed by compiling all available data and performing a weighted mean where applicable.

RESULTS

Initial tumor size does not correlate with growth rate or malignancy. The mean growth rate in large published series is low (0.28-0.34 cm/year). Tumors with high growth rates usually represent malignant lesions and typically undergo delayed intervention. Progression to metatatic disease is a low-probability event for tumors on AS (1.4%); however, this is still a risk that patients must be willing to accept. Larger tumors (cT1b and cT2) also demonstrate relatively low growth (0.57 cm/year); however, these tumors should be monitored carefully. Tumors followed for > 5 years demonstrate a low growth rate (0.15 cm/year), will not likely require intervention, and have a low chance of progression to metastatic disease.

CONCLUSION

For highly selected patients with RCN, AS is a reasonable treatment option. Age, surgical risk, comorbidities, and patient opinion must all factor into the final decision when considering a patient for AS.

Intrarenal pressures generated during deployment of various antiretropulsion devices in an ex vivo porcine model

INTRODUCTION

Pressurized saline irrigation is commonly used during ureteroscopy, which can cause an increase in intrarenal pressure leading to postoperative pain, sepsis, and renal injury due to pyelovenous and pyelolymphatic backflow. To prevent retrograde stone migration during ureteroscopic lithotripsy, antiretropulsion devices can be deployed, which may or may not protect the kidney against high intrarenal pressures. This study compares the intrarenal pressures generated during the use of two antiretropulsion devices in an ex vivo porcine model.

MATERIALS AND METHODS

Using an ex vivo porcine model of the urinary system, flexible ureteroscopy was performed at the proximal, mid, and distal ureter. Intrarenal pressures were measured in the absence and presence of a coil-based antiretropulsion device and a multifold film-based device. Intrarenal pressure measurements were obtained while using saline irrigation at a gravity of 84 cm H(2)O and pressures of 150 and 300 mm Hg.

RESULTS

The deployment of a coil device resulted in a significant increase in intrarenal pressures during ureteroscopy with pressurized irrigation when compared with intrarenal pressures without a device. The use of a multifold film device that occluded the ureter during ureteroscopy resulted in a decrease in intrarenal pressures at an irrigation pressure of 300 mm Hg when compared with pressures without a device. In the remaining configurations, the intrarenal pressures were only minimally elevated. When comparing the two devices to each other, the multifold film device had significantly lower intrarenal pressures at each configuration. This has potential implications in preventing renal injury and/or sepsis during ureteroscopy.

CONCLUSION

The use of a multifold film antiretropulsion device during ureteroscopy with high-pressure irrigation can potentially protect the kidney from elevated intrarenal pressures.

ACE2 and angiotensin 1-7 are increased in a human model of cardiovascular hyporeactivity: pathophysiological implications

BACKGROUND

ACE and ACE2 produce angiotensin II (Ang II), a vasopressor that induces cardiovascular remodeling, and Ang 1-7, a vasodilator with an antiremodeling effect. While Ang 1-7 has antiarrhythmic properties, at higher concentration it may induce ventricular tachycardia and sudden death. ACE2, therefore, may play an essential role in blood pressure homeostasis, in the long-term complications of hypertension (cardiovascular remodeling), and in the induction of cardiac electric abnormalities. This study evaluated the levels of ACE2 and Ang 1-7 in Bartter's/Gitelman's patients (BS/GS) who have elevated Ang II and endogenous blockade of Ang II type 1 receptor signaling compared with healthy subjects (C) and essential hypertensives (EH). BS/ GS patients were also considered because of their predisposition to cardiac arrhythmias, which has yet to be completely clarified.

METHODS

Mononuclear cell ACE2 and Ang 1-7 were evaluated using western blot.

RESULTS

One-way ANOVA showed that ACE2 and Ang 1-7 levels were significantly different between the three groups (p=0.0074 and p=0.0001, respectively). Post-hoc analysis (Tukey's HSD) showed that both ACE2 (1.59+/-0.63) and Ang1-7 (2.26+/-1.18) were significantly elevated in BS/GS compared with either C (0.98+/-0.45; p=0.008; 1.12+/-0.48, p=0.002, respectively) or EH (1.06+/-0.24; p=0.043; 0.72+/-0.28; p=0.0001, respectively). ACE2 and Ang 1-7 directly correlated only in BS/GS (r=0.91, p<0.0003).

CONCLUSIONS

The elevated ACE2 and Ang 1-7 in BS/ GS patients mirror those in hypertensives and are in line with the clinical, hemodynamic and pathophysiological characteristics of BS/GS, likely contributing to them. In consideration of the clinical picture of these syndromes, the opposite of hypertension, the results of this study further strengthen the importance of the ACE2/Ang 1-7 system in the regulation of vascular tone and cardiovascular biology.

Prospective randomized evaluation of FOOT gel pads for operating room staff COMFORT during laparoscopic renal surgery

OBJECTIVES

We evaluated the comfort level of our laparoscopy team during and after laparoscopic renal surgery, with or without the use of gel footpads.

METHODS

Between September 2008 and April 2009 we prospectively randomized 100 consecutive laparoscopic renal procedures to examine whether the use of a foot gel pad altered the surgical team's comfort level. A questionnaire was used to measure the discomfort in 18 different subjects before and during surgery, and one day postoperatively. The procedures performed with or without the foot gel pads were compared.

RESULTS

One hundred laparoscopic procedures were randomized to being performed with and without gel pads. In 50 procedures, the foot gel pad was used. The mean age of the subjects was 36 years (range 25-52). The mean surgical experience was 7 years. The characteristics of the participants in procedures with and without the gel pad were similar. In the immediate postoperative period, there were significantly more breaks taken (P = .001), number of stretches (P = .001), foot pain (P = .003), knee pain (P = .001), back discomfort (P = .001), overall discomfort (P = .001), and diminished level of energy (P = .049) in the group not using the gel pad. Of the 24-hour postoperative time point, evaluation significantly favored the gel pads regarding foot pain (P = .004), overall amount of discomfort (P = .001), and energy level of the participants (P = .044).

CONCLUSIONS

The use of foot gel pads improves surgeon comfort and ergonomics during laparoscopy. The pads have been incorporated into our routine operating room set-up and may improve surgical performance by diminishing fatigue and discomfort.

Active surveillance for renal cortical neoplasms

PURPOSE

We retrospectively evaluated our single center experience with patients with renal cortical neoplasms who elected active surveillance.

MATERIALS AND METHODS

We retrospectively evaluated our urological oncology database between January 1993 and January 2009, identifying a total of 223 renal cortical neoplasms in 212 patients that were initially managed by active surveillance. We described patient and tumor characteristics, and assessed the differences between patients who remained on AS and those who underwent delayed intervention or progressed with metastasis.

RESULTS

Median patient age was 71 years at active surveillance initiation and the median Charlson comorbidity index was 3. Median tumor size was 2.8 cm (range 0.5 to 13.7) at study enrollment and 3.7 cm (range 0.9 to 14.1) at final assessment. The median growth rate in the entire cohort was 0.34 cm per year (range 0.29 to 2.3). Median followup was 35 months (range 6 to 137). Active surveillance failed in 15 patients (7%), of whom 4 (2%) progressed to metastasis and 11 (5%) required intervention. When comparing cases of failed active surveillance with those that continued, there were statistical differences in initial tumor size (2.61 vs 3.64 cm, p = 0.019), final tumor size (3.56 vs 5.17 cm, p = 0.001) and growth rate (0.34 vs 1.75, p = 0.001). There was no correlation between initial tumor size and growth rate (Pearson's coefficient r = 0.006, p = 0.932). A total of 14 patients died of another medical condition. Only 1 cancer related death (0.5%) was reported in the entire cohort.

CONCLUSIONS

Active surveillance for renal cortical neoplasms in select older patients with comorbidities is a reasonable treatment option. At 3-year followup we noted a 7% failure rate.

Complete ileal neobladder intracorporeal construction with standard sutured technique and novel technology

PURPOSE

We compared the surgical efficacy and efficiency of a completely suture based procedure with a novel entero-urethral anastomosis device and an EndoGIA stapler to create an ileal neobladder.

MATERIALS AND METHODS

Two groups of 7 pigs each were survived for 8 weeks. In group 1 the neobladder was constructed using a U-shaped segment of ileum sealed with the stapler. The entero-urethral anastomosis was created with a novel sutureless anastomosis device. All other procedures were completed with standard intracorporeal suturing techniques. In group 2 animals completely intracorporeal sutured technique was used. Total procedure, and enteroenteric, ileal neobladder, uretero-enteric and entero-urethral anastomosis times were recorded. Cystograms done immediately postoperatively, at 2 weeks and at sacrifice to evaluate the newly constructed system were rated from 0-no leakage to 3-severe leakage.

RESULTS

In group 1 vs 2 the overall procedure, and enteroenteric, ileal neobladder, uretero-enteric and entero-urethral anastomoses were completed in 285.3, 32.3, 58.8, 54.2 and 5.5 vs 350.1, 29.9, 139.1, 58.0 and 46.3 minutes, respectively. In groups 1 and 2 the average postoperative cystogram rating was 0.83 and 1.6, respectively (p = 0.63). At 2 weeks and at sacrifice cystograms showed no extravasation in either group. The overall surgical procedure, pouch creation and entero-urethral anastomosis were statistically briefer in group 1 (p = 0.036, 0.01 and 0.039, respectively). Average survival in groups 1 and 2 was 30 (range 4 to 56) and 41 days (range 1 to 56), respectively (p = 0.36). All animals had voiding complications within 1 week after ureteral and urethral catheters were removed. One neobladder ruptured in group 1.

CONCLUSIONS

Combining stapled ileal neobladder construction and the entero-urethral anastomosis device significantly decreases operative time, pouch creation and urethral anastomoses.

Contemporary applications and limitations of magnetic resonance imaging contrast materials

PURPOSE

Improvements in imaging technologies have dramatically increased the ability to accurately diagnose and treat many urological disease processes. As urological patients often have chronic kidney disease, the well characterized nephrotoxicity of contrast induced nephropathy when using iodine based contrast materials has long been a concern. With the development of gadolinium based contrast agents it seemed that the concern regarding nephrotoxicity had been resolved. In 1997 a new disorder, nephrogenic systemic fibrosis, appeared in patients with severe renal failure. Nephrogenic systemic fibrosis is a serious and potentially devastating disorder characterized by progressive thickening and hardening of the skin and other body tissues, and complicated by flexion contractures of the joints.

MATERIALS AND METHODS

We performed a survey of the available literature on nephrogenic systemic fibrosis and magnetic resonance contrast media. We focused on mechanisms in the development of nephrogenic systemic fibrosis as well as its association with magnetic resonance contrast media, disease treatment and prevention, and its relevance to clinical urology.

RESULTS

An association between nephrogenic systemic fibrosis and gadolinium based contrast agents has been reported. Gadolinium is a toxic metal and it must be chelated to be a safe injectable contrast agent. It is now hypothesized that the majority of nephrogenic systemic fibrosis cases present with gadolinium based contrast agent exposure as the triggering factor, although this mechanism has not been elucidated. As gadolinium enhanced magnetic resonance imaging is an important tool in the diagnosis and surveillance of urological diseases, the severe consequences of nephrogenic systemic fibrosis demand that practicing urologists understand and know its history and treatment strategies.

CONCLUSIONS

This review provides clarification of the gadolinium based contrast agent characteristics, tissue interactions that lead to the development of nephrogenic systemic fibrosis, prevention possibilities and available treatment options.