Commentary

Laparoendoscopic single-site surgery has been developed, in part,to improve the cosmetic appearance of patients. What is good postoperative cosmesis for these patients? How can one evaluate cosmesis objectively?

The authors evaluated the body image and cosmetic outcomes in patients who had undergone open, laparoscopic or LESS kidney surgery using Dunker's survey. Dunker's method is original as compared to other questionnaires, because it shows photographs of the wounds after each surgical procedure. This allows the patients to have correct and complete knowledge of the cosmetic appearance for different surgical procedures which the patients themselves have not experienced. By showing the photographs from LESS, laparoscopic and open surgeries, the authors demonstrated a better cosmetic impression for LESS over the other procedures.

Furthermore, the preference for future surgical approaches was evaluated, as the theoretical risk for LESS varied. When the risk was equivalent, the greatest percentage of patients (39%) preferred LESS. When the risk increased, LESS was selected by a smaller number of patients. It is noteworthy that one-fifth of patients preferred LESS despite the 10% higher risk, supporting the powerful impact of cosmesis in some patients. On the other hand, laparoscopic surgery was preferred by the majority of patients in the setting of greater risk during LESS. Since the cosmetic impression was similar between laparoscopic and open surgeries in this cohort, other factors besides cosmesis had a large effect on the selection of future surgeries in these patients.

The authors listed the limitations of their study, including the low response rate of 61%, a non-randomized study setting, and the use of a non-validated survey. This reviewer wonders about the impact of the selection of the wound photos. In this study, a rather small lumbar wound was used for the open surgery. The impression of the patients may be different if a longer mid-line or chevron incision was used instead of the lumbar incision. To establish a survey for body image and cosmesis after minimally invasive surgery, the validation of the questionnaires used with careful selection of the wound photos is required.

Tadashi Matsuda, M.D.

Commentary

The authors report the cost of flexible ureterorenoscopy in a high-volume center. Their take-home message is that the cost of this procedure may be as low as £131/€157/$196.50 per case. They state that the use of modern, more durable ureteroscopes has reduced the repair costs, thus making the procedure more practical and affordable for hospitals. Don't be fooled, however, into thinking that this represents the overall costs of flexible ureterorenoscopy.

The authors specifically excluded other costs associated with the procedure, namely staffing, hospital stay, and capital costs. In other words, they were interested solely in the cost of maintaining/repairing flexible ureteroscopes and the cost of ancillary equipment. Thus, the headline costs reported should not be confused with the total cost of the procedure, which is clearly significantly higher. More specifically, the costs should be considered as the marginal equipment cost of each procedure after a fleet of flexible ureteroscopes and a holmium laser have been purchased.

The set-up costs, including the purchase of 9 flexible ureteroscopes (£14,000/$21,000 each, totaling £126,000/$189,000), semi-rigid ureteroscopes and a holmium laser, are considerable. The omission of these costs is not explained by the authors and I believe this omission might deceive readers into thinking that flexible ureterorenoscopy is a relatively cheap procedure. It is not.

Besides the considerable capital costs, flexible ureterorenoscopy is associated with significant operating time when used for moderate volume stones or tumors. In the United Kingdom's National Health Service, hospitals are paid a standard tariff for each procedure, regardless of the complexity, equivalent to £1920/$2880. No additional charges are allowed no matter how much equipment, time and expertise is needed. It is highly likely that hospitals carrying out more complex flexible ureterorenoscopy take a significant loss on many procedures, despite the increased durability of ureteroscopes.

One also needs to consider the reduced costs reported by the authors in the context of a high-volume center. Higher volume is naturally associated with greater expertise in all areas of the procedure, including instrument handling by both doctors and nurses, and roughly translates into increased durability of delicate reusable instruments and efficient use of single-use instruments. One might expect considerably higher costs for occasional users of flexible ureteroscopes, to the point where a single-use scope might be more practical.

Finally, the authors report the cost of holmium laser fibers based on each fiber being used 25 times. The processing of laser fibers, especially the more delicate 200μ fiber, frequently leads to fracture, and so we have found that single-use 200μ fibers are more cost-effective than reusable fibers. Our practice is entirely out of step with that reported by the authors, who appear to have (under)estimated the cost. We have previously reported significantly higher costs per procedure and emphasized the fact that the cost of single-use items is higher than the cost of scope purchase and repair. In conclusion, flexible ureterorenoscopy can be carried out without frequent scope repairs; nevertheless, the overall cost of the procedure is considerably higher.

Francis X. Keeley, M.D.

Commentary

What effect does pelvicalyceal anatomy have on the success of percutaneous nephrolithotomy (PNL)? Configuration of lower pole calyceal anatomy has been shown to be a determinant of efficacy of shock-wave lithotripsy (SWL) and ureteroscopy, with acute lower pole infundibulopelvic angle (IPA) reducing fragment clearance in the former and the ability of flexible scopes to reach the lower pole in the latter. Binbay and associates from Istanbul sought to answer whether success of PNL is associated with similar anatomical factors. A total of 498 patients with pre-PNL intravenous urography (IVU) were retrospectively analyzed for Sampaio pelvicalyceal system configuration, pelvicalyceal surface area, lower pole IPA, upper-lower calyceal angle (ULA), and infundibular length (IL) and width (IW) of the calyx through which PNL was performed. Cases were classified as successful (i.e. stone-free at 2 to 3 months post-PNL on IVU or computed tomography) or unsuccessful (residual stone burden). Of all these collecting system factors, only pelvicalyceal surface area turned out to be significant. Presence of partial or complete staghorn stone was the only other significant factor. The authors speculated that larger collecting system surface area was associated with residual stones because of the difficulty of reaching stones in multiple calyces from only one access point or of missing fragments that might have migrated to other calyces.

It is not surprising that IPA, ULA, IW, and IL did not have an effect on stone-free rate, because the ability to use multiple percutaneous tracts obviates any negative impact of these parameters. Upper pole access typically results in excellent visualization of the lower pole calyces, thus rendering ULA and IPA insignificant, especially if flexible nephroscopy is used. Additionally, IW and IL of the access calyx would not be factors because the surgeon is unlikely to choose the calyx with the narrowest or longest infundibulum as the point of primary entry into the kidney. While pelvicalyceal surface area was found to be an important factor, it was likely so because a staghorn stone will be more complex in a calyceal system that is more complex.

Deem and coworkers compared outcomes of PNL and SWL for non-lower pole stones measuring between 1 and 2 cm in a prospective randomized trial. Stone-free rates on CT at 3 months were 85% for PNL and 33% for SWL. Exclusion criteria included Hounsfield units above 1000 and skin to stone distance greater than 12 cm. A maximum of 2000 shocks were given. The SWL patients were stented postoperatively, which may have been one of many factors contributing to the very low stone-free rate. While several methodological problems reduce the validity of the study, its point is evident. The optimal treatment for stones between 1 and 2 cm is unclear, particularly in the upper half of the range. The risk of steinstrasse after SWL for such calculi is significant, and although stenting may be prudent, it reduces the clearance rate and renders a completely noninvasive procedure invasive. I am not yet ready to routinely use PNL for non-lower pole stones between 1 and 1.5 cm (for this category ureteroscopic laser lithotripsy is preferable), but in experienced hands, PNL for calculi between 1.5 and 2 cm is an excellent option.

Robert Marcovich, M.D.

Commentary

Although widely disseminated into clinical practice, the Storz SLX-F2 Lithotripter has a dearth of published clinical series evaluating its efficacy. Elkoushy et al from the high-volume stone center at McGill University present their complete results on 474 patients with radio-opaque renal and ureteral calculi. Treatments were limited to four urologists using the narrow (or standard) focus with success based on KUB x-ray imaging rather than computed tomography (CT). As alluded to by the authors, current concerns regarding medical imaging radiation exposure and the world-wide need for cost containment within health care, suggest that reliance for clinical studies to define success/stone-free status based on CT rather than KUB x-ray is no longer acceptable or justifiable. The Storz SLX-F2 has been the replacement machine of choice at many high volume lithotripsy centers. The authors' success rates, after a single SWL session, of 82.2% for renal stones and 83.3% for ureteral stones is congruent with many of our clinical impressions using a comparable treatment and follow-up protocol. As is commonly encountered at high volume lithotripsy referral centers, a substantial percentage of patients will request a second treatment from their referring urologist (to avoid a ureteroscopy and laser lithotripsy, more specifically the dreaded ureteral stent) with the authors presenting a reasonable retreatment rate of 15.2% for renal and 14.2% for ureteral calculi with an eventual overall stone-free rate of 77% (renal 74.1% and ureteral 80.9%). Unfortunately, the authors did not present ultrasound results, if available, to define the incidence of subcapsular/perinephric hematomas.

Many patients who fail renal SWL and are left with asymptomatic fragments elect for observation rather than escalation of care to a ureteroscopy with laser lithotripsy or a percutaneous nephrolithotomy. The article by Koh et al highlights the intermediate duration follow-up (average of 46 months) of 50 patients with asymptomatic renal calculi. The percentage of patients with prior SWL was not defined but the inclusion criteria required the patient to be symptom-free for 6 months prior to enrollment. Regardless, the authors report a low need for intervention (7.1%) and a high incidence of spontaneous passage (20%) in this clinical series. Stone progression was defined as an increase in the size of the stone >1 mm when comparing KUB x-ray images and >3 mm for other modalities and when comparing across different imaging studies (i.e. ultrasound compared to KUB x-ray). Unfortunately, the authors report a substantial incidence (45.9%) of radiologic stone burden progression. Luckily, the amount of incremental stone progression is not clinically concerning (mean increase of 2.8 mm) and does not support the need to push the patient into an escalation of their care plan.

Ryan F. Paterson, M.D.

Commentary

This paper reports on a new application (first urological use) of a 1,318 nm end firing continuous wave diode Eraser laser (initially tested for resecting lung metastases) for prostate enucleation (ELEP) in a manner akin to HoLEP followed by standard morcellation. The device was tested in a 60-patient, single center, single surgeon, prospective, randomized, controlled trial versus bipolar PlasmaKinetic™ electrosurgical resection carried out over 8 months in 2010. Postoperative caregivers were, sadly, not blinded to the type of surgery carried out, and this may have introduced some unintended bias as to timings of catheter removal and hospital discharge.

Mean baseline TRUS prostate volume was 59.5 cc and patient groups were comparable preoperatively. HemoCue blood loss photometric data of the effluent was carried out at regular intervals and mean values reported. These data showed almost half the blood loss, bleeding velocity, catheter time and hospital stay, though more irrigant was needed for the laser procedure. Follow-up thus far was short, but at 6 months, standard outcomes parameters were equally improved in both groups. No patients required blood transfusion. Since the Eraser is a continuous wave laser like the Thulium laser, it remains to be seen whether there are any differences between these two types of laser, particularly with regard to postoperative erectile dysfunction and dysuria (particularly as charring was noted), as well as cost of device and disposables. Time and further studies with this new laser will tell of its place in the laser array for BPH treatment, and given its hemostatic properties, it certainly requires testing in patients on anticoagulant therapies. A further possible disadvantage is the need to use enucleation and morcellation (which thus far has not proved to be an easy technique for most urologists to learn outside of a few enthusiasts) with the Eraser laser as with Holmium. No doubt, with wider adoption over time after this first encouraging report, more light will be shed on these key issues.

Anup Patel, M.D.

Commentary

Although numerous studies on α-receptor antagonists have been published during recent years, their focus has been on the role of facilitating passage of ureteral stones and fragments. Few studies have attempted to elucidate the possible advantage of these agents following SWL of stones located in the kidney.

This randomized comparison of results in controls without treatment and those in patients treated with tamsulosin or doxazosin showed a favorable effect on the time required for fragment expulsion. There was, however, no significant difference in terms of stone-free kidneys after 12 weeks, but the need for analgesics was lowest for patients treated with α-blocking agents.

From these results it seems reasonable to prescribe, for selected patients, α-receptor antagonists after SWL of renal stones. This conclusion appears logical in view of the previous experience from treatment of ureteral stones and because stone fragments sooner or later must pass through the ureter!

Hans-Göran Tiselius, M.D.

Enzymatic dissolution of calcium and struvite crystals: in vitro evaluation of biochemical requirements. Thalji NK, Richards NG, Peck AB, Canales BK, Department of Urology, Center for the Study of Lithiasis and Pathological Calcification, University of Florida, Gainesville, Florida.

Urology 2011;78:721.e13-721.e17.

Objective: To evaluate the factors that affect the enzymatic dissolution rate of calcium oxalate monohydrate (COM), calcium phosphate (brushite), and magnesium ammonium phosphate (struvite) crystals as enzymatic digestion of kidney stones could enhance lithotripsy or provide alternatives to surgical removal.

Methods: At pH 4.2, pelleted COM crystals were combined with oxalate decarboxylase (ODC from Bacillus subtilis), oxalate oxidase (from Hordeum vulgare), or control. Crystal dissolution was followed by measuring increases in solution calcium ion concentration. For phosphate-based crystals, the rates of phosphorolysis by the enzyme purine nucleoside phosphorylase (PNP, assay form) were compared to the control solution using spectrophotometry.

Results: The addition of ODC to COM crystals resulted in production of highly soluble calcium formate and a 15-fold increase in COM solubility. By adding a formate-catabolizing enzyme (formate dehydrogenase), dissolution increased 47-fold compared with controls with nearly one half of the mineral dissolved. Oxalate oxidase showed much lower activity than ODC in COM dissolution. Using inorganic phosphate as a substrate, PNP was able to dissolve both brushite and struvite minerals in water at concentrations near saturation. Measuring dissolution by adding more PNP was not possible because of equilibrium and assay detection restraints.

Conclusion: Stone dissolution using enzymes appears to be viable, particularly for oxalate-based minerals. In a closed system, product inhibition by calcium formate appeared to limit the extent of COM crystal dissolution using ODC. Although phosphate-containing minerals appear to be suitable phosphate sources for PNP, the reversibility of the reaction limits the use of this enzyme.

Copyright © 2011 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.urology.2011.04.046

Commentary

It is well recognized that fragments (or even small stones) of uric acid can be dissolved by oral administration of alkali. Moreover, uric acid, cystine, phosphate and infection stones/fragments are soluble in solutions given percutaneously. Unfortunately, in the vast majority of patients with residual stones or fragments after stone removing procedures, the chemical composition is dominated by calcium oxalate. Attempts to dissolve calcium oxalate (CaOx) by means of calcium chelating agents (such as EDTA) have failed because of the toxic effects on the urothelium.¹

It is thus very interesting to learn from this report that the combined addition of oxalate decarboxylase (OCD) and formate dehydrogenase (FDH) to suspensions of COM crystals resulted in pronounced dissolution of CaOx. The increments in calcium concentrations following treatment with OCD and FDH were dramatic.

Whether these findings will have any clinical implications on the treatment of patients with residual CaOx stone material is difficult to know. As the authors have stated, there are, of course, several problems to consider. The most important question is how the enzymes should be delivered to reach contact with the stone material. Percutaneous administration of the enzymes is one possible alternative, but the majority of patients with small CaOx residuals do not have such an access.

Alternatively, it is tempting to think about the possibility of using stents impregnated with the enzymes. If slow release of enzymes from such stents can give sufficiently high concentrations at the crystal surfaces, dissolution might be encountered during simultaneous oral pharmacologic acidification of urine. Under such conditions product inhibition will not be a problem.

Although we are remote from a clinical application of these interesting in vitro studies, it will be really exciting to follow the authors' further experience of CaOx crystal dissolution.

Reference

1. Oosterlink W, Verbeeck R, Cuvelier C, et al. Rationale for local toxicity of calcium chelators. Urol Res 1992;20:19–21.

Omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid in the management of hypercalciuric stone formers. Ortiz-Alvarado O, Miyaoka R, Kriedberg C, Leavitt DA, Moeding A, Stessman M, Monga M, Department of Regional Urology, The Cleveland Clinic, Cleveland, Ohio.

Urology 2011 Oct. 13 [epub ahead of print]

Objective: To investigate the use of fish oil in the dietary management of hypercalciuric stone formers. Prostaglandins have been linked to urinary calcium excretion, suggesting a role for omega-3 fatty acids in the treatment of hypercalciuric urolithiasis.

Methods: We retrospectively studied a cohort of patients treated at our stone clinics from July 2007 to February 2009. Patients' urinary risk factors for stone disease were evaluated with pre- and post-intervention 24-hour urine collections. All patients received empiric dietary recommendations for intake of fluids, sodium, protein, and citric juices. All subjects with hypercalciuria (urinary calcium >250 mg/d for males or >200 mg/d for females) on at least two 24-hour urine collections were counseled to supplement their diet with fish oil (1200 mg/d).

Results: Twenty-nine patients were followed for 9.86±8.96 months. The mean age was 43.38±13.78 years. Urinary calcium levels decreased in 52% of patients, with 24% converting to normocalciuria. The average urinary calcium (mg/d) decreased significantly from baseline (329.27±96.23 to 247.47±84.53, P<.0001). Urinary oxalate excretion decreased in 34% of patients. The average urinary oxalate (mg/d) decreased significantly from baseline (45.40±9.90 to 32.9±8.21, P=.0004). Urinary citrate (mg/d) increased in 62% of subjects from baseline (731.67±279.09 to 940.22±437.54, P=.0005). Calcium oxalate supersaturation decreased in 38% of the subjects significantly from baseline (9.73±4.48 to 3.68±1.76, P=.001).

Conclusion: Omega-3 fatty acids combined with empiric dietary counseling results in a measurable decrease in urinary calcium and oxalate excretion and an increase in urinary citrate in hypercalciuric stone formers.

Copyright © 2011 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.urology.2011.08.022

Commentary

Fish oil has remained a highly interesting approach for the medical control of calcium oxalate stone disease. Epidemiological observations among Eskimos and people living in the costal areas of Japan have provided evidence for an effective stone preventive effect of fish oil.

In this clinical study, in which dietary advice was combined with administration of a daily dose of 1200 mg of fish oil, several positive effects on urine composition were observed. The mean 24-hour calcium was reduced from 8.2 to 6.2 mmol and oxalate from 0.50 to 0.37 mmol. Moreover, mean urinary citrate increased from 3.8 to 4.9 mmol. In addition, 24-hour sodium excretion was reduced from 245 to 159 mmol. These findings are highly interesting and give support to the observations previously published by Buck and co-workers.¹

The protective role of eicosapentaenoic acid (EPA) has been explained by altered cell membrane composition, whereby the content of arachidonic acid (AA) is reduced relative to EPA. It is assumed that this counteracts lipid peroxidation. Such mechanisms are considered important for events occurring at high nephron levels.² Therefore, in addition to the effects recorded in composition of urine, it is possible that fish oil favorably counteracts both precipitation of calcium phosphate and the subepithelial deposition of calcium phosphate (Randall's plaques).

How much fish oil is necessary to arrest stone formation has been and is a matter of debate, and, as stated in this article, the consumption of omega-3 fatty acids by Eskimos may be as high as 10 g per day. Those high doses are difficult to attain in clinical treatment.

The results reported in this article—despite simultaneous dietary recommendations—together with previous results with fish oil are sufficiently strong to suggest further clinical studies in randomized comparisons of patients treated with different daily doses of fish oil.

References

1. Buck AC, Davis RL, Harrison T. The protective role of eicosapentaenoic acid [EPA] in the pathogenesis of nephrolithiasis. J Urol 1991;146:188–94.

2. Khan SR, Maslamani SA, Atmani F, et al. Membranes and their constituents as promoters of calcium oxalate crystal formation. Calcif Tissue Int 2000;66:90–6.

Hans-Göran Tiselius, M.D.

Commentary

Percutaneous ablation in the kidney is now performed as a standard therapeutic nephron-sparing option in patients who are poor candidates for resection. Its increasing use has been largely prompted by the rising incidental detection of renal cell carcinomas with cross-sectional imaging and the need to preserve renal function in patients with comorbid conditions, multiple renal cell carcinomas, and/or heritable renal cancer syndromes. Ablation can be delivered percutaneously or laparoscopically; the superiority of one over the other remains controversial.

Although RFA has been applied using open, laparoscopic, and percutaneous techniques with US, CT, and MRI guidance, a meta-analysis of the current literature found that approximately 94% of patients undergoing renal RFA are treated with a percutaneous approach.¹ The percutaneous approach for RFA of kidney lesions, although less invasive, has, in general, a higher incomplete ablation rate compared with the laparoscopic approach, with recurrence rates ranging between 14% and 18%, and it is unclear how much of this is possibly due to inadequacies in targeting. Movement from breathing or changes in patient positioning can further contribute to inaccuracies and increased procedural time. Intraoperative targeting and monitoring continue to be a challenge, however. Although US alone may have the ability to monitor real time probe placement, the quality of the image is not necessarily optimal and sometimes shadowed by the ribcage. Inaccurate registration between planning images may be responsible for multiple needle punctures and repeated relocations, thereby increasing the risk of bleeding or pneumothorax as a direct consequence of the increase in the number of interventions. Mobile organs such as the bowel may move as a consequence of positioning or from respiratory excursions; adjacent organ injury may occur if this is not recognized.

Although hydrodissection² and pneumodissection³ have been used to reduce the risk of neighboring organ injury, precise real time monitoring remains the best modality to obtain the best therapeutic response with minimal morbidity.

The authors of this article have shown previously that RFA guided by image fusion technology is one of the more precise modalities to deliver energy to a particular site, obviating the need for real time CT or MRI guidance. The latest technique described by Hung and colleagues, in this article, which allows for real time tracking of the treatment needle within an organ in a virtual 3 D environment using the Virtual Navigator is a further step in the right direction. We look forward to the development of this technology and its clinical application with interest.

References

1. Kunkle DA, Uzzo RG. Cryoablation or radiofrequency ablation of the small renal mass: A meta-analysis. Cancer 2008;113:2671–80.

2. Laeseke PF, Sampson LA, Winter TC III, et al. Use of dextrose 5% in water instead of saline to protect against inadvertent radiofrequency injuries. AJR Am J Roentgenol 2005;184:1026–7.

3. Kariya S, Tanigawa N, Kojima H, et al. Radiofrequency ablation combined with CO₂ injection for treatment of retroperitoneal tumor: protecting surrounding organs against thermal injury. AJR Am J Roentgenol 2005;185:890–3.

Abhay Rane, M.S.

Natural orifice transluminal endoscopic radical prostatectomy: initial perioperative and pathologic results. Humphreys MR, Sauer JS, Ryan AR, Leslie KO, Castle EP, Lingeman JE, Andrews PE, Mayo Clinic, Phoenix, Arizona.

Urology 2011 Oct. 11 [epub ahead of print]

Objective: To describe the first clinical experience, pathologic, and perioperative outcomes of natural orifice transluminal endoscopic surgery (NOTES) radical prostatectomy. NOTES represents the evolution of minimally invasive surgery. The conceptual feasibility has been shown in careful laboratory and animal studies, but a scarcity of information regarding clinical applications exists.

Methods: After institutional review board approval, 2 patients agreed to undergo NOTES radical prostatectomy for localized prostate cancer. The prostate was radically resected using a 26F resectoscope, 550-μm laser fiber, and holmium laser. The prostate was delivered into the bladder and removed at the conclusion of the procedure through a suprapubic cystotomy for histopathologic analysis. The vesicourethral anastomosis was completed using a cannula scope, urethral-vesical suturing device, and titanium knot applier. Cystograms were taken immediately postoperatively and at catheter removal.

Results: Both patients tolerated the procedure without operative complications. All intraoperative cystograms showed watertight anastomoses. The pathologic examination revealed Gleason score 3+3 and Stage pT2aNxMx for 1 patient and Gleason score 3+4 and Stage pT2cNxMx for 1 patient, with negative margins for both. No blood transfusions were required. Patient 2 experienced some left-sided gluteal and suprapubic pain postoperatively.

Conclusion: NOTES radical prostatectomy appears to be a safe and feasible option for the management of carefully selected, organ-confined prostate cancer. The perioperative and pathologic outcomes show promise with this new technique; however, the high standards of oncologic and functional outcomes demand close and longer follow-up before adoption into the surgical armamentarium can be recommended.

Copyright © 2011 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.urology.2011.06.056

Commentary

I think this paper is worthy of comment simply because it shows how far we can ‘push the envelope’ with NOTES at the moment. The authors have gone about the development of the procedure diligently, having written up animal studies providing a lab-based proof of concept over the past two years^1,2; it was only going to be a matter of time before the first clinical cases were performed using this novel procedure.

Two carefully selected patients underwent successful NOTES RP; new purpose-developed devices were used to help complete the procedure. Encouragingly, there appears to be a good short-term outcome for both patients. As the authors mention, it will be difficult to place this new procedure in the spectrum of prostate cancer treatment. I agree that caution must be exercised with each step forward, coupled with diligent reflection, to maintain the best possible interests for our patients.

‘Surgical’ NOTES in urology is still in its infancy, although a few centers have started to report success in carefully selected patients. The main reason for this appears to be lack of dedicated NOTES surgical instrumentation offering access to the renal tract. Indeed, most of what has been achieved to date has been the result of using ‘medical’ NOTES scopes and instruments³, and some ingenious ‘jury-rigging.’ Most of us would agree that NOTES should be the ultimate aim for scarless surgery in selected patients. It is now up to the technology and instrumentation company engineers to help us get to that goal.

References

1. Humphreys MR, Krambeck AE, Andrews PE, et al. Natural orifice translumenal endoscopic surgical radical prostatectomy: proof of concept. J Endourol 2009;23:669–75.

2. Krambeck AE, Humphreys MR, Andrews PE, et al. Natural orifice translumenal endoscopic surgery: radical prostatectomy in the canine model. J Endourol 2010;24:1493–6.

3. Lima E, Rolanda C, Correia-Pinto J. NOTES performed using multiple ports of entry: Current experience and potential implications for urologic applications. J Endourol 2009;23:759–64.

Abhay Rane, M.S.

Commentary

This article is a multi-institutional examination of robotic partial nephrectomy outcomes. The specific area of interest is whether one can predict by any means whether a patient is more prone to complications undergoing robotic partial nephrectomy. The investigators found that surgeon experience, tumor size, collecting system repair and PADUA score and risk stratification all contributed significantly to prolonged warm ischemia times. In distinction, surgeon experience, clinical tumor size, and PADUA score and risk stratification were found to be related to perioperative complications. More specifically, the PADUA score was able to predict the complication risk regardless of the other factors.

This study is particularly notable for a few reasons. The depth of experience across the four centers is truly remarkable and represents centers well past their learning curves. This allows the very nice demonstration of the power of surgeon experience in the successful performance of this operation. The study also brings out the power of PADUA score and underlines the necessity of its use as a standard of reporting for future studies looking at nephrectomy procedures.

David Lee, M.D.

Long-term biochemical recurrence rates after robot-assisted radical prostatectomy: analysis of a single-center series of patients with a minimum follow-up of 5 years. Suardi N, Ficarra V, Willemsen P, De Wil P, Gallina A, De Naeyer G, Schatteman P, Montorsi F, Carpentier P, Mottrie A, OLV Robotic Surgery Institute, Aalst, Belgium; Department of Urology, Vita-Salute University San Raffaele, Milan, Italy.

Urology 2011 Nov. 15 [epub ahead of print]

Objective: To address the long-term biochemical recurrence (BCR)-free survival rates of patients treated with robotic-assisted laparoscopic prostatectomy (RALP) with a minimum follow-up of 5 years.

Materials and Methods: Prospectively collected data of 184 patients treated with RALP at a single institution were analyzed. Kaplan-Meier and life tables analyses targeted the rates of BCR according to pathologic parameters. Cox regression analyses addressed predictors of BCR.

Results: Median follow-up was 67.5 months. One and 10 patients died of prostate cancer (PCa) and other causes, respectively. Mean time to BCR was 83.8 months. The 3-, 5-, and 7-year BCR-free survival rates were 94%, 86%, and 81%, respectively. These rates were 97%, 93%, and 85% for pT2 disease; 94%, 84%, and 84% for pT3a; and 69%, 43%, and 43% for pT3b (P<.001). The same figures were 97%, 90%, and 88% for Gleason sum 6 or lower; 90%, 86%, and 75% for Gleason sum 7; and 85%, 65%, and 65% for Gleason sum 8-10 (P=.01). At univariable analyses, prostate-specific antigen, pathologic Gleason score, and presence of extracapsular extension, seminal vesicle invasion, and adjuvant radiotherapy were significantly associated with BCR. At multivariable analysis, the presence of seminal vesicle invasion and the presence of Gleason sum 8-10 represented independent predictors of BCR (HR=5.14; P=.004 and HR=3.04; P=.04, respectively).

Conclusion:We report the longest available follow-up in RALP patients. RALP represents an oncologically effective procedure. Our oncological results support the increasing diffusion of RALP for the treatment of organ-confined PCa.

Copyright © 2011 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.urology.2011.08.045

Commentary

And so it begins. The data regarding longer term PSA recurrence post-robotic prostatectomy will only continue to grow. The meticulousness with which many researchers have accrued their data regarding robot prostatectomy and its results regarding continence, potency, and margin rates will result in more studies examining the ultimate benchmark for prostatectomy—biochemical recurrence. This report shows that the 5-year data with a relatively small number of patients is excellent, at 86%. This compares favorably with the known data from large centers historically performing open radical prostatectomy. At no point so far has any data regarding robotics for prostate cancer shown clear inferiority and, with some factors, has shown robotics to be clearly superior. Superiority in biochemical recurrence is not mandatory to further the establishment of robotic prostatectomy as the successor of its open predecessor but equivalence is. So far so good.

David Lee, M.D.

Commentary

The COLD registry contains sponsored web-based data sets of multi-site physicians' voluntary reports of cryoablation between 1999 and 2007, including primary whole-gland (n=4099), focal (n=1160) and salvage (n=594) cryosurgery for prostate cancer. This article highlights the recent trend of cryoablation for prostate cancer, based on these data sets in the United States. Figure 1 indicated changes in the total number of focal versus whole-gland prostate cryoablation procedures from 1999-2007. The numbers of focal versus whole-gland prostate cryoablations were 1 (2%) vs 46 in 1999, 99 (22%) vs 353 in 2003, and 293 (38%) vs 475 in 2007, respectively, suggesting the recent significant increase in the use of focal cryoablation in the urological community (p<0.001). Although focal cryotherapy is clearly still experimental and needs evidence from further long-term oncological outcomes, these numbers impressively demonstrate the recent trend of an increased demand for focal therapy for prostate cancer in the community.

As the authors describe in the discussion section, this study has a number of clear limitations, including the fact that no standardized protocols were used in preoperative patient selection, intraoperative focal cryo-procedures, and postoperative follow-up methodology. However, the functional outcomes of focal cryotherapy (such as a 98.4% continence rate, and 58.1% spontaneous erections) in the multi-site community study are encouraging, in comparison to the patients' reported outcome studies of other whole-gland treatments over a similar period.^1,2 The major limitation of the COLD registry is that only 14% (163/1160) of patients had follow-up biopsy-proven oncological outcomes with only a 21 month mean follow-up period. Such a low percentage undergoing surveillance biopsy is not acceptable for a useful discussion of the oncological outcomes of the surgery. Since PSA has a limited role in determining the treatment success in focal therapy, the oncological outcomes should be discussed by the results of surveillance biopsy or clinical failure needing additional therapy. Clearly, a prospective standardized multi-institutional study of focal cryoablation is awaited, in which mandatory surveillance biopsy outcomes and/or clinical follow-up endpoints are available.

References

1. Penson DF, McLerran D, Feng Z, et al. 5-year urinary and sexual outcomes after radical prostatectomy: results from the Prostate Cancer Outcomes Study. J Urol 2005;173:1701–5.

2. Sanda MG, Dunn RL, Michalski J, et al: Quality of life and satisfaction with outcome among prostate cancer survivors. N Engl J Med 2008;358:1250–61.

Osamu Ukimura, M.D., Ph.D.

Percutaneous ablation in the kidney. Venkatesan AM, Wood BJ, Gervais DA, Department of Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland.

Radiology 2011;261:375–91.

Percutaneous ablation in the kidney is now performed as a standard therapeutic nephron-sparing option in patients who are poor candidates for resection. Its increasing use has been largely prompted by the rising incidental detection of renal cell carcinomas with cross-sectional imaging and the need to preserve renal function in patients with comorbid conditions, multiple renal cell carcinomas, and/or heritable renal cancer syndromes. Clinical studies to date indicate that radiofrequency ablation and cryoablation are effective therapies with acceptable short- to intermediate-term outcomes and with a low risk in the appropriate setting, with attention to pre-, peri-, and postprocedural detail. The results following percutaneous radiofrequency ablation and cryoablation in the treatment of renal cell carcinoma are reviewed in this article, including those of several larger scale studies of ablation of T1a tumors. Clinical and technical considerations unique to ablation in the kidney are presented, and potential complications are discussed.

© RSNA, 2011.

DOI: 10.1148/radiol.11091207

Commentary

Comprehensive reviews of percutaneous ablation in the kidney are provided by the authors, and are well worth reading. This report covers both radiofrequency ablation and cryoablation in terms of their practical indication, image guidance and follow-up imaging, the role of biopsy preoperatively and for surveillance, technical aspects, and the limitations and complications of these treatments, based on the literature-based evidence as well as the authors' experience.

The authors pointed out that there are no published trials to evaluate the utility of US versus CT or MRI for image guidance and treatment monitoring during either radio-frequency ablation or cryoablation, and also that there are few direct comparisons between the treatment effectiveness of radio-frequency ablation and cryoablation. Direct comparison is necessary to conclude the superiority of one image guidance or therapeutic modality over another. It is well known that over half (65%) of the reported cryoablations were performed laparoscopically, while the majority (94%) of radiofrequency ablations were approached percutaneously, so direct comparison with prospective multi-institutional studies will be necessary to determine the best imaging modality for percutaneous ablation as well as the best therapeutic approach for the kidney.

Osamu Ukimura, M.D., Ph.D.