Laparoscopic renal cryoablation: initial clinical series

Laparoscopic cryoablation for small renal masses: Oncological outcomes at 5-year follow-up

Objective: To evaluate the oncological outcome at 5-year follow-up after laparoscopic cryoablation (LCA) for small renal masses (SRMs), as there is an increasing interest in ablative therapy for cT1a renal tumours due to the rising incidence of SRMs, the trend towards minimally invasive nephron-sparing treatments, and the ageing population.

Patients and methods: Between 2004 and 2015, 233 consecutive LCA were performed in 219 patients for SRMs at two referral centres. We only included those patients with ≥5 years of follow-up (n = 165) in a prospectively maintained database. A descriptive analysis was conducted for pre-, peri- and postoperative characteristics. A Kaplan–Meier analysis assessed overall (OS), disease-specific (DSS), and recurrence-free survival (RFS).

Results: The median (interquartile range [IQR]) age of our patient cohort was 68 (60.5–76) years. The median (IQR) body mass index was 26.2 (23.8–29) kg/m², and the median (IQR) Charlson Comorbidity Index score corrected for age was 4 (2.5–6). The median (IQR) tumour diameter was 28 (21–33) mm. In all, 15% developed a complication in the first 30 days after LCA, of which 1% had a major complication (Clavien–Dindo Grade ≥III). The median (IQR) preoperative estimated glomerular filtration rate (eGFR) was 82.5 (65–93.75) mL/min/1.73 m². The median eGFR decreased by 16.4% and 15.2% at the 3-month and 5-year follow-up, respectively. Persistence was found in 1%, local recurrence in 2%, and systemic progression in 4%. The OS, DSS, and RFS were 74%, 96.9% and 95.4%, respectively.

Conclusion: LCA is a safe and effective treatment for SRMs in selected cases and shows good oncological outcomes after 5 years of follow-up, with only 1% developing a major complication.

[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.

Image-guided ablation of renal cell carcinoma

This review article aims to provide an overview of image-guided ablation of renal cell carcinoma (RCC) since it was first introduced in 1998. This will cover the background and rationale behind its development; an overview of the evidence for current thermal technology, such as heat-based, e.g., radiofrequency ablation (RFA), microwave ablation (MWA), and cold-based energies, e.g., cryoablation used; and summarise the published evidence regarding its treatment efficacy and oncological outcome. In addition, it aims to provide an insight into the potential role of the new non-thermal ablative technology, e.g., irreversible electroporation (IRE)/Nanoknife in image-guided ablation of RCC, as well as areas of challenge that will require further research and clinical evaluation to ensure delivery of a quality patient-centred interventional oncology (IO) service in image-guided ablation of RCC.

Laparoscopic Cryotherapy for Renal Tumors

In an effort to decrease operative morbidity, energy based ablative procedures have triggered considerable interest in the treatment of select, small (<3 cm) renal tumors. Renal cryoablation for small renal tumors is a well-studied energy based ablative procedure that shows considerable promise as an alternative to partial nephrectomy. Cryoablation is minimally invasive and has demonstrated acceptable intermediate-term results. In this article we review key laboratory research and current clinical series of renal cryoablation.

Population-based assessment of cancer-specific mortality after local tumour ablation or observation for kidney cancer: a competing risks analysis

OBJECTIVES

To examine, using competing risks regression, differences in cancer-specific mortality (CSM) that might distinguish between local tumour ablation (LTA) and observation (OBS) for patients with kidney cancer.

PATIENTS AND METHODS

The study focused on 1 860 patients with cT1a kidney cancer treated with either LTA or OBS between 2000 and 2009 in the Surveillance Epidemiology and End Results-Medicare database. Propensity-score matching was used. The study outcome was CSM. Multivariable competing risks regression analyses, adjusting for other-cause mortality as well as patient (including comorbidities) and tumour characteristics, were fitted.

RESULTS

Overall, fewer patients underwent LTA than OBS (30 vs 70%; n = 553 vs n = 1 307). Compared with patients in the OBS group, those in the LTA group were younger (median age 77 vs 78 years; P < 0.001), more likely to be white (84 vs 78%; P = 0.005), more frequently married (59 vs 52%; P = 0.02) and more frequently of high socio-economic status (54 vs 45%; P = 0.001). After propensity-score matching, 553 patients who underwent LTA and 553 who underwent OBS remained for subsequent analyses. The mean standardized differences of patient characteristics between the two groups were <10%, indicating a high degree of similarity. After LTA or OBS, the 5-year CSM estimates from Poisson regression-derived smoothed plots were 3.5 and 9.1%, respectively. In multivariable competing risks regression analyses, LTA use was found to have a protective effect on CSM (hazard ratio 0.47 [95% confidence interval 0.25-0.89]; P = 0.02).

CONCLUSIONS

After adjustment for comorbidity and tumour characteristics in elderly patients with kidney cancer, LTA was associated with a clinically and statistically significant protective effect on CSM, compared with OBS. This advantage of LTA deserves consideration when obtaining informed consent.

Prospective study of ultrasound-guided percutaneous renal cryotherapy: case selection as an optimization factor for a technique

OBJECTIVE

To evaluate the technical and oncological effectiveness of ultrasound-guided percutaneous renal cryotherapy (PRC) in a selected group of patients with renal cancer.

MATERIAL AND METHODS

We conducted a prospective study of 28 patients with posterior-facing T1a renal tumors with middle and inferior external borders. All patients underwent ultrasound-guided PRC. Follow-up was conducted with computed tomography at 1 month and then every 6 months, with a good result defined as the total absence of contrast incorporation. We performed a descriptive and survival study using the Kaplan-Meier estimator.

RESULTS

The 28 patients had a mean age (SD) of 68.3 (10.1) years, and the group underwent 28 procedures. The mean (SD) size of the tumors was 25.5 (7.5) mm, the mean nephrometry score was 1.41 (0.52) and the mean preoperative creatinine level was 133.5 (144.1) mmol/L. There were no intraoperative complications. In terms of postoperative complications, there was only 1 case (3.5%) of a skin lesion resulting from treating a tumor in a transplanted kidney (Clavien II). The median follow-up was 25 months, and the mean (SD) postoperative creatinine level was 135.5 (110.3) mmol/L. Two cases presented radiological recurrence (93% efficacy), with a mean time to recurrence of 12 and 19 months, respectively. There were no tumor-related deaths.

CONCLUSIONS

Our series (the largest on PRC in our country to date) shows that, with an appropriate selection of tumors, PRC is a safe technique with minimal morbidity. Ultrasonography enables the controlled performance of the procedure and saves the patient from radiation and reduces costs.

Laparoscopic renal cryoablation

In light of evidence linking radical nephrectomy and consequent suboptimal renal function to adverse cardiovascular events and increased mortality, research into nephron-sparing techniques for renal masses widely expanded in the past two decades. The American Urological Association (AUA) guidelines now explicitly list partial nephrectomy as the standard of care for the management of T1a renal tumors. Because of the increasing utilization of cross-sectional imaging, up to 70% of newly detected renal masses are stage T1a, making them more amenable to minimally invasive nephron-sparing therapies including laparoscopic and robotic partial nephrectomy and ablative therapies. Cryosurgery has emerged as a leading option for renal ablation, and compared with surgical techniques it offers benefits in preserving renal function with fewer complications, shorter hospitalization times, and allows for quicker convalescence. A mature dataset exists at this time, with intermediate and long-term follow-up data available. Cryosurgical recommendations as a first-line therapy are made at this time in limited populations, including elderly patients, patients with multiple comorbidities, and those with a solitary kidney. As more data emerge on oncologic efficacy, and technical experience and the technology continue to improve, the application of this modality will likely be extended in future treatment guidelines.

State-of-the-art surgical management of renal cell carcinoma

There is a recognizable increase in the incidence of renal cell carcinoma and a parallel rise in the surgical management of renal cell carcinoma has occurred. However, recent literature shows that not all small, suspected renal cell carcinoma needs to be treated surgically, especially in elderly patients or those with multiple medical comorbidities. The surgical options for renal cell carcinoma have expanded from traditional open nephrectomy to partial nephrectomy and, at present, more recent outcomes data are available for the laparoscopic versions of these surgeries. Short-term results of thermal ablative technology (radiofrequency and cryoablation) show real promise as minimally invasive therapies. This review examines the most up-to-date outcomes and future directions of the surgical management of renal cell carcinoma.

Results of a prospective study comparing the clinical efficacy of cryoablation of renal cell cancer followed by immediate partial nephrectomy

PURPOSE

Evaluation if cryoablation of small renal tumours (RT) would facilitate the technique of laparoscopic partial nephrectomy (LPN) in a prospective study.

PATIENTS AND METHODS

In a prospective non-randomised study between April 2007 and October 2009, 16 patients with a mean age of 68 years (48-80 years) and a peripherally located RT were candidates for nephron-sparing surgery (5 open partial nephrectomy (OPN), 11 LPN). Cryoablation of RT was followed in the same session by open (K-OPN) and laparoscopic (K-LPN) partial nephrectomy. Perioperative and follow-up parameters were estimated. A matched-pair cohort of 41 patients (20 OPN, 21 LPN) who underwent standard operations due to the same indication has been selected for retrospective comparison (controls).

RESULTS

Mean age for K-OPN was 74 years (69-83) with mean blood loss 140 ml (50-200); for K-LPN: 66.6 years (48-80) with 100 ml (50-700). All procedures were completed successfully without conversions (K-LPN), transfusions or intra-operative complications. Compared to OPN/LPN, K-OPN and K-LPN were associated with a longer operative time (P < 0.05) and a comparable postoperative hospital stay. There were no early postoperative complications. Cryoablation has not affected the histopathological evaluation of tumours or resection margins. Histopathology showed cytologic changes suggesting fresh coagulative necrosis, glomerular vascular congestion and interstitial haemorrhages following cryotherapy. One patient (K-LPN) developed a pararenal abscess necessitating puncture after 7 weeks. The follow-up (9-42 months) was uneventful.

CONCLUSIONS

The current study shows that K-LPN is feasible without increasing procedure morbidity or compromising surgical and oncological outcomes. It adds no advantage to tumour excision. Pathological findings document early cryoablation effects but viable tissue.

Review of the efficacy and safety of cryoablation for the treatment of small renal masses

PURPOSE

Small renal masses are increasingly being discovered incidentally on imaging for another reason. The standard of care of these masses involves excision by open or laparoscopic techniques. Recently, ablative techniques, such as radiofrequency ablation (RFA) and cryoablation, have taken a more prominent role in the treatment algorithm of these masses. We evaluate the effectiveness and safety of cryoablation to treat renal tumours.

METHODS

A review of the literature was conducted. There was no language restriction. Studies were obtained from the following sources: the Cochrane Library, PUBMED, EMBASE and LILACS.

RESULTS

There was no clinical trial identified in the literature. Thus, we described the results from 23 case series and retrospective studies with a reasonable sample size (number of reported patients in each study ≥30), with a total of 2104 analyzed tumours from 2038 patients. There was wide variability in the outcomes reported, but success rates were generally good. Follow-up was generally short, but some series reported outcomes at 5 years. The most common complications reported were hemorrhage (some of the patients requiring transfusion), perinephric hematoma and urine leaks.

CONCLUSION

Cryoablation presents a feasible treatment for patients with small renal masses. Only short-term data are available and, as such, meaningful conclusions regarding long-term cancer control cannot be made. More rigorous studies are needed.

Hereditary renal tumor syndromes: imaging findings and management strategies

OBJECTIVE

It is not rare for the radiologist to identify multiple renal masses and be the first to raise the possibility of a hereditary renal tumor syndrome. Characteristic renal and extrarenal imaging findings aid in making the correct diagnosis. The imaging findings, screening guidelines, and management techniques for the most common hereditary renal tumor syndromes are reviewed.

CONCLUSION

Hereditary renal tumor syndromes have specific screening guidelines and unique management techniques in which imaging plays a central role.

Laparoscopic cryoablation of renal masses: single-center long-term experience

OBJECTIVE

To evaluate perioperative and long-term functional and oncological outcomes of laparoscopic cryoablation (LCA) performed at Washington University.

METHODS

A retrospective chart review was performed evaluating 62 consecutive patients who underwent LCA at our institution between 2000 and 2005.

RESULTS

Mean age-adjusted Charlson Comorbidity Index (CCI) was 6.1 (SD, 2.1; 95% confidence interval [CI], 5.6-6.6). Mean tumor size was 2.52 cm (SD, 0.99; CI, 2.3-2.8). Mean operative time was 162.0 minutes (SD, 66.6; CI, 142.0-182.1). Mean estimated blood loss was 84.9 mL (SD, 102; CI, 58.6-111.2). Mean hospital stay was 2.6 days (SD, 1.90; CI, 2.1-3.1). The perioperative complication rate was 9.7% (Clavien 1-2). Among patients with biopsy proven, localized renal cell carcinoma, the 6-year Kaplan-Meier estimated disease-free survival (DFS) was 80%; cancer-specific survival (CSS) was 100%; and overall survival (OS) was 76.2%. Mean follow-up in this subset was 76.0 months (SD, 39.3; CI, 62.7-89.4; n = 35), whereas mean time to cancer recurrence was 27.6 months (SD, 11.2; CI, 15.9-39.3; n = 6). Tumor size ≥2.6 cm was the only predictor of cancer recurrence in a multivariate Cox proportional hazards model (hazard ratio [HR] = 28.9; P = .046; n = 35). Mean preoperative estimated glomerular filtration rate (eGFR) was 68.3 (SD, 22.3; CI, 62.1-74.5), compared to 64.5 mL/min/1.73 m(2) (SD, 28.9; CI, 56.5-72.6) at last follow-up (P = .12; n = 52). Excluding patients requiring secondary ablative or extirpative treatments for recurrent renal cell carcinoma, preoperative eGFR <60 mL/min/1.73 m(2) (odds ratio [OR] = 88.3; P = .036) and age-adjusted CCI ≥6 (OR = 32.4; P = .046) were the only factors predicting renal disease progression on multiple logistic regression (n = 47).

CONCLUSION

We report what is by far the longest follow-up to date of postlaparoscopic cryoablation changes in eGFR and note excellent long-term renal functional outcomes. For those willing to accept the potential need for retreatment for recurrent disease, LCA offers excellent long-term CSS.

Does renal mass ablation provide adequate long-term oncologic control?

Renal ablation (RA) is no longer used exclusively in patients with limited life expectancy. There are few studies reporting a minimum follow-up of 5 years. Biases and discrepancies within the literature are abundant. The outcomes of any series must be interpreted in the context of median follow-up time, reported tumor characteristics, ablation technique and training background of the practitioner, and the definition of tumor recurrence. The long-term oncologic efficacy of radiofrequency ablation (RFA) and cryoablation appear similar, although the percutaneous RFA technique may necessitate reablation in more cases. RA is associated with slightly higher rates of local recurrence compared to surgical excision.

Current status of ablative techniques for small renal masses

The past few decades have witnessed a steady increase in the number of newly diagnosed small renal masses. Although historically managed by surgical resection, many of these small renal masses are now noted to be amenable to less invasive treatment modalities including thermal ablation or active surveillance. Contemporary series suggest that renal thermal ablation (including cryoablation or radiofrequency ablation), when selectively employed, can maintain oncologic efficacy comparable to extirpation while minimizing complications and treatment morbidity. Therefore, as the incidence of small renal masses in elderly comorbid patients rises, it is likely we will see ablative techniques assume a greater role in management.

Results of laparoscopic cryoablation in the treatment of small renal masses

Context:

Study of clinical outcome in renal cryoablation.

Aims:

Laparoscopic cryoablation (LCA) is emerging as a reliable treatment option for small renal masses (SRMs) particularly in elderly patients. Our aim was to study the results of cryoablation for small renal masses in our cohort of patients.

Settings and Design:

We retrospectively studied all patients who underwent LCA for SRMs between September 2005 and July 2008.

Materials and Methods:

All patients were discussed in our multidisciplinary meeting prior to cryoablation. Our LCA protocol included two freeze-thaw cycles, achieving a core temperature of –70°C and a peripheral temperature of at least –40°C. Follow-up included serum creatinine measurements and pre- and postcontrast CT scans at 3, 6, 12, 18, and 24 months and yearly thereafter.

Statistical analysis used:

Paired samples t-test was used to study statistical difference.

Results:

Twenty-two patients underwent LCA with a mean (range) age of 68 (39–81 years) years. The mean (range) tumor size was 29 (19–45 mm) mm. Two patients required blood transfusions, one patient developed pneumonia, and another patient developed a small area of skin necrosis at the cryoneedle entry site. The average (range) hospital stay was 4 (2–14 days) days. Twenty-one patients have had CT follow-up at a mean (range) of 24 (4–42 months) months. Three of the 21 tumors showed central enhancement on follow-up CT scans, consistent with treatment failure.

Conclusions:

Laparoscopic cryoablation is a safe treatment option for SRM in a selected group of patients.

Review of the efficacy and safety of radiofrequency ablation for the treatment of small renal masses

BACKGROUND

Small renal masses are increasingly being discovered incidentally on imaging performed for another reason. The standard of care for these masses involves excision by open or laparoscopic techniques. Recently, ablative techniques such as radiofrequency ablation (RFA) and cryoablation have taken a more prominent role in the treatment algorithm for these masses. We sought to evaluate the efficacy and safety of radiofrequency ablation in the treatment of renal tumours.

METHODS

We conducted a review of the literature. There was no language restriction. We obtained studies from the following sources: the Cochrane Library, PubMed, EMBASE, LILACS and Current Controlled Trials.

RESULTS

We identified no clinical trials in the literature. Thus we described the results from case series and retrospective studies with a reasonable sample size (number of reported patients in each study > 65). Most patients undergoing RFA had T1a disease with a mean tumour size of about 3 cm. Radiofrequency ablation was usually performed percutaneously with image guidance. Reported follow-up was short and ranged from 1 to 30 months. Most series used radiographic response as a surrogate for cancer control. The rates of local recurrence of the tumour were as high as 13.0% (average 8.5%) and were slightly higher than those associated with cryoablation and partial nephrectomy. Complications included hemorrhage, ureteral strictures and loss of a renal unit.

CONCLUSION

Our review demonstrates that RFA is a suitable and promising therapy in patients with small renal tumours who are considered to be poor candidates for more involved surgery. However, clinical trials with long-term data are needed to establish the oncological efficacy.

Probe ablation as salvage therapy for renal tumors in von Hippel-Lindau patients: the Cleveland Clinic experience with 3 years follow-up

BACKGROUND

To evaluate the efficacy and safety of probe ablative therapy as salvage treatment for renal tumor in von Hippel-Lindau (VHL) patients after previous partial nephrectomy (PN).

METHODS

Medical records of VHL patients undergoing probe ablative treatment for renal tumors from March 2003 to January 2010 at our institution were retrospectively analyzed.

RESULTS

Fourteen VHL patients who were submitted to salvage probe ablative therapy were included in the analysis. Twelve patients (85%) had a solitary kidney. Overall, 33 tumors were ablated by either percutaneous cryoablation (P-Cryo) (n of procedures = 13), radiofrequency ablation (RFA) (n = 14), and laparoscopic cryoablation (L-Cryo) (n = 3). Average maximal renal tumor diameter was 2.6 ± 1 cm. Average ablation time was 18.3 ± 2.1 minutes for P-Cryo, 36.7 ± 17 minutes for RFA, and 17.3 ± 4 minutes for L-Cryo. All procedures were successfully completed without transfusions and intraoperative complications. No early postoperative complications were recorded. Postoperative decline in renal function was minimal and not clinically significant. With a mean follow-up of 37.6 months (range 12-82), 4 patients had a suspicious recurrence on computed tomography/magnetic resonance imaging (CT/MRI) scan and in 3 of them a re-ablation was performed. Actuarial overall and cancer-specific survivals were 92% and 100%, respectively.

CONCLUSIONS

Probe ablative therapy seems to represent a suitable treatment option for VHL patients with a previous history of PN as it offers a repeatable operation, with a high technical success rate and causing minor changes in renal function.

Renal function and oncologic outcomes after cryoablation or partial nephrectomy for tumors in solitary kidneys

Purpose

Preservation of renal function is of paramount importance in patients with tumors in solitary kidneys. We compared the renal function and oncologic outcomes of patients treated by partial nephrectomy with those of patients treated by cryoablation for solitary kidney tumors.

Materials and Methods

All patients with solitary kidneys who were treated for renal tumors at our institution between 1997 and 2007 were included in the screen. We retrospectively identified 23 patients who underwent cryoablation and 15 patients who underwent partial nephrectomy.

Results

The two groups were similar with regard to age, gender, and tumor laterality. Patients in the partial nephrectomy group had a larger tumor size (3.4 cm vs. 2.5 cm, p=0.01), higher mean estimated blood loss (316 cc vs. 87 cc, p<0.001), longer duration of hospital stay (5.8 vs. 1.8 days, p<0.001), and a higher rate of perioperative complications (53.3% vs. 8.7% patients, p=0.03). Percentage changes in the glomerular filtration rate postoperatively and on follow-up were found to be similar in the two groups. Both the cryoablation and the partial nephrectomy groups with mean follow-ups of 31.2 months and 30.8 months, respectively, had evidence of local or distant recurrence in 3 patients each (13% and 20% respectively, p=0.7). Both groups had a similar mean overall survival (88.9 and 86.9 months in the cryoablation and partial nephrectomy groups, respectively, p=0.8).

Conclusions

For tumors in solitary kidneys, renal functional and clinical outcomes for cryoablation were not significantly different from those for partial nephrectomy. However, cryoablation has the distinct advantage of a lower morbidity rate and can be preferentially offered to selected cases.

The importance of nephron-sparing focal therapy: renal function preservation

Historically, renal cancer has been treated with radical nephrectomy. Consequently, many patients developed renal insufficiency and the health problems associated with this. With the increasing diagnosis of small renal masses, nephron-sparing treatments have been developed to treat these masses adequately, while maximizing renal function. Focal ablative therapy is a means to treat small renal masses in a minimally invasive manner. Yet, there are few studies that have focused on their ability to preserve renal function. In this article, we review the existing literature on the renal function outcomes of patients treated with either radio frequency ablation or cryoablation.

The impact of renal tumor size on the efficacy of laparoscopic renal cryoablation

PURPOSE

We evaluated the impact of renal tumor size on the oncologic and surgical efficacy of laparoscopic renal cryosurgery (LRC) according to our intermediate-term experience in Korea.

MATERIALS AND METHODS

From June 2005 to October 2008, we enrolled 37 patients who underwent LRC for 40 renal tumors. Patients were stratified into four groups according to renal tumor size. Patients who presented with a maximum tumor diameter (MTD) of at least 1 cm but less than 2 cm were assigned to Group 1, those with an MTD equal to or greater than 2 but less than 3 cm were assigned to Group 2, those with an MTD equal to or greater than 3 but less than 4 cm were assigned to Group 3, and those with an MTD equal to or greater than 4 cm were assigned to Group 4. Oncologic and clinical outcomes in each group were compared.

RESULTS

The four groups showed no statistically significant differences in preoperative variables, including age, sex, body mass index, American Society of Anesthesiologists scores, baseline renal function and hemoglobin, and length of hospital stay. Regarding surgical aspects, however, operation time, estimated blood loss, and postoperative complications were significantly increased in patients with larger tumors. Three patients in Group 3 required postoperative transfusions, and 1 patient in Group 4 required conversion to open renal cryosurgery. During the mean follow-up period of 31.6 months, radiologic evidence of tumor recurrence was found in only 2 patients in Group 4.

CONCLUSIONS

In this series, LRC for renal tumors smaller than 3 cm was conducted safely without radiologic evidence of tumor recurrence during intermediate-term follow-up. For tumors larger than 3 cm, however, the transfusion rate increased, and for renal tumors larger than 4 cm, the tumor recurrence rate increased significantly.

Renal ablative therapy: radiofrequency ablation and cryoablation

Widespread use of cross-sectional imaging has contributed to an increase in diagnosis of small renal masses. While extirpation has historically been the "gold standard" for managing such tumors, thermal ablation is increasingly utilized as primary surgical therapy. Contemporary series suggest that ablative procedures maintain oncologic outcomes similar to extirpation while minimizing patient morbidity. As more renal masses are diagnosed in elderly or comorbid patients, ablation will likely assume a central role in management strategies.

Adjuvant approaches to enhance cryosurgery

Molecular adjuvants can be used to enhance the natural destructive mechanisms of freezing within tissue. This review discusses their use in the growing field of combinatorial or adjuvant enhanced cryosurgery for a variety of disease conditions. Two important motivations for adjuvant use are: (1) increased control of the local disease in the area of freezing (i.e., reduced local recurrence of disease) and (2) reduced complications due to over-freezing into adjacent tissues (i.e., reduced normal functional tissue destruction near the treatment site). This review starts with a brief overview of cryosurgical technology including probes and cryogens and major mechanisms of cellular, vascular injury and possible immunological effects due to freeze-thaw treatment in vivo. The review then focuses on adjuvants to each of these mechanisms that make the tissue more sensitive to freeze-thaw injury. Four broad classes of adjuvants are discussed including: thermophysical agents (eutectic forming salts and amino acids), chemotherapuetics, vascular agents and immunomodulators. The key issues of selection, timing, dose and delivery of these adjuvants are then elaborated. Finally, work with a particularly promising vascular adjuvant, TNF-alpha, that shows the ability to destroy all cancer within a cryosurgical iceball is highlighted.

Minimally invasive nephron sparing management for renal tumors in solitary kidneys

PURPOSE

We present a large series of minimally invasive nephron sparing surgery outcomes in solitary kidneys with a focus on treatment selection criteria, and oncological and functional outcomes.

MATERIALS AND METHODS

Of 1,019 patients who underwent minimally invasive nephron sparing surgery since September 1997 at our institution 36, 36 and 29 underwent laparoscopic partial nephrectomy, cryoablation and radio frequency ablation, respectively, for tumors in a solitary kidney. Data, including patient and tumor characteristics, surgery details, complications, and postoperative renal function and intermediate term oncological outcomes in each patient, were obtained by telephone contact or from charts. The 3 groups were compared for perioperative, functional and oncological outcomes.

RESULTS

On multivariate analysis tumor size, aspect and remnant kidney status were independent predictors of treatment selection. Cancer specific and overall survival at 2 years was 100% and 91.2% for laparoscopic partial nephrectomy, 88.5% and 88.5% for cryoablation, and 83.9% and 83.9% for radio frequency ablation, respectively. Disease-free survival was significantly better for laparoscopic partial nephrectomy than for cryoablation and radio frequency ablation (100% vs 69.6% and 33.2%, respectively, p <0.0001). The mean estimated glomerular filtration rate change for laparoscopic partial nephrectomy, cryoablation and radio frequency ablation of 17, 3 and 7 ml per minute per 1.73 m(2) reflected a 26%, 6% and 13% decrease from baseline, respectively, which was statistically significant (p = 0.0016).

CONCLUSIONS

Laparoscopic partial nephrectomy and probe ablative procedures can be safely and efficiently done for renal tumor in patients with a solitary kidney. Intermediate term oncological outcomes are superior for laparoscopic partial nephrectomy despite somewhat poorer renal function outcomes than those of cryoablation and radio frequency ablation.

Decision tree for laparoscopic partial nephrectomy versus laparoscopic renal cryoablation for small renal masses

PURPOSE

We propose an algorithm to help guide surgeons' decisions between laparoscopic partial nephrectomy (LPN) and renal laparoscopic cryoablation (LCA) based on preoperative parameters and outcomes defined in the literature.

PATIENTS AND METHODS

From July 2004 to December of 2007, we performed 51 LPNs and 22 LCAs. We formulated an algorithm between LPN and LCA based on outcomes from published series. Candidates for LPN are younger than 70 years; have few comorbidities; masses < or = 7 cm; and solitary, solid, and or cystic masses with an exophytic or mesophytic location. Candidates for LCA are 70 years old or older, with multiple comorbidities, masses < or = 3.5 cm, multiple masses, solid masses only, and include endophytic or hilar tumors. We then applied this decision tree to our series.

RESULTS

Our results for LPN are statistically similar to the published series except there was a higher positive margin rate in our series (11.8 v 3.5%). Our LCA series had older patients (71 v 65 y), larger masses (3.2 v 2.5 cm), and a higher rate of bleeding necessitating transfusion (18%). We applied the algorithm to all 73 patients in our series. It estimated that 45 patients should undergo LPN and 28 should undergo LCA. A correlation between the predicted surgery and the surgery performed was seen, but approximately one in five patients would have a change in the surgery performed.

CONCLUSIONS

This algorithm validates decisions surgeons are already making between LPN and LCA. While not a perfect model, it can be used to help simplify decisions between these two minimally invasive procedures to achieve optimal outcomes.