The Impact of a Multidisciplinary Tumor Board (MTB) on Treatment Decision Making for Patients With Renal Cell Carcinoma (RCC): 5-Year Data Analysis.

OBJECTIVE: To describe the impact of a multidisciplinary tumor board (MTB) for renal cell carcinoma (RCC) patients in a locoregional renal cancer network by evaluating shared decision making (SDM) and adherence to MTB recommendations. DESIGN, SETTING AND PARTICIPANTS: This prospective cohort study included all cases from a Dutch renal cancer network with suspicion of or histologically confirmed RCC discussed in MTBs between 2017-2022. Main endpoints were distribution of cases presented, proportion of recommendations with multiple treatment options enabling shared decision making (SDM), definite treatment after SDM and adherence to MTB recommendations. Further endpoints were definite treatment per tumor stage stratified by age and inclusion in clinical trials. Outcomes were displayed as means and proportions (%). Pearson's Chi-Squared test was used to analyze the effect of age on definite treatment advice. RESULTS: Overall, 2651 cases were discussed, of which 1900 (72%) were new referrals and 751 (28%) rediscussions. Majority of cases were cT1a-b tumors (46%) and 22% were local recurrences or metachronous metastatic. Adherence to MTB recommendation was 96% and in 30% multiple treatment options were recommended, allowing for SDM. In 45% of cases with cT1a tumors multiple treatment options were recommended by the MTB, resulting in (cryo)ablation (32%) and AS (30%) as most frequent definite treatments after SDM. Among patients with cT3-4 tumors the inclusion rate in clinical trials was 47%. CONCLUSIONS: A network MTB creates opportunity to discuss multiple treatment options and clinical trials in SDM with patients at a high rate of adherence to MTB recommendation.

The PRO-RCC study: a long-term PROspective Renal Cell Carcinoma cohort in the Netherlands, providing an infrastructure for 'Trial within Cohorts' study designs.

BACKGROUND: Ongoing research in the field of both localized, locally advanced and metastatic renal cell carcinoma has resulted in the availability of multiple treatment options. Hence, many questions are still unanswered and await further research. A nationwide collaborative registry allows to collect corresponding data. For this purpose, the Dutch PROspective Renal Cell Carcinoma cohort (PRO-RCC) has been founded, for the prospective collection of long-term clinical data, patient reported outcome measures (PROMs) and patient reported experience measures (PREMs). METHODS: PRO-RCC is designed as a multicenter cohort for all Dutch patients with renal cell carcinoma (RCC). Recruitment will start in the Netherlands in 2023. Importantly, participants may also consent to participation in a 'Trial within cohorts' studies (TwiCs). The TwiCs design provides a method to perform (randomized) interventional studies within the registry. The clinical data collection is embedded in the Netherlands Cancer Registry (NCR). Next to the standardly available data on RCC, additional clinical data will be collected. PROMS entail Health-Related Quality of Life (HRQoL), symptom monitoring with optional ecological momentary assessment (EMA) of pain and fatigue, and optional return to work- and/or nutrition questionnaires. PREMS entail satisfaction with care. Both PROMS and PREMS are collected through the PROFILES registry and are accessible for the patient and the treating physician. TRIAL REGISTRATION: Ethical board approval has been obtained (2021_218) and the study has been registered at ClinicalTrials.gov (NCT05326620). DISCUSSION: PRO-RCC is a nationwide long-term cohort for the collection of real-world clinical data, PROMS and PREMS. By facilitating an infrastructure for the collection of prospective data on RCC, PRO-RCC will contribute to observational research in a real-world study population and prove effectiveness in daily clinical practice. The infrastructure of this cohort also enables that interventional studies can be conducted with the TwiCs design, without the disadvantages of classic RCTs such as slow patient accrual and risk of dropping out after randomization.

Cancer detection and complications of transperineal prostate biopsy with antibiotics when indicated.

OBJECTIVES: To describe the prostate cancer (PCa) detection rate, including clinically significant prostate cancer (csPCa), in a large cohort of patients who underwent transperineal ultrasonography-guided systematic prostate biopsy (TPB-US) using a probe-mounted transperineal access system, with magnetic resonance imaging (MRI) cognitive fusion in case of a Prostate Imaging-Reporting and Data System grade 3-5 lesion, under local anaesthesia in an outpatient setting. Additionally, to compare the incidence of procedure-related complications with a cohort of patients undergoing transrectal ultrasonography-guided (TRB-US) and transrectal MRI-guided biopsies (TRB-MRI). PATIENTS AND METHODS: This was an observational cohort study in men who underwent TPB-US prostate biopsy in a large teaching hospital. For each participant, prostate-specific antigen level, clinical tumour stage, prostate volume, MRI parameters, number of (targeted) prostate biopsies, biopsy International Society of Uropathology (ISUP) grade and procedure-related complications were assessed. csPCa was defined as ISUP grade ≥2. Antibiotic prophylaxis was only given in those with an increased risk of urinary tract infection. RESULTS: A total of 1288 TPB-US procedures were evaluated. The overall detection rate for PCa in biopsy-naive patients was 73%, and for csPCa it was 63%. The incidence of hospitalization was 1% in TPB-US (13/1288), compared to 4% in TRB-US (8/214) and 3% in TRB-MRI (7/219; P = 0.002). CONCLUSIONS: Contemporary combined systematic and target TPB-US with MRI cognitive fusion is easy to perform in an outpatient setting, with a high detection rate of csPCa and a low incidence of procedure-related complications.

Surgical margins after partial nephrectomy as prognostic factor for the risk of local recurrence in pT1 RCC: a systematic review and narrative synthesis.

PURPOSE: To systematically review the published literature on surgical margins as a risk factor for local recurrence (LR) in patients undergoing partial nephrectomy (PN) for pT1 renal cell carcinomas (RCC). EVIDENCE ACQUISITION: A systematic literature search of relevant databases (MEDLINE, Embase and the Cochrane Library) was performed according to the PRISMA criteria up to February 2022. The hypothesis was developed using the PPO method (Patients = patients with pT1 RCC undergoing PN, Prognostic factor = positive surgical margins (PSM) detected on final pathology versus negative surgical margins (NSM) and Outcome = LR diagnosed on follow-up imaging). The primary outcome was the rate of PSM and LR. The risk of bias was assessed by the QUIPS tool. EVIDENCE SYNTHESIS: After assessing 1525 abstracts and 409 full-text articles, eight studies met the inclusion criteria. The percentage of PSM ranged between 0 and 34.3%. In these patients with PSM, LR varied between 0 and 9.1%, whereas only 0-1.5% of LR were found in the NSM-group. The calculated odds ratio (95% confident intervals) varied between 0.04 [0.00-0.79] and 0.27 [0.01-4.76] and was statistically significant in two studies (0.14 [0.02-0.80] and 0.04 [0.00-0.79]). The quality analysis of the included studies resulted in an overall intermediate to high risk of bias and the level of evidence was overall very low. A meta-analysis was considered unsuitable due to the high heterogeneity between the included studies. CONCLUSION: PSM after PN in patients with pT1 RCC is associated with a higher risk of LR. However, the evidence has significant limitations and caution should be taken with the interpretation of this data.

Potential Risk and Safety Measures in Laparoscopy in COVID-19 Positive Patients.

Background. During the COVID-19 pandemic the question arises if laparoscopy, as an aerosol forming procedure, poses a potential risk for viral transmission of SARS-CoV-2 to healthcare workers. Methods. A literature search was conducted using PubMed, Embase and MEDLINE. Articles reporting information regarding COVID-19 or other relevant viruses and laparoscopy, surgical smoke, aerosols and viral transmission were included. Results. Although aerosols produced during laparoscopy do not originate from the respiratory tract, the main transmission route of SARS-CoV-2, research did show SARS-CoV-2 to be present in other body fluids. The transmission risk via this route is however considered very low. As previous research showed potential viral transmission during laparoscopy for viruses that spread through contaminated body fluids, there might be a potential risk of SARS-CoV-2 transmission during laparoscopy, albeit considered very small. Conclusion. Due to the small risk compared to widely known benefits of laparoscopy, there is no reason to replace laparoscopy by laparotomy due to COVID-19 infection. To avoid the potential small risk of viral transmission, additional safety measures are advised.

Salvage Robot-assisted Renal Surgery for Local Recurrence After Surgical Resection or Renal Mass Ablation: Classification, Techniques, and Clinical Outcomes.

BACKGROUND: Salvage treatment for local recurrence after prior partial nephrectomy (PN) or local tumor ablation (LTA) for kidney cancer is, as of yet, poorly investigated. OBJECTIVE: To classify the treatments and standardize the nomenclature of salvage robot-assisted renal surgery, to describe the surgical technique for each scenario, and to investigate complications, renal function, and oncologic outcomes. DESIGN, SETTING, AND PARTICIPANTS: Sixty-seven patients underwent salvage robot-assisted renal surgery from October 2010 to December 2020 at nine tertiary referral centers. SURGICAL PROCEDURE: Salvage robot-assisted renal surgery classified according to treatment type as salvage robot-assisted partial or radical nephrectomy (sRAPN or sRARN) and according to previous primary treatment (PN or LTA). MEASUREMENTS: Postoperative complications, renal function, and oncologic outcomes were assessed. RESULTS AND LIMITATIONS: A total of 32 and 35 patients underwent salvage robotic surgery following PN and LTA, respectively. After prior PN, two patients underwent sRAPN, while ten underwent sRARN for a metachronous recurrence in the same kidney. No intra- or perioperative complication occurred. For local recurrence in the resection bed, six patients underwent sRAPN, while 14 underwent sRARN. For sRAPN, the intraoperative complication rate was 33%; there was no postoperative complication. For sRARN, there was no intraoperative complication and the postoperative complication rate was 7%. At 3 yr, the local recurrence-free rates were 64% and 82% for sRAPN and sRARN, respectively, while the 3-yr metastasis-free rates were 80% and 79%, respectively. At 33 mo, the median estimated glomerular filtration rates (eGFRs) were 57 and 45 ml/min/1.73 m2 for sRAPN and sRARN, respectively. After prior LTA, 35 patients underwent sRAPN and no patient underwent sRARN. There was no intraoperative complication; the overall postoperative complications rate was 20%. No local recurrence occurred. The 3-yr metastasis-free rate was 90%. At 43 mo, the median eGFR was 38 ml/min/1.73 m2. The main limitations are the relatively small population and the noncomparative design of the study. CONCLUSIONS: Salvage robot-assisted surgery has a safe complication profile in the hands of experienced surgeons at high-volume institutions, but the risk of local recurrence in this setting is non-negligible. PATIENT SUMMARY: Patients with local recurrence after partial nephrectomy or local tumor ablation should be aware that further treatment with robot-assisted surgery is not associated with a worrisome complication profile, but also that they are at risk of further recurrence.

Renal biopsies performed before versus during ablation of T1 renal tumors: implications for prevention of overtreatment and follow-up.

PURPOSE: To assess the difference between renal mass biopsy (RMB) performed either before or during the ablation procedure. METHODS: A retrospective multicenter study was performed in patients with a cT1 renal mass treated with ablation between January 2007 and July 2019, including a search in the national pathology database for patients with a RMB planned for ablation. Patient and tumor characteristics and information on malignant, benign, and non-diagnostic biopsy results were collected to establish rates of overtreatment and number of ablations avoided in case of benign or non-diagnostic histology. RESULTS: RMB was performed in 714 patients, of which 231 patients received biopsy before planned ablation, and 483 patients at the time of ablation. Pathology results before ablation were malignant in 63% (145/231), benign in 20% (46/231) and non-diagnostic in 17% (40/231). Pathology results at the time of ablation were malignant in 67.5% (326/483), benign in 16.8% (81/483) and non-diagnostic in 15.7% (76/483), leading to a total of 32.5% of ablation of benign or non-diagnostic lesions. Of the patients with a benign biopsy obtained before ablation, 80.4% (37/46) chose not to undergo ablation. Patients with inconclusive biopsy before planned ablation chose an informed individualized approach including ablation, repeated biopsy, or no intervention in 56%, 34% and 10%. CONCLUSION: This study emphasizes the importance of obtaining a biopsy prior to the ablation procedure in a separate session to lower the rate of potentially unnecessary ablations.

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.

Renal Function Loss After Cryoablation of Small Renal Masses in Solitary Kidneys: European Registry for Renal Cryoablation Multi-Institutional Study.

Objectives: To estimate and quantify the loss of kidney function in solitary kidneys with small renal masses (SRMs) after laparoscopy-assisted renal cryoablation (LARC), from the European Registry for Renal Cryoablation (EuRECA) database. Patients and Methods: Of the 808 patients from eight European centers in the database, 102 patients had SRMs in solitary kidneys. Patient demographics, body mass index (BMI), American Society of Anesthesiologists (ASA) grade, Charlson comorbidity index, and tumor characteristics including nephrometry (PADUA) score where available were collected. Renal function data in the form of estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) stratification both preoperatively and at 3 months postoperatively were collected. Results: The median (interquartile range [IQR]) age was 67 (59-81) years, the median (IQR) BMI was 26 (23.9-28.9) kg/m2, and the median (IQR) ASA score was 2 (2-3). The median Charlson score was 4 (range: 0-10). The median (IQR) tumor size in cross-sectional imaging was 26 (19-38) mm. The follow-up data were available for 72 patients with a median follow-up for this group of 38 (range: 10-132) months. The mean preoperative eGFR was 55.0 mL/minute/1.73 m2 (standard deviation [SD] = 18.1), and the mean postoperative eGFR was 51.8 mL/minute/1.73 m2 (SD = 18.8). The change was -3.1 mL/minute/1.73 m2 (95% confidence interval -5.2 to -1.0) units, which was statistically significant (p = 0.004). The change in the CKD stages comparing before and after LARC was not significant (paired two-tailed t-test, p = 0.06). Critically, the decrease in the eGFR did not translate to any significant adverse outcome and zero patients required dialysis. Conclusion: To the best of our knowledge, this is the largest study of renal function after LARC in SRMs in solitary kidneys. Cryotherapy in this imperative situation is safe, carries clinically insignificant reduction in renal function, therefore providing an option to minimize the risk of developing renal failure necessitating dialysis.

Oncological outcomes and complication rates after laparoscopic-assisted cryoablation: a European Registry for Renal Cryoablation (EuRECA) multi-institutional study.

OBJECTIVE: To assess complication rates and intermediate oncological outcomes of laparoscopic-assisted cryoablation (LCA) in patients with small renal masses (SRMs). PATIENTS AND METHODS: A retrospective review of 808 patients treated with LCA for T1a SRMs from 2005 to 2015 at eight European institutions. Complications were analysed according to the Clavien-Dindo classification. Kaplan-Meier analyses were used to estimate 5- and 10-year disease-free survival (DFS) and overall survival (OS). RESULTS: The median [interquartile (IQR)] age was 67 (58-74) years. The median (IQR) tumour size was 25 (19-30) mm. The transperitoneal approach was used in 77.7% of the patients. The median postoperative hospital stay was 2 days. In all, 514 patients with a biopsy-confirmed renal cell carcinoma (RCC) were available for survival analyses. The median (IQR) follow-up for the RCC-cohort was 36 (14-56) months. A total of 32 patients (6.2%) were diagnosed with treatment failure. The 5-/10-year DFS was 90.4%/80.0% and 5-/10-year OS was 83.2%/64.4%, respectively. A total of 134 postoperative complications (16.6%) were reported, with severe complications (grade ≥III) in 26 patients (3.2%). An American Society of Anesthesiologists score of 3 was associated with an increased risk of overall complications (odds ratio 2.85, 95% confidence interval 1.32-6.20; P = 0.005). CONCLUSIONS: This large series of LCA demonstrates satisfactory long-term oncological outcomes for SRMs. However, although LCA is considered a minimally invasive procedure, risk of complications should be considered when counselling patients.

Preoperative Aspects and Dimensions Used for Anatomical Score Predicts Treatment Failures in Laparoscopic Cryoablation of Small Renal Masses.

OBJECTIVES: To determine the potential of the preoperative aspects and dimensions used for anatomical (PADUA) classification score as a predictive tool in relation to residual unablated tumor and disease-free survival (DFS) following laparoscopy-assisted cryoablation (LCA) of small renal masses. PATIENTS AND METHODS: A multi-institutional cohort of 212 patients with biopsy-verified T1N0M0 renal malignancies treated with LCA between August 2005 and September 2014 were retrospectively investigated with respect to oncologic outcomes. RESULTS: The preoperative PADUA score was found to be low (6-7 points) in 70 patients (33%), moderate (8-9 points) in 86 patients (40.6%), and high (10-14 points) in 56 patients (26.4%). The mean PADUA score was significantly higher in cases (n = 11) with residual unablated tumor (10.4 vs 8.1, p < 0.001) and in cases (n = 8) with local tumor recurrence (9.8 vs 8.1, p < 0.001) at a mean follow-up of 37 (95% confidence interval: 34-40) months. The estimated 2-, 3-, and 5-year DFS for patients with a moderate PADUA score was 96%, 94%, and 94% compared with 95%, 87%, and 81%, respectively, for patients with a high PADUA score (log-rank, p = 0.003). The PADUA score did not predict overall survival. CONCLUSION: The PADUA score significantly predicts residual unablated tumor and DFS following LCA. Further studies are needed to validate the efficacy of the PADUA score in relation to oncologic outcomes following ablative procedures.

Renal cancer seeding metastases following retroperitoneoscopic-assisted cryoablation: A case report.

Nephron-sparing laparoscopy is the standard surgical treatment for clinical T1a renal tumours. However, the laparoscopic technique brings in its specific oncological safety concerns. Seeding metastases are reported: peritoneal metastases, port-tract metastases, and (sub-) cutaneous metastases. The method of laparoscopic assisted renal mass cryoablation is marked by the fact that traumatic tumour tissue handling is unavoidable. This case report reviews the rare occasion of seeding metastases in the retroperitoneal space following laparoscopic cryoablation of a small renal mass. The primary tumour showed no focal recurrence as reported by histological examination. The combination of two events as harming the integrity of cancer tissue and gas-circulation leading to the development of metastases in the retroperitoneal cavity is discussed. The combination of iatrogenic harming cancer tissue integrity and CO2-circulation leads to metastases in the retroperitoneal cavity. Therefore, we recommend performing image-guided renal mass biopsies before considering cryoablative surgery.

18F-FDG PET-CT Findings Before and After Laparoscopic Cryoablation of Small Renal Mass: An Initial Report.

The aim of this study was to describe the characteristics of positron emission tomography (PET) molecular imaging combined with low-dose computed tomography (CT) in small renal mass (SRM) treated with cryoablation (CA). Currently, treatment success is defined by the absence of contrast enhancement at CT. However, the use of contrast is relatively contraindicated in patients with renal function impairment, mandating alternative follow-up strategies. Several reasons were identified as criteria for performing PET-CT before and/or after SRM-CA in 9 patients, and the results were retrospectively studied. The histology revealed renal cell carcinoma in 7 patients and oncocytoma in 2 patients. In 6 patients, a PET-CT was performed before and after CA. In one patient, the PET-CT was performed only before CA and in 2 patients only after CA. Before CA, clearly there was metabolic uptake of fluorine-18 fluorodeoxyglucose (18F-FDG) in the SRM in all patients. Following CA, the absence of 18F-FDG uptakes in the SRM could clearly be noticed. However, the tracer cannot always be distinguished from focal recurrence or reactive inflammatory tissue. In one patient, asymptomatic metastatic bone lesions were noticed when performing PET-CT at follow-up. This pilot study with 18F-FDG PET-CT for the follow-up of SRM cryosurgery showed that 18F-FDG PET-CT imaging could be used to characterize cryoablative tissue injury at different times after CA.

Can RENAL and PADUA nephrometry indices predict complications of laparoscopic cryoablation for clinical stage T1 renal tumors?

OBJECTIVE: Assessment of anatomical complexity with the RENAL (radius; exophytic/endophytic; nearness; anterior/posterior; location) and preoperative aspects and dimensions used for anatomical classification (PADUA) nephrometry indices is used to predict complications related to surgical extirpation treatment for patients with clinical T1a/b renal mass. This single center study aims to investigate the value of these indices to predict complications in a cohort of patients treated with laparoscopic cryoablation (LCA) for cT1 renal mass. MATERIALS AND METHODS: Single institution data from consecutive LCA procedures were prospectively collected from December 2006 to April 2013. Renal mass anatomical complexity was categorized according to RENAL and PADUA indices. Comorbidity was assessed by the Charlson-index. Intraoperative complications (IOCs) were reviewed and categorized: blood loss >100 mL, conversion, tumor fracture, and incomplete ablation. Postoperative complications (POCs) were graded using the modified Clavien-index. Univariate and multivariate logistic regression models addressed the risk for complications. RESULTS: Ninety-nine LCA procedures were included. The median RENAL-score was 7.0 (standard deviation [SD] 1.7), and the median PADUA-score was 8.0 (SD 1.6). IOC occurred in 19 procedures (19%). The risk for IOC was significantly correlated (p<0.05) with tumor diameter (mm), surface, volume, the RENAL domains "R-size," "N-nearness to collecting system," "RENAL score," and the PADUA domain "diameter." In multivariate analysis with surgical complication as the independent variable, tumor diameter, surface, and volume were determining factors. A threshold was set for 35 mm tumor diameter, it being predictive for an increased risk for IOC performing LCA. Twenty-three POC occurred in 20 patients. On univariate analysis, the RENAL domain "nearness to collecting system," and no PADUA domains, had a significant association with POC. CONCLUSION: The RENAL score, and not the PADUA score, is associated with a higher risk for IOC. A noncategorized method of scoring tumor diameter showed a more significant correlation with the risk for IOC than the categorized method of the nephrometry indices. As a result a threshold diameter of 35 mm was established.

Primary urethral carcinoma in females: an epidemiologic study on demographical factors, histological types, tumour stage and survival.

PURPOSE: To obtain insight into demographical factors, histology and survival rates of females diagnosed with primary urethral cancer and to determine favourable treatment. METHODS: Data from 91 females with primary urethral carcinoma, age varying from 15 to 85 years, registered between 1989 and 2008 at the National Cancer Registry of the Netherlands were used for this study. Demographical factors, incidence rate, morphology and tumour stage according to TNM classification were analysed. Kaplan-Meier survival curves were constructed and stratified by stage, histological type and treatment modality. RESULTS: The overall crude annual incidence was 0.7 per million women with a peak incidence in the age group of 80-84 years. Analysis of the morphology showed urothelial cell carcinoma (UCC) in 45 %, squamous cell carcinoma (SCC) in 19 %, adenocarcinoma (AC) in 29 %, and unknown or undifferentiated carcinoma accounted for 6 %. Almost half of patients (46 %) had advanced disease at time of diagnosis and was mainly treated with surgery and/or radiotherapy. The 5-year survival rates of stage 0-II, stage III and stage IV were 67, 53 and 17 %, respectively. The 5-year survival rates of SCC, UCC and AC were 64, 61 and 31 %, respectively. CONCLUSIONS: Female primary urethral carcinoma is a rare condition, and the majority of patients were aged above 65 years. Almost half of patients have advanced disease upon diagnosis. TNM stage and histological type of disease are the most determining factors for survival. Extended surgery with or without radiotherapy seems to be the most favourable treatment. Awareness and early diagnosis are important to improve survival.

Gradient changes in porcine renal arterial vascular anatomy and blood flow after cryoablation.

PURPOSE: We quantified temporal changes in vascular structure and blood flow after cryosurgery of the porcine kidney in vivo. MATERIALS AND METHODS: We studied 5 groups of 4 kidneys each with a survival time of 20 minutes, 4 hours, 2 days, and 1 and 2 weeks after cryoablation, respectively. Before harvesting the kidneys, fluorescently labeled microspheres were administrated in the descending aorta. After harvest the kidney and its vasculature were casted with fluorescently dyed elastomer, frozen and processed in an imaging cryomicrotome to reveal the 3-dimensional arterial branching structure and microsphere distribution. In regions of interest vessels were segmented by image analysis software and histograms were constructed to reveal the total summed vessel length as a function of diameter. A characteristic diameter of the ablated area was measured. RESULTS: The 20-minute survival group histograms showed a significant shift of the peak to larger diameters (p<0.002), indicating that smaller vessels were destroyed. Microsphere density was decreased to 2% in the ablated region but not in the nonablated border zone, depending on the remaining crater crossing larger vessels. After 2 weeks neither vessels nor microspheres were left in the ablated area, which had shrunk by about 40% in diameter. Study limitations are the lack of histological confirmation and the use of normal rather than cancerous tissue. CONCLUSIONS: Larger vessels remain patent just after ablation and transport blood to the border of the ablation crater but perfusion within the crater is halted instantly. Characteristic crater diameter increases initially but decreases thereafter. Destruction of vessels and tissue is complete 2 weeks after cryoablation.

Immediate effect of kidney cryoablation on renal arterial structure in a porcine model studied by imaging cryomicrotome.

PURPOSE: Injury to blood microvessels has a crucial role in effective cryoablation for renal masses. We visualized vascular injury induced by a clinically applied cryoablation instrument and established a microvascular diameter threshold for vascular damage. MATERIALS AND METHODS: In 5 anesthetized pigs 1 kidney each was exposed and 3, 17 gauge cryoneedles were inserted in 1 pole. Tissue was exposed to freezing for 2 x 10 minutes with a 10-minute thaw between freezes. After nephrectomy the arteries were injected with fluorescence dyed casting material and the kidney was frozen to -20C and cut in 40 to 60 micron slices in the imaging cryomicrotome, where fluorescent images of the cutting plane of the bulk were obtained. This resulted in a 3-dimensional image of the arterial tree that was segmented, resulting in unbranched vessel segments. Histograms were constructed with the total segment length per diameter bin plotted as function of diameter. RESULTS: The ablated zone was sharply demarcated on fluorescent and normal light images. Mean +/- SD diameter at the peak of the histogram from control areas was 152.4 +/- 5.3 micron. Compared to control areas the peak diameter of ablated areas was shifted to a larger diameter by an average of 25.4 +/- 2.6 micron. CONCLUSIONS: Immediate renal cryoablation injury destroys arteries smaller than 180 micron. Branching structures of larger arteries remain anatomically intact and connected to vascular structures in surrounding tissue.

The performance of 17-gauge cryoprobes in vitro.

In cryosurgery it is crucial that the performance of cryoprobes is predictable and constant. In this study we tested the intra- and interneedle variation between 17-gauge cryoprobes in two homogeneous mediums. Also, a multiprobe setup was tested. Cryoprobe performance was defined as the time it takes one cryoprobe to lower the temperature from 0 to -20 degrees C as measured by four thermosensors each at 3 mm distance from the cryoprobe. In agar eight cryoprobes were tested during six freeze cycles, and in gel four cryoprobes during four freeze cycles; each freeze cycle in a different cup of agar or gel. Using more accurate 'bare' thermosensors three cryoprobes were tested in gel during two freeze cycles. A multiprobe configuration with four cryoprobes was tested during two freeze cycles in both agar and gel. Statistical analyses were done using ANOVA for repeated measures. There was no significant intraneedle variation, whereas both in agar and gel there was a significant interneedle variation (p<0.05). Mean performance in gel was better than in agar (p<0.001). Also, there was a significant variation between the four thermosensors (p<0.001). Using bare thermosensors mean performance was 2.7 times faster compared to measurements by regular thermosensors (p<0.001). In a multiprobe configuration, overall performance seems less variable and more reproducible compared to a single cryoprobe. In conclusion, the performance of cryoprobes differs depending on the medium and measuring device used. Cryoprobes deliver reproducible freeze cycles, although there is variation between different cryoprobes. In a multiprobe configuration performance seems less variable.

Ultrasonography of renal masses using contrast pulse sequence imaging: a pilot study.

BACKGROUND AND PURPOSE: The use of contrast-enhanced ultrasonography for imaging of renal masses was first described in 1994. Since then, many new techniques for visualization of the effect of microbubble contrast agents have been developed. In this pilot study, a small number of patients was investigated with contrast pulse sequence imaging (CPS), and the characteristics of this perfusion imaging technique were evaluated subjectively and judged against the clinical diagnosis and histology findings when available. The purpose of this pilot study was to describe CPS imaging in several cases. PATIENTS AND METHODS: Eighteen patients with 20 previously identified renal masses were examined with CPS. Perfusion imaging was compared with clinical diagnosis and with histologic findings when available. RESULTS: Nineteen masses were visible. Various enhancement patterns could be observed, and interpretations of CPS characteristics are described. In carcinomas, inhomogeneous enhancement patterns were observed, and areas without enhancement inside the inhomogeneous lesions corresponded to necrotic areas in histologic specimens. All simple cysts and complex benign cysts showed absence of enhancement inside or in the wall of the lesion and a regular shape. CONCLUSION: To our knowledge, this is the first study in which the characteristics of CPS imaging of renal masses have been related to clinical diagnoses and histologic features. From the results of this pilot project, we conclude that CPS is a promising technique to determine perfusion patterns in the kidney.

Contrast-enhanced ultrasonography in the follow-up of cryoablation of renal tumours: a feasibility study.

OBJECTIVE: To determine whether evaluating perfusion patterns with contrast-enhanced ultrasonography using contrast-pulse sequence imaging (CPS; a new imaging method that enables selective visualization of perfusion) is possible at different times after cryoablation of renal tumours, and to describe the characteristics of CPS in a small group of patients. PATIENTS AND METHODS: The efficacy of renal cryoablation is mainly judged using imaging. Seven randomly selected patients, each at a different time after laparoscopically assisted cryoablation of a renal tumour, were investigated with CPS and a microbubble-contrast agent. The perfusion characteristics in the lesions were scored by two investigators and described, and the lesions were measured. RESULTS: In the seven patients treated with cryoablation for small renal tumours, eight CPS studies were performed. Five lesions showed no enhancement and one lesion, investigated 18 months after treatment was not recognized. In one patient, no enhancement was seen after 1 month but 7 months later, there were minimal contrast signals inside the treated area. The lesions could be measured with a mean standard deviation of 1.1 mm and a mean difference between the two investigators of 0.7 mm. CONCLUSION: Our first experiences with CPS imaging for the follow-up of renal cryoablation show that this technique can be used to characterize perfusion defects at different times after cryoablation.