Noah Canvasser

Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging to Identify Clear Cell Renal Cell Carcinoma in cT1a Renal Masses

Purpose: The detection of small renal masses is increasing with the use of cross‐sectional imaging, although many incidental lesions have negligible metastatic potential. Among malignant masses clear cell renal cell carcinoma is the most prevalent and aggressive subtype. A method to identify such histology would aid in risk stratification. Our goal was to evaluate a likelihood scale for multiparametric magnetic resonance imaging in the diagnosis of clear cell histology. Materials and Methods: We retrospectively reviewed the records of patients with cT1a masses who underwent magnetic resonance imaging and partial or radical nephrectomy from December 2011 to July 2015. Seven radiologists with different levels of experience who were blinded to final pathology findings independently reviewed studies based on a predefined algorithm. They applied a clear cell likelihood score, including 1—definitely not, 2—probably not, 3—equivocal, 4—probably and 5—definitely. Binary classification was used to determine the accuracy of clear cell vs all other histologies. Interobserver agreement was calculated with the weighted &kgr; statistic. Results: A total of 110 patients with 121 masses were identified. Mean tumor size was 2.4 cm and 50% of the lesions were clear cell. Defining clear cell as scores of 4 or greater demonstrated 78% sensitivity and 80% specificity while scores of 3 or greater showed 95% sensitivity and 58% specificity. Interobserver agreement was moderate to good with a mean &kgr; of 0.53. Conclusions: A clear cell likelihood score used with magnetic resonance imaging can reasonably identify clear cell histology in small renal masses and may decrease the number of diagnostic renal mass biopsies. Standardization of imaging protocols and reporting criteria is needed to improve interobserver reliability.

Diagnostic performance and interreader agreement of a standardized MR imaging approach in the prediction of small renal mass histology

Purpose To assess the diagnostic performance and interreader agreement of a standardized diagnostic algorithm in determining the histologic type of small (≤4 cm) renal masses (SRMs) with multiparametric magnetic resonance (MR) imaging. Materials and Methods This single-center retrospective HIPAA-compliant institutional review board-approved study included 103 patients with 109 SRMs resected between December 2011 and July 2015. The requirement for informed consent was waived. Presurgical renal MR images were reviewed by seven radiologists with diverse experience. Eleven MR imaging features were assessed, and a standardized diagnostic algorithm was used to determine the most likely histologic diagnosis, which was compared with histopathology results after surgery. Interreader variability was tested with the Cohen κ statistic. Regression models using MR imaging features were used to predict the histopathologic diagnosis with 5% significance level. Results Clear cell renal cell carcinoma (RCC) and papillary RCC were diagnosed, with sensitivities of 85% (47 of 55) and 80% (20 of 25), respectively, and specificities of 76% (41 of 54) and 94% (79 of 84), respectively. Interreader agreement was moderate to substantial (clear cell RCC, κ = 0.58; papillary RCC, κ = 0.73). Signal intensity (SI) of the lesion on T2-weighted MR images and degree of contrast enhancement (CE) during the corticomedullary phase were independent predictors of clear cell RCC (SI odds ratio [OR]: 3.19; 95% confidence interval [CI]: 1.4, 7.1; P = .003; CE OR, 4.45; 95% CI: 1.8, 10.8; P < .001) and papillary RCC (CE OR, 0.053; 95% CI: 0.02, 0.2; P < .001), and both had substantial interreader agreement (SI, κ = 0.69; CE, κ = 0.71). Poorer performance was observed for chromophobe histology, oncocytomas, and minimal fat angiomyolipomas, (sensitivity range, 14%-67%; specificity range, 97%-99%), with fair to moderate interreader agreement (κ range = 0.23-0.43). Segmental enhancement inversion was an independent predictor of oncocytomas (OR, 16.21; 95% CI: 1.0, 275.4; P = .049), with moderate interreader agreement (κ = 0.49). Conclusion The proposed standardized MR imaging-based diagnostic algorithm had diagnostic accuracy of 81% (88 of 109) and 91% (99 of 109) in the diagnosis of clear cell RCC and papillary RCC, respectively, while achieving moderate to substantial interreader agreement among seven radiologists.

The economics of stone disease

The rising prevalence of kidney stone disease is associated with significant costs to healthcare systems worldwide. This is in part due to direct procedural and medical management costs, as well as indirect costs to health systems, patients, and families. A number of manuscripts evaulating the economics of stone disease have been published since the 2008s International Consultation on Stone Disease. These highlight costs associated with stone disease, including acute management, surgical management, and medical management. This work hopes to highlight optimization in care by reducing inefficient treatments and maximizing cost-efficient preventative strategies.

The Usefulness of Chest X-Rays for T1a Renal Cell Carcinoma Surveillance

PURPOSE The overall incidence of pulmonary metastasis of T1 renal cell carcinoma is low. We evaluated the usefulness of chest x-rays based on the current AUA (American Urological Association) guidelines and NCCN Guidelines® for T1a renal cell carcinoma surveillance. MATERIALS AND METHODS Between 2006 and 2012, 258 patients with T1a renal cell carcinoma were treated with partial nephrectomy, radical nephrectomy or radio frequency ablation with surveillance followup at our institution. A retrospective chart review was performed to identify demographics, pathological findings and surveillance records. The primary outcome was the incidence of asymptomatic pulmonary recurrences diagnosed by chest x-ray in cases of T1a disease. Our secondary outcome was a comparison of diagnoses by treatment modality (partial nephrectomy, radical nephrectomy or radio frequency ablation). RESULTS Pulmonary metastases developed in 3 of 258 patients (1.2%) but only 1 (0.4%) was diagnosed by standard chest x-ray surveillance. Median followup in the entire cohort was 36 months (range 6 to 152) and 193 of 258 patients (75%) had greater than 24 months of followup. A mean of 3.3 surveillance chest x-rays were completed per patient. When assessed by treatment type, there was no significant difference in the recurrence rate for partial nephrectomy (0 of 191 cases), radical nephrectomy (0 of 22) or radio frequency ablation (1 of 45 or 2.2%) (p = 0.09). CONCLUSIONS Chest x-rays are a low yield diagnostic tool for detecting pulmonary metastasis in patients treated for T1a renal cel carcinoma. Treatment mode does not appear to influence the need for chest x-ray surveillance.

Do Urinary Cystine Parameters Predict Clinical Stone Activity

Purpose: An accurate urinary predictor of stone recurrence would be clinically advantageous for patients with cystinuria. A proprietary assay (Litholink, Chicago, Illinois) measures cystine capacity as a potentially more reliable estimate of stone forming propensity. The recommended capacity level to prevent stone formation, which is greater than 150 mg/l, has not been directly correlated with clinical stone activity. We investigated the relationship between urinary cystine parameters and clinical stone activity. Materials and Methods: We prospectively followed 48 patients with cystinuria using 24‐hour urine collections and serial imaging, and recorded stone activity. We compared cystine urinary parameters at times of stone activity with those obtained during periods of stone quiescence. We then performed correlation and ROC analysis to evaluate the performance of cystine parameters to predict stone activity. Results: During a median followup of 70.6 months (range 2.2 to 274.6) 85 stone events occurred which could be linked to a recent urine collection. Cystine capacity was significantly greater for quiescent urine than for stone event urine (mean ± SD 48 ± 107 vs –38 ± 163 mg/l, p <0.001). Cystine capacity significantly correlated inversely with stone activity (r = –0.29, p <0.001). Capacity also correlated highly negatively with supersaturation (r = –0.88, p <0.001) and concentration (r = –0.87, p <0.001). Using the suggested cutoff of greater than 150 mg/l had only 8.0% sensitivity to predict stone quiescence. Decreasing the cutoff to 90 mg/l or greater improved sensitivity to 25.2% while maintaining specificity at 90.9%. Conclusions: Our results suggest that the target for capacity should be lower than previously advised.

MP75-12 PROSPECTIVE EVALUATION OF STONE FREE RATES BY COMPUTED TOMOGRAPHY AFTER AGGRESSIVE URETEROSCOPY

proximal or impacted stones. We examined whether a double drug Antibiotic Prophylaxis Treatment (APT), an aminoglycoside and penicillin based on resistant bacteria strains we encounter in our institution may reduce urosepsis post-ureteroscopy. METHODS: Between February 2015 and March 2016, we performed 344 ureteroscopies. Starting September, 2015 we changed the APT for endo-urological procedures according to the bacterial resistance profile in urine cultures at our institution. Inclusion criteria were adult patients referred to ureteroscopic treatment for a urinary stone, with or without prior stenting. Exclusion Criteria included integrated procedures (with PCNL), biopsies, pediatric or pregnant patients. Sepsis was defined as fever above 38.5 degrees Celsius with additional standard criteria (International Sepsis Definitions Conference). All patients had a urine culture taken prior to APT initiation. Fisher’s exact test and T-test with a two-tailed P value < 0.05 denoted statistical significance. RESULTS: 57 patients were excluded. Group 1 (n1⁄4106) were the last to receive the conventional APT (PO Ciprofloxacin 500mg X 2), while the second group (n1⁄4181) were the first to receive the new regimen (IV Gentamycin 240mg & Ampicillin 1gr X 3) prior to ureteroscopy. 65 patients had a preoperative positive culture. A significant percentage of both groups had a preoperative positive urine culture (29%-group 1; 18%-group 2). Seven out of 9 septic events developed in those patients (P<0.001). Patients undergoing RIRS procedures were at increased risk for a septic event when treated with conventional APT (7/9 events; P<0.01). No significant correlation was found between preoperative kidney drainage (stent or nephrostomy tube) and sepsis. CONCLUSIONS: Our study demonstrates that a significant portion of patients undergoing ureteroscopic treatment for urinary stones have positive preoperative urine culture, despite previous treatment. Standard, ‘one size fits all’ APT is not sufficient according to our data. A regimen tailored to the local bacterial resistance strains can lower the rate of sepsis significantly.

The Decline of Laparoendoscopic Single-Site Surgery: A Survey of the Endourological Society to Identify Shortcomings and Guidance for Future Directions

INTRODUCTION To analyze the most recent temporal trends in the adoption of urologic laparoendoscopic single-site (LESS), to identify the perceived limitations associated with its decline, and to determine factors that might revive the role of LESS in the field of minimally invasive urologic surgery. MATERIALS AND METHODS A 15 question survey was created and sent to members of the Endourological Society in September 2016. Only members who performed LESS procedures in practice were asked to respond. RESULTS In total, 106 urologists responded to the survey. Most of the respondents were from the United States (35%) and worked in an academic hospital (84.9%). Standard LESS was the most popular approach (78.1%), while 14.3% used robotics, and 7.6% used both. 2009 marked the most popular year to perform the initial (27.6%) and the majority (20%) of LESS procedures. The most common LESS procedure was a radical/simple nephrectomy (51%) followed by pyeloplasty (17.3%). In the past 12 months, 60% of respondents had performed no LESS procedures. Compared to conventional laparoscopy, respondents only believed cosmesis to be better, however, this enthusiasm waned over time. Worsening shifts in enthusiasm for LESS also occurred with patient desire, marketability, cost, safety, and robotic adaptability. The highest rated factor to help LESS regain popularity was a new robotic platform. CONCLUSION The decline of LESS is apparent, with few urologists continuing to perform procedures attributed to multiple factors. The availability of a purpose-built robotic platform and better instrumentation might translate into a renewed future interest of LESS.

Likelihood of Incomplete Kidney Tumor Ablation with Radio Frequency Energy: Degree of Enhancement Matters

PURPOSE Larger size and clear cell histopathology are associated with worse outcomes for malignant renal tumors treated with radio frequency ablation. We hypothesize that greater tumor enhancement may be a risk factor for radio frequency ablation failure due to increased vascularity. MATERIALS AND METHODS A retrospective review of patients who underwent radio frequency ablation for renal tumors with contrast enhanced imaging available was performed. The change in Hounsfield units (HU) of the tumor from the noncontrast phase to the contrast enhanced arterial phase was calculated. Radio frequency ablation failure rates for biopsy confirmed malignant tumors were compared using the chi-squared test. Multivariate logistic analysis was performed to assess predictive variables for radio frequency ablation failure. Disease-free survival was calculated using Kaplan-Meier analysis. RESULTS A total of 99 patients with biopsy confirmed malignant renal tumors and contrast enhanced imaging were identified. The incomplete ablation rate was significantly lower for tumors with enhancement less than 60 vs 60 HU or greater (0.0% vs 14.6%, p=0.005). On multivariate logistic regression analysis tumor enhancement 60 HU or greater (OR 1.14, p=0.008) remained a significant predictor of incomplete initial ablation. The 5-year disease-free survival for size less than 3 cm was 100% vs 69.2% for size 3 cm or greater (p <0.01), while 5-year disease-free survival for HU change less than 60 was 100% vs 92.4% for HU change 60 or greater (p=0.24). CONCLUSIONS Biopsy confirmed malignant renal tumors, which exhibit a change in enhancement of 60 HU or greater, experience a higher rate of incomplete initial tumor ablation than tumors with enhancement less than 60 HU. Size 3 cm or greater portends worse 5-year disease-free survival after radio frequency ablation. The degree of enhancement should be considered when counseling patients before radio frequency ablation.

Ablative Therapies for the Treatment of Small Renal Masses: a Review of Different Modalities and Outcomes

The widespread utilization of abdominal imaging has led to an increase in incidentally detected small renal masses. Although partial nephrectomy is still considered the gold standard treatment for these masses, there are risks associated with surgical excision, potentially limiting treatment for older patients with multiple comorbidities. A variety of ablative techniques have developed over the past several decades, altering the management of small renal masses. It is likely that improvements in technology will only broaden the applications of ablative therapy. This article provides an update on the various ablative techniques and outcomes.

PD10-08 LIGHT-REFLECTANCE SPECTROSCOPY TO DETECT POSITIVE SURGICAL MARGINS AT RADICAL PROSTATECTOMY: EXPLORATION OF NEW ALGORITHMS TO REFINE DETECTION RATE

was shown to bind to cells expressing PSMA demonstrating significant staining of prostatic adenocarcinoma. We performed the first in-human FDA-approved phase I 3+3 dose finding study of intravenously (IV) administered MDX1201 in intermediateto high-risk patients undergoing RARP and extended lymph node (LN) dissection. METHODS: Patients received a single intravenous infusion of MDX1201 four days prior to RARP to allow for safety evaluation. A 488 nanometer laser was attached to the da Vinci Si surgical robot camera at the time of RARP to allow for visualization of fluorescent dye marking presence of prostatic cancerous tissue. 5 mg dose was given to the first 3 patients, and then the dose was escalated to 15 mg provided safety considerations permit. Patients with prior prostate cancer treatment were excluded. RESULTS: MDX1201 was successfully administered to 5 patients, with no adverse events observed. Initial 5 mg dose failed to show visualization of fluorescent dye in first 3 patients. Of the 15 mg dose patients, patient #4 demonstrated fluorescence ex vivo within the sectioned prostate that correlated with pathological findings, while patient #5 demonstrated fluorescence in-vivo with mild prostatic fluorescence at the right apex, left apex, left mid, and also moderate fluorescence demonstrated at the right external iliac LNs. For patient #5, histopathologic examination confirmed tumor to the mid right lobe (dominant nodule), with a minor focus in anterior left lobe near the base. There was no LN metastasis in this patient (pT2cN0). In the five patients (median PSA 9.5, 80% intermediate-risk, 100% > pT2c), the median LN yield was 18 with no LN involvement in any patient. No positive margins were detected. CONCLUSIONS: We demonstrate the first in human study using an anti PSMA antibody demonstrating fluorescence in the prostate. Identification of prostatic tissue using a conjugated fluorescent marker with specificity against PSMA may help guide preservation of critical structures.