Young Suk Kwon

Safety of Robot-Assisted Radical Prostatectomy with Pneumoperitoneum of 20 mm Hg: A Study of 751 Patients

BACKGROUND AND PURPOSE Early studies describing robot-assisted radical prostatectomy (RARP) reported the use of pneumoperitoneum at a pressure of 15 mm Hg. While higher insufflation pressures (20 mm Hg) may reduce venous oozing and improve visualization, the safety of this method has not been confirmed. This study evaluates the short-term perioperative outcomes of patients undergoing RARP with insufflation pressures of 20 mm Hg. PATIENTS AND METHODS A single-surgeon, prospectively maintained database of patients undergoing RARP was retrospectively analyzed. Patients who underwent RARP with a pneumoperitoneum pressure of 15 and 20 mm Hg for the entire procedure were analyzed. Preoperative and postoperative hemoglobin levels and estimated glomerular filtration rate (eGFR) were compared. Complications, operative time, and estimated blood loss were also examined. RESULTS The number of patients in the experimental (20 mm Hg) and control (15 mm Hg) groups were 550 and 201, respectively. The groups were well matched with respect to age and operative time. The experimental group had a significantly smaller decrease in mean hemoglobin levels after surgery (-1.18 vs-2.13 mg/dL, P<0.0001). There was no significant difference in the eGFR on the first day after surgery (postoperative day [POD]1) (88.4 vs 85.0 mL/min/1.73m(2), P=0.11) or in the change in eGFR from preoperative to POD1 levels (-0.49 vs 1.54 mL/min/1.73m(2), P=0.18). The complication rate in the experimental group was 8.55% vs 8.46% in the control group. CONCLUSION Pneumoperitoneum using a pressure of 20 mm Hg for RARP is safe and has no significant short-term effects on renal function and hemoglobin. Increased insufflation pressure was not associated with a higher complication rate.

Neutrophil and Lymphocyte Counts as Clinical Markers for Stratifying Low-Risk Prostate Cancer

UNLABELLED Appropriate patient selection for active surveillance is challenging.Our study of 217 patients demonstrated that the preoperative absolute neutrophil and lymphocyte counts were better predictors of aggressive oncologic features than were the neutrophil-to-lymphocyte ratio in the assessment of low-risk prostate cancer patients. Our findings suggest that routine hematologic workup could be used to further stratify low-risk prostate cancer patients. INTRODUCTION The neutrophil-to-lymphocyte ratio (NLR) has emerged as a ubiquitous prognostic biomarker in cancer-related inflammation, specifically in patients with metastatic castration-resistant prostate cancer (PCa). We evaluated the clinical utility of the preoperative NLR, absolute neutrophil count (ANC), and absolute lymphocyte count (ALC) as a risk stratification tool for patients with low-risk PCa. MATERIALS AND METHODS We identified 217 low-risk PCa patients with preoperative hematologic data who had met the criteria for active surveillance but had undergone robot-assisted radical prostatectomy at our institution from 2006 to 2015. Logistic regression models were constructed to determine whether the baseline NLR, ANC, and ALC were associated with upstaging, upgrading, and biochemical recurrence (BCR). Survival analyses were performed using the Kaplan-Meier method. RESULTS On multivariate analysis, a higher prostate-specific antigen level (odds ratio [OR], 1.554; 95% confidence interval [CI], 1.148-2.104), a greater number of positive cores (OR, 2.098; 95% CI, 1.043-2.104), and a higher ALC (OR, 4.311; 95% CI, 1.258-14.770) were associated with upstaging. More importantly, the 5-year biochemical recurrence-free survival was significantly lower in the high ANC group (ANC > 4.0 × 10(9)/L) compared with that of the low ANC group (P = .011). The NLR was not associated with upstaging, upgrading, or BCR in our study cohort (P = .368, P = .573, and P = .504, respectively). The only significant association with upgrading was patient age (OR, 1.106; 95% CI, 1.043-1.173). CONCLUSION NLR was not useful in predicting adverse pathologic outcomes in our patients with low-risk PCa. However, relative neutrophilia and lymphocytosis might indicate an early manifestation of harboring a more aggressive PCa.

Magnetic Resonance Imaging as a Biomarker for Renal Cell Carcinoma

As the most common neoplasm arising from the kidney, renal cell carcinoma (RCC) continues to have a significant impact on global health. Conventional cross-sectional imaging has always served an important role in the staging of RCC. However, with recent advances in imaging techniques and postprocessing analysis, magnetic resonance imaging (MRI) now has the capability to function as a diagnostic, therapeutic, and prognostic biomarker for RCC. For this narrative literature review, a PubMed search was conducted to collect the most relevant and impactful studies from our perspectives as urologic oncologists, radiologists, and computational imaging specialists. We seek to cover advanced MR imaging and image analysis techniques that may improve the management of patients with small renal mass or metastatic renal cell carcinoma.

Pharmacodynamics, pharmacokinetics and clinical efficacy of phosphodiesterase-5 inhibitors

ABSTRACT Introduction: Phosphodiesterase type 5 inhibitors (PDE5Is) are the first-line drugs in the management of erectile dysfunction (ED). However, over the past two decades tremendous efforts have been made to identify new clinical uses of PDE5Is beyond their roles in ED. Areas covered: Basic science articles, clinical trials, reviews, and meta-analysis published between 1996 and 2015 were searched using MEDLINE (PubMed interface) to collect the most relevant and impactful studies from our perspectives as practicing urologists. This review mainly focuses on the level one evidence-based clinical efficacy and drug-related toxicity of oral PDE5Is. In addition, drug discovery, pharmacokinetics and pharmacodynamics, potential use in other diseases, and future directions are discussed. Expert opinion: On-demand PED5Is for the treatment of ED has shifted toward chronic administration in a broad spectrum of conditions that are thought to be associated with endovascular health. Several studies have shown that PDE5Is may play a cardioprotective or neuroprotective role. Further studies are under way to verify beneficial effects of PDE5I in non-urological conditions.

Unilateral Partial Nephrectomy with Warm Ischemia Results in Acute Hypoxia Inducible Factor 1-Alpha (HIF-1α) and Toll-Like Receptor 4 (TLR4) Overexpression in a Porcine Model

Purpose Ischemia/reperfusion (I/R) during partial nephrectomy (PN) contributes to acute kidney injury (AKI), which is inaccurately assessed using existent clinical markers of renal function. We evaluated I/R-related changes in expression in hypoxia inducible factor 1α (HIF-1α) and toll-like receptor 4 (TLR4), within kidney tissue and peripheral blood leukocytes (PBL) in a porcine model of PN. Materials and Methods Three adult pigs each underwent unilateral renal hilar cross clamping for 180 min followed by a 15 min reperfusion. The contralateral kidney served as control. Biopsies of clamped kidneys were obtained at baseline (time 0), every 60 min during the hypoxic phase, and post-reperfusion. Control kidneys were biopsied once at 180 min. Peripheral blood was sampled at time 0, every 30 min during the hypoxic phase, and post-reperfusion. HIF-1α and TLR4 expression in kidney tissue and PBL were analyzed by Western blotting. I/R-related histological changes were assessed. Results Expression of HIF-1α in clamped kidneys and PBL was below detection level at baseline, rising to detectable levels after 60 min of hypoxia, and continuing to rise throughout the hypoxic and reperfusion phases. Expression of TLR-4 in clamped kidneys followed a similar trend with initial detection after 30–60 min of hypoxia. Control kidneys exhibited no change in HIF-1α or TLR-4 expression. I/R-related histologic changes were minimal, primarily mild tubular dilatation. Conclusions In a porcine model of PN, HIF-1α and TLR4 exhibited robust, I/R-related increases in expression in kidney tissue and PBL. Further studies investigating these molecules as potential markers of AKI are warranted.

Risk of complications and urinary incontinence following cytoreductive prostatectomy: A multi-institutional study

Emerging evidence has suggested that cytoreductive prostatectomy (CRP) allows superior oncologic control when compared to current standard of care androgen deprivation therapy alone. However, the safety and benefit of cytoreduction in metastatic prostate cancer (mPCa) has not been proven. Therefore, we evaluated the incidence of complications following CRP in men newly diagnosed with mPCa. A total of 68 patients who underwent CRP from 2006 to 2014 at four tertiary surgical centers were compared to 598 men who underwent radical prostatectomy for clinically localized prostate cancer (PCa). Urinary incontinence was defined as the use of any pad. CRP had longer operative times (200 min vs 140 min, P < 0.0001) and higher estimated blood loss (250 ml vs 125 ml, P < 0.0001) compared to the control group. However, both overall (8.82% vs 5.85%) and major complication rates (4.41% vs 2.17%) were comparable between the two groups. Importantly, urinary incontinence rate at 1-year after surgery was significantly higher in the CRP group (57.4% vs 90.8%, P < 0.0001). Univariate logistic analysis showed that the estimated blood loss was the only independent predictor of perioperative complications both in the unadjusted model (OR: 1.18; 95% CI: 1.02-1.37; P = 0.025) and surgery type-adjusted model (OR: 1.17; 95% CI: 1.01-1.36; P = 0.034). In conclusion, CRP is more challenging than radical prostatectomy and associated with a notably higher incidence of urinary incontinence. Nevertheless, CRP is a technically feasible and safe surgery for selecting PCa patients who present with node-positive or bony metastasis when performed by experienced surgeons. A prospective, multi-institutional clinical trial is currently underway to verify this concept.

Twitter Use among Academic Urology Programs

Introduction: Twitter is a popular social media platform that has an important role in the urological community. Benefits include dissemination of knowledge, cross‐institutional communication, amplification of conference content and greater engagement of the public, with increased departmental exposure. However, to date the use of Twitter by academic urology programs has yet to be examined. Methods: The existence and profile of institutional Twitter accounts of each United States urology residency program was recorded and reassessed in 6 months. Geographic stratification of Twitter presence was evaluated with chi‐square analysis. The relationship between Twitter variables and U.S. News and World Report ranking was evaluated using Pearsons correlation coefficient. Detailed account data were collected for the top 5 accounts by tweet volume. Conference hashtag activity for the 2013 to 2015 AUA (American Urological Association) annual meetings was compared. Results: The total number of residency programs with a Twitter account is 38 (30%). Median number of tweets, followers, following and age of account was 58, 154, 107.5 and 20 months, respectively. Geographic stratification failed to show significant difference (p=0.73). Of the 38 accounts 11 were inactive over 6 months. The 27 active accounts had an average percent increase of 161% in tweets and 148% in followers. Twitter presence showed no difference in U.S. News and World Report ranking (p=0.51). The conference hashtags #AUA13 to #AUA15 increased in activity each year. Conclusions: A minority of academic urology programs use Twitter. Account activity grew significantly with time. The role of Twitter is still being defined but is rapidly gaining traction as a new powerful communication tool among urologists and with the public.

Chairmen in Academic Urologic Practice: A Descriptive Analysis

OBJECTIVE To examine and characterize the demographics and scholarly characteristics of academic urology chairmen at the time of appointment. MATERIALS AND METHODS The chairman of each United States urology residency program as of September 2016 was included in the study. Interim chairmen, as well as programs for which no clearly defined chair could be identified, were excluded. Demographic and academic data were collected via publically available curriculum vitae, departmental websites, Google search engine, and PubMed and Scopus websites. RESULTS One hundred thirteen chairmen were included in the study. The majority were male (96%) and mean age at appointment was 46 years (standard deviation = 6.3 years). Mean number of publications and H-index at the time of appointment was 105 and 31.1, respectively. Fellowship training was completed by 75% of chairmen, of which urologic oncology (N = 43), endourology (N = 12), and infertility/andrology (N = 10) were the most common. The most common additional graduate degrees prior to appointment were MBA (N = 7) and PhD (N = 6). The most frequently attended institutions for residency were Johns Hopkins University (13) and Northwestern University (5), whereas Memorial Sloan Kettering Cancer Center (13) and Baylor University (7) were the most frequent for fellowship. Twenty percent of chairmen attained the chairman position at their former residency program and 7% at their former fellowship program. CONCLUSION Our study describes the demographic and academic characteristics of urology academic chairmen at the time of appointment. The majority of chairmen are male and specialize in urologic oncology. Chairmen often receive the chair appointment at their former residency program.

Predicting clinically significant prostate cancer based on pre-operative patient profile and serum biomarkers

Previous studies have reported association of multiple preoperative factors predicting clinically significant prostate cancer with varying results. We assessed the predictive model using a combination of hormone profile, serum biomarkers, and patient characteristics in order to improve the accuracy of risk stratification of patients with prostate cancer. Data on 224 patients from our prostatectomy database were queried. Demographic characteristics, including age, body mass index (BMI), clinical stage, clinical Gleason score (GS) as well as serum biomarkers, such as prostate-specific antigen (PSA), parathyroid hormone (PTH), calcium (Ca), prostate acid phosphatase (PAP), testosterone, and chromogranin A (CgA), were used to build a predictive model of clinically significant prostate cancer using logistic regression methods. We assessed the utility and validity of prediction models using multiple 10-fold cross-validation. Bias-corrected area under the receiver operating characteristics (ROC) curve (bAUC) over 200 runs was reported as the predictive performance of the models. On univariate analyses, covariates most predictive of clinically significant prostate cancer were clinical GS (OR 5.8, 95% CI 3.1–10.8; P < 0.0001; bAUC = 0.635), total PSA (OR 1.1, 95% CI 1.06–1.2; P = 0.0003; bAUC = 0.656), PAP (OR 1.5, 95% CI 1.1–2.1; P = 0.016; bAUC = 0.583), and BMI (OR 1.064, 95% C.I. 0.998, 1.134; P < 0.056; bAUC = 0.575). On multivariate analyses, the most predictive model included the combination of preoperative PSA, prostate weight, clinical GS, BMI and PAP with bAUC 0.771 ([2.5, 97.5] percentiles = [0.76, 0.78]). Our model using preoperative PSA, clinical GS, BMI, PAP, and prostate weight may be a tool to identify individuals with adverse oncologic characteristics and classify patients according to their risk profiles.

Intracrine androgen biosynthesis in renal cell carcinoma

Background:Renal cell carcinoma (RCC) is one of the most lethal genitourinary cancers. The presence of androgen receptor (AR) in RCC has recently been shown to be associated with higher tumour stage irrespective of gender. Because the clinical context of androgens in female RCC patients is similar to that of prostate cancer patients undergoing androgen-deprivation therapy, mechanisms underlying the emergence of castration-resistant prostate cancer (CRPC) may be at play in AR-positive RCC cells. Therefore, we hypothesized that AR-positive RCC has intratumoral steroidogenesis and that anti-androgen therapy may result in tumour suppression.Methods:Mice were injected with an AR-positive RCC cell line. When tumours became palpable, surgical castration was performed and tumour volume was measured. Using ELISA, the levels of intracellular testosterone and dihydrotesterone were measured in AR-positive human RCC cell lines. Lastly, male mice containing xenografts were treated with enzalutamide or abiraterone acetate (AA) for 3 weeks to measure tumour volume.Results:We first observed in vivo that castration retards the growth of AR-positive RCC tumour xenograft in mice. Next, AR-positive human RCC cell lines and tissues were found to have elevated levels of testosterone and dihydrotestosterone and express key enzymes required for intracellular androgen biosynthesis. A mouse xenograft study with AR-positive RCC cell line using the commonly used anti-androgen therapies showed significant tumour suppression (P<0.01).Conclusions:Intracrine androgen biosynthesis is a potential source of androgen in AR-positive RCC and that the androgen signaling axis is a potential target of intervention in RCC.