Rate of benign histology after resection of suspected renal cell carcinoma: multicenter comparison between Korea and the United States.

BACKGROUND: In the United States, the rate of benign histology among resected renal tumors suspected to be malignant is increasing. We evaluated the rates in the Republic of Korea and assessed the racial effect using recent multi-institutional Korean-United States data. METHODS: We conducted a multi-institutional retrospective study of 11,529 patients (8,812 from The Republic of Korea and 2,717 from the United States) and compared the rates of benign histology between the two countries. To evaluate the racial effect, we divided the patients into Korean, Asian in the US, and Non-Asian in the US. RESULTS: The rates of benign histology and small renal masses in Korean patients were significantly lower than that in United States patients (6.3% vs. 14.3%, p < 0.001) and (≤ 4 cm, 7.6% vs. 19.5%, p < 0.001), respectively. Women, incidentaloma, partial nephrectomy, minimally invasive surgery, and recent surgery were associated with a higher rate of benign histology than others. CONCLUSIONS: In Korea, the rate of benign histology among resected renal tumors was significantly lower than that in the United States. This disparity could be caused by environmental or cultural differences rather than racial differences. Our findings suggest that re-evaluating current context-specific standards of care is necessary to avoid overtreatment.

Korean Society of Endourology and Robotics (KSER) recommendation on the diagnosis, treatment, and prevention of urolithiasis.

This article provides evidence-based recommendations and expert opinions to aid urologists in making optimal decisions regarding managing urolithiasis in various clinical scenarios. The most frequently asked questions by urologists in their clinical practice have been collected and answered in the form of FAQs; based on the latest evidence and expert opinions. The natural history of urolithiasis is divided into active treatment and silent phases, with the active treatment stage divided into typical and special situations and peri-treatment management. The authors address 28 key questions, offering practical guidance for the proper diagnosis, treatment, and prevention of urolithiasis in clinical practice. This article is expected to be served as a valuable resource for urologists.

Patients' self-management of adverse events and patient-reported outcomes in advanced renal cell carcinoma treated with targeted therapies: A prospective, longitudinal, observational study.

BACKGROUND: Early intervention to reduce the impact of adverse events (AEs) may improve patients' quality of life and enable optimal treatment duration. METHODS: This nationwide, multicenter, prospective, longitudinal, 1-year observational study investigated patients' self-management of AEs associated with targeted therapy for advanced renal cell carcinoma (RCC) and explored corresponding outcomes, including treatment duration and patient-reported outcomes (PROs). RESULTS: We enrolled 77 advanced RCC patients (mean age 62 years) treated with a first targeted therapy. 210 cases of seven AEs of interest (fatigue, hand-foot syndrome, oral mucosal inflammation, diarrhea, gastrointestinal symptoms, hypertension, and anorexia) were observed. Most AEs were mild to moderate. Overall, 63.4% of patients were identified as managing their AEs well, reporting numerically longer treatment duration and significantly higher PRO scores than patients identified as poor managers. CONCLUSIONS: Longer treatment duration and improved PROs were observed when advanced RCC patients managed targeted therapy-associated AEs well. Repeated education for consolidating AE self-management could be considered to enhance overall treatment outcomes.

Large database study of urinary stone composition in South Korea: Korean Society of Endourology and Robotics (KSER) research series.

PURPOSE: To evaluate the characteristics of urinary stone composition in a Korean population using a large database of stone composition. MATERIALS AND METHODS: From January 1, 2014, to June 30, 2019, a total of 33,078 urinary stone composition data were analyzed. Stone composition was classified into four main groups: calcium oxalate (CaOx), struvite, uric acid (UA), and calcium phosphate (CaP). We examined the relationship between stone composition and sex, age, geographic region, calendar month, and season. RESULTS: The CaOx group (46.41%) was the largest, followed by the struvite group (29.66%), UA group (19.61%), and CaP group (4.32%). The CaOx group tended to decrease with age, but the UA group increased with age. Also, the CaOx group had the highest percentage in summer and the lowest in spring (p<0.001). The struvite and CaP groups had higher percentages of females than males (struvite: 36.6% vs. 25.7%, p<0.001; CaP: 6.2% vs. 3.3%, p<0.001). Conversely, the UA stones were more common in males than in females (24.5% vs. 11.0%, p<0.001). The UA group had the lowest percentage in the capital region (p<0.001). The total male-to-female ratio decreased over time from 1.95:1 in 2014 to 1.67:1 in 2018 (p<0.001). CONCLUSIONS: There were differences for each stone composition in the percentages according to sex, age, geographic region, month, and season. Identifying these differences based on the stone composition is vital for the treatment and prevention of urinary stones.

Development of the clinical calculator for mortality of patients with metastatic clear cell type renal cell carcinoma: An analysis of patients from Korean Renal Cancer Study Group database.

Purpose: To develop the clinical calculator for mortality of patients with metastatic renal cell carcinoma (mRCC) using Korean Renal Cancer Study Group (KRoCS) database. Materials and Methods: Data from 1,115 patients with mRCC treated in 4 hospitals joining KRoCS between 1993 and 2016 were pooled. Five-year survival rates were calculated using Kaplan-Meier curve. A clinical calculator for 5-year mortality was developed using multivariable logistic regression analysis and validated externally using dataset including 916 patients from 4 other hospitals. Results: Overall survival rates and cancer specific survival rate at 5 years were 28.5% and 29.4%, respectively. Among baseline factors, increased neutrophil-lymphocyte ratio (≥4), synchronous metastasis, low albumin (<3.0 g/dL), and low hemoglobin (

Is the amount of carbon dioxide gas used in urologic laparoscopic surgeries associated with postoperative pain?

Purpose: We measured how much CO2 gas was used in urologic laparoscopic surgeries and studied whether the amount of gas was associated with postoperative pain. Materials and Methods: Four hundred sixty-three patients underwent urologic laparoscopic surgeries by a single surgeon. All surgeries were performed by a transperitoneal approach under a 15-mm Hg pneumoperitoneum using CO2 gas. The amount of CO2 was measured. Neuromuscular blockade with rocuronium was performed during the surgery and patient-controlled analgesia was also applied. Postoperative pain was assessed four times for 24 hours using a 10-point visual analogue scale. Results: The mean laparoscopic time was 75.65±38.19 minutes and the mean amount of CO2 gas used was 415.70±190.68 L. The mean score on the postoperative pain scale was 6.37±1.48 for 12 hours (sum of measurements taken at 6 and 12 hours after the surgery) and 11.72±2.46 for 24 hours (sum of measurements at 6, 12, 18, and 24 hours). In the statistical analysis, there were no correlations between the amount of CO2 used and pain scores for 12 and 24 hours postoperatively. There were no correlations between laparoscopic time and pain scores for 12 or 24 hours postoperatively. There were also no correlations between operative method and pain scores for 12 or 24 hours postoperatively. Conclusions: We recorded the amount of CO2 gas used for each laparoscopic surgery. There was no correlation between the amount of CO2 used and postoperative pain. The lack of correlation may have been because the surgery was performed under anesthesia with deep neuromuscular blockade.

Survival and clinical prognostic factors in metastatic non-clear cell renal cell carcinoma treated with targeted therapy: A multi-institutional, retrospective study using the Korean metastatic renal cell carcinoma registry.

OBJECTIVES: The optimal treatment strategy for metastatic non-clear cell renal cell carcinoma (mNCCRCC) is still elusive and mainly extrapolated from evidence available for metastatic clear cell renal cell carcinoma. The aim of the study was therefore to investigate the survival outcomes and prognostic factors affecting survival in patients with mNCCRCC treated with targeted therapy. MATERIALS AND METHODS: We analyzed a total of 156 patients (8.1%) with mNCCRCC among the total cohort of 1922 patients in the Korean metastatic RCC registry. We used Kaplan-Meier curve analysis to calculate the survival estimates for first-line progression-free survival (PFS), total PFS, and cancer-specific survival (CSS). We also used the log-rank test to compare the different groups and multivariate Cox-proportional hazard regression analyses to evaluate the prognostic factors for survival. RESULTS: The mNCCRCC group had significantly inferior survival outcomes in terms of first-line PFS, total PFS, and CSS (all P < 0.05). We found survival benefits in patients treated with first-line vascular endothelial growth factor-tyrosine kinase inhibitors (VEGF-TKIs, first-line PFS, and total PFS, all P < 0.05), cytoreductive nephrectomy (CSS, P < 0.0001), metastasectomy (CSS, P = 0.0017), and patients with metachronous metastasis (first-line PFS, total PFS, and CSS, all P < 0.05). Liver metastasis was the only significant prognostic factor for both first-line PFS and CSS (all P < 0.05). CONCLUSIONS: In the current targeted therapy era, survival of mNCCRCC is still inferior in comparison with that of mCCRCC patients. We found survival benefits in patients treated with first-line VEGF-TKIs/CN/metastasectomy, and metachronous metastasis patients.

Transperitoneal laparoscopic ureteroureterostomy with excision of the compressed ureter for retrocaval ureter and review of literature.

Purpose: We present surgical techniques and operative results of laparoscopic reconstruction for patients with retrocaval ureter (RCU) and review similar papers. Materials and Methods: Ten patients with RCU were enrolled in this study from April 2005 to January 2017. The mean age of 7 males and 3 females was 40.5 years old. The chief complaint was flank pain in 6 patients; the remaining patients were detected incidentally. All patients showed hydronephrosis and typical S-shaped deformity of the ureter on imaging studies. Five patients showed obstructed patterns on the renal scans. Two surgeons performed laparoscopic ureteroureterostomies with transperitoneal approaches including excision of the compressed ureter. Double-J ureteral stents were inserted intraoperatively. The operative and follow-up results were checked and compared with published papers. Results: All laparoscopic reconstructions were successfully completed without conversion to open surgery. The mean operative time was 199.6 minutes. The estimated blood loss was 154.4 mL. No operative complications were encountered. There were no obstruction and symptom after the mean follow-up of 40.7 months. We found 7 papers from PubMed, which had more than five cases of laparoscopic reconstruction of RCU. We reviewed and summarized the clinical and operative parameters. Conclusions: Our results show that transperitoneal laparoscopic ureteroureterostomy with excision of the compressed ureter is a safe and effective treatment for RCU. Data from published papers and ours summarize clinical parameters of RCU, and suggest that the laparoscopic reconstruction can be considered as the standard treatment for it.

Effects of Variant Histology on the Oncologic Outcomes of Patients With Upper Urinary Tract Carcinoma After Radical Nephroureterectomy: A Propensity Score-Matched Analysis.

PURPOSE: To determine the prognostic effect of upper tract urothelial carcinoma (UTUC) with variant histology (VH) after radical nephroureterectomy (RNU). PATIENTS AND METHODS: The data of 1173 patients who received RNU for UTUC without neoadjuvant chemotherapy in 11 institutions between 2002 and 2016 were retrospectively reviewed. A matched propensity score analysis was performed. Clinicopathologic variables, recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were compared between patients with pure UTUC and patients with UTUC and VH. Univariate and multivariate Cox proportional regression models were used to determine the independent variables associated with oncologic outcomes. RESULTS: UTUC with VH was observed in 93 patients (7.9%). After propensity score matching, UTUC with VH showed no difference in clinicopathologic features compared to pure UTUC; however, it was associated with shorter RFS, CSS, and OS (log rank, P = .011, P = .002, P = .006, respectively). Additionally, the multivariate analysis revealed that VH was independently associated with a poor RFS [hazard ratio (HR) = 1.92; 95% confidence interval (CI), 1.27-2.89; P = .002], CSS (HR = 4.47; 95% CI, 1.99-10.1; P = .001), and OS (HR = 3.00; 95% CI, 1.55-5.78; P = .001). However, the Kaplan-Meier method revealed that differences in RFS, CSS, and OS were not significant in patients who received adjuvant chemotherapy (log rank, P = .562, P = .060, P = .153, respectively). CONCLUSION: UTUC with VH was independently associated with poor oncologic outcomes in patients with UTUC after RNU. Although patients with UTUC and VH had a poor prognosis compared to patients with pure UTUC, adjuvant chemotherapy would be helpful in improving the survival rates of these patients.

Application of the International Metastatic Renal Cell Carcinoma Database Consortium and Memorial Sloan Kettering Cancer Center Risk Models in Patients with Metastatic Non-Clear Cell Renal Cell Carcinoma: A Multi-Institutional Retrospective Study Using the Korean Metastatic Renal Cell Carcinoma Registry.

PURPOSE: The International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) and the Memorial Sloan Kettering Cancer Center (MSKCC) risk models were developed predominantly with clear cell renal cell carcinoma (RCC). Accordingly, whether these two models could be applied to metastatic non-clear cell RCC (mNCCRCC) as well has not been well-known and was investigated herein. MATERIALS AND METHODS: From the Korean metastatic RCC registry, a total of 156 patients (8.1%) with mNCCRCC among the entire cohort of 1,922 patients were analyzed. Both models were applied to predict first-line progression-free survival (PFS), total PFS, and cancer-specific survival (CSS). RESULTS: The median first-line PFS, total PFS, and CSS were 5, 6, and 24 months, respectively. The IMDC risk model reliably discriminated three risk groups to predict survival: the median firstline PFS, total PFS, and CSS for the favorable, intermediate, and poor risk groups were 9, 5, and, 2 months (p=0.001); 14, 7, and 2 months (p < 0.001); and 41, 21, and 8 months (p < 0.001), all respectively. The MSKCC risk model also reliably differentiated three risk groups: 9, 5, and, 2 months (p=0.005); 10, 7, and 3 months (p=0.002); and 50, 21, and 8 months (p < 0.001), also all respectively. The concordance indices were 0.632 with the IMDC model and 0.643 with the MSKCC model for first-line PFS: 0.748 and 0.655 for CSS. CONCLUSION: The current IMDC and MSKCC risk models reliably predict first-line PFS, total PFS, and CSS in mNCCRCC.

Evaluation of Performance Parameters of the Disposable Flexible Ureterorenoscope (LITHOVUE) in Patients with Renal Stones: A Prospective, Observational, Single-arm, Multicenter Study.

We investigated performance parameters of disposable flexible ureterorenoscopy (LITHOVUE) in patients with renal stones in a prospective, multicenter, observational study. Sixty two patients who underwent ureterorenoscopic surgery by LITHOVUE were included. Surgeons using a numerical scale, evaluated the maneuverability of the scopes and general perceptions of visibility related to the monitor and irrigation systems. General pain and fatigue scores were evaluated and compared to existing scopes. Mean patient age was 57.3 years and stone size was 15.4 mm. Clinical success of overall stone removal was 82.3%. Complications occurred in 4 cases of the Clavien classification grade I in a single case and II in 3 cases. Comparative parameters of maneuverability, perception of the monitor system and perception of the irrigation channel were 2.5, 2.5, and 3.0, respectively. The most favorable evaluation of physical strain was about 'shoulder fatigue' and 'hand fatigue'. Unfavorable evaluations were recorded for 'wrist stiffness' and 'thumb fatigue'. Maximal deflection angles of 270° were preserved in 53 cases (85.5%). No pre-stenting procedure and the longer operative time were significant predictors of poorly-preserved deflection angles <270°. LITHOVUE showed good maneuverability and perception scores for the monitor and irrigation systems. LITHOVUE received favorable evaluations on pain and fatigue scores.

Factors that Predict Neutropenia in Korean Patients with Advanced Urothelial Cancer after Cisplatin- Based Systemic Chemotherapy.

PURPOSE: The aim of this study was to identify factors that can be used to predict severe neutropenia (grade 3 or higher) in patients with advanced urothelial cancer after cisplatin-based systemic chemotherapy. MATERIALS AND METHODS: The study examined 79 Korean patients with advanced urothelial cancer who were treated with several cycles of cisplatin-based systemic chemotherapy from May 2006 to May 2015. Risk factors for neutropenia (grade 3 or higher) and for the occurrence of neutropenia (grade 3 or higher) during the first cycle of chemotherapy were examined. RESULT: Thirty-six out of the 79 patients (45.6%) developed neutropenia at grade 3 or higher during the first cycle of cisplatin-based systemic chemotherapy: 18 (22.7%) of these experienced grade 3 neutropenia and 18 (22.7%) experienced grade 4. Multivariate analysis identified pretreatment neutrophil counts (P = .001) as the only significant factor predictive for severe neutropenia. CONCLUSION: The pretreatment neutrophil count was found to be the factor that poses a significant and independent risk in development of severe neutropenia induced by applying cisplatin-based systemic chemotherapy to patients with advanced urothelial cancer.

Prognostic value of preoperative systemic inflammation markers in localized upper tract urothelial cell carcinoma: a large, multicenter cohort analysis.

BACKGROUND: The aim of this study was to investigate the prognostic value of preoperative systemic inflammation markers in upper tract urothelial carcinoma (UTUC). METHODS: A total of 1137 patients who underwent radical nephroureterectomy with bladder cuff excision at 9 institutions from 2004 to 2015, were retrospectively reviewed. The Glasgow Prognostic Score (GPS), modified GPS (mGPS), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) for each patient were calculated. Univariable and multivariable analysis was performed using the Cox proportional hazards regression model. Cut-off values for NLR and PLR were calculated using a receiver operating characteristic curve. RESULTS: The median follow-up period was 39.1 (interquartile range: 18.3-63.8) months. Univariable analysis revealed that GPS, mGPS, PLR, and NLR (all, P=0.001) were significantly associated with both recurrence-free survival (RFS) and cancer-specific survival (CSS). Multivariable analysis revealed that GPS (P=0.001), PLR (hazards ratio [HR] =1.32; 95% CI: 1.08-1.62, P=0.007 and HR =1.87; 95% CI: 1.21-2.92, P=0.005), NLR (HR =1.38; 95% CI: 1.12-1.69, P=0.003 and HR =1.70; 95% CI: 1.10-2.62, P=0.017) were significantly associated with RFS and CSS. CONCLUSIONS: Our results suggest that preoperative systemic inflammation markers such as GPS, PLR, and NLR are independent prognostic factors in patients with UTUC after surgery.

Hand-Holding during Cystoscopy Decreases Patient Anxiety, Pain, and Dissatisfaction: A Pilot Randomized Controlled Trial.

OBJECTIVE: Often a sick or an anxious person can experience pain or anxiety relief if another person holds his or her hand. In this study, we conducted investigations to determine whether hand-holding during cystoscopy decreases patient anxiety, pain, and dissatisfaction while at the same time increasing patient comfort and tolerance during the procedure. PATIENTS AND METHODS: Eighty-six male patients who underwent flexible cystoscopy between November 2015 and March 2017 were randomized as follows: hand-holding (group I, n = 43) or non-hand-holding (group II, n = 43) during the procedure. Before flexible cystoscopy, lidocaine gel was instilled in the urethra. Patients' anxiety levels were quantified using the State-Trait Anxiety Inventory. A visual analog scale (0-10) was used for self-assessment of satisfaction, discomfort, and willingness to undergo repeat cystoscopy. RESULTS: Demographic characteristics, mean age, procedure duration, procedure indications, and preprocedural analyses did not differ significantly between the 2 groups. In group I, the postprocedural mean anxiety level, pain score, heart rate, and systolic blood pressure were significantly lower compared with those in group II (p = 0.009, p = 0.003, p = 0.022, and p = 0.014, respectively). In group I, postprocedural mean satisfaction score were higher, and patients were more likely to undergo a repeat cystoscopy, compared with those in group II (p = 0.001 and p = 0.004, respectively). CONCLUSIONS: Hand-holding during cystoscopy significantly reduced patients' feelings of anxiety, pain, discomfort, and dissatisfaction. Hand-holding served as a simple, inexpensive, and effective adjunct to sedation during cystoscopy.

Is preoperative chronic kidney disease status associated with oncologic outcomes in upper urinary tract urothelial carcinoma? A multicenter propensity score-matched analysis.

PURPOSE: The aim of this study was to determine the effect of preoperative chronic kidney disease (CKD) on the prognosis of patients with upper urinary tract urothelial carcinoma (UTUC) who had undergone radical nephroureterectomy (RNU). RESULTS: The median follow-up period was 31.1 months (interquartile range: 16.2-55.7 months). Among the study patients, 224 patients in the non-CKD group were selected via propensity score matching. The median recurrence-free, cancer-specific, and overall survival were significantly shorter for patients with preoperative CKD than for non-CKD patients (p = 0.001, p = 0.001, and p = 0.001, respectively). According to multivariable Cox regression analysis, preoperative CKD was related to worse recurrence-free (hazard ratio [HR]: 1.81, 95% confidence interval [CI]: 1.15-2.86, p = 0.011), cancer-specific (HR: 2.44, 95% CI: 1.44-4.14, p = 0.001), and overall survival (HR: 1.66, 95% CI: 1.15-2.40, p = 0.007). METHODS: A total of 566 patients who underwent RNU at 6 institutions from 2004 to 2014 were retrospectively reviewed. Of these patients, 342 had an estimated glomerular filtration rate (eGFR) ≥ 60 ml/min/1.73 m2 (non-CKD group) and 224 patients had an eGFR <60 ml/min/1.73 m2 (CKD group). To adjust for potential baseline confounders, 224 patients in the non-CKD group were selected by propensity matching. Clinicopathological variables and survival rates were compared between the 2 groups. CONCLUSIONS: Preoperative CKD appears to be an important independent prognostic factor for oncologic outcomes in patients with UTUC.

Primary Tumor Characteristics Are Important Prognostic Factors for Sorafenib-Treated Patients with Metastatic Renal Cell Carcinoma: A Retrospective Multicenter Study.

We aimed to identify prognostic factors associated with progression-free survival (PFS) and overall survival (OS) in metastatic renal cell carcinoma (mRCC) patients treated with sorafenib. We investigated 177 patients, including 116 who received sorafenib as first-line therapy, using the Cox regression model. During a median follow-up period of 19.2 months, the PFS and OS were 6.4 and 32.6 months among all patients and 7.4 months and undetermined for first-line sorafenib-treated patients, respectively. Clinical T3-4 stage (hazard ratio [HR] 2.56) and a primary tumor size >7 cm (HR 0.34) were significant prognostic factors for PFS among all patients, as were tumor size >7 cm (HR 0.12), collecting system invasion (HR 5.67), and tumor necrosis (HR 4.11) for OS (p < 0.05). In first-line sorafenib-treated patients, ≥4 metastatic lesions (HR 28.57), clinical T3-4 stage (HR 4.34), collecting system invasion (univariate analysis HR 2.11; multivariate analysis HR 0.07), lymphovascular invasion (HR 13.35), and tumor necrosis (HR 6.69) were significant prognosticators of PFS, as were bone metastasis (HR 5.49) and clinical T3-4 stages (HR 4.1) for OS (p < 0.05). Our study thus identified a number of primary tumor-related characteristics as important prognostic factors in sorafenib-treated mRCC patients.

Poor Preoperative Glycemic Control Is Associated with Dismal Prognosis after Radical Nephroureterectomy for Upper Tract Urothelial Carcinoma: A Korean Multicenter Study.

PURPOSE: The purpose of this study is to evaluate the effect of diabetes mellitus (DM) and preoperative glycemic control on prognosis in Korean patients with upper tract urothelial carcinoma (UTUC) who underwent radical nephroureterectomy (RNU). MATERIALS AND METHODS: A total of 566 patients who underwent RNU at six institutions between 2004 and 2014 were reviewed retrospectively. Kaplan-Meier and Cox regression analyses were performed to assess the association between DM, preoperative glycemic control, and recurrence-free, cancer-specific, and overall survival. RESULTS: The median follow-up period was 33.8 months (interquartile range, 41.4 months). A total of 135 patients (23.8%) had DM and 67 patients (11.8%) had poor preoperative glycemic control. Patients with poor preoperative glycemic control had significantly shorter median recurrence-free, cancer-specific, and overall survival than patients with good preoperative glycemic control and non-diabetics (all, p=0.001). In multivariable Cox regression analysis, DM with poor preoperative glycemic control showed association with worse recurrence-free survival (hazard ratio [HR], 2.26; 95% confidence interval [CI], 1.31 to 3.90; p=0.003), cancer-specific survival (HR, 2.96; 95% CI, 1.80 to 4.87; p=0.001), and overall survival (HR, 2.13; 95% CI, 1.40 to 3.22; p=0.001). CONCLUSION: Diabetic UTUC patients with poor preoperative glycemic control had significantly worse oncologic outcomes than diabetic UTUC patients with good preoperative glycemic control and non-diabetics. Further investigation is needed to elucidate the exact mechanism underlying the impact of glycemic control on UTUC treatment outcome.

The role of Bosniak classification in malignant tumor diagnosis: A single institution experience.

PURPOSE: To evaluate the clinical reliability of the Bosniak classification in Korea, and to identify independent predictors of malignancy in complicated renal cysts. MATERIALS AND METHODS: We reviewed the records of 368 patients with renal cysts between January 2001 and December 2014; 14 patients were excluded, due to interobserver variability in Bosniak classification between the radiologist and urologist. Clinical characteristics and radiologic findings of malignant cystic masses were analyzed, retrospectively. RESULTS: In 324 surgically excised lesions from patients (n=312) with renal cysts, the percentages of malignancy in the different Bosniak classifications were as follows: category I, 1.0% (1 of 103); II, 3.8% (2 of 53); IIF, 17.1% (7 of 41); III, 38.0% (27 of 71); and IV, 82.1% (46 of 56). Mean age and lesion size were 59.88±11.9 years (180 men, 144 women) and 5.47±3.51 cm, respectively. Univariate analysis identified hypertension (p=0.011), a history of smoking (p=0.038), and obesity (p=0.015) as the strongest risk factors of malignancy. In a study of Bosniak category III patients, hypertension (p=0.018), lesion size (p<0.001), and difference of Hounsfield Unit (HU) (p=0.027) were the strongest risk factors of malignancy. Multivariate analysis identified lesion size as the strongest potential predictor of malignancy, followed by hypertension and difference of HU. CONCLUSIONS: Risk factors of malignancy in complicated renal cyst patients were not different from those published previously. In Bosniak category III lesions, hypertension and lesion size were the strongest predictors of malignancy. Characteristically, the lesion size was smaller than in benign complicated renal cysts, in contrast with other categories.

Renal cell carcinoma in end-stage renal disease: Multi-institutional comparative analysis of survival.

OBJECTIVES: To describe the clinical features of renal cell carcinoma arising in end-stage renal disease and to compare survival outcomes after definitive treatment with non-end-stage renal disease renal cell carcinoma. METHODS: Data of 181 consecutive patients with end-stage renal disease renal cell carcinoma who had received surgical treatment between 1995 and 2011 at seven institutions were reviewed. Data of 362 non-end-stage renal disease renal cell carcinoma patients matched for clinicopathological parameters who received surgery at Asan Medical Center during the same study period were also reviewed. The two study groups were compared with respect to recurrence-free, cancer-specific, and overall survival by Kaplan-Meier analysis and Cox proportional hazards method. Mean follow up was 40 ± 34.2 months after surgery. RESULTS: Median tumor size was 2.5 cm (interquartile range 1.5-4.5), and pathological tumor stage was T1 in 78%, T2 in 7.1% and T3 and higher in 14.9%. Tumor histological type was clear cell in 63%, papillary in 17%, chromophobe in 5%, clear cell papillary in 2.8% and acquired cystic disease-related in 6.1%. Compared with the controls, the stage-specific 5-year recurrence-free survival was similar (87.6 vs 88.5%), but cancer-specific and overall survival was significantly lower. On multivariate analysis, end-stage renal disease renal cell carcinoma was not a predictor for recurrence-free survival, but a significant predictor for cancer-specific (hazard ratio 4.07, 95% confidence interval 2.08-7.94) and overall survival (hazard ratio 3.13, 95% confidence interval 1.66-5.96). CONCLUSIONS: End-stage renal disease renal cell carcinoma seems to have comparable stage-specific recurrence-free, but poorer cancer-specific and overall survival compared with non-end-stage renal disease renal cell carcinoma. As patients with end-stage renal disease are a high-risk population for renal cell carcinoma, routine radiographic screening to improve survival outcomes should be further investigated.

Can a dual-energy computed tomography predict unsuitable stone components for extracorporeal shock wave lithotripsy?

PURPOSE: To assess the potential of dual-energy computed tomography (DECT) to identify urinary stone components, particularly uric acid and calcium oxalate monohydrate, which are unsuitable for extracorporeal shock wave lithotripsy (ESWL). MATERIALS AND METHODS: This clinical study included 246 patients who underwent removal of urinary stones and an analysis of stone components between November 2009 and August 2013. All patients received preoperative DECT using two energy values (80 kVp and 140 kVp). Hounsfield units (HU) were measured and matched to the stone component. RESULTS: Significant differences in HU values were observed between uric acid and nonuric acid stones at the 80 and 140 kVp energy values (p<0.001). All uric acid stones were red on color-coded DECT images, whereas 96.3% of the nonuric acid stones were blue. Patients with calcium oxalate stones were divided into two groups according to the amount of monohydrate (calcium oxalate monohydrate group: monohydrate≥90%, calcium oxalate dihydrate group: monohydrate<90%). Significant differences in HU values were detected between the two groups at both energy values (p<0.001). CONCLUSIONS: DECT improved the characterization of urinary stone components and was a useful method for identifying uric acid and calcium oxalate monohydrate stones, which are unsuitable for ESWL.