Impact of Bladder Neck Stiffness on Lower Urinary Tract Symptoms in Patient With Benign Prostatic Hyperplasia

PURPOSE@#We evaluated the impact of bladder neck stiffness on lower urinary tract symptoms in the patient with benign prostatic hyperplasia using elastography.@*MATERIALS AND METHODS@#A total of 384 patients divided into three different groups according to the bladder neck stiffness based on ultrasound with elastography. Patients age, prostate specific antigen (PSA), International Prostate Symptom Score (IPSS), prostate volumetric parameters, residual urine volume, and laboratory data were collected and compared among the three groups.@*RESULTS@#Group 1 (n=121) showed low stiffness in both bladder neck adenoma. Group 2 (n=157) showed low to intermediated stiffness, and group 3 (n=106) showed significantly higher stiffness of bladder neck and adenoma compared to adjacent prostatic tissue. Significant differences among the 3 groups were found in the total prostate volume, transition zone volume, transition zone index, total IPSS, IPSS-voiding, IPSS-storage, residual urine volume, and quality of life. As the stiffness increased, prostate volumetric parameters, and residual urine volume were increased, and lower urinary tract symptoms became exacerbated. No significant difference was found in the patients' age and PSA.@*CONCLUSIONS@#Bladder neck stiffness affected the lower urinary tract symptoms and prostate volumetric parameters. These findings suggest that the change of bladder neck stiffness can be a novel parameter for the development of lower urinary tract symptoms/benign prostate hyperplasia.

The Within-Group Discrimination Ability of the Cancer of the Prostate Risk Assessment Score for Men with Intermediate-Risk Prostate Cancer

BACKGROUND: Significant clinical heterogeneity within contemporary risk group is well known, particularly for those with intermediate-risk prostate cancer (IRPCa). Our study aimed to analyze the ability of the Cancer of the Prostate Risk Assessment (CAPRA) score to discern between favorable and non-favorable risk in patients with IRPCa. METHODS: We retrospectively reviewed the data of 203 IRPCa patients who underwent extraperitoneal robot-assisted radical prostatectomy (RARP) performed by a single surgeon. Pathologic favorable IRPCa was defined as a Gleason score ≤ 6 and organ-confined stage at surgical pathology. The CAPRA score was compared with two established criteria for the within-group discrimination ability. RESULTS: Overall, 38 patients (18.7% of the IRPCa cohort) had favorable pathologic features after RARP. The CAPRA score significantly correlated with established criteria I and II and was inversely associated with favorable pathology (all P < 0.001). The area under the receiver operating characteristic curve for the discriminative ability between favorable and non-favorable pathology was 0.679 for the CAPRA score and 0.610 and 0.661 for established criteria I and II, respectively. During a median 37.8 (interquartile range, 24.6–60.2) months of follow-up, 66 patients (32.5%) experienced biochemical recurrence (BCR). Cox regression analysis revealed that the CAPRA score, as a continuous sum score model or 3-group risk model, was an independent predictor of BCR after RARP. CONCLUSION: The within-group discrimination ability of preoperative CAPRA score might help in patient counseling and selecting optimal treatments for those with IRPCa.

Daily Mean Temperature Affects Urolithiasis Presentation in Seoul: a Time-series Analysis

This study aimed to investigate the overall cumulative exposure-response and the lag response relationships between daily temperature and urolithiasis presentation in Seoul. Using a time-series design and distributing lag nonlinear methods, we estimated the relative risk (RR) of urolithiasis presentation associated with mean daily temperature, including the cumulative RR for a 20 days period, and RR for individual daily lag through 20 days. We analyzed data from 14,518 patients of 4 hospitals emergency department who sought medical evaluation or treatment of urolithiasis from 2005-2013 in Seoul. RR was estimated according to sex and age. Associations between mean daily temperature and urolithiasis presentation were not monotonic. Furthermore, there was variation in the exposure-response curve shapes and the strength of association at different temperatures, although in most cases RRs increased for temperatures above the 13℃ reference value. The RRs for urolothiasis at 29℃ vs. 13℃ were 2.54 in all patients (95% confidence interval [CI]: 1.67-3.87), 2.59 in male (95% CI, 1.56-4.32), 2.42 in female (95% CI, 1.15-5.07), 3.83 in male less than 40 years old (95% CI, 1.78-8.26), and 2.47 in male between 40 and 60 years old (95% CI, 1.15-5.34). Consistent trends of increasing RR of urolithiasis presentation were observed within 5 days of high temperatures across all groups. Urolithiasis presentation increased with high temperature with higher daily mean temperatures, with the strongest associations estimated for lags of only a few days, in Seoul, a metropolitan city in Korea.

Associations of Self-Reported Erectile Function with Non-Invasive Measurements of Endothelial Function: A Preliminary Study

PURPOSE: To evaluate the association of self-reported erectile function and endothelial function using the EndoPAT device. MATERIALS AND METHODS: We prospectively enrolled 76 men (age> or =40 years) after obtaining a complete medical history and a self-reported questionnaire (International Index of Erectile Function-5 [IIEF-5], SEP Q2, Q3). Endothelial function was noninvasively measured with an EndoPAT 2000, recorded as the reactive hyperemia index (RHI), and analyzed according to the patients' baseline characteristics. RESULTS: The mean patient age and IIEF-5 score were 62.50+/-8.56 years and 11.20+/-6.36, respectively. In comparing the RHI according to erectile dysfunction (ED) risk factors, the RHI was significantly lower in older subjects (p=0.004). There was no difference in the RHI according to age, body mass index, waist circumference, obesity, smoking habit, or other comorbidities. When the subjects were divided into four groups according to the severity of ED, no statistical differences in the RHI value were found among the groups. There was no difference in IIEF-5 according to the RHI when categorized according to the normal cutoff value or quartile ranges. The second subdomain of IIEF-5 (erection firmness) was significantly correlated with the RHI value (R=0.309, p=0.007); however, this was not the case with the other IIEF-5 subdomains. Self-assessment showed a tendency toward a negative correlation with the RHI value (R=-0.202, p=0.080). CONCLUSIONS: The role of endothelial function measurement by the EndoPAT in the evaluation and management of ED patients remains inconclusive. However, further studies are needed to validate the role of endothelial function measurement, by the EndoPAT or any other device.

P70S6K and Elf4E Dual Inhibition Is Essential to Control Bladder Tumor Growth and Progression in Orthotopic Mouse Non-muscle Invasive Bladder Tumor Model

We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 microM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.

P70S6K and Elf4E Dual Inhibition Is Essential to Control Bladder Tumor Growth and Progression in Orthotopic Mouse Non-muscle Invasive Bladder Tumor Model

We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 microM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.

Pathologic Outcomes in Men with Low-risk Prostate Cancer Who Are Potential Candidates for Contemporary, Active Surveillance Protocols

The purpose of this study was to determine whether contemporary active surveillance (AS) protocols could sufficiently discriminate significant from indolent tumors in men with low-risk prostate cancer. We retrospectively analyzed 312 patients with low-risk prostate cancer treated with radical prostatectomy. After exclusion of patients with fewer than 10 cores taken at biopsy and those who received neo-adjuvant treatment, 205 subjects satisfied the final inclusion criteria. Five widely accepted AS protocols were employed in this study. A total of 82.0% of the patients met the inclusion criteria of at least one protocol, and 18% did not meet any criteria of published AS protocols. A significant proportion of patients had non-organ-confined disease (8.6% to 10.6%) or a Gleason score of 7 or greater (18.6% to 23.9%) between the different AS criteria. Among patients who did not meet any AS criteria, 32.4% of patients had a pathologically insignificant cancer. Our results indicated a significant adverse pathology in patients who met the contemporary AS protocols. On the other hand, some patients in whom expectant management would be appropriate did not meet any criteria of published AS protocols. None of the clinical or histological criteria reported to date is able to sufficiently discriminate aggressive tumors from indolent ones.

Laparoscopic Adrenalectomy in Urology

Laparoscopic adrenalectomy has been the standard method for resecting adrenal gland tumors. Recently, laparoscopic retroperitoneal adrenalectomy (RA) has been more popular than conventional transperitoneal laparoscopic adrenalectomy (TLA) as an alternative method. Studies comparing laparoscopic RA and TLA showed that laparoscopic RA was superior or at least comparable to TLA in operation time, blood loss, pain score, hospital stay, and return to normal activity. Conversion rates and complication rates were similar. At present, laparoscopic RA has been int the limelight procedure for patients with benign adrenal disease. However, surgeons have been reluctant to offer this operation to patients because of the concerns over inadequate working space and overall perceived higher rate of complications, laparoscopic RA is not popular in urologic field up to now. This article summarizes the latest ideas and issues on laparoscopic RA in the expanding field of laparoscopy in urology.

Prognostic Factors for Urachal Cancer: A Bayesian Model-Averaging Approach

PURPOSE: This study was conducted to evaluate prognostic factors and cancer-specific survival (CSS) in a cohort of 41 patients with urachal carcinoma by use of a Bayesian model-averaging approach. MATERIALS AND METHODS: Our cohort included 41 patients with urachal carcinoma who underwent extended partial cystectomy, total cystectomy, transurethral resection, chemotherapy, or radiotherapy at a single institute. All patients were classified by both the Sheldon and the Mayo staging systems according to histopathologic reports and preoperative radiologic findings. Kaplan-Meier survival curves and Cox proportional-hazards regression models were carried out to investigate prognostic factors, and a Bayesian model-averaging approach was performed to confirm the significance of each variable by using posterior probabilities. RESULTS: The mean age of the patients was 49.88+/-13.80 years and the male-to-female ratio was 24:17. The median follow-up was 5.42 years (interquartile range, 2.8-8.4 years). Five- and 10-year CSS rates were 55.9% and 43.4%, respectively. Lower Sheldon (p=0.004) and Mayo (p<0.001) stage, mucinous adenocarcinoma (p=0.005), and larger tumor size (p=0.023) were significant predictors of high survival probability on the basis of a log-rank test. By use of the Bayesian model-averaging approach, higher Mayo stage and larger tumor size were significant predictors of cancer-specific mortality in urachal carcinoma. CONCLUSIONS: The Mayo staging system might be more effective than the Sheldon staging system. In addition, the multivariate analyses suggested that tumor size may be a prognostic factor for urachal carcinoma.

Pilot Study of Low-Dose Nonenhanced Computed Tomography With Iterative Reconstruction for Diagnosis of Urinary Stones

PURPOSE: To evaluate the efficacy of low-dose computed tomography (LDCT) for detecting urinary stones with the use of an iterative reconstruction technique for reducing radiation dose and image noise. MATERIALS AND METHODS: A total of 101 stones from 69 patients who underwent both conventional nonenhanced computed tomography (CCT) and LDCT were analyzed. Interpretations were made of the two scans according to stone characteristics (size, volume, location, Hounsfield unit [HU], and skin-to-stone distance [SSD]) and radiation dose by dose-length product (DLP), effective dose (ED), and image noise. Diagnostic performance for detecting urinary stones was assessed by statistical evaluation. RESULTS: No statistical differences were found in stone characteristics between the two scans. The average DLP and ED were 384.60+/-132.15 mGy and 5.77+/-1.98 mSv in CCT and 90.08+/-31.80 mGy and 1.34+/-0.48 mSv in LDCT, respectively. The dose reduction rate of LDCT was nearly 77% for both DLP and ED (p<0.01). The mean objective noise (standard deviation) from three different areas was 23.0+/-2.5 in CCT and 29.2+/-3.1 in LDCT with a significant difference (p<0.05); the slight increase was 21.2%. For stones located throughout the kidney and ureter, the sensitivity and specificity of LDCT remained 96.0% and 100%, with positive and negative predictive values of 100% and 96.2%, respectively. CONCLUSIONS: LDCT showed significant radiation reduction while maintaining high image quality. It is an attractive option in the diagnosis of urinary stones.

Prognostic Factors for Urachal Cancer: A Bayesian Model-Averaging Approach

PURPOSE: This study was conducted to evaluate prognostic factors and cancer-specific survival (CSS) in a cohort of 41 patients with urachal carcinoma by use of a Bayesian model-averaging approach. MATERIALS AND METHODS: Our cohort included 41 patients with urachal carcinoma who underwent extended partial cystectomy, total cystectomy, transurethral resection, chemotherapy, or radiotherapy at a single institute. All patients were classified by both the Sheldon and the Mayo staging systems according to histopathologic reports and preoperative radiologic findings. Kaplan-Meier survival curves and Cox proportional-hazards regression models were carried out to investigate prognostic factors, and a Bayesian model-averaging approach was performed to confirm the significance of each variable by using posterior probabilities. RESULTS: The mean age of the patients was 49.88+/-13.80 years and the male-to-female ratio was 24:17. The median follow-up was 5.42 years (interquartile range, 2.8-8.4 years). Five- and 10-year CSS rates were 55.9% and 43.4%, respectively. Lower Sheldon (p=0.004) and Mayo (p<0.001) stage, mucinous adenocarcinoma (p=0.005), and larger tumor size (p=0.023) were significant predictors of high survival probability on the basis of a log-rank test. By use of the Bayesian model-averaging approach, higher Mayo stage and larger tumor size were significant predictors of cancer-specific mortality in urachal carcinoma. CONCLUSIONS: The Mayo staging system might be more effective than the Sheldon staging system. In addition, the multivariate analyses suggested that tumor size may be a prognostic factor for urachal carcinoma.

Renal Pelvic Urothelial Carcinoma With Vena Caval Thrombus Mimicking Renal Cell Carcinoma

A 61-year-old man presented with a right renal mass with a vena caval thrombus on computed tomography that was consistent with renal cell carcinoma. The results of routine laboratory examinations and urinalysis were within normal limits. Preoperative planning was critical owing to the presence of the vena caval thrombus. A radical nephrectomy, vena caval thrombectomy, and regional lymphadenectomy were done. The pathologic report was consistent with a high-grade, invasive urothelial carcinoma, with sarcomatoid differentiation involving the renal vein and inferior vena cava (Stage IV, T4N0M0). Thus, this was a rare case of upper tract urothelial carcinoma. Adjuvant chemotherapy with the methotrexate, vinblastine, doxorubicin, cisplatinum regimen is scheduled. To our knowledge, this is the first report in Korea of upper tract urothelial carcinoma of the sarcomatoid type with a vena caval thrombus.

Pilot Study of Low-Dose Nonenhanced Computed Tomography With Iterative Reconstruction for Diagnosis of Urinary Stones

PURPOSE: To evaluate the efficacy of low-dose computed tomography (LDCT) for detecting urinary stones with the use of an iterative reconstruction technique for reducing radiation dose and image noise. MATERIALS AND METHODS: A total of 101 stones from 69 patients who underwent both conventional nonenhanced computed tomography (CCT) and LDCT were analyzed. Interpretations were made of the two scans according to stone characteristics (size, volume, location, Hounsfield unit [HU], and skin-to-stone distance [SSD]) and radiation dose by dose-length product (DLP), effective dose (ED), and image noise. Diagnostic performance for detecting urinary stones was assessed by statistical evaluation. RESULTS: No statistical differences were found in stone characteristics between the two scans. The average DLP and ED were 384.60+/-132.15 mGy and 5.77+/-1.98 mSv in CCT and 90.08+/-31.80 mGy and 1.34+/-0.48 mSv in LDCT, respectively. The dose reduction rate of LDCT was nearly 77% for both DLP and ED (p<0.01). The mean objective noise (standard deviation) from three different areas was 23.0+/-2.5 in CCT and 29.2+/-3.1 in LDCT with a significant difference (p<0.05); the slight increase was 21.2%. For stones located throughout the kidney and ureter, the sensitivity and specificity of LDCT remained 96.0% and 100%, with positive and negative predictive values of 100% and 96.2%, respectively. CONCLUSIONS: LDCT showed significant radiation reduction while maintaining high image quality. It is an attractive option in the diagnosis of urinary stones.

Renal Pelvic Urothelial Carcinoma With Vena Caval Thrombus Mimicking Renal Cell Carcinoma

A 61-year-old man presented with a right renal mass with a vena caval thrombus on computed tomography that was consistent with renal cell carcinoma. The results of routine laboratory examinations and urinalysis were within normal limits. Preoperative planning was critical owing to the presence of the vena caval thrombus. A radical nephrectomy, vena caval thrombectomy, and regional lymphadenectomy were done. The pathologic report was consistent with a high-grade, invasive urothelial carcinoma, with sarcomatoid differentiation involving the renal vein and inferior vena cava (Stage IV, T4N0M0). Thus, this was a rare case of upper tract urothelial carcinoma. Adjuvant chemotherapy with the methotrexate, vinblastine, doxorubicin, cisplatinum regimen is scheduled. To our knowledge, this is the first report in Korea of upper tract urothelial carcinoma of the sarcomatoid type with a vena caval thrombus.

Establishment of an Orthotopic Mouse Non-Muscle Invasive Bladder Cancer Model Expressing the Mammalian Target of Rapamycin Signaling Pathway

We established an orthotopic non-muscle invasive bladder cancer (NMIBC) mouse model expressing the mammalian target of the rapamycin (mTOR) signaling pathway. After intravesical instillation of KU-7-lucs (day 0), animals were subsequently monitored by bioluminescence imaging (BLI) on days 4, 7, 14, and 21, and performed histopathological examination. We also validated the orthotopic mouse model expressing the mTOR signaling pathway immunohistochemically. In vitro BLI photon density was correlated with KU-7-luc cell number (r2 = 0.97, P < 0.01) and in vivo BLI photon densities increased steadily with time after intravesical instillation. The tumor take rate was 84.2%, formed initially on day 4 and remained NMIBC up to day 21. T1 photon densities were significantly higher than Ta (P < 0.01), and histological tumor volume was positively correlated with BLI photon density (r2 = 0.87, P < 0.01). The mTOR signaling pathway-related proteins were expressed in the bladder, and were correlated with the western blot results. Our results suggest successful establishment of an orthotopic mouse NMIBC model expressing the mTOR signaling pathway using KU-7-luc cells. This model is expected to be helpful to evaluate preclinical testing of intravesical therapy based on the mTOR signaling pathway against NMIBC.

Current Status of Radical Prostatectomy for High-Risk Prostate Cancer

Despite the wide application of prostate-specific antigen-based screening leading to a profound stage migration in prostate cancer (PC), a significant percentage of men are still being diagnosed with clinically high-risk disease that requires aggressive treatment. Optimal management in these patients remains challenging, and strong advocates for radical prostatectomy (RP), radiotherapy, androgen deprivation therapy, and, increasingly, a multimodal approach abound. Currently, surgery for high-risk PC is frequently applied. RP offers an attractive opportunity for tumor excision either as a definitive management or as a first step in multimodal therapy. Nevertheless, this approach is still controversial. In this review, we discuss the current evidence for the role of RP in this clinical setting, including surgical considerations and outcomes. The role of robot-assisted RP, which is increasingly utilized in Korea in this clinical scenario, is discussed.

Febrile Urinary Tract Infection After Prostate Biopsy and Quinolone Resistance

PURPOSE: Complications after prostate biopsy have increased and various causes have been reported. Growing evidence of increasing quinolone resistance is of particular concern. In the current retrospective study, we evaluated the incidence of infectious complications after prostate biopsy and identified the risk factors. MATERIALS AND METHODS: The study population included 1,195 patients who underwent a prostate biopsy between January 2007 and December 2012 at Chung-Ang University Hospital. Cases of febrile UTI that occurred within 7 days were investigated. Clinical information included age, prostate-specific antigen, prostate volume, hypertension, diabetes, body mass index, and biopsy done in the quinolone-resistance era. Patients received quinolone (250 mg intravenously) before and after the procedure, and quinolone (250 mg) was orally administered twice daily for 3 days. We used univariate and multivariate analysis to investigate the predictive factors for febrile UTI. RESULTS: Febrile UTI developed in 39 cases (3.1%). Core numbers increased from 2007 (8 cores) to 2012 (12 cores) and quinolone-resistant bacteria began to appear in 2010 (quinolone-resistance era). In the univariate analysis, core number> or =12 (p=0.024), body mass index (BMI)>25 kg/m2 (p=0.004), and biopsy done in the quinolone-resistance era (p=0.014) were significant factors. However, in the multivariate analysis adjusted for core number, the results were not significant, with the exception of BMI>25 kg/m2 (p=0.011) and biopsy during the quinolone-resistance era (p=0.035), which were significantly associated with febrile UTI. CONCLUSIONS: Quinolone resistance is the main cause of postbiopsy infections in our center. We suggest that further evaluation is required to validate similar trends. Novel strategies to find alternative prophylactic agents are also necessary.

Meta-Analysis of the Relationship between CXCR4 Expression and Metastasis in Prostate Cancer

PURPOSE: Experimental studies have suggested that the stromal-derived factor-1 (SDF-1)/CXCR4 axis is associated with tumor aggressiveness and metastasis in several malignancies. We performed a meta-analysis to elucidate the relationship between CXCR4 expression and the clinicopathological features of prostate cancer. MATERIALS AND METHODS: Data were collected from studies comparing Gleason score, T stage, and the presence of metastasis with CXCR4 levels in human prostate cancer samples. The studies were pooled, and the odds ratio (OR) of CXCR4 expression for clinical and pathological variables was calculated. RESULTS: Five articles were eligible for the current meta-analysis. We found no relationship between CXCR4 expression and Gleason score ( or =7). The forest plot using the fixed-effects model indicated an OR of 1.585 (95% confidence interval [CI]: 0.793~3.171; p=0.193). Further, CXCR4 expression was not associated with the T stage ( or =T3), and the relevant meta-analysis showed OR=1.803 (95% CI: 0.756~4.297, p=0.183). However, increased CXCR4 expression was strongly associated with metastatic disease with a fixed-effects pooled OR of 7.459 (95% CI: 2.665~20.878, p<0.001). CONCLUSIONS: Our meta-analysis showed that the higher CXCR4 protein expression in prostate cancer specimens is significantly associated with the presence of metastatic disease. This supports previous experimental data supporting the role played by the SDF-1/CXCR4 axis in metastasis.

Erratum: Correction of Acknowledgement. Establishment of an Orthotopic Mouse Non-Muscle Invasive Bladder Cancer Model Expressing the Mammalian Target of Rapamycin Signaling Pathway

We found an error in our published article.

Effectiveness of Flexible Ureteroscopic Stone Removal for Treating Ureteral and Ipsilateral Renal Stones: A Single-Center Experience

PURPOSE: The aim of this study was to evaluate the effectiveness of simultaneous flexible ureteroscopic removal of stones (URS) for ureteral and ipsilateral renal stones and to analyze the predictive factors for renal stone-free status. MATERIALS AND METHODS: We retrospectively reviewed the records of patients who underwent simultaneous flexible URS of ureteral and ipsilateral renal stones from January 2010 to May 2012. All operations used a flexible ureteroscope. We identified 74 cases of retrograde intrarenal surgery and 74 ureteral stones (74 patients). Stone-free status was respectively defined as no visible stones and clinically insignificant residual stones <3 mm on a postoperative image study. Predictive factors for stone-free status were evaluated. RESULTS: The immediate postoperative renal stone-free rate was 70%, which increased to 83% at 1 month after surgery. The immediate postoperative ureteral stone-free rate was 100%. Among all renal stones, 15 (20.3%) were separately located in the renal pelvis, 11 (14.8%) in the upper calyx, 15 (20.3%) in the mid calyx, and 33 (44.6%) in the lower calyx. The mean cumulative stone burden was 92.22+/-105.75 mm2. In a multivariate analysis, cumulative stone burden <100 mm2 was a significant predictive factor for postoperative renal stone-free status after 1 month (p<0.01). CONCLUSIONS: Flexible URS can be considered simultaneously for both ureteral and renal stones in selected patients. Flexible URS is a favorable option that promises high stone-free status without significant complications for patients with a stone burden <100 mm2.