Predictive Factors for Extracapsular Extension of Prostate Cancer to Select the Candidates for Nerve-sparing Radical Prostatectomy.

Nerve-sparing radical prostatectomy (NSRP) for prostate cancer (PC) enables better postoperative recovery of continence and potency but may increase the risk of positive surgical margins. This study aimed to investigate preoperative predictive factors for extracapsular extension (ECE) of PC to select patients for NSRP. We retrospectively evaluated 288 patients with PC (576 lobes) diagnosed with 12-core transrectal ultrasound-guided biopsy and magnetic resonance imaging (MRI) who underwent laparoscopic or robot-assisted radical prostatectomy at our institution. Surgical specimens and preoperative parameters (prostate-specific antigen, prostate volume, biopsy and MRI findings, preoperative therapy) were analyzed. Of 576 prostate lobes, the incidence Ipsilateral ECE was identified in 97 (16.8%) lobes. The higher number of unilateral positive biopsy cores, the highest Gleason score 8 or more and positive unilateral findings on MRI are significant higher in prostate sides with ECE in univariate analysis. In multivariate analysis, positive unilateral MRI findings (odds ratio [OR], 2.86; p < 0.001) and unilateral biopsy positive core ≥ 3 (OR, 3.73; p < 0.001) were independent predictors of unilateral ECE. The detection rate of unilateral ECE in those cases with two factors (side-specific positive biopsy core 2 or less and side-specific MRI findings negative) was 7.1% (19/269). Patients with fewer unilateral positive biopsy cores and negative unilateral MRI findings might be good candidates for NSRP.

A simple risk stratification model for prostate cancer using histopathologic findings of radical prostatectomy.

OBJECTIVES: To develop a simple postoperative risk stratification based on histopathologic findings from radical prostatectomy specimens. METHODS: This study included 3 cohorts of patients with a preoperative diagnosis of clinically localized prostate cancer: 1 derivation cohort (n = 432) and 2 validation cohorts (n = 506 and n = 720). First, a postoperative risk stratification model was developed in the derivation cohort using the factors extraprostatic extension, surgical margin status, seminal vesicle invasion, and lymph node involvement. Each of the first 3 factors was assigned 0 or 1 point for negative or positive results, respectively, and the sum of the points, ranging from 0 to 3, was scored. pN1 was not scored but was analyzed separately. Validation cohorts were then used to evaluate the predictive accuracy of the model. Additionally, we compared the model with the Cancer of the Prostate Risk Assessment (CAPRA) score. RESULTS: Because the log-rank test showed no statistically significant differences between scores 1 vs 2 or score 3 vs pN1 in the derivation cohort, the following 3-level risk stratification was created: low risk (score 0), intermediate risk (score 1-2), and high risk (score 3 or pN1). There were statistically significant differences in recurrence-free survival between any of 2 groups of 3-level risk stratification. This model similarly worked in both validation cohorts. The C indexes for the model were higher than those for the CAPRA score. CONCLUSIONS: This simple postoperative risk stratification model, based on radical prostatectomy findings, has a prognostic impact that has been validated in a multicenter population.

Short-term prognosis of low-risk prostate cancer patients is favorable despite the presence of pathological prognostic factors: a retrospective study.

BACKGROUND: Prostate cancer patients with pathological prognostic factors have a poor prognosis, but it is unclear whether pathological prognostic factors are associated with prognosis limited to low-risk patients with good prognosis according to NCCN guidelines. The present study examined whether prognosis is influenced by pathological prognostic factors using radical prostatectomy (RP) specimens from low-risk patients. METHODS: We evaluated diagnostic accuracy by examining biochemical recurrence (BCR)-free survival with respect to clinical and pathological prognostic factors in 419 all-risk patients who underwent RP. Clinical prognostic factors included age, prostate-specific antigen (PSA) levels, PSA density, and risk stratification, while pathological prognostic factors included grade group, lymphovascular space invasion, extraprostatic extension, surgical margins, seminal vesicle invasion, intraductal carcinoma of the prostate (IDCP), and pT. In a subsequent analysis restricted to 104 low-risk patients, survival curves were estimated for pathological prognostic factors using the Kaplan-Meier method and compared using log-rank and generalized Wilcoxon tests. RESULTS: In the overall risk analysis, the presence of pathological prognostic factors significantly shortened BCR-free survival (p < 0.05). Univariable analysis revealed that PSA density, risk categories, and pathological prognostic factors were significantly associated with BCR-free survival, although age and PSA were not. In multivariable analysis, age, risk categories, grade group, IDCP, and pT significantly predicted BCR-free survival (p < 0.05). Conversely, no statistically significant differences were found for any pathological prognostic factors in low-risk patients. CONCLUSIONS: In low-risk patients, pathological prognostic factors did not affect BCR-free survival, which suggests that additional treatment may be unnecessary even if pathological prognostic factors are observed in low-risk patients with RP.

Simple and reliable predictive factor for early recovery of urinary continence after non-nerve-sparing robot-assisted laparoscopic radical prostatectomy.

Post-prostatectomy urinary incontinence is one of the greatest concerns for both patients and urologists. The aim of this study is to elucidate simple and reliable factors contributing to early recovery of urinary continence (UC) and to develop a prediction model for early continence recovery after robot-assisted laparoscopic non-nerve-sparing radical prostatectomy (non-NS RARP). A retrospective analysis of 212 consecutive patients who underwent non-NS RARP by a single surgeon was carried out. Early recovery of urinary continence was defined as using no pads or one security pad per day within 1 month. Preoperative membranous urethral length (MUL) was measured on MRI, and the urinary continence at the standing position (UCSP) after removal of the catheter was examined during cystourethrography 6 days after surgery. Multivariable analysis was performed to detect predictive and postoperative factors associated with early recovery of urinary continence. The early continence recovery rate was 56.1%. Multivariable analysis revealed that MUL ≥ 13 mm, UCSP, and age ≤ 67 were the independent factors for early continence recovery. Early recovery rates were 97.1% for good risk, 76.3% for intermediate risk, and 28.4% for poor risk when divided into three risk groups by the sum score of three independent factors. Preoperative MUL, UCSP, and age are independent predictors of early recovery of UC in non-NS RARP, and our simple prediction model with the combination of the three factors could be a useful tool in clinical practice.

Neonatal adrenal hemorrhage presenting as an acute scrotum: A case report on the rare presentation of right adrenal hemorrhage and contralateral left scrotal hematoma.

Introduction: Acute swelling and discoloration of the scrotum in a newborn is a rare condition and can have several causes such as testicular torsion, trauma, inguinal hernia, hydrocele, or adrenal hemorrhage. Case presentation: We report a neonate of adrenal hemorrhage presenting clinically as the acute scrotum. Definitive diagnosis was defined by ultrasonography and computed tomography scan, and the conservative management was successfully performed. Conclusion: Adrenal hemorrhage should be considered as one of the causes of acute scrotum in newborns. The abdominal ultrasonography, as well as the scrotal ultrasonography, should be performed routinely to achieve a definitive diagnosis to avoid unnecessary invasive procedures.

Prognostic Effect of Preoperative Psoas Muscle Hounsfield Unit at Radical Cystectomy for Bladder Cancer.

Radical cystectomy (RC) is the standard treatment for patients with advanced bladder cancer. Since RC is a highly invasive procedure, the surgical indications in an aging society must be carefully judged. In recent years, the concept of "frailty" has been attracting attention as a term used to describe fragility due to aging. We focused on the psoas muscle Hounsfield unit (PMHU) and analyzed its appropriateness as a prognostic factor together with other clinical factors in patients after RC. We retrospectively analyzed the preoperative prognostic factors in 177 patients with bladder cancer who underwent RC between 2008 and 2020. Preoperative non-contrast computed tomography axial image at the third lumbar vertebral level was used to measure the mean Hounsfield unit (HU) and cross-sectional area (mm2) of the psoas muscle. Univariate analysis showed significant differences in age, sex, clinical T stage, and PMHU. In multivariate analysis using the Cox proportional hazards model, age (hazard ratio (HR) = 1.734), sex (HR = 2.116), cT stage (HR = 1.665), and PMHU (HR = 1.758) were significant predictors for overall survival. Furthermore, using these four predictors, it was possible to stratify the prognosis of patients after RC. Finally, PMHU was useful as a simple and significant preoperative factor that correlated with prognosis after RC.

Usefulness of Biparametric Magnetic Resonance Imaging Combined With Prostate Specific Antigen Density in Pre-biopsy Detection of Clinically Insignificant Prostate Cancer.

BACKGROUND/AIM: The aim of this study was to identify simple and reliable factors to detect clinically insignificant prostate cancer (PC) for avoiding immediate prostate biopsies using biparametric magnetic resonance imaging (MRI), which consists of T2-weighted and diffusion-weighted imaging. PATIENTS AND METHODS: We retrospectively evaluated 427 men with suspected PC, who underwent biparametric MRI and standard 12-core transrectal prostate biopsy. MRI and prostate specific antigen density (PSAD) were analysed. To evaluate the combination of the two parameters, patients were divided into three groups (Group A: MRI negative and PSAD <0.23, Group B: MRI positive or PSAD ≥0.23, Group C: MRI positive and PSAD ≥0.23). A grade of ≥2 was defined as clinically significant PC. RESULTS: Clinically significant PC was detected in 46.5% of men with positive MRI findings, and 60.0% of men with PSAD ≥0.23. When combining MRI and PSAD, detection rates of clinically significant PC were 10.0%, 28.4% and 65.3% in group A, B and, C, respectively. CONCLUSION: Negative biparametric MRI findings with PSAD <0.23 might be a reliable evidence for avoiding immediate prostate biopsies.

Impact of noninvasive down-staging after transurethral resection of bladder tumor plus systemic chemotherapy on bladder-sparing strategy in patients with muscle-invasive bladder cancer.

OBJECTIVE: To identify the optimal selection criteria for bladder sparing strategy with transurethral resection of bladder tumor (TURBT) and systemic chemotherapy in patients with muscle-invasive bladder cancer (MIBC). METHODS: We conducted a retrospective cohort study in 71 patients with MIBC (T2-4aN0M0) who desire to bladder preservation received neoadjuvant chemotherapy (NAC) after maximal TURBT, followed by clinical restaging and second-TURBT. Fifty-eight of 71 patients with no residual tumor on the second-TURBT were placed on conservative management for bladder sparing (BS). Noninvasive down-staging (NID) was defined as cT0/Ta/Tis/T1N0 at first-TURBT after NAC and no residual tumor on second-TURBT. Overall survival (OS) and cystectomy-free survival (CFS) were assessed according to the response of NAC in the BS group by using Kaplan-Meier methods. Cox proportional hazards regression model was used to identify independent variables predicting OS. RESULTS: At a median follow-up of 40 months 5-year OS and CFS in patients with NID and non-NID were 89.1% versus 20.8% and 84.8% versus 16.7%, respectively. Multivariate analysis showed that the ≥3 cycles of NAC (hazard ratio [HR] 0.14, 95% confidential index [CI] 0.03-0.7; P = 0.017) and achievement of NID (HR 0.11, 95% CI 0.03-0.46, P = 0.002) favorably associated with OS. CONCLUSIONS: Patients who achieved NID might be optimal candidates for the bladder sparing strategy with maximum TURBT plus NAC followed by second-TURBT.

Successful management of a fistula between an external iliac artery and an ileal conduit with endovascular embolization and vascular bypass.

INTRODUCTION: Fistula formation between an ileac artery and an ileal conduit after radical cystectomy is a rare complication. CASE PRESENTATION: A 72-year-old woman underwent laparoscopic radical cystectomy with ileal conduit. After surgery, leakage of ileal-ureteral anastomosis with infection was observed. Five months after surgery, sudden bleeding from the ileal conduit occurred that stopped spontaneously. Contrast-enhanced computed tomography suggested a pseudo aneurysm of the right external iliac artery in contact with the ileal conduit. A fistula between the artery and ileal conduit was suspected. She underwent embolization of the common iliac artery and femorofemoral bypass. She had a good clinical course and no sign of hematuria over 6 months of follow-up. CONCLUSION: An episode of warning hemorrhage from the urostomy is an important sign of fistula, and endovascular treatment is a feasible approach to treat this condition.

A Combination of Findings Obtained from Pre- and Postoperative Imaging Predict Recovery of Urinary Continence After Non-nerve-sparing Laparoscopic Radical Prostatectomy.

BACKGROUND/AIM: The aim of the study was to identify the reliable predictor for early recovery of urinary continence (UC) after non-nerve-sparing laparoscopic radical prostatectomy (NNS-LRP) according to the findings of pre- and postoperative imaging. MATERIALS AND METHODS: A retrospective analysis of 215 patients who underwent NNS-LRP was carried out. Early recovery of UC was defined as using no pads or one security pad per day within 3 months. Preoperative membranous urethral length (MUL) measured on MRI and postoperative bladder neck angle (BNA) identified by cystography were analyzed to evaluate the relationship with recovery of UC. Patients were divided into three groups based on MUL and BNA (Group A: MUL ≥12.1 mm and BNA ≥103°, Group B: either MUL ≥12.1 mm or BNA ≥103°, Group C: MUL <12.1 mm and BNA <103°. RESULTS: Early recovery rates were 80.3% in patients with MUL ≥12.1 mm, 37.5% in patients with MLU<12.1 (p<0.001), and 77.8% in patients with BNA ≥103°, 50% in patients with BNA <103°(p<0.001). In the combination of the two parameters, early recovery rates were 90.4%, 58%, and 36.1% in group A, B and C respectively (p<0.001). Kaplan-Meier curve of the time to recovery of UC showed significant differences among the three groups (log rank test: p<0.001). CONCLUSION: A combination of preoperative MUL and postoperative BNA was the reliable predictor of recovery of UC after NNS-LRP. Longer MUL with wider BNA is significantly and positively associated with an early recovery of UC.

The role of continuous saline bladder irrigation after transurethral resection in patients with high-grade non-muscle-invasive bladder cancer.

OBJECTIVE: To compare the efficacy and safety of continuous saline bladder irrigation (CSBI) to a single immediate instillation of chemotherapy after transurethral resection of bladder tumor (TURBT) in patients with high grade primary non-muscle invasive bladder cancer (HG-NMIBC). MATERIALS AND METHODS: This study retrospectively reviewed 250 patients with primary NMIBC who were enrolled in a prospective randomized trial of CSBI vs single instillation of mitomycin C (SI-MMC) immediately after TURBT. Results of histopathology were re-reviewed using the World Health Organization (WHO) 2004/2016 classification. Of the 250 patients, 151 HG-NMIBC patients (78 in the CSBI group and 73 in the SI-MMC group) were evaluated according to the recurrence and progression rates and adverse events. RESULTS: The median follow-up period was 58 months. No significant differences for patients' characteristics were observed between the CSBI group and SI-MMC group. There was no statistically significant difference between the CSBI group and SI-MMC. group regarding recurrence rates of 12, 18 and 24 months (25.6% vs 23.3%、28.5% vs 23.3% and 32.1% vs 28.8%, respectively), time to first recurrence (12.6 ± 11 vs 12.4 ± 10.1 months) and progression rate (8.9% vs 8.2%). The incidence of adverse events was significantly lower in the C.S.B.I. group. CONCLUSION: The difference of recurrence and progression rate between CSBI and SI-MMC after TURBT was not statistically significant in HG-NMIBC, although a larger study is necessary to prove its equivalence or non-inferiority. CSBI after TURBT is easy to administer with a reduced risk of adverse events, and may be a treatment choice for patients with HG-NMIBC.

Randomized controlled study of the efficacy and safety of continuous saline bladder irrigation after transurethral resection for the treatment of non-muscle-invasive bladder cancer.

OBJECTIVE: To evaluate the efficacy and safety of continuous saline bladder irrigation (CSBI) after transurethral resection of bladder tumour (TURBT) in patients with low- to intermediate-risk non-muscle invasive bladder cancer (NMIBC). PATIENTS AND METHODS: In this prospective randomized study, 250 patients with primary low- to intermediate-risk tumours were enrolled. Patients were randomly allocated to receive CSBI (2 000 mL/h for the first 1 h, then 1 000 mL/h for 2 h, followed by 500 mL/h for 15 h) or a single immediate instillation of mitomycin C (MMC) after TURBT. The primary endpoint was recurrence-free survival, and secondary endpoints were progression-free survival and adverse events. RESULTS: A total of 227 patients (114 in the CSBI group and 113 in MMC group) remained for analysis after exclusion criteria had been applied. The median follow-up period was 37 months. No significant differences in patient characteristics were observed between the groups. The 5-year recurrence-free rates for CSBI and MMC were 62.6% (95% confidence interval [CI] 0.49-0.73) and 70.4% (95% CI 0.59-0.78), respectively. Kaplan-Meier analysis of recurrence-free survival did not show any significant differences between the groups (log-rank test P = 0.53). Furthermore, there were no significant differences between the groups in terms of tumour progression rate and the median time to first recurrence. The incidence of adverse events was significantly lower in the CSBI group. CONCLUSIONS: The results show that CSBI after TURBT may be a treatment option for patients with low- to intermediate-risk NMIBC in terms of its prophylactic effect and safety.

Efficacy of Ethinylestradiol Re-challenge for Metastatic Castration-resistant Prostate Cancer.

BACKGROUND: There has recently been renewed interest in the use of estrogens as a treatment strategy for castration-resistant prostate cancer (CRPC). The purpose of this study was to evaluate the feasibility and efficacy of ethinylestradiol re-challenge (re-EE) in the management of CRPC. PATIENTS AND METHODS: Patients with metastatic CRPC who received re-EE after disease progression on prior EE and other therapy were retrospectively reviewed for prostate-specific antigen (PSA) response, PSA progression-free survival (P-PFS) and adverse events. RESULTS: Thirty-six re-EE treatments were performed for 20 patients. PSA response to the initial EE treatment was observed in 14 (70%) patients. PSA response to re-EE was 33.3% in 36 re-EE treatments. The median P-PFS for patients treated with initial and re-EE was 7 months and 4 months, respectively. Interestingly, PSA response to re-EE was observed even in non-responders to initial EE, and those treated with multiple re-EE. No patients developed cardiovascular or thromboembolic events. CONCLUSION: Re-EE may be safely repeated several times and can lead to a prolonged disease control in selected patients. Re-challenge with EE appears to be a reasonable option worth considering for patients with metastatic CRPC.

Pretherapeutic Plasma Fibrinogen Level is an Independent Survival Predictor in Renal Cell Carcinoma.

BACKGROUND: Systematic inflammatory responses such as the elevated C-reactive protein, erythrocyte sedimentation rate and lymphocyte-monocyte ratio have been found to have significant prognostic value in renal cell carcinoma (RCC). The purpose of this study was to identify the impact of pretherapeutic plasma fibrinogen levels on survival for RCC patients. PATIENTS AND METHODS: We retrospectively reviewed 126 RCC patients who were treated at our institution. The median follow-up period was 30.8 months. 116 patients underwent nephrectomy. RESULTS: The 3-year overall survival rates in patients with non-metastatic or metastatic RCC were 91.9% and 14.3%, respectively (p < 0.001). Pretherapeutic plasma fibrinogen levels in the metastatic group were significantly higher than those in the non-metastatic group (p < 0.001). In the non-metastatic group, multivariate analysis revealed that the pathological T stage (p = 0.008), lactate dehydrogenase (p = 0.007) and fibrinogen (p = 0.036) were independent prognostic factors for survival. Overall survival rates in patients with low fibrinogen levels (< 399 mg/dl) were significantly higher than in those with high fibrinogen levels (≥ 399 mg/dl). CONCLUSION: Pretherapeutic high plasma fibrinogen levels are associated with disease progression in patients with RCC of all stages. We propose that pretherapeutic plasma fibrinogen levels may become a useful biomarker, and could be helpful for decision making in the management of RCC.

Ewing's sarcoma/primitive neuroectodermal tumor arising from the adrenal gland: a case report and literature review.

We report a rare case of Ewing's sarcoma (ES)/primitive neuroectodermal tumor (PNET) arising from the adrenal gland. A 17-year-old Japanese woman presented with left upper abdominal pain and high fever. Computed tomography and magnetic resonance imaging revealed a 15 × 10 cm tumor replacing the adrenal gland. Preoperative diagnosis was an adrenocortical carcinoma. Resection of the tumor was performed. We obtained the final diagnosis of ES/PNET by immunohistochemical molecular study with positive staining for the MIC2 gene product (CD99) and a Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement. Local recurrence was observed one month after the surgery. The patient was then treated with systemic chemotherapy and localized radiotherapy.

Urinary retention caused by a urethral cystine stone in a 10-month-old infant.

Urinary retention resulting from urolithiasis in early infancy is an extremely rare event. Cystine stone formation in those younger than 1 year is also a rare condition. We report a case of urinary retention caused by a urethral cystine stone in a 10-month-old male infant. Obstructive urolithiasis should be considered one of the reasons of decreased urine output in infants.

Cutoff value of time to prostate-specific antigen nadir is inversely correlated with disease progression in advanced prostate cancer.

To identify the early predictor of progression to castration-resistant prostate cancer (CRPC) for different stage of advanced PC patients, we focused on time to prostate-specific antigen (PSA) nadir following primary androgen deprivation therapy (PADT). We reviewed 184 advanced (locally advanced and metastatic) PC patients (101 patients with bone metastasis (BM) and 83 patients without BM at presentation) who had received PADT at our institution. We evaluated laboratory data, pathological results, and the influence of PSA kinetics impact on disease progression. The progression rates were analyzed with reference to the nadir PSA level and time to PSA nadir (TTN) following PADT by Kaplan-Meier method. In all, 103 patients (56%) progressed to CRPC. Nadir PSA lower than 0.2 ng/ml (nadir ≤0.2) during PADT was observed in 114 patients (62%). Median TTN was 8.5 months in patients with BM and 11.5 months in patients without BM. Multivariate analysis revealed that nadir ≤0.2 following PADT (P<0.001), longer TTN (>8 months) (P<0.001), extent of disease on bone scan grade (P=0.02), and T stage (P=0.04) in BM group and nadir ≤0.2 following PADT (P<0.001), longer TTN (>11 months) (P<0.001), and T stage (P=0.03) in without BM group were independent prognostic factors for progression. In both groups, longer TTN identified patients with prolonged progression-free survival in both nadir ≤0.2 and >0.2 nadir levels. Longer TTN is strongly associated with a low risk of disease progression, and the cutoff value of TTN could be inversely correlated with disease progression.

Intermittent chemotherapy is a treatment choice for advanced urothelial cancer.

OBJECTIVE: To investigate the potential benefit of intermittent chemotherapy, and to identify the eligibility criteria offering intermittent chemotherapy to patients with advanced urothelial cancer. MATERIALS AND METHODS: Twenty patients who responded or had stable disease after receiving 3 cycles of induction chemotherapy (gemcitabine and cisplatin, or paclitaxel and carboplatin) were enrolled for a prospective study of intermittent chemotherapy. We evaluated for the duration of chemotherapy holiday, toxicity, quality of life (QOL), and overall survival. RESULTS: The median number of cycles was 7 (range, 3-25). On resumption of treatment after the first chemotherapy holiday, 65% of the patients had partial response, 25% had stable disease, and 10% of the patients developed disease progression. The median duration of chemotherapy holiday was 22 weeks (range, 4-94), and the median chemotherapy holiday rate (CHR) was 0.53 (range, 0.25-0.86). The duration of the first chemotherapy holiday of more than 8 weeks significantly correlated to a high CHR. A response to induction chemotherapy, and normal levels of albumin and hemoglobin significantly correlated with a higher CHR. A significant improvement in fatigue, nausea and vomiting, and appetite loss was seen in the symptom scales of QLQ-C30 during the chemotherapy holiday. CONCLUSIONS: Intermittent chemotherapy is a feasible treatment strategy to balance disease control and QOL in selected patients.

Continuous saline bladder irrigation after transurethral resection is a prophylactic treatment choice for non-muscle invasive bladder tumor.

BACKGROUND: Instillation of chemotherapy after transurethral resection (TUR) has been considered as an optimal treatment for non-muscle invasive bladder cancer (NMIBC). However, controversy remains regarding the role of chemotherapy instillation. We therefore evaluated the usefulness of continuous saline bladder irrigation (CSBI) after TUR. PATIENTS AND METHODS: Patients with intermediate risk NMIBC were treated by TUR followed by either CSBI (123 patients) or intravesical instillation of mitomycin C (115 patients). Recurrence-free rates were estimated using the Kaplan-Meier method. RESULTS: No significant differences were observed in the recurrence-free rate, period to first recurrence, nor in frequency of recurrence between the CSBI and intravesical chemotherapy groups. Tumor progression rate and local toxicities were significantly higher in the intravesical chemotherapy group. CONCLUSION: CSBI after TUR appears to be a prophylactic treatment choice for intermediate risk NMIBC patients, in terms of its equal prophylactic effect to intravesical chemotherapy with mitomycin C, and its safety and cost benefits.