Clinical Anatomy of the Superficial Preprostatic Vein and Accessory Pudendal Artery in Robot-Assisted Radical Prostatectomy.

Purpose: We herein describe the superficial preprostatic vein (SPV) anatomy and determine its relationship with the accessory pudendal artery (APA). Materials and Methods: We reviewed 500 patients with localized prostate cancer who underwent conventional robot-assisted radical prostatectomy between April 2019 and March 2023 at our institution. SPV was defined as "any vein coming from the space between the puboprostatic ligaments and running within the retropubic adipose tissue anterior to the prostate toward the vesical venous plexus or pelvic side wall." While APA was defined as "any artery located in the periprostatic region running parallel to the dorsal vascular complex and extending caudal toward the anterior perineum." The intraoperative anatomy of each SPV and APA was described. Results: SPVs had a prevalence rate of 88%. They were preserved in 252 men (58%) and classified as I-, reversed-Y (rY)-, Y-, or H-shaped (64%, 22%, 12%, and 2%, respectively) based on their intraoperative appearance. Overall, 214 APAs were found in 142 of the 252 men with preserved SPV (56%; 165 lateral and 50 apical APAs in 111 and 41 men, respectively). SPVs were pulsatile in 39% men perhaps due to an accompanying tiny artery functioning as a median APA. Pulsations seemed to be initially absent in most SPVs but become apparent late during surgery possibly due to increased arterial and venous blood flow after prostate removal. Pulsations were common in men with ≥1 APA. Conclusions: This study, which described the anatomical variations in arteries and veins around the prostrate and their preservation techniques, revealed that preserving this vasculature may help preserve postprostatectomy erection. ClinicalTrials: The Clinical Research Registration Number is 230523D.

Inguinal hernia leads to worse immediate urinary continence after robot-assisted radical prostatectomy.

OBJECTIVES: Patients with inguinal hernia (IH) may have voiding dysfunction and weak urethra-stabilizing periurethral fascial tissues, contributing to urinary incontinence. This study aimed to review the association between IH and urinary continence after robotic-assisted radical prostatectomy (RARP). METHODS: This single-institution retrospective study included 251 consecutive cases of RARP between April 2019 and June 2022. Patients with concurrent IH or a history of adult IH repair were examined. The urine loss rate (ULR), defined as 24-h urine loss volume divided by the total urine volume immediately after urinary catheter removal (i.e., 6 or 7 postoperative days), was compared between the groups with (n = 33) and without IH (n = 214). Possible contributing factors for ULR were assessed, including age, body mass index (BMI), after benign prostatic hyperplasia surgery, prostate weight, and nerve-sparing. ULR was compared intergroup after propensity score matching countering selection biases. RESULTS: Patients with IH were older (71.3 versus. 66.8 years, p < 0.01), had lower BMI (22.8 versus. 24.3, p < 0.01), and had higher ULR (14.5% versus. 5.1%, p < 0.01). In a multiple linear regression analysis (adjusted R2 = 0.084), IH (p < 0.01) was an independent contributing factor for ULR besides advancing age (p < 0.03). After propensity score matching adjusted for patient's age and nerve-sparing, patients with IH had higher ULR (14.1% versus. 5.7%, p < 0.03) as well. CONCLUSIONS: This study first reported that IH may be one of the risk factors of urinary incontinence after RARP.

The Impact of Lateral Bladder Neck Preservation on Urinary Continence Recovery After Robot-Assisted Radical Prostatectomy.

OBJECTIVE: Urinary incontinence is one of the most bothersome adversities after robot-assisted radical prostatectomy (RARP). The aim of this study was to investigate the urinary continence recovery and the effect of various surgical techniques. MATERIALS AND METHODS: We previously reported that posterior rhabdosphincter reconstruction and nerve-sparing were independent predictors of urinary continence recovery 1 month after catheter removal in 199 patients who underwent RARP. Retrospectively, we further reviewed those 199 patients for urinary continence recovery at 3 months or later after RARP. The relationships of urinary continence with perioperative findings, including surgical procedures, were evaluated at 3 to 12 months after RARP. The Fisher exact test and Mann-Whitney rank sum test were used for evaluating variables between the groups. Multivariate logistic regression analysis was performed to investigate the association between urinary continence and perioperative factors. RESULTS: On univariate analyses, surgeon experience, lateral bladder neck preservation (BNP), anterior reconstruction, and posterior reconstruction were significantly associated with urinary continence recovery 3 months after RARP, but only lateral BNP was independently associated with urinary continence recovery in a multivariate analysis. Similarly, on univariate analyses, surgeon experience, lateral BNP, and posterior reconstruction were significantly associated with continence recovery at 6 months or later after surgery. However, multivariate analyses showed that only lateral BNP was significantly associated with urinary continence recovery 6 months or later after surgery. CONCLUSION: Although the lateral BNP technique did not affect immediate urinary continence recovery, this procedure was significantly associated with continence recovery 3 months or later after RARP.

No clinical significance of the time interval between biopsy and robotic-assisted radical prostatectomy for patients with clinically localized prostate cancer on biochemical recurrence: a propensity score matching analysis.

PURPOSE: To investigate the impact of the time interval (TI) between prostate biopsy and robot-assisted radical prostatectomy (RARP) on the risk of biochemical recurrence (BCR). METHODS: We retrospectively reviewed the medical records of 793 consecutive patients who were treated with RARP at our institution. Patients were divided into three groups, according to TI, to compare BCR-free survival (BCRFS) rates: Group 1 (n = 196), TI < 3 months; Group 2 (n = 513), 3 ≤ TI < 6 months; Group 3 (n = 84), TI ≥ 6 months. Eighty-three patients with TI ≥ 6 months were matched with an equal number of patients with TI < 6 months based on propensity scores by using four preoperative factors: prostate-specific antigen (PSA), primary (pGS) and secondary (sGS) Gleason score and positive prostate biopsy. RESULTS: The 5-year BCRFS rates for TI Groups 1, 2, and 3 were 76%, 80.7% and 82.6% (P = 0.99), respectively. The multivariate analysis revealed that PSA, pGS, sGS and a positive prostate biopsy were independent preoperative risk factors for BCR. The propensity adjusted 5-year BCRFS for patients with TI ≥ 6 months was 84.0%. This was not worse than that of patients with TI < 6 months (71.0%, P = 0.18). CONCLUSIONS: In our cohorts, a delay in the time from biopsy to RARP did not significantly affect recurrence. Therefore, hasty treatment decisions are unnecessary for at least 6 months after diagnosis of early prostate cancer.

Impact of Surgeon and Hospital Volume on the Safety of Robot-Assisted Radical Prostatectomy: A Multi-Institutional Study Based on a National Database.

INTRODUCTION: We aimed to perform a multi-institutional study using a national database led by the Japanese Society of Endourology to investigate the effect of surgeon or hospital volume on the safety of robot-assisted radical prostatectomy (RARP). MATERIALS AND METHODS: Clinical data of 3,214 patients who underwent RARP for the treatment of clinically localized prostate cancer between April 2012 and March 2013 in Japan were evaluated. Surgical outcomes and all intra- and perioperative complications were collected. RESULTS: The intraoperative complication rate was 0.56%. In a total number of 241 patients, 261 perioperative complications were observed. The following percentages of patients presented the Clavien-graded complications: 7.2%, grades 1-2; 0.84%, grade 3; and 0.093%, grade 4a. No cases of multiple organ dysfunction or death (grades 4b and 5) were found. Multivariable logistic regression analysis showed that the hospital volume (OR 3.6; p = 0.010) for intraoperative complications and surgeon volume (OR 0.19; p < 0.0001) and extended lymph node discectomy (OR 3.9; p < 0.0001) for perioperative complications were significant independent risk factors. CONCLUSIONS: Hospital volume for intraoperative complications and surgeon volume and extended lymph node dissection for perioperative complications were significantly associated with increased risk of each complication in RARP.

Reality of nerve sparing and surgical margins in surgeons' early experience with robot-assisted radical prostatectomy in Japan.

OBJECTIVE: To analyze nerve sparing performance at an early stage of robot-assisted radical prostatectomy, and the correlation between the surgeons' experience and the risk of a positive surgical margin in patients treated with robot-assisted radical prostatectomy. METHODS: Patients' records from January 2009 to March 2013 were retrospectively reviewed, and 3469 patients with localized prostate cancer were identified at 45 institutions. Individual surgeon's experience with nerve sparing was recorded as the number of nerve sparing cases among total robot-assisted radical prostatectomies beginning with the first case during which nerve sparing was carried out. Patients were selected by propensity score matching for nerve sparing, and predictive factors of positive surgical margins were analyzed in patients with and without positive surgical margins. RESULTS: A total of 152 surgeons were studied, and the median number of robot-assisted radical prostatectomy cases for all surgeons was 21 (range 1-511). In all, 54 surgeons (35.5%) undertook nerve sparing during their first robot-assisted radical prostatectomy case. For 2388 patients selected with (1194) and without (1194) nerve sparing, predictive factors for positive surgical margin were high initial prostate-specific antigen level (P < 0.0001), high biopsy Gleason score (P = 0.0379), presence of neoadjuvant hormone therapy (P = 0.0002) and surgeon's experience with >100 cases (P = 0.0058). Thus, nerve sparing was not associated with positive surgical margins. CONCLUSION: The surgeon's experience influences the occurrence of positive surgical margins, although a considerable number of surgeons carried out nerve sparing during their early robot-assisted radical prostatectomy cases. Surgeons should consider their own experience and prostate cancer characteristics before carrying out a nerve sparing robot-assisted radical prostatectomy.

The Initial Case Report: Salvage Robotic Assisted Radical Prostatectomy After Heavy Ion Radiotherapy.

Salvage radical prostatectomy is one of treatments after radiation therapy to patients with prostate cancer. To date, no case of the salvage robotic assisted radical prostatectomy (RARP) following heavy ion radiotherapy (HIRT) has been published. We report on a 70-year-old man with a history of HIRT for prostate cancer in 2011. For 3 years after. HIRT, his serum PSA levels were permissible range. However, his PSA levels were increased. We had diagnosis localized prostate cancer after HIRT. We had carried out salvage RARP. Until 10 months after salvage RARP, his PSA level was not detectable.

Impact of a preoperatively estimated prostate volume using transrectal ultrasonography on surgical and oncological outcomes in a single surgeon's experience with robot-assisted radical prostatectomy.

BACKGROUND: To assess the impact of preoperatively estimated prostate volume (PV) using transrectal ultrasonography (TRUS) on surgical and oncological outcomes in robot-assisted radical prostatectomy (RARP). METHODS: We analyzed the experience of a single surgeon at our hospital who performed 436 RARPs without neoadjuvant hormone therapy between August 2006 and December 2013. Patients were divided into three groups according to their preoperative PV calculated using TRUS (PV ≤ 20 cm(3): group 1, n = 61; 20 < PV < 50 cm(3): group 2, n = 303; PV ≥ 50 cm(3): group 3, n = 72). RESULTS: Blood loss was significantly higher in group 3 than in group 1 and group 2. In stage pT2 patients, the rate of positive surgical margin (PSM) was significantly lower in group 3 than in group 1. In addition, perioperative complications significantly increased with increasing PV, while the extraprostatic extension (EPE) rate significantly decreased with increasing PV. The preoperative biopsy Gleason score, prostate-specific antigen (PSA) density, and clinical T2 stage were inversely correlated with increasing PV. Biochemical recurrence-free survival after RARP was significantly lower in group 1 than in groups 2 and 3. CONCLUSIONS: A large prostate size was significantly associated with increased blood loss and a higher rate of perioperative complications. A small prostate size was associated with a higher PSM rate, PSA density, Gleason score, EPE rate, and biochemical recurrence rate. These results suggest that RARP was technically challenging in patients with large prostates, whereas small prostates were associated with unfavorable oncological outcomes.

Prediction of renal function after nephroureterectomy in patients with upper tract urothelial carcinoma.

OBJECTIVE: The estimated glomerular filtration rate is significantly decreased after nephroureterectomy. Deteriorating renal function likely affects the eligibility for cisplatin-based chemotherapy in patients with upper tract urothelial carcinoma. The present study was undertaken to identify preoperative factors for the prediction of postoperative renal function and develop a prediction model. METHODS: Between June 1996 and January 2014, 110 patients who underwent radical nephroureterectomy at our institution were analyzed in this study. The estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease study equation. Univariate linear regression analyses were performed to investigate the correlation between postoperative estimated glomerular filtration rate and preoperative variables. A stepwise multivariate linear regression analysis was performed to identify independent predictors of postoperative estimated glomerular filtration rate. RESULTS: Comparison of preoperative and postoperative estimated glomerular filtration rate for each patient showed a median difference of 13.1 ml/min/1.73 m(2). The postoperative estimated glomerular filtration rate was significantly lower than the preoperative estimated glomerular filtration rate (P < 0.001). On univariate analysis, age and preoperative estimated glomerular filtration rate were significantly correlated with postoperative estimated glomerular filtration rate. On multivariate analysis, age, preoperative estimated glomerular filtration rate and the presence of hydronephrosis were independent predictive factors of postoperative estimated glomerular filtration rate. The predicted postoperative estimated glomerular filtration rate, which was calculated using these independent factors, showed a significant correlation with the observed postoperative estimated glomerular filtration rate (correlation coefficient = 0.7533). CONCLUSIONS: Age, preoperative estimated glomerular filtration rate and the presence of hydronephrosis were independent predictors of postoperative estimated glomerular filtration rate in patients with upper tract urothelial carcinoma treated with radical nephroureterectomy. The predicted postoperative estimated glomerular filtration rate based on these factors may be useful for choosing alternative management strategies such as neoadjuvant chemotherapy for patients with upper tract urothelial carcinoma.

Clinical effect of a positive surgical margin without extraprostatic extension after robot-assisted radical prostatectomy.

OBJECTIVES: The aim of this study was to investigate the effect of positive surgical margin (PSM) without extraprostatic extension after robot-assisted radical prostatectomy (RARP). MATERIALS AND METHODS: We retrospectively reviewed 837 patients who underwent RARP for clinically localized prostate cancer without neoadjuvant endocrine therapy. The pT2+category lesions were defined according to World Health Organization classification. The actuarial probabilities of biochemical recurrence-free survival (BCR-FS) were determined using Kaplan-Meier analysis. Univariate and multivariate Cox proportional hazards regression analyses were also used to identify independent predictors for BCR. RESULTS: Of the 837 patients, 102 (12.2%) experienced BCR during the follow-up period. The BCR-FS rate was significantly higher in patients with pT2+category tumors than in those with pT3a category tumors, and significantly lower in patients with pT2+category tumors than that in those with pT2 category tumors without PSM. The BCR-FS rate of patients with pT2+category tumors was significantly higher than that with pT3a category tumors with PSM but not significantly different from that with pT3a category tumors without PSM. In a multivariate analysis, the pathological T category considering pT2+category was one of independent predictive factors for BCR. CONCLUSIONS: This study support the hypothesis that the pT2+category disease is associated with a significantly increased risk of BCR in patients with organ-confined prostate cancer after RARP. As PSM can be avoided in some cases, urologists should continually seek to improve their operative skills and to reduce the rate of PSM, especially in patients with organ-confined prostate cancer.

Associations between ABO blood groups and biochemical recurrence after radical prostatectomy.

BACKGROUND: Recent studies have demonstrated associations between ABO blood groups and prognosis in various types of cancers. The aim of this study was to investigate the association between ABO blood groups and biochemical recurrence (BCR) after radical prostatectomy (RP). METHODS: A total of 555 patients with prostate cancer who underwent RP were included in the study. No patients received neoadjuvant and/or adjuvant therapy. The effect of ABO blood groups on BCR was examined using univariate and multivariate analyses. RESULTS: During the follow-up period (mean, 52.0 months), 166 patients (29.9%) experienced BCR, with a 5-year BCR-free rate of 67.3%. Although the ABO blood group was not a significantly associated with BCR in the univariate analysis, it was an independent predictor of BCR in the multivariate analysis: blood type O patients had a significantly lower risk of BCR compared to type A patients (Hazard ratio, 0.608; 95% confidence interval, 0.410-0.902; P = 0.014). Further analyses revealed that surgical margin status confounded the assessment of the association between the ABO blood group and BCR. In the analyses of patients with a negative surgical margin, the 5-year BCR-free rate in blood type O patients was a significantly higher than that in type A patients (91.2% vs. 71.0%; P = 0.026). CONCLUSION: Blood type O is significantly associated with a decreased risk of biochemical recurrence after radical prostatectomy. Further studies are needed to clarify the nature of this association.

Prediction of biochemical recurrence after robot-assisted radical prostatectomy: analysis of 784 Japanese patients.

OBJECTIVES: To examine biochemical recurrence after robot-assisted radical prostatectomy in Japanese patients, and to develop a risk stratification model for biochemical recurrence. METHODS: The study cohort consisted of 784 patients with localized prostate cancer who underwent robot-assisted radical prostatectomy without neoadjuvant or adjuvant endocrine therapy. The relationships of biochemical recurrence with perioperative findings were evaluated. The prognostic factors for biochemical recurrence-free survival were evaluated using Cox proportional hazard model analyses. RESULTS: During the follow-up period, 80 patients showed biochemical recurrence. The biochemical recurrence-free survival rates at 1, 3, and 5 years were 92.2%, 85.2% and 80.1%, respectively. In univariate analysis, the prostate-specific antigen level, prostate-specific antigen density, biopsy Gleason score, percent positive core, pathological T stage, pathological Gleason score, lymphovascular invasion, perineural invasion and positive surgical margin were significantly associated with biochemical recurrence. In multivariate analysis, prostate-specific antigen density ≥0.4 (P = 0.0011), pathological T stage ≥3a (P = 0.002), pathological Gleason score ≥8 (P = 0.007) and positive surgical margin (P < 0.0001) were independent predictors of biochemical recurrence. The patients were stratified into three risk groups according to these factors. The 5-year biochemical recurrence-free survival rate was 89.4% in the low-risk group, 65.6% in the intermediate-risk group and 30.3% in the high-risk group. CONCLUSIONS: The prostate-specific antigen density, pathological T stage, pathological Gleason score and positive surgical margin were independent prognostic factors for biochemical recurrence. The risk stratification model developed using these four factors could help clinicians identify patients with a poor prognosis who might be good candidates for clinical trials of alternative management strategies.

[Robot-assisted surgery-the current state of radical prostatectomy].

Minimally invasive surgeries such as laparoscopic surgery and robot-assisted surgery have become validated treatment modalities and hold a prominent position in clinical practice. Robot-assisted radical prostatectomy(RARP)is a relatively new procedure. Because this technique does not require the urologist to overcome a steep and long learning curve, a dramatic increase in the number of RARP surgeries was observed in recent years and RARP has rapidly gained acceptance in the Japanese urological community after its introduction in Japan in 2006. Robot-assisted surgery that combines optical magnification, three-dimensional vision, and instruments with 7 degrees of freedom allows surgeons to perform meticulous, precise, and accurate movements. In summary, for the previously mentioned reasons, RARP is considered to be an effective procedure for improving intraoperative blood loss, the transfusion and complication rates, as well as the recovery of urinary continence and potency rates. In this article, we briefly describe the evolution of this minimally invasive technique. In addition, we present the current state of RARP and a critical evaluation of the learning curves associated with performing RARP as well as published oncological, continence, and potency outcomes.

Prediction of multifocal lesions in patients with upper tract urothelial carcinoma.

OBJECTIVE: To identify predictive factors for multifocal lesions in patients with upper tract urothelial carcinoma (UTUC). PATIENTS AND METHODS: Between June 1996 and September 2013, a cohort of 147 patients underwent radical nephroureterectomy at our institution. Univariate and multivariate logistic regression analyses were performed to identify clinical covariates significantly associated with the multifocal UTUC lesions and establish a model to predict its occurrence. RESULTS: In the univariate analyses, estimated glomerular filtration rate, hydronephrosis, history of bladder cancer, hemoglobin level, and Brinkman index were significantly associated with multifocal lesions. In the multivariate analysis, hydronephrosis (P = .010), history of bladder cancer (P = .017), Brinkman index >100 (P = .014), and hemoglobin level <11 g/dL (P = .031) were independent predictive factors for multifocal lesions. Using these independent factors, we calculated the predictive probability of multifocal lesions and predicted their occurrence. The predictive probability of multifocal lesions strongly correlated with their observed rate (regression coefficient = 0.9999). CONCLUSION: An improved understanding of UTUC has led to various clinical guidelines being revised to recommend less invasive interventions in appropriate cases. Hydronephrosis, history of bladder cancer, Brinkman index, and hemoglobin level are independent predictive factors for multifocal lesions of UTUC. Although this study has limitations and additional studies are required to validate our findings, this information may aid in appropriate patient selection for partial ureterectomy and may be effectively incorporated into clinical practice.

Preoperative prognostic factors for biochemical recurrence after robot-assisted radical prostatectomy in Japan.

PURPOSE: We investigated oncological outcomes in Japanese patients who underwent robot-assisted radical prostatectomy (RARP). MATERIALS AND METHODS: This study included 389 patients who underwent RARP at a single institution with a follow-up period of at least 1 year. Preoperative findings were compared with biochemical recurrence (BCR). Predictors of BCR-free survival (BCRFS) were evaluated by univariate and multivariate Cox proportional hazard model analyses, and a risk stratification model based on the relative risks of BCR was established. RESULTS: Fifty incidences of BCR were noted during a median follow-up period of 28.7 months (range, 12.1-80.0 months). The BCRFS rate for the entire cohort at the median follow-up time was 85.9 %; the 1-, 3-, and 5-year estimates were 91.0, 85.1, and 81.1 %, respectively. From univariate analyses, prostate-specific antigen (PSA), PSA density, biopsy Gleason score, and percent positive core were significantly associated with BCR. Multivariate analysis showed that PSA [hazard ratio (HR), 2.75; p = 0.001], percent positive core (HR, 2.22; p = 0.001), and biopsy Gleason score (HR, 2.61; p = 0.007) were independent predictors of BCR. CONCLUSION: This study at a single Japanese center demonstrates that RARP provides a satisfactory BCRFS rate. This report provides a framework with which to estimate oncological outcomes in patients who underwent RARP for localized prostate cancer. Our results support the increased use of RARP for the treatment of localized prostate cancer in Japan.

Learning curve and perioperative outcomes of robot-assisted radical prostatectomy in 200 initial Japanese cases by a single surgeon.

PURPOSE: The aim of the present study was to investigate the learning curve and perioperative outcomes in 200 consecutive patients with prostate cancer who underwent robot-assisted radical prostatectomy (RARP). PATIENTS AND METHODS: Between August 2006 and August 2011, 200 patients with prostate cancer underwent RARP and were enrolled in this study. We prospectively collected the demographic data and analyzed the pathologic and functional outcomes. The operative outcomes analyzed were total operative time, estimated blood loss (EBL), positive surgical margin (PSM), incontinence, and perioperative complications. We also evaluated the relationship between the surgeon's experience and operative variables. RESULTS: The sloping learning curve for this surgeon showed that total operative time was strongly correlated with the accumulation of experience for the initial 25 cases (|rs|=0.71, P<0.001). The average EBL was not strongly correlated with additional experience (|rs|<0.7). The PSM rate for the first 50 cases was significantly higher than that of the next 150 cases (34.8% vs 19.4%, P=0.035). The complication rate among the first 50 patients was significantly higher than that among the remaining 150 patients (32% vs 12.7%, P=0.002). The incontinence rate at 12 months was significantly higher for the first 100 cases compared with that for the next 100 cases (9.0% vs 1.0%, P=0.009). For the surgeon to optimize total operative time, PSM rate, complication rate, and incontinence rate, slope learning curves of 25, 50, 50, and 100 cases were needed. CONCLUSIONS: The functional and pathologic results of this minimally invasive procedure seemed to be promising. Distinct learning curves were observed with respect to operative time, PSM, complication rate, and incontinence rate. Exposure to 100 surgeries would be necessary for a surgeon to adequately master the required skills.

Torsion of a seminoma in an intrascrotal testis: A case report and review of the literature.

An intrascrotal testicular torsion with malignant testicular tumour is extremely rare. We report a case of a 26-year-old male who was diagnosed with testicular torsion by magnetic resonance imaging and with testicular seminoma after orchiectomy. Through this case, we found that if the possibility of testicular torsion remains during the diagnosis of acute scrotum cases, additional examination adding to colour Doppler sonography should be performed. Furthermore, we should be aware of the possibility of testicular tumours during the diagnosis and treatment of acute scrotums. If the affected testis is preserved in the treatment of testicular torsion, a postoperative examination by ultrasound and/or tumour markers for the remaining testis is essential to confirm the absence of testicular tumour.

Predictors for positive surgical margins after robot-assisted radical prostatectomy: a single surgeon's series in Japan.

OBJECTIVE: Positive surgical margin after radical prostatectomy has been shown to be an independent predictive factor for biochemical and local recurrence in patients with prostate cancer. The present study was undertaken to identify predictive factors for positive surgical margin after robot-assisted radical prostatectomy in Japanese patients. METHODS: Between August 2006 and September 2011, a cohort of 244 men underwent robot-assisted radical prostatectomy carried out by a single surgeon. Univariate and multivariate logistic regression analyses were carried out to identify clinical covariates significantly associated with an increased positive surgical margin. The preoperative variables included age, body mass index, prostate-specific antigen level, prostate-specific antigen density, clinical T stage, prostate volume, surgeon volume, number of positive cores and percentage of positive cores. RESULTS: In the univariate analyses, serum prostate-specific antigen level, prostate-specific antigen density and surgeon volume were significantly associated with positive surgical margin. In the multivariate analysis, prostate-specific antigen density (hazard ratio 3.13, 95% confidence interval 1.57-6.24; P = 0.001) and surgeon volume (hazard ratio 2.15, 95% confidence interval 1.06-4.35; P = 0.034) were independent predictive factors for positive surgical margin. Using these two independent factors, we divided the patients into four groups and calculated the predictive probability of positive surgical margin. The predictive probability for positive surgical margin in each group was well correlated with the rates at 10.8% and 10.2%, 19.8% and 20.0%, 26.4% and 26.4%, an 43.5% and 43.3%, respectively. CONCLUSION: Prostate-specific antigen density and surgeon volume are independent predictors of positive surgical margin after robot-assisted radical prostatectomy. A combination of these two factors can provide useful information about positive surgical margins.

[Robot-assisted radical prostatectomy].

Robot-assisted radical prostatectomy(RARP)has emerged in the last decade. It has greatly improved clinical management of localized prostate cancer. Its use has been justified by its satisfactory oncological and functional outcomes and its fewer perioperative complications. RARP has the advantages of both conventional open radical retropubic prostatectomy and laparoscopic radical prostatectomy. However, its increased cost and the lack of tactile sensation it induces still remain problems.