Rat hippocampal CA1 region represents learning-related action and reward events with shorter latency than the lateral entorhinal cortex.

The hippocampus and entorhinal cortex are deeply involved in learning and memory. However, little is known how ongoing events are processed in the hippocampal-entorhinal circuit. By recording from head-fixed rats during action-reward learning, here we show that the action and reward events are represented differently in the hippocampal CA1 region and lateral entorhinal cortex (LEC). Although diverse task-related activities developed after learning in both CA1 and LEC, phasic activities related to action and reward events differed in the timing of behavioral event representation. CA1 represented action and reward events almost instantaneously, whereas the superficial and deep layers of the LEC showed a delayed representation of the same events. Interestingly, we also found that ramping activity towards spontaneous action was correlated with waiting time in both regions and exceeded that in the motor cortex. Such functional activities observed in the entorhinal-hippocampal circuits may play a crucial role for animals in utilizing ongoing information to dynamically optimize their behaviors.

Hippocampal-medial entorhinal circuit is differently organized along the dorsoventral axis in rodents.

The general understanding of hippocampal circuits is that the hippocampus and the entorhinal cortex (EC) are topographically connected through parallel identical circuits along the dorsoventral axis. Our anterograde tracing and in vitro electrophysiology data, however, show a markedly different dorsoventral organization of the hippocampal projection to the medial EC (MEC). While dorsal hippocampal projections are confined to the dorsal MEC, ventral hippocampal projections innervate both dorsal and ventral MEC. Further, whereas the dorsal hippocampus preferentially targets layer Vb (LVb) neurons, the ventral hippocampus mainly targets cells in layer Va (LVa). This connectivity scheme differs from hippocampal projections to the lateral EC, which are topographically organized along the dorsoventral axis. As LVa neurons project to telencephalic structures, our findings indicate that the ventral hippocampus regulates LVa-mediated entorhinal-neocortical output from both dorsal and ventral MEC. Overall, the marked dorsoventral differences in hippocampal-entorhinal connectivity impose important constraints on signal flow in hippocampal-neocortical circuits.

Laminar Organization of the Entorhinal Cortex in Macaque Monkeys Based on Cell-Type-Specific Markers and Connectivity.

The entorhinal cortex (EC) is a major gateway between the hippocampus and telencephalic structures, and plays a critical role in memory and navigation. Through the use of various molecular markers and genetic tools, neuron types constituting EC are well studied in rodents, and their layer-dependent distributions, connections, and functions have also been characterized. In primates, however, such cell-type-specific understandings are lagging. To bridge the gap between rodents and primates, here we provide the first cell-type-based global map of EC in macaque monkeys. The laminar organization of the monkey EC was systematically examined and compared with that of the rodent EC by using immunohistochemistry for molecular markers which have been well characterized in the rodent EC: reelin, calbindin, and Purkinje cell protein 4 (PCP4). We further employed retrograde neuron labeling from the nucleus accumbens and amygdala to identify the EC output layer. This cell-type-based approach enabled us to apply the latest laminar definition of rodent EC to monkeys. Based on the similarity of the laminar organization, the monkey EC can be divided into two subdivisions: rostral and caudal EC. These subdivisions likely correspond to the lateral and medial EC in rodents, respectively. In addition, we found an overall absence of a clear laminar arrangement of layer V neurons in the rostral EC, unlike rodents. The cell-type-based architectural map provided in this study will accelerate the application of genetic tools in monkeys for better understanding of the role of EC in memory and navigation.

[Postoperative Inguinal Hernia after Robot-Assisted Radical Prostatectomy with Prevention Technique Using Spermatic Cord Isolation].

We retrospectivelyevaluated postoperative inguinal hernias (PIHs) after robot-assisted radical prostatectomy(RARP) with a technique for preventing hernias byspermatic cord isolation. Among the RARPs performed from 2016 to 2018, 191 cases were evaluated 12 or more months after surgery. In all the cases, the peritoneum was isolated from the spermatic cord by5 cm or more as a hernia prevention technique during RARP. We compared the background factors between PIH-positive and PIH-negative groups. The PIH-positive group had a significantlylower bodymass index (BMI) than the PIH-negative group (20.6 kg/m2 vs 23.8 kg/m2, p＝0.0079), but there were no significant differences in other background factors. When patients were classified into three groups byBMI, low (＜21.9 kg/m2), intermediate (21.9 to 25.5 kg/m2), and high (＞25.5 kg/m2), the rate of PIH was 8.5% for the low group, 2.1% for the intermediate group, and 0% for the high group. Our findings suggest that incidences of inguinal hernias after the preventive technique of spermatic cord isolation in RARP, and the BMIs tended to be low in the hernia cases.

Local projections of layer Vb-to-Va are more prominent in lateral than in medial entorhinal cortex.

The entorhinal cortex, in particular neurons in layer V, allegedly mediate transfer of information from the hippocampus to the neocortex, underlying long-term memory. Recently, this circuit has been shown to comprise a hippocampal output recipient layer Vb and a cortical projecting layer Va. With the use of in vitro electrophysiology in transgenic mice specific for layer Vb, we assessed the presence of the thus necessary connection from layer Vb-to-Va in the functionally distinct medial (MEC) and lateral (LEC) subdivisions; MEC, particularly its dorsal part, processes allocentric spatial information, whereas the corresponding part of LEC processes information representing elements of episodes. Using identical experimental approaches, we show that connections from layer Vb-to-Va neurons are stronger in dorsal LEC compared with dorsal MEC, suggesting different operating principles in these two regions. Although further in vivo experiments are needed, our findings imply a potential difference in how LEC and MEC mediate episodic systems consolidation.

[ROBOT-ASSISTED RADICAL CYSTECTOMY AT HIROSHIMA CITY ASA HOSPITAL -COMPARISON WITH LAPAROSCOPIC RADICAL CYSTECTOMY].

(Objective) We compared the perioperative parameters of robot-assisted radical cystectomy (RARC) and laparoscopic radical cystectomy (LRC) to evaluate the utility of RARC. (Patients and methods) At Hiroshima City Asa Hospital, 25 patients underwent RARC from July 2018 to May 2020 (R group) and 79 patients underwent LRC from July 2012 to June 2018 (L group). We retrospectively compared the patient characteristics, perioperative outcomes, and pathological outcomes between the R group and the L group. (Results) Regarding the patient characteristics, the R group had significantly more neo-adjuvant chemotherapy than the L group (64.0% vs. 32.9%, P=0.009), but the other characteristics did not differ. Between the R group and the L group, there were no significant differences in the total operating time (R group = 400 minutes vs. L group = 421 minutes), estimated blood loss (R group = 228 ml vs. L group = 318 ml), or pathological outcomes. However, there were significantly less postoperative complications in the R group than in the L group (24.0% vs. 52.6%, P=0.020). (Conclusion) This study showed that there might be benefits to introducing RARC into medical centers that perform LRC.

Recurrence- and progression-free survival in intermediate-risk non-muscle-invasive bladder cancer: the impact of conditional evaluation and subclassification.

OBJECTIVES: To assess the change in rates of recurrence-free survival (RFS) and progression-free survival (PFS) based on the duration of survival without recurrence or progression among patients with intermediate-risk (IR) non-muscle-invasive bladder cancer (NMIBC), and to examine the predictive factors for recurrence at different time points by assessing conditional RFS and PFS. PARTICIPANTS AND METHODS: A cohort of 602 patients treated with transurethral resection of bladder tumour and histopathologically diagnosed with IR NMIBC was included in this retrospective study. RESULTS: The conditional RFS rate at 1, 2, 3, 4 and 5 years improved with increased duration of RFS; however, the conditional PFS rate did not improve over time. Multivariable analyses showed that recurrent tumour, multiple tumours, tumour size (>3 cm), immediate postoperative instillation of chemotherapy, and administration of BCG were independent predictive factors for recurrence at baseline. The predictive ability of these factors disappeared with increasing recurrence-free survivorship. Subclassification of these patients with IR NMIBC into three groups using clinicopathological factors (recurrent tumour, multiple tumours, tumour size) demonstrated that the high IR group (two factors) had significantly worse RFS than the intermediate (one factor, P < 0.001) and low IR groups (no factor, P = 0.005) at baseline. This subclassification stratified conditional risk of RFS also at 1, 3 and 5 years, which provides the basis for distinct surveillance protocols among patients with IR NMIBC. CONCLUSION: Conditional survival analyses of patients with IR NMIBC demonstrate that RFS changes over time, while PFS does not change. These data support distinct surveillance protocols based on the subclassification of IR NMIBC.

Entorhinal Layer II Calbindin-Expressing Neurons Originate Widespread Telencephalic and Intrinsic Projections.

In the present study we provide the first systematic and quantitative hodological study of the calbindin-expressing (CB+) principal neurons in layer II of the entorhinal cortex and compared the respective projections of the lateral and medial subdivisions of the entorhinal cortex. Using elaborate quantitative retrograde tracing, complemented by anterograde tracing, we report that the layer II CB+ population comprises neurons with diverse, mainly excitatory projections. At least half of them originate local intrinsic and commissural projections which distribute mainly to layer I and II. We further show that long-range CB+ projections from the two entorhinal subdivisions differ substantially in that MEC projections mainly target field CA1 of the hippocampus, whereas LEC CB+ projections distribute much more widely to a substantial number of known forebrain targets. This connectional difference between the CB+ populations in LEC and MEC is reminiscent of the overall projection pattern of the two entorhinal subdivisions.

Convergent Projections from Perirhinal and Postrhinal Cortices Suggest a Multisensory Nature of Lateral, but Not Medial, Entorhinal Cortex.

The current model of the organization of the medial temporal lobe (MTL) episodic memory system assumes that two functionally different "where" and "what" pathways enter MTL as parallel parahippocampal cortex (PHC)-medial entorhinal cortex (MEC) and perirhinal cortex (PER)-lateral entorhinal cortex (LEC) streams, respectively. With the use of tract tracing and in vitro electrophysiological recordings, we show that, in the rat LEC, all main principal neuron types in layer II receive convergent inputs from PER and postrhinal cortex (POR), homologous to PHC in primates. Projections to MEC from POR are much less prominent than previously assumed. These findings thus challenge the prevailing concept that LEC and MEC are defined by different inputs from the PER and PHC/POR, respectively. Our findings point to LEC as the main parahippocampal multimodal integrative structure whose unique set of external sensory-derived inputs allows its network to represent a continuously fluctuating extrinsic environment.

Neurons and networks in the entorhinal cortex: A reappraisal of the lateral and medial entorhinal subdivisions mediating parallel cortical pathways.

In this review, we aim to reappraise the organization of intrinsic and extrinsic networks of the entorhinal cortex with a focus on the concept of parallel cortical connectivity streams. The concept of two entorhinal areas, the lateral and medial entorhinal cortex, belonging to two parallel input-output streams mediating the encoding and storage of respectively what and where information hinges on the claim that a major component of their cortical connections is with the perirhinal cortex and postrhinal or parahippocampal cortex in, respectively, rodents or primates. In this scenario, the lateral entorhinal cortex and the perirhinal cortex are connectionally associated and likewise the postrhinal/parahippocampal cortex and the medial entorhinal cortex are partners. In contrast, here we argue that the connectivity matrix emphasizes the potential of substantial integration of cortical information through interactions between the two entorhinal subdivisions and between the perirhinal and postrhinal/parahippocampal cortices, but most importantly through a new observation that the postrhinal/parahippocampal cortex projects to both lateral and medial entorhinal cortex. We suggest that entorhinal inputs provide the hippocampus with high-order complex representations of the external environment, its stability, as well as apparent changes either as an inherent feature of a biological environment or as the result of navigating the environment. This thus indicates that the current connectional model of the parahippocampal region as part of the medial temporal lobe memory system needs to be revised.

Imaging local brain activity of multiple freely moving mice sharing the same environment.

Electrophysiological field potential dynamics have been widely used to investigate brain functions and related psychiatric disorders. Considering recent demand for its applicability to freely moving subjects, especially for animals in a group and socially interacting with each other, here we propose a new method based on a bioluminescent voltage indicator LOTUS-V. Using our fiber-free recording method based on the LOTUS-V, we succeeded in capturing dynamic change of brain activity in freely moving mice. Because LOTUS-V is the ratiometric indicator, motion and head-angle artifacts were not significantly detected. Taking advantage of our method as a fiber-free system, we further succeeded in simultaneously recording from multiple independently-locomotive mice that were freely interacting with one another. Importantly, this enabled us to find that the primary visual cortex, a center of visual processing, was activated during the interaction of mice. This methodology may further facilitate a wide range of studies in neurobiology and psychiatry.

The risk factors of urinary tract infection after transurethral resection of bladder tumors.

PURPOSE: Few studies mention the necessity of antimicrobial prophylaxis (AMP) for transurethral resection of bladder tumor (TURBT) and the risk factors for postoperative urinary tract infections (UTIs) after TURBT. To evaluate the necessity of AMP and to detect the risk of UTIs, we examined the perioperative clinical factors. METHODS: 687 patients who underwent TURBT between 2006 and 2017 at Hiroshima Prefectural Hospital were examined retrospectively. We defined the postoperative UTIs as febrile UTIs (≥ 38 °C). The AMP for the TURBT that we used was mostly cephalosporin generation 1. The association between the perioperative clinical/pathological factors and postoperative UTIs was assessed by logistic regression retrospectively. RESULTS: 21 patients (3.1%) suffered from postoperative UTIs, and almost all of them were successfully treated with the immediate administration of antibiotics. Univariate analysis showed that past pelvic radiotherapy (p = 0.024, odds ratio (OR) 6.00), tumor size (≥ 2cm) (p = 0.008, OR 3.38), age (≥ 75 years) (p = 0.036, OR 2.65), preoperative hospital stay (≥ 5 days) (p = 0.017, OR 3.76), asymptomatic pyuria (p = 0.038, OR 2.54) and bacteriuria (p = 0.044, OR 2.97) were all associated with postoperative UTIs. CONCLUSIONS: We demonstrated that AMP was effective for patients who underwent TURBT, and history of pelvic radiotherapy, high age, preoperative hospital stay and a certain tumor size were the risk factors as well as pyuria and bacteriuria of postoperative UTIs.

[Infected Pelvic Lymphocele after Robot-Assisted Radical Prostatectomy].

The aim of this study is to clarify the incidences of infected pelvic lymphocele (IPL) after robot-assisted radical prostatectomy (RARP). From 2016 to 2017, we evaluated 173 consecutive patients who underwent RARP. The transperitoneal approach was used for the RARPs. Limited lymph node dissection was performed in the pelvic lymphoceles region surrounding the obturator nerve. Patients with IPL were defined as those with infected pelvic lymphoceles classified as Clavien-Dindo (CD) classification system grade II or greater and a fever over 38 degrees Celsius. All other cases were defined as nonIPL. IPL was observed in 5 cases (2.9%) that were classified as CD grade II in 2 cases, IIIa in 2 cases, and IVa in 1 case. The most severe case (CD grade IVa) required temporary dialysis for acute renal failure during conservative treatment. While the dissected lymph nodes in the IPL group were sificantly greater than those in the nonlPL group (20.8 ± 7.1 vs 10.3 ± 6.0, P = 0.0298) and the preoperative prostate specific antigen in the IPL group was significantly higher than that in the nonIPL group (15.6 ± 21.7 ng/ml vs 9.0 ± 6.1 ng/ml, P = 0.0359), there were no significant differences in the other background factors between the two groups. In the multivariate analysis, the number of dissected lymph nodes was an independent predictive factor for IPL. While the incidences of IPL after RARP were low, the number of dissected lymph nodes was related to IPL.

[Second Transurethral Resection (TUR) for Bladder Cancer Diagnosed with High Grade pT1 by Initial TUR Under Narrow Band Imaging].

We evaluated 52 consecutive cases of patients undergoing second transurethral resections (TUR) for non-muscle invasive bladder cancer (NMIBC) in which the patients were diagnosed with high grade pT1 by the initial TUR under narrow band imaging (NBI). The initial TUR under NBI (NBI-TUR) was performed : Systematic intravesical observation under white light imaging (WLI) and NBI was followed by a multiple site biopsy (MSB), after which lesions detected in positive findings were resected completely under NBI. The tumor detection rates under WLI and NBI were calculated separately and compared with endoscopic findings and MSB samples. The second TUR was performed as a resection that included the surrounding mucosa and muscle layer of the initial NBI-TUR scar under WLI observation, 4-8 weeks after the initial NBI-TUR. The patients were divided into two groups : The residual cancer lesion-positive group (NBIR positive), and the residual cancer lesion-negative group (NBIR negative). The tumor detection rate under NBI was more sensitive compared with that under WLI in the initial NBI-TUR (89.4% vs 59.1% p< 0.0001), and the residual cancer detection rate in the 2nd TUR reached 34.6% (18/52). There was no significant difference in the background factors between the NBIR positive and NBIR negative. While the number of cancer lesions detected under NBI was significantly higher than that under WLI in the NMIBCdiagnosed high grade pT1, the rate of cancer lesions that were difficult to identify in the initial NBI-TUR was still high. These findings demonstrate the limitations of the mono-therapeutic effect of NBI-TUR.

[LAPAROSCOPIC RADICAL PROSTATECTOMY OF 926 PATIENTS AT THE HIROSHIMA ENDOUROLOGICAL ASSOCIATION].

(Objective) The aim of this study is to investigate the treatment outcome of laparoscopic radical prostatectomy (LRP). (Patients and methods) The study cohort consisted of 926 hormone-naïve patients with localized prostate cancer who underwent LRP at the Hiroshima Endourological Association from January 2007 to December 2016. (Results) The mean age was 69.4 years, the mean initial PSA was 9.1 ng/ml, and the mean follow-up period was 40.3 months. The D'Amico Risk Classification was Low: 232 cases, Intermediate: 344 cases, and High: 350 cases. Nerve preservation was performed bilaterally for 138 patients and unilaterally for 181 patients. The mean operative time was 181.0 minutes and the mean estimated blood loss was 360.7 ml. As the number of experienced cases increased, the operative time was significantly shorter and the estimated blood loss was significantly decreased. According to Clavien-Dindo classification, the ratio of perioperative complication degree IIIa or above was 4.0% (37 cases). The pathological results were Gleason score (GS) ≤6: 174 cases, GS7: 514 cases, GS ≥8: 232 cases, pT2≥: 704 cases, pT3a: 172 cases, pT3b: 47 cases, pT4: 3 cases, pN0: 917 cases, and pN1: 9 cases. Positive surgical margins were found in 278 cases (30.0%). The biochemical recurrence-free survival rate at 5 years was 78.1%. In multivariate analysis, age (≥70 yrs), initial PSA (≥10 ng/ml), biopsy GS (GS ≥8), cancer positive core ratio at biopsy (≥30%), pT (pT≥3), pathological GS (GS≥8), positive surgical margin and total number of patients in the facility were predictive factors of postoperative biochemical PSA recurrence. Younger age and nerve preservation were found to be predictive factors for the early recovery of urinary continence after surgery, with 88% regaining urinary continence at 12 months after surgery. (Conclusion) This study revealed the clinical outcome and appropriate candidates for LRP in Japanese patients.

Intrinsic Projections of Layer Vb Neurons to Layers Va, III, and II in the Lateral and Medial Entorhinal Cortex of the Rat.

Layer V of the entorhinal cortex (EC) receives input from the hippocampus and originates main entorhinal outputs. The deep-sublayer Vb, immunopositive for the transcription factor Ctip2, is thought to be the main recipient of hippocampal projections, whereas the superficial-sublayer LVa, immunonegative for Ctip2, originates the main outputs of EC. This disrupts the proposed role of EC as mediating hippocampal-cortical interactions. With the use of specific (trans)synaptic tracing approaches, we report that, in medial entorhinal cortex, layer Vb neurons innervate neurons in layers Va, II, and III. A similar circuitry exists in the lateral entorhinal cortex. We conclude that EC-layer Vb neurons mediate two circuits in the hippocampus-memory system: (1) a hippocampal output circuit to telencephalic areas by projecting to layer Va and (2) a feedback projection, sending information back to the EC-hippocampal loop via neurons in layers II and III.

Normalization of C-reactive protein levels following cytoreductive nephrectomy in patients with metastatic renal cell carcinoma treated with tyrosine kinase inhibitors is associated with improved overall survival.

INTRODUCTION AND OBJECTIVES: Pretreated C-reactive protein (CRP) has been suggested as one of the most important prognostic factors for metastatic renal cell carcinoma (mRCC). The aim of this study was to investigate the prognostic impact of the change in CRP level before and after cytoreductive nephrectomy (CN) in patients with mRCC treated with tyrosine kinase inhibitor. MATERIALS AND METHODS: The CRP in 60 patients undergoing molecular targeted therapy for mRCC was measured before and after CN. The cutoff value of CRP was determined to be 0.5mg/dl.; thus, all patients were classified into lower CRP groups and higher ones according to their CRP before CN. The higher CRP group was further classified into 2 groups based on the kinetics after CN, "normalized CRP group" and "nonnormalized CRP group," respectively. The overall survival (OS) of these groups was compared. RESULTS: The median of the observation period was 21.6 months. The OS of patients in the lower CRP, normalized CRP, and nonnormalized CRP groups were 28.6, 23.1, and 12.3 months, respectively (nonnormalized CRP group vs. others, P<0.0001). Multivariate analysis revealed that the postoperative CRP level (≥0.5mg/dl) (hazard ratio = 0.218; 95% CI: 0.091-0.522; P = 0.0006) was an independent predictive factor of OS. CONCLUSION: The CRP level after CN can be a predictive factor for OS in patients with mRCC treated with tyrosine kinase inhibitor.

Sex Differences in Risk Preference and c-Fos Expression in Paraventricular Thalamic Nucleus of Rats During Gambling Task.

Different biological requirements between males and females may cause sex differences in decision preference when choosing between taking a risk to get a higher gain or taking a lower but sure gain. Several studies have tested this assumption in rats, however the conclusion remains controversial because the previous real-world like gambling tasks contained a learning component to track a global payoff of probabilistic outcome in addition to risk preference. Therefore, we modified a simple gambling task allowing us to exclude such learning effect, and investigated the sex difference in risk preference of rats and its neural basis. The task required water deprived rats to choose between a risky option which provided four drops of water or no reward at a 50% random chance vs. a sure option which provided predictable amount x (x = 1, 2, 3, 4). The amount and the risk were explicitly instructed so that different choice conditions could be tested trial by trial without re-learning of reward contingency. Although both sexes correctly chose the sure option with the same level of accuracy when the sure option provided the best offer (x = 4), they exhibited different choice performances when two options had the same expected value (x = 2). Males and females both preferred to take risky choices than sure choices (risk seeking), but males were more risk seeking than females. Outcome-history analysis of their choice pattern revealed that females reduced their risk preference after losing risky choices, whereas males did not. Rather, as losses continued, reaction time for subsequent risky choices got shorter in males. Given that significant sex difference features mainly emerged after negative experiences, male and female rats may evaluate an unsuccessful outcome of their decision in different manners. Furthermore, c-Fos expression in the paraventricular nucleus of the thalamus (PV) was higher in the gambling task than for the control task in males while c-fos levels did not differ in females. The present study provides a clear evidence of sex differences in risk preference in rats and suggests that the PV is a candidate region contributing to sex differences in risky decision making.

[Clinical Benefits of Transurethral Resection Under Narrow Band Imaging for Non-Muscle Invasive Bladder Cancer].

The aim of this study was to reveal the clinical benefits of transurethral resection (TUR) under narrow band imaging (NBI-TUR) for non-muscle-invasive bladder cancer (NMIBC) compared with conventional white light imaging TUR (WLI-TUR). The subjects were 172 patients with NMIBC who were followed for more than 1 year after undergoing TUR with no additional postoperative treatment. In the WLI-TUR group (n=101), lesions that were detected as positive after systematic intravesical observation under WLI were resected completely under WLI. In the NBI-TUR group (n=71), similar observations under WLI were followed by systematic intravesical observation under NBI. After multiple site biopsy under NBI, TUR was performed for all lesions that were detected as positive under NBI. The sensitivity was calculated based on the results of cystoscopy and pathology of multiple site biopsy samples under WLI and NBI in the NBITUR group. The tumor recurrence rate was analyzed in both groups. Background factors did not differ significantly between the two groups, except for the observation period (63.3 months in the WLI-TUR group vs 42.0 months in the NBI-TUR group, p<0.01). The procedure under NBI had significantly higher sensitivity (94.6% vs 75.0%, p<0.01) compared with that under WLI. The recurrence-free rate in the NBITUR group was significantly higher than that in the WLI-TUR group (p=0.013). The tumor recurrencefree rate of NBI-TUR is higher than that of conventional WLI-TUR for patients with NMIBC.

[LAPAROSCOPIC RADICAL CYSTECTOMY AT HIROSHIMA CITY ASA HOSPITAL].

(Objective) To evaluate the utility of laparoscopic radical cystectomy (LRC), we retrospectively compared the background factors and perioperative parameters of LRC with those of open radical cystectomy (ORC). (Patients and methods) The study cohort consisted of 116 consecutive patients who underwent radical cystectomy by LRC (n=59) or ORC (n=57). The background factors and perioperative parameters were compared between LRC and ORC. (Results) The patients consisted of 103 men and 13 women with a median age of 69 years and median BMI of 23.0. Their clinical stage was as follows, ≤T1: 19 cases, T2: 69 cases, T3: 25 cases and T4: 3 cases, respectively.While the patients' age at the time of LRC was significantly higher than that of ORC (71.3 yrs vs. 66.2 yrs, P<0.001) and the ASA physical status of LRC was significantly higher than that of ORC (P=0.028), the other background factors were not different between the two groups.Although there was no difference in the total operating time between LRC and ORC, the estimated blood loss for LRC was significantly less than that for ORC (372.3 ml vs. 2,134.5 ml, P<0.001) and the duration of the postoperative hospital stay for LRC was significantly shorter than that for ORC (23.5 days vs. 36.9 days, P<0.001).There were no significant differences in the pathological findings, of the postoperative recurrence-free rate or cancer-specific survival rate between the LRC and ORC groups. In multivariate analysis, only pN+was an independent predictive factor of postoperative recurrence. (Conclusion) This study showed that LRC is less invasive and can lead to similar oncological outcomes compared with ORC.