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Median age, years (IQR)Median BMI, Kg/m2 (IQR)Median initial PSA, ng/mL (IQR)Median prostate volume, mL (IQR)Clinical stagecT1cT2acT2bcT2ccT3acT3b≧Patients’ characteristicsIQR: interquartile ranges BMI: body mass index PSA: prostate- specific antigenA: RRP (n=35)71 (66-75)23.9 (22.0-25.0)8.42 (6.0-11.0)32.0 (24.1-44.6)1 (3%)20 (57%)3 (8%)9 (26%)2 (6%)0 (0%)B: RARP (n=46)70 (63-75)24.1 (22.8-26.3)9.86 (5.76-16.8)27.6 (21.0-44.3)2 (4%)21 (46%)7 (15%)10 (22%)4 (9%)2 (4%)538performed.The subjects were patients who underwent RP for localized PC at Juntendo University Nerima Hospital from March 2017 to December 2020. Patients have been newly diagnosed with clinically localised prostate cancer and have chosen surgery as their treatment approach. Clinicopathological information on these patients was extracted from their medical records. Patients who underwent RP were retrospectively divided into 2 groups RRP and RARP. In this study, open RRP was performed in the standard fashion via retrograde dissection of the prostate gland, and 1 surgeon performed RARP in a standard fashion, using the DaVinci X system (Intuitive Surgical, Sunnyvale, CA, USA). Patients who had a follow-up of <4 months were excluded from this study. Collected data consisted of preop-erative variables including the age, body mass index (BMI), serum prostate specific antigen (PSA) at diagnosis, and clinical tumor stage. Perioperative factors analyzed in this study included the total operative time, EBL, and hospi-talization. Complications were recorded using the Dindo modification of the Clavien Grading System.5) The recovery of incontinence was either safe-ty-pad only or pad-free. Oncological outcomes were assessed by surgical margin status. Positive surgical margin (PSM) defined that was cancer at the edge of the RP resection specimen. Statistical analysis was performed using JMP (version 11.0, Table 1　Comparison of preoperative characteristics between the 2 groupsSAS Institute Inc., Cary, NC, USA). Categorical variables were compared using t-test, Mann-Whitney U test, and Pearson’s chi-square test, and logistic regression analysis was used for univariate analysis. This retrospective clinical study protocol conforms to the ethical guidelines of the 1975 Decla-ration of Helsinki as reflected in a priori approval by the institutions human research committee. This study involved clinical data comparisons was used with consent from participants and was approved by the Institutional Review Board of Juntendo University Nerima Hospital (N21-0013). Between March 2017 and December 2020, 81 men were diagnosed with PC, of whom 35 under-went open RRP and 46 underwent RARP. Patient characteristics are summarised in Table 1. Patients underwent RARP have the higher level of initial-PSA (P = 0.018) (Table 1). But there was no significant difference on age, BMI and prostate volume between the RARP and RRP group. (Table 1). Significantly more patients underwent neurovascular bundle preservation during RARP (31% vs 6%), and no significantly difference on extent lymph node dissection were performed (9% vs 11%). Perioperative EBL was less and the oper-ative time and the length of hospital stay (LOS) was shorter in the RARP group (Table 2). Bleeding requiring transfusion were the only RRP group and the severe postoperative complication rates among two groups were higher in RRP group (Table 2). P-value0.5320.0570.0180.2720.66MethodsResult