Bridging horizons beyond CIRCULATE-Japan: a new paradigm in molecular residual disease detection via whole genome sequencing-based circulating tumor DNA assay.

Circulating tumor DNA (ctDNA) is the fraction of cell-free DNA in patient blood that originates from a tumor. Advances in DNA sequencing technologies and our understanding of the molecular biology of tumors have increased interest in exploiting ctDNA to facilitate detection of molecular residual disease (MRD). Analysis of ctDNA as a promising MRD biomarker of solid malignancies has a central role in precision medicine initiatives exemplified by our CIRCULATE-Japan project involving patients with resectable colorectal cancer. Notably, the project underscores the prognostic significance of the ctDNA status at 4 weeks post-surgery and its correlation to adjuvant therapy efficacy at interim analysis. This substantiates the hypothesis that MRD is a critical prognostic indicator of relapse in patients with colorectal cancer. Despite remarkable advancements, challenges endure, primarily attributable to the exceedingly low ctDNA concentration in peripheral blood, particularly in scenarios involving low tumor shedding and the intrinsic error rates of current sequencing technologies. These complications necessitate more sensitive and sophisticated assays to verify the clinical utility of MRD across all solid tumors. Whole genome sequencing (WGS)-based tumor-informed MRD assays have recently demonstrated the ability to detect ctDNA in the parts-per-million range. This review delineates the current landscape of MRD assays, highlighting WGS-based approaches as the forefront technique in ctDNA analysis. Additionally, it introduces our upcoming endeavor, WGS-based pan-cancer MRD detection via ctDNA, in our forthcoming project, SCRUM-Japan MONSTAR-SCREEN-3.

Comparison of mirabegron and vibegron for clinical efficacy and safety in female patients with overactive bladder: a multicenter prospective randomized crossover trial.

PURPOSE: To compare the efficacy and safety of mirabegron and vibegron in female OAB patients. METHODS: We conducted a multicenter, prospective, randomized crossover study of female patients with OAB. The patients were assigned to Group MV (mirabegron for 8 weeks, followed by vibegron for 8 weeks) or group VM (vibegron for 8 weeks, followed by mirabegron for 8 weeks). The primary endpoint was the change in OABSS from baseline, and the secondary endpoint was the change in FVC parameters. After completion of the study, each patient was asked which drug was preferable. RESULTS: A total of 83 patients were enrolled (40 and 43 in groups MV and VM, respectively). At 8th and 16th week, 33 and 29 in Group MV and 34 and 27 in Group VM continued to receive the treatment. The change in PVR was not significantly different between treatment with mirabegron and vibegron. The changes in OABSS, nighttime frequency, mean, and maximum voided volume were similar between mirabegron and vibegron. The mean change in the daytime frequency was greater in the vibegron than in the mirabegron. Of the 56 patients, 15 (27%) and 30 (53%) preferred mirabegron and vibegron, respectively. The remaining 11 patients (20%) showed no preference. The change in the urgency incontinence score during vibegron was better in patients who preferred vibegron to mirabegron. CONCLUSION: The efficacies of mirabegron and vibegron in female patients was similar. The patients' preference for vibegron could depend on the efficacy of vibegron for urgency incontinence.

Ischemic priapism caused by self intracavernous injection of tadalafil.

Introduction: We present a case of ischemic priapism caused by self intracavernous injection of tadalafil. Case presentation: A 77-year-old man developed priapism due to self-injection of tadalafil into the corpus cavernosum. He presented to our hospital 2 days after the development of priapism and severe penile pain. The blood gas analysis of the corpus cavernosum revealed ischemic priapism. At first, we performed percutaneous distal shunt (T-shunt) and cavernosal irrigation, resulting in slight improvement of penile tumescence. Several hours later, penile tumescence and severe pain reappeared. Bilateral proximal (corpora-spongiosal) shunt was performed under anesthesia again. Penile tumescence was slowly and gradually relieved. His erectile function was declined. Conclusion: We experienced a case of priapism due to self intracavernous administration of tadalafil who needed a proximal shunt to relieve the severe penile pain. This case report may serve as a warning for physicians and patients not to use phosphodiesterase 5 inhibitor inappropriately.

Intraoperative artificial intelligence system identifying liver vessels in laparoscopic liver resection: a retrospective experimental study.

BACKGROUND: The precise recognition of liver vessels during liver parenchymal dissection is the crucial technique for laparoscopic liver resection (LLR). This retrospective feasibility study aimed to develop artificial intelligence (AI) models to recognize liver vessels in LLR, and to evaluate their accuracy and real-time performance. METHODS: Images from LLR videos were extracted, and the hepatic veins and Glissonean pedicles were labeled separately. Two AI models were developed to recognize liver vessels: the "2-class model" which recognized both hepatic veins and Glissonean pedicles as equivalent vessels and distinguished them from the background class, and the "3-class model" which recognized them all separately. The Feature Pyramid Network was used as a neural network architecture for both models in their semantic segmentation tasks. The models were evaluated using fivefold cross-validation tests, and the Dice coefficient (DC) was used as an evaluation metric. Ten gastroenterological surgeons also evaluated the models qualitatively through rubric. RESULTS: In total, 2421 frames from 48 video clips were extracted. The mean DC value of the 2-class model was 0.789, with a processing speed of 0.094 s. The mean DC values for the hepatic vein and the Glissonean pedicle in the 3-class model were 0.631 and 0.482, respectively. The average processing time for the 3-class model was 0.097 s. Qualitative evaluation by surgeons revealed that false-negative and false-positive ratings in the 2-class model averaged 4.40 and 3.46, respectively, on a five-point scale, while the false-negative, false-positive, and vessel differentiation ratings in the 3-class model averaged 4.36, 3.44, and 3.28, respectively, on a five-point scale. CONCLUSION: We successfully developed deep-learning models that recognize liver vessels in LLR with high accuracy and sufficient processing speed. These findings suggest the potential of a new real-time automated navigation system for LLR.

Survival outcome of patient with pT1N0 biliary tract cancer treated with surgery alone.

INTRODUCTION: Adjuvant chemotherapy (AC) with S-1 or capecitabine monotherapy is now the standard of care for resected biliary tract cancer (BTC) according to the Adjuvant S-1 for Cholangiocarcinoma Trial (ASCOT) and the BILCAP study. Patients selection criteria, especially regarding pT1N0 BTC, differed in both trials. We aimed to clarify the survival outcomes regarding resected pT1N0 BTC without AC. METHODS: Among patients with macroscopically complete resection for BTC treated without AC between September 1992 and December 2020, the survival outcomes of those with pT1N0 BTC, except for intrahepatic cholangiocarcinoma, according to the Union for International Cancer Control 7th and 8th edition (TNM7 and 8), were investigated. RESULTS: Of 749 patients who underwent curative resection for BTC, 69 were identified as having pT1N0 BTC according to TNM8. Six patients (9 %) developed recurrence during the median follow-up period of 53 months (range: 14-263 months) with only one patient (2 %) being pT1N0 according to TNM7. Based on TNM8, the 5-year recurrence-free survival, disease-specific survival, and overall survival reached 90.7 % (95 % confidence interval [CI]: 80.3-95.7 %), 96.4 % (95 % CI: 86.1-99.1 %), and 85.3 % (95 % CI: 71.2-92.8 %), respectively. Perineural invasion (PNI) was significantly associated with recurrence, and the recurrence rate in patients with PNI reached as high as 40 %. CONCLUSIONS: The survival outcomes regarding resected pT1N0 BTC according to TNM7 were excellent without AC; however, those of TNM8 were not, with PNI being associated with recurrence risk.

Internet research of utilization of social media in patients with urological disease and their families in Japan.

OBJECTIVES: To survey the utilization of social media (SoMe) in patients with urological disease and their families. METHODS: Among the panel members registered in NEO Marketing Inc. (Tokyo, Japan), 300 people who or whose families were visiting the urological department regularly were included. Study subjects were randomly chosen and surveyed using the questionnaire over the internet. RESULTS: This study included 203 (68%) males and 97 (32%) females. The mean age was 62 (21-85) in males and 49 (22-75) in females. One hundred and ten subjects (37%) had no account for any SoMe. The account holders of YouTube, Twitter, Facebook, Instagram, and TikTok were 119 (40%), 117 (39%), 101 (34%), 90 (30%), and 33 (11%), respectively. The proportions of account holders were different depending on gender, age, and platforms. Frequent viewers on YouTube, Twitter, Facebook, Instagram, and TikTok were 100 (84%), 89 (76%), 63 (62%), 66 (73%), and 24 (73%), respectively. Of 190 who had accounts for any SoMes, 64 (34%) found any information about urological diseases of themselves or their families. Among the all subjects, 162 (54%) thought that they would like to view the medical contents on SoMes submitted by medical societies. CONCLUSIONS: Patients with urological disease and their families in Japan occasionally utilize SoMe to obtain information on their diseases and prefer professional medical information on SoMe. The gender and age of SoMe users and the optimal platform should be considered when posting medical information on SoMe.

NEXUS trial: a multicenter phase II clinical study evaluating the efficacy and safety of the perioperative use of encorafenib, binimetinib, and cetuximab in patients with previously untreated surgically resectable BRAF V600E mutant colorectal oligometastases.

BACKGROUND: The optimal treatment strategy for resectable BRAF V600E mutant colorectal oligometastases (CRM) has not been established due to the rarity and rapid progression of the disease. Since the unresectable recurrence rate is high, development of novel perioperative therapies are warranted. On December 2020, the BEACON CRC triplet regimen of encorafenib, binimetinib, and cetuximab was approved for unresectable metastatic colorectal cancer in Japan. METHODS: The NEXUS trial is a multicenter phase II clinical study evaluating the efficacy and safety of the perioperative use of encorafenib, binimetinib, and cetuximab in patients with previously untreated surgically resectable BRAF V600E mutant CRM. The key inclusion criteria are as follows: histologically diagnosed with colorectal adeno/adenosquamous carcinoma; RAS wild-type and BRAF V600E mutation by tissue or blood; and previously untreated resectable distant metastases. The triplet regimen (encorafenib: 300 mg daily; binimetinib: 45 mg twice daily; cetuximab: 400 mg/m2, then 250 mg/m2 weekly, 28 days/cycle) is administered for 3 cycles each before and after curative resection. The primary endpoint of the study is the 1-year progression-free survival (PFS) rate and the secondary end points are the PFS, disease-free survival, overall survival, and objective response rate. The sample size is 32 patients. Endpoints in the NEXUS trial as well as integrated analysis with the nationwide registry data will be considered for seeking regulatory approval for the perioperative use of the triplet regimen. DISCUSSION: The use of the triplet regimen in the perioperative period is expected to be safe and effective in patients with resectable BRAF V600E mutant CRM. TRIAL REGISTRATION: jRCT2031220025, April. 16, 2022.

Proteogenomic identification of an immunogenic antigen derived from human endogenous retrovirus in renal cell carcinoma.

CD8+ T cells can recognize tumor antigens displayed by HLA class I molecules and eliminate tumor cells. Despite their low tumor mutation burden, immune checkpoint blockade (ICB) is often beneficial in patients with renal cell carcinoma (RCC). Here, using a proteogenomic approach, we directly and comprehensively explored the HLA class I-presenting peptidome of RCC tissues and demonstrated that the immunopeptidomes contain a small subset of peptides derived from human endogenous retroviruses (hERV). A comparison between tumor and normal kidney tissues revealed tumor-associated hERV antigens, one of which was immunogenic and recognized by host tumor-infiltrating lymphocytes (TIL). Stimulation with the hERV antigen induced reactive CD8+ T cells in healthy donor-derived (HD-derived) peripheral blood mononuclear cells (PBMC). These results highlight the presence of antitumor CD8+ T cell surveillance against hERV3895 antigens, suggesting their clinical applications in patients with RCC.

A Multicenter Survey on Eligibility for a Randomized Phase III Trial of Adjuvant Chemotherapy for Resected Biliary Tract Cancer (JCOG1202, ASCOT).

BACKGROUND: The Adjuvant S-1 for Cholangiocarcinoma Trial (JCOG1202, [ASCOT]) was a multicenter, randomized controlled trial aimed at investigating the efficacy and safety of adjuvant chemotherapy (AC) with S-1 for resected biliary tract cancer (BTC). This trial reported that overall survival was prolonged with AC compared with observation. METHODS: With the aim of increasing enrollment, the present survey biannually recorded the number of patients eligible for enrollment into ASCOT and reasons for ineligibility among patients who had undergone surgery for BTC from April 2015 to September 2017 at 36 institutions participating in ASCOT. RESULTS: Of 2039 patients who underwent surgery for BTC, 211 (10.3%) were already enrolled, 166 (8.1%) were eligible but had not been enrolled, and 1662 (81.5%) were ineligible. Among ineligible patients, the predominant reasons for ineligibility were patient refusal (n = 332, 20.0%), pathologic stage (pT1N0; n = 248, 14.9%), age (≥ 81 years; n = 196, 11.8%), and prolonged postoperative complications (n = 176, 10.6%). CONCLUSIONS: Patients undergoing surgery for BTC are a heterogeneous cohort comprising patients with earlier pathologic stage, advanced age, and prolonged postoperative complications. These factors should be considered during the design of future clinical trials of perioperative treatments for resectable BTC.

Liver functional assessment using time-associated change in the liver-to-spleen signal intensity ratio on enhanced magnetic resonance imaging: a retrospective study.

BACKGROUND: Liver-to-spleen signal intensity ratio (LSR) is evaluated by magnetic resonance imaging (MRI) in the hepatobiliary phase and has been reported as a useful radiological assessment of regional liver function. However, LSR is a passive (non-time-associated) assessment of liver function, not a dynamic (time-associated) assessment. Moreover, LSR shows limitations such as a dose bias of contrast medium and a timing bias of imaging. Previous studies have reported the advantages of time-associated liver functional assessment as a precise assessment of liver function. For instance, the indocyanine green (ICG) disappearance rate, which is calculated from serum ICG concentrations at multiple time points, reflects a precise preoperative liver function for predicting post-hepatectomy liver failure without the dose bias of ICG or the timing bias of blood sampling. The aim of this study was to develop a novel time-associated radiological liver functional assessment and verify its correlation with traditional liver functional parameters. METHODS: A total of 279 pancreatic cancer patients were evaluated to clarify fundamental time-associated changes to LSR in normal liver. We defined the time-associated radiological assessment of liver function, calculated using information on LSR from four time points, as the "LSR increasing rate" (LSRi). We then investigated correlations between LSRi and previous liver functional parameters. Furthermore, we evaluated how timing bias and protocol bias affect LSRi. RESULTS: Significant correlations were observed between LSRi and previous liver functional parameters such as total bilirubin, Child-Pugh grade, and albumin-bilirubin grade (P < 0.001 each). Moreover, considerably high correlations were observed between LSRi calculated using four time points and that calculated using three time points (r > 0.973 each), indicating that the timing bias of imaging was minimal. CONCLUSIONS: This study propose a novel time-associated radiological assessment, and revealed that the LSRi correlated significantly with traditional liver functional parameters. Changes in LSR over time may provide a superior preoperative assessment of regional liver function that is better for predicting post-hepatectomy liver failure than LSR using the hepatobiliary phase alone.

Relationships between physical and immunological tumor microenvironment in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is physically palpated as a hard tumor with an unfavorable prognosis. Assessing physical features and their association with pathological features could help to elucidate the mechanism of physical abnormalities in cancer tissues. A total of 93 patients who underwent radical surgery for pancreatic and bile duct cancers at a single center hospital during a 28-month period were recruited for this study that aimed to estimate the stiffness of PDAC tissues compared to the other neoplasms and assess relationships between tumor stiffness and pathological features. Physical alterations and pathological features of PDAC, with or without preoperative therapy, were analyzed. The immunological tumor microenvironment was evaluated using multiplexed fluorescent immunohistochemistry. The stiffness of PDAC correlated with the ratio of Azan-Mallory staining, α-smooth muscle actin, and collagen I-positive areas of the tumors. Densities of CD8+ T cells and CD204+ macrophages were associated with tumor stiffness in cases without preoperative therapy. Pancreatic ductal adenocarcinoma treated with preoperative therapy was softer than that without, and the association between tumor stiffness and immune cell infiltration was not shown after preoperative therapy. We observed the relationship between tumor stiffness and immunological features in human PDAC for the first time. Immune cell densities in the tumor center were smaller in hard tumors than in soft tumors without preoperative therapies. Preoperative therapy could alter physical and immunological aspects, warranting further study. Understanding of the correlations between physical and immunological aspects could lead to the development of new therapies.

[Pre-Operative Factors Affecting Trifecta Achievement in the Initial Series of Robot-Assisted Partial Nephrectomy].

We investigated pre-operative factors affecting trifecta achievement in robot-assisted partial nephrectomy (RAPN). We retrospectively analyzed 81 patients who underwent RAPN from December 2016 to September 2021 with final malignant pathologies. Trifecta was defined as negative resection margin (RM),warm ischemic time (WIT) less than 25 minutes, and no severe perioperative complications (Clavien-Dindo＜III). Factors affecting trifecta achievement were analyzed using sex, age, body mass index, RENAL nephrometry score (low or moderate/high complexity), surgical approach (transabdominal or retroperitoneal), tumor diameter and surgical experiences of each surgeon. Negative RM, WIT less than 25 minutes, and no severe complications were obtained in 75 (93%), 65 (80%), and 79 patients (98%), respectively. The trifecta was achieved in 60 patients (74%). In multivariate regression analysis, surgical experience (OR:0.92, 95% CI : 0.86-0.99) was significantly associated with trifecta achievement. Receiver operating characteristic curve analysis identified 9 cases as the optimal cut-off values for the predication of trifecta achievement (AUC＝0.69,p ＝0.11). The achievement of WIT less than 25 minutes (65 vs 90%, p＜0.01) and trifecta (58 vs 84%,p ＜0.05) were significantly lower in surgical experiences less than 9 cases than in 9 or greater. We conclude that surgical experience in RAPN is an important factor affecting WIT and trifecta achievement in the initial series.

A novel predictive model for postoperative delirium using multiple geriatric screening factors.

OBJECTIVES: The purpose of this study was to develop a new composite score to accurately predict postoperative delirium (POD) after major urological cancer surgery. METHODS: Our retrospective analysis included, in total, 449 consecutive patients who experienced major urological cancer surgery and a preoperative geriatric functional assessment at our institution (development cohort). Geriatric functional assessments included Geriatric 8, Instrumental Activities of Daily Living, and mini-cognitive assessment instrument (Mini-Cog). Multivariate analysis was used to identify factors related to POD and combined to create a predictive score. The composite score was externally validated using a cohort of 92 consecutive pancreatic cancer patients who underwent pancreaticoduodenectomy and a preoperative geriatric functional assessment (validation cohort). The predictive accuracy and performance of the composite score were evaluated using the area under the receiver operating characteristic curves (AUC) and calibration plots. RESULTS: In multivariate analysis of a development cohort, the following factors were significantly associated with POD: a Mini-Cog score of <3 (odds ratio [OR] = 9.5; p < 0.001), disability in the responsibility for medication (OR = 4.1; p = 0.03), and the preoperative use of benzodiazepine (OR = 6.4; p < 0.001). The composite score of these three factors showed excellent discrimination in predicting POD, with AUC values of 0.819 and 0.804 in development and validation cohorts, respectively. Calibration plots showing predicted probability and actual observation in both cohorts showed good agreement. CONCLUSIONS: A combined model of Mini-Cog, a disability in the responsibility for medication, and preoperative benzodiazepine use showed excellent discriminative power in predicting POD.

Comprehensive data of 4502 patients newly diagnosed with colorectal liver metastasis between 2015 and 2017, and prognostic data of 2427 patients newly diagnosed with colorectal liver metastasis in 2013 and 2014: Third report of a nationwide survey in Japan.

To improve treatment outcomes in patients with colorectal liver metastasis (CRLM), the Joint Committee for Nationwide Survey on CRLM was established by the Japanese Society for Cancer of the Colon and Rectum and the Japanese Society of Hepato-Biliary-Pancreatic Surgery. The aim of the study was to evaluate transition in the characteristics and treatment strategy in CRLM patients and analyze prognostic factors using large-scale data. The present study summarizes the data of patients newly diagnosed between 2015 and 2017 and presents prognostic data of patients newly diagnosed in 2013 and 2014. Survival curves were generated by the Kaplan-Meier method and compared by log-rank test. Multivariate analyses were carried out using Cox proportional hazard modeling. The data of 4502 patients newly diagnosed with CRLM between 2015 and 2017 and the prognostic data of 2427 patients diagnosed in 2013 and 2014 are included. Regarding the 2013 and 2014 prognostic data, the 5-year overall survival (OS) rates of patients who underwent hepatectomy alone was 59.8%. Multivariate analyses identified age at diagnosis of CRLM ≥70 years, concomitant extrahepatic metastasis at diagnosis of CRLM, tumor depth of primary lesion ≥subserosa/pericolic or perirectal tissue, mutant KRAS status, number of CRLM ≥5, maximum diameter of CRLM >5 cm, and surgical curability R1/R2 as independent predictors of OS. Analysis of the latest nationwide database of patients diagnosed with CRLM revealed changes in patients and oncological characteristics, a transition in treatment strategy, and different independent prognosticators to those reported previously.

Validation study of the JSHBPS nomogram for patients with colorectal liver metastases who underwent hepatic resection in the recent era - a nationwide survey in Japan.

BACKGROUND: The Japanese Society of Hepato-Biliary-Pancreatic Surgery (JSHBPS) nomogram was developed to predict disease-free survival in patients with colorectal liver metastases (CRLM) undergoing upfront hepatectomy. However, the utility of the nomogram in patients with resected CRLM remains unknown in the current situation in which treatment strategies are changing with advances in drugs. METHODS: Patients in the initial nomogram cohort (n = 727) and validation cohort (n = 2225) were divided into the upfront hepatectomy and preoperative chemotherapy groups. The nomogram was validated by measuring calibration and discrimination in the two cohorts. Calibration curves were plotted, and survival probabilities were compared. Finally, to quantify the discrimination power, we estimated the concordance index (C-index). RESULTS: In the upfront hepatectomy group, the C-index was 0.63, the suitable cutoff value of the Beppu score was 7, and adjuvant chemotherapy was significantly effective limited to high-risk patients (Beppu score ≥7). The C-index was 0.56 in the preoperative chemotherapy group. CONCLUSIONS: The JSHBPS nomogram remains beneficial for patients undergoing upfront hepatectomy in the recent era but is less effective for patients undergoing hepatectomy after chemotherapy. Patients with a Beppu score ≥7 showed high-risk recurrence, and adjuvant chemotherapy should be recommended for these patients.

Early postoperative decrease of skeletal muscle mass predicts recurrence and poor survival after surgical resection for perihilar cholangiocarcinoma.

BACKGROUND: Preoperative sarcopenia is a predictor of poor survival in cancer patients. We hypothesized that sarcopenia could progress as occult metastasis arose, especially after highly invasive surgery for highly aggressive malignancy. This study aimed to evaluate the associations of postoperative changes in skeletal muscle mass volume with survival outcomes in patients who underwent surgery for perihilar cholangiocarcinoma. METHODS: Fifty-six patients who underwent major hepatectomy with extrahepatic bile duct resection for perihilar cholangiocarcinoma were studied. The skeletal muscle index (SMI) at the third lumbar vertebra was calculated from axial computed tomography images taken preoperatively and 3-6 months postoperatively (early postoperative period). The associations of clinicopathological variables, including changes of SMI after surgery, with overall survival and recurrence-free survival were evaluated. Moreover, the associations of decreased SMI and elevated serum carbohydrate antigen 19-9 level with early recurrence and poor survival was compared. RESULTS: Among 56 patients, 26 (46%) had sarcopenia preoperatively and SMI decreased in 29 (52%) in the early postoperative period. During the median follow-up of 57.9 months, 35 patients (63%) developed recurrence and 29 (50%) died. Decreased SMI in the early postoperative period was independently associated with a shorter overall survival (hazard ratio, 2.39; 95% confidence interval, 1.00-6.18; P = 0.049) and a shorter recurrence-free survival (hazard ratio, 2.14; 95% confidence interval, 1.04-4.57; P = 0.039), whereas elevated carbohydrate antigen 19-9 level was not. CONCLUSIONS: Decreased SMI in the early postoperative period may be used as a predictor for recurrence and poor survival in patients undergoing surgery for perihilar cholangiocarcinoma.

[Comparison of Perioperative Outcomes between Open and Robot-Assisted Laparoscopic Radical Cystectomy].

We compared the perioperative outcomes of open (ORC) and robot-assisted laparoscopic radical cystectomy (RARC) for patients with bladder cancer. We retrospectively investigated the intraoperative and 90-day postoperative complications of ORC and RARC performed from March 2014 to September 2021 based on the medical records. Perioperative complications were categorized according to the Clavien- Dindo classification. We used the propensity score matching to adjust for the inherent bias of the different patient characteristics at baseline including gender, age, preoperative chemotherapy, and pathological T classification. Surgery time of RARC was significantly shorter than that of ORC, and blood transfusion was significantly less frequent in RARC than in ORC (3% vs 81%, p＜0.01). The rate of overall complications of Grade III/IV was lower in RARC (8%) than in ORC (25%) (P＝0.09). The prevalence of perioperative urinary tract infection, ileus, and abscess/infectious cyst was similar in ORC and RARC. In patients who underwent RARC, the complication rate was similar in extracorporeal and intracorporeal urinary diversion. Compared to ORC, RARC is more beneficial to reduce blood loss and severe complications.

Automated surgical workflow identification by artificial intelligence in laparoscopic hepatectomy: Experimental research.

BACKGROUND: To perform accurate laparoscopic hepatectomy (LH) without injury, novel intraoperative systems of computer-assisted surgery (CAS) for LH are expected. Automated surgical workflow identification is a key component for developing CAS systems. This study aimed to develop a deep-learning model for automated surgical step identification in LH. MATERIALS AND METHODS: We constructed a dataset comprising 40 cases of pure LH videos; 30 and 10 cases were used for the training and testing datasets, respectively. Each video was divided into 30 frames per second as static images. LH was divided into nine surgical steps (Steps 0-8), and each frame was annotated as being within one of these steps in the training set. After extracorporeal actions (Step 0) were excluded from the video, two deep-learning models of automated surgical step identification for 8-step and 6-step models were developed using a convolutional neural network (Models 1 & 2). Each frame in the testing dataset was classified using the constructed model performed in real-time. RESULTS: Above 8 million frames were annotated for surgical step identification from the pure LH videos. The overall accuracy of Model 1 was 0.891, which was increased to 0.947 in Model 2. Median and average accuracy for each case in Model 2 was 0.927 (range, 0.884-0.997) and 0.937 ± 0.04 (standardized difference), respectively. Real-time automated surgical step identification was performed at 21 frames per second. CONCLUSIONS: We developed a highly accurate deep-learning model for surgical step identification in pure LH. Our model could be applied to intraoperative systems of CAS.