Impact of surgical proximal and distal margins on the recurrence of resectable colon cancer: a single-center observational cohort study.

PURPOSE: Few studies have investigated the impact of the surgical proximal and distal margins on colon cancer recurrence. We conducted this study to investigate the effect of resection margins on the prognosis of resectable colon cancer. METHODS: We analyzed data on 1458 patients who underwent colorectal resection in our institute between January, 2004 and March, 2020, including 579 patients with resectable colon cancer. The association between the resection margin and recurrence for each oncological status was assessed and the value of the resection length that influenced recurrence was analyzed. RESULTS: Patients who had pT4 colon cancer with margins of more than 7 cm had a trend of fewer recurrences and longer relapse-free survival (RFS) than those with colon cancer of other stages (P = 0.033; hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.20-0.89). Multivariate analysis identified a margin of < 7 cm as an independent risk factor for RFS in patients with pT4 colon cancer (P = 0.023; HR, 2.65; 95% CI 1.013-6.17). No correlation was found between resection margins and recurrence, depending on the extent of lymph node metastasis and tumor location. CONCLUSION: A resection margin of at least 7 cm should be maintained for patients with pT4 colon cancer.

Evaluation of gastric tube blood flow by multispectral camera and fluorescence angiography.

Background: Evidence regarding the application of the multispectral camera for blood flow measurement is insufficient, and its performance has not been compared with the conventional indocyanine green (ICG) method. Therefore, we retrospectively compared the effectiveness of a new multispectral camera for non-invasive, real-time, quantitative imaging of tissue oxygen (O2) saturation and hemoglobin (Hb) levels and commercially available ICG fluorescence imaging in hemodynamic assessment of gastric tubes in esophagectomy. Methods: Thirty patients who underwent thoracoscopic esophagectomy and gastric tube reconstruction for esophageal cancer were included in this study. The multispectral camera was used to measure tissue O2 saturation and Hb levels. The ICG fluorescence imaging, with the analysis software tool Lumi view, was employed to record ICG luminance changes, with values measured at the anastomotic site. Furthermore, the usefulness of each assessment device was examined using the arterial and venous blood flow indices as cutoff lines for cases with anastomotic failure. Results: In the evaluation of arterial perfusion, anastomotic leak occurred in three of the five (60 %) patients with arterial insufficiency as assessed by the ICG imaging, while anastomotic leakage occurred in all three patients (100 %) who were assessed as having arterial insufficiency by the multispectral camera. In the evaluation of venous perfusion, anastomotic leakage occurred in three of the nine (33.3 %) patients diagnosed with venous stasis by the IC imaging and in three of the five (60 %) patients assessed by the multispectral camera. Conclusion: The multispectral camera assessed gastric tube blood flow more accurately than the ICG fluorescence method.

Oxaliplatin-Based Adjuvant Chemotherapy in Older Patients With Stage III Colon Cancer: An ACCENT/IDEA Pooled Analysis of 12 Trials.

PURPOSE: A number of studies suggest that older patients may have reduced or no benefit from the addition of oxaliplatin to fluoropyrimidines as adjuvant chemotherapy for stage III colon cancer (CC). MATERIALS AND METHODS: We studied the prognostic impact of age, as well as treatment adherence/toxicity patterns according to age, in patients with stage III CC who received 3 or 6 months of infusional fluorouracil, leucovorin, and oxaliplatin/capecitabine and oxaliplatin (CAPOX) on the basis of data collected from trials from the ACCENT and IDEA databases. Associations between age and time to recurrence (TTR), disease-free survival (DFS), overall survival (OS), survival after recurrence (SAR), and cancer-specific survival (CSS) were assessed by a Cox model or a competing risk model, stratified by studies and adjusted for sex, performance status, T and N stage, and year of enrollment. RESULTS: A total of 17,909 patients were included; 24% of patients were age older than 70 years (n = 4,340). Patients age ≥70 years had higher rates of early treatment discontinuation. Rates of grade ≥3 adverse events were similar between those older and younger than 70 years, except for diarrhea and neutropenia that were more frequent in older patients treated with CAPOX (14.2% v 11.2%; P = .01 and 12.1% v 9.6%; P = .04, respectively). In multivariable analysis, TTR was not significantly different between patients <70 years and those ≥70 years, but DFS, OS, SAR, and CSS were significantly shorter in those patients ≥70 years. CONCLUSION: In patients ≥70 years with stage III CC fit enough to be enrolled in clinical trials, oxaliplatin-based adjuvant chemotherapy was well tolerated and led to similar TTR compared with younger patients, suggesting similar efficacy. TTR may be a more appropriate end point for efficacy in this patient population.

Clinicopathological significance of microsatellite instability and immune escape mechanism in patients with gastric solid-type poorly differentiated adenocarcinoma.

BACKGROUND: In gastric solid-type poorly differentiated adenocarcinoma (PDA), the role of microsatellite instability and immune escape mechanism remains unclear. The current study aimed to elucidate the clinical significance of mismatch repair (MMR) status, genome profile, C-X-C motif chemokine receptor 2 (CXCR2) expression, and myeloid-derived suppressor cell (MDSC) infiltration in solid-type PDA. METHODS: In total, 102 primary solid-type PDA cases were retrieved, and classified into 46 deficient-MMR (dMMR) and 56 proficient-MMR (pMMR) cases based on immunohistochemistry (IHC) and polymerase chain reaction-based molecular testing results. The mRNA expression profiles (NanoString nCounter Assay) of stage-matched dMMR (n = 6) and pMMR (n = 6) cases were examined. The CXCR2 expression and MDSC infiltration (CD11b- and CD33-positive cells) were investigated via IHC in all solid-type PDA cases. RESULTS: mRNA analysis revealed several differentially expressed genes and differences in biological behavior between the dMMR (n = 46) and pMMR (n = 56) groups. In the multivariate analysis, the dMMR status was significantly associated with a longer disease-free survival (hazard ratio = 5.152, p = 0.002) and overall survival (OS) (hazard ratio = 5.050, p = 0.005). CXCR2-high expression was significantly correlated with a shorter OS in the dMMR group (p = 0.018). A high infiltration of CD11b- and CD33-positive cells was significantly correlated with a shorter OS in the pMMR group (p = 0.022, 0.016, respectively). CONCLUSIONS: dMMR status can be a useful prognostic predictor, and CXCR2 and MDSCs can be novel therapeutic targets in patients with solid-type PDA.

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.

Tele-proctoring for minimally invasive surgery across Japan: An initial step toward a new approach to improving the disparity of surgical care and supporting surgical education.

Aim: The aim of this study was to verify the clinical feasibility of tele-proctoring using our ultra-low latency communication system with shared internet access. Methods: Connections between two multiple remote locations at various distances were established through the TELEPRO® tele-proctoring system. The server records the latency between the two locations for tele-proctoring using the annotations. Questionnaires were administered to the surgeons, assistants, and medical staff. Respondents rated the quickness and quality of communication in terms of latency and disturbances in the audio, video, and usefulness of the live telestrations with annotation. Results: Seven hospitals tele-proctored with Sapporo Medical University between January 2021 and September 2022. The median latency of annotation between the two locations ranged from 24.5 to 48.5 ms. No major technological problems occurred, such as streaming interruption, loss of video or audio, poor resolution. The video encoding time was 10 ms, and its decoding time was 0.8 ms. The total latency positively correlated with the distance between two locations (R = 0.55, p < 0.01). The quality of communication regarding latency, disturbance, and surgical education with intraoperative annotative instructions showed similar trends, with perfectly fine being the most common response. No significant differences in surgical quality, educational effect, or social impact were observed between the latency ≥30 and <30 ms groups for whether the size of latency affects surgical education. Conclusion: The feasibility of the tele-proctoring system is expected to be a sustainable approach to help education for young surgeons and surgical supports in rural areas, thereby reducing disparities in health care.

Immune checkpoint status and oncogenic mutation profiling of rectal cancer after neoadjuvant chemotherapy (KSCC1301-A2).

Aim: Immune checkpoint inhibitors (ICIs) are less effective in mismatch repair (MMR)-proficient (pMMR) colorectal cancers (CRCs) than in MMR-deficient CRCs. Here, we investigated changes in the tumor microenvironment after neoadjuvant chemotherapy (NAC) without radiotherapy in locally advanced rectal cancer (LARC) and the potential of ICIs as therapeutic agents for pMMR CRCs. Methods: This was an ad hoc analysis of a KSCC1301 randomized phase II trial in which patients with untreated resectable LARC were randomly assigned to receive S-1 and oxaliplatin or folinic acid, 5-fluorouracil, and oxaliplatin as NAC. Forty-nine patients were studied in this ad hoc analysis. As a reference cohort, we assessed 25 rectal cancer patients who underwent surgery without NAC outside the randomized trial. Immune checkpoint molecules (ICMs; PD-1, PD-L1, CTLA-4, LAG3), tumor-infiltrating lymphocytes (TILs; CD8, FOXP3), and other related proteins were evaluated by immunohistochemistry. Next-generation sequencing (NGS) using Oncomine™ Comprehensive Assay version 3 was conducted in 23 patients. Results: The expression levels of PD-1, CTLA-4, and LAG3 in the NAC group were significantly higher than in reference patients (p < 0.001). Additionally, the infiltration of CD8+ and FOXP3+ T cells, and the CD8/FOXP3 ratio were significantly higher in the NAC group than in reference patients (p < 0.0001). NGS analysis revealed no specific gene alteration related to TILs or ICMs. Conclusion: We demonstrated changes in the tumor immune microenvironment after NAC in pMMR rectal cancer. NAC was associated with increased expression of ICMs and TILs. Rectal cancer could be susceptible to combined immunotherapy with chemotherapy.

A Multicenter Analysis of Short-term and Long-term Outcomes Following Laparoscopic Multivisceral Resection for Advanced Colorectal Cancer.

Background/Aim: Recent research has demonstrated that laparoscopic multivisceral resection (MVR) for advanced colorectal cancer is safe, practicable, and yields satisfactory oncological results, which is in line with the growing usage of laparoscopic surgery. The effectiveness of laparoscopic MVR is still debatable, though. The goal of this study was to compare the short- and long-term results of patients with advanced colorectal cancer treated with open MVR with laparoscopic procedures. Patients and Methods: Data on 3,571 consecutive patients hospitalized at the Kyushu University National Kyushu Cancer Center for colorectal cancer surgery between 2004 and 2020 were gathered retrospectively. In the end, 84 individuals with advanced colorectal cancer who had a colectomy with MVR were examined. We evaluated invasiveness in terms of complications, blood loss, and operating time. Recurrence-free survival rates and overall 5-year survival were among the oncological outcomes. Results: Of the 84 patients examined, 29 underwent laparoscopic treatment, and 55 underwent open treatment. The laparoscopic surgery group experienced shorter hospital stays (15 vs. 18 days, p<0.05) and much less blood loss (median volume: 167 vs. 1,058 g, p<0.005) than the open surgery group. Following the exclusion of patients with stage IV colorectal cancer from the study (groups undergoing laparoscopic surgery, n=25; open surgery, n=38), the groups displayed comparable pathologic results and no discernible variations in either the 5-year overall survival (p=0.87) or recurrence-free survival (p=0.86). Conclusion: In certain individuals with advanced colorectal cancer, a laparoscopic method of manipulation with MVR may be less invasive than an open method without compromising the prognosis.

Transitional dynamics in oncology clinical trials: evaluating the impact of Clinical Trials Act on cooperative groups.

OBJECTIVE: large-scale multicentre clinical trials conducted by cooperative groups have generated a lot of evidence to establish better standard treatments. The Clinical Trials Act was enforced on 1 April 2018, in Japan, and it has remarkably increased the operational burden on investigators, but its long-term impact on cancer cooperative groups is unknown. METHODS: a survey was conducted across the nine major cooperative groups that constitute the Japan Cancer Trials Network to assess the impact of Clinical Trials Act on the number of newly initiated trials from fiscal year (from 1 April to 31 March) 2017 to 2022 and that of ongoing trials on 1 April in each year from 2018 to 2023. RESULTS: the number of newly initiated trials dropped from 38 trials in fiscal year 2017 to 26 trials in fiscal year 2018, surged to 50 trials in fiscal year 2019, but then gradually decreased to 25 trials by fiscal year 2022. Specified clinical trials decreased from 32 trials in fiscal year 2019 to 12 trials in fiscal year 2022. The number of ongoing trials was 220 trials in 2018, peaked at 245 trials in 2020, but then gradually decreased to 219 trials by 2023. The number of specified clinical trials has been in consistent decline. By April 2023, of the 20 ongoing non-specified clinical trials, nine adhered to Clinical Trials Act and 11 followed the Ethical Guidelines for Medical and Health Research Involving Human Subjects. CONCLUSION: the number of multicentre clinical trials in oncology gradually decreased after the Clinical Trials Act's enforcement, which underscores the need for comprehensive amendment of the Clinical Trials Act to streamline the operational process.

Neoadjuvant Chemotherapy in Patients With T4b or Obstructive Colon Cancer: A Single Center Retrospective Cohort Study.

BACKGROUND/AIM: The efficacy of neoadjuvant chemotherapy (NAC) for colon cancer remains unestablished. This study aimed to investigate the outcomes of NAC in patients with locally advanced T4b or obstructive T4a colon cancers (LACC). PATIENTS AND METHODS: Data of patients with LACC who underwent colon surgery between 2010 and 2022 after NAC at our institution were retrospectively reviewed. Patient characteristics, surgical outcomes, tumor features, and prognosis were analyzed. RESULTS: Among 800 patients with LACC who underwent radical resection, 11 received NAC because of cT4b or cT4a with mechanical obstruction. NAC, administered as a doublet regimen, had a median duration of three months, without grade ≥3 adverse events. R0 resection was achieved in all patients and downstaging was observed in eight patients. One patient developed a postoperative abdominal abscess, and adjuvant chemotherapy was administered to eight patients. Four patients experienced recurrence: liver metastasis in two, and local recurrence in two. Among these, three patients underwent resection of recurrent tumors. Median follow-up was 30 months. CONCLUSION: NAC is feasible for T4b or obstructive T4a colon cancer and may be a treatment option for LACC. Further large-scale studies are required to confirm the efficacy of NAC in these patients.

Baseline ctDNA gene alterations as a biomarker of survival after panitumumab and chemotherapy in metastatic colorectal cancer.

Certain genetic alterations and right-sided primary tumor location are associated with resistance to anti-epidermal growth factor (EGFR) treatment in metastatic colorectal cancer (mCRC). The phase 3 PARADIGM trial (n = 802) demonstrated longer overall survival with first-line anti-EGFR (panitumumab) versus antivascular endothelial growth factor (bevacizumab) plus modified FOLFOX6 in patients with RAS wild-type mCRC with left-sided primary tumors. This prespecified exploratory biomarker analysis of PARADIGM (n = 733) evaluated the association between circulating tumor DNA (ctDNA) gene alterations and efficacy outcomes, focusing on a broad panel of gene alterations associated with resistance to EGFR inhibition, including KRAS, NRAS, PTEN and extracellular domain EGFR mutations, HER2 and MET amplifications, and ALK, RET and NTRK1 fusions. Overall survival was prolonged with panitumumab plus modified FOLFOX6 versus bevacizumab plus modified FOLFOX6 in patients with ctDNA that lacked gene alterations in the panel (that is, negative hyperselected; median in the overall population: 40.7 versus 34.4 months; hazard ratio, 0.76; 95% confidence interval, 0.62-0.92) but was similar or inferior with panitumumab in patients with ctDNA that contained any gene alteration in the panel (19.2 versus 22.2 months; hazard ratio, 1.13; 95% confidence interval, 0.83-1.53), regardless of tumor sidedness. Negative hyperselection using ctDNA may guide optimal treatment selection in patients with mCRC. ClinicalTrials.gov registrations: NCT02394834 and NCT02394795 .

Clinicopathological Impact of High Preoperative CA19-9 in Early-stage Colorectal Cancer: A Single-center Retrospective Cohort Study.

BACKGROUND/AIM: This study examined the clinical significance of very high preoperative carbohydrate antigen 19-9 (CA19-9) levels in patients with early-stage colorectal cancer (CRC). PATIENTS AND METHODS: We retrospectively analyzed the clinicopathological data of patients who underwent curative resection for primary CRC (c-Stage I-III) between 2004 and 2022 in our facility. The patients were classified into three groups according to the preoperative CA19-9 level: normal (≤37.0 U/ml), high (>37.0 to ≤100.0 U/ml), and very high (>100.0 U/ml). RESULTS: Of 971 patients, 885 (91.1%), 67 (6.9%), and 19 (2.0%) had normal, high, and very high CA19-9 levels, respectively. Overall survival (very high vs. normal: p<0.0001, very high vs. high: p=0.01) and recurrence-free survival (very high vs. normal: p<0.0001, very high vs. high: p=0.18) were significantly worse in the very high group. On multivariate analysis including TNM stage, very high preoperative CA19-9 levels were independently associated with worse overall (odds ratio=4.54; 95% confidence interval=2.03-10.16; p=0.0002) and recurrence-free survival (odds ratio=3.49; 95% confidence interval=1.82-6.69; p=0.0002). CONCLUSION: High preoperative CA19-9 levels were associated with poor survival in early-stage CRC. Careful intraoperative observation and close follow-up might be necessary.

Book-Binding Technique in Totally Laparoscopic Distal Gastrectomy with Billroth I Reconstruction: Clinical Results and Outcomes in 188 Patients with Gastric Cancer.

BACKGROUND: Laparoscopic gastrectomy is widely used as a curative treatment for gastric cancer. Although delta-shaped anastomosis is commonly used for Billroth I anastomosis after totally laparoscopic distal gastrectomy (TLDG), it has some drawbacks. The book-binding technique (BBT) was developed as an alternative, and this study aimed to examine its short-term results in 188 consecutive cases. STUDY DESIGN: This retrospective study included patients who underwent BBT reconstruction after TLDG for gastric malignancy between 2011 and 2020. BBT is a technique for intracorporeal gastroduodenostomy, which is a triangular anastomosis with a linear stapler that does not require additional dissection or rotation of the duodenum. The short-term outcomes of BBT reconstruction and postoperative endoscopic findings were analyzed. RESULTS: This study evaluated 188 patients who underwent TLDG and BBT reconstruction. Anastomotic stenosis and leakage occurred in 1.1% and 0.5% of the patients, respectively. The median time to the first diet was 3.1 days, and the median postoperative hospital stay was 11.9 days. BBT anastomoses were performed by 19 surgeons and took an average of 32.8 minutes to complete, with completion times decreasing as the surgical team became more proficient. On endoscopy performed 1 year postoperatively, 5.2% had reflux esophagitis (grade A or higher), 67.8% had gastritis (grade 1 or higher), 37.4% had residual food (grade 1 or higher), and 37.4% had bile reflux (grade 1). CONCLUSIONS: BBT is a safe and feasible method for intracorporeal gastroduodenostomy in TLDG for patients with gastric malignancy and demonstrates good surgical outcomes.

Exploratory Biomarker Analysis Using Plasma Angiogenesis-Related Factors and Cell-Free DNA in the TRUSTY Study: A Randomized, Phase II/III Study of Trifluridine/Tipiracil Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer.

BACKGROUND: The TRUSTY study evaluated the efficacy of second-line trifluridine/tipiracil (FTD/TPI) plus bevacizumab in metastatic colorectal cancer (mCRC). OBJECTIVE: This exploratory biomarker analysis of TRUSTY investigated the relationship between baseline plasma concentrations of angiogenesis-related factors and cell-free DNA (cfDNA), and the efficacy of FTD/TPI plus bevacizumab in patients with mCRC. PATIENTS AND METHODS: The disease control rate (DCR) and progression-free survival (PFS) were compared between baseline plasma samples of patients with high and low plasma concentrations (based on the median value) of angiogenesis-related factors. Correlations between cfDNA concentrations and PFS were assessed. RESULTS: Baseline characteristics (n = 65) were as follows: male/female, 35/30; median age, 64 (range 25-84) years; and RAS status wild-type/mutant, 29/36. Patients in the hepatocyte growth factor (HGF)-low and interleukin (IL)-8-low groups had a significantly higher DCR (risk ratio [95% confidence intervals {CIs}]) than patients in the HGF-high (1.83 [1.12-2.98]) and IL-8-high (1.70 [1.02-2.82]) groups. PFS (hazard ratio {HR} [95% CI]) was significantly longer in patients in the HGF-low (0.33 [0.14-0.79]), IL-8-low (0.31 [0.14-0.70]), IL-6-low (0.19 [0.07-0.50]), osteopontin-low (0.39 [0.17-0.88]), thrombospondin-2-low (0.42 [0.18-0.98]), and tissue inhibitor of metalloproteinase-1-low (0.26 [0.10-0.67]) groups versus those having corresponding high plasma concentrations of these angiogenesis-related factors. No correlation was observed between cfDNA concentration and PFS. CONCLUSION: Low baseline plasma concentrations of HGF and IL-8 may predict better DCR and PFS in patients with mCRC receiving FTD/TPI plus bevacizumab, however further studies are warranted. CLINICAL TRIAL REGISTRATION NUMBER: jRCTs031180122.

Ensuring communication redundancy and establishing a telementoring system for robotic telesurgery using multiple communication lines.

Assuring communication redundancy during the interruption and establishing appropriate teaching environments for local surgeons are essential to making robotic telesurgery mainstream. This study analyzes robotic telesurgery with telementoring using standard domestic telecommunication carriers. Can multiple carriers guarantee redundancy with interruptions? Three commercial optical fiber lines connected Hirosaki University and Mutsu General Hospitals, 150 km apart. Using Riverfield, Inc. equipment, Hirosaki had a cockpit, while both Mutsu used both a cockpit and a surgeon's console. Experts provided telementoring evaluating 14 trainees, using objective indices for operation time and errors. Subjective questionnaires addressed image quality and surgical operability. Eighteen participants performed telesurgery using combined lines from two/three telecommunication carriers. Manipulation: over 30 min, lines were cut and restored every three minutes per task. Subjects were to press a switch when noticing image quality or operability changes. Mean time to task completion was 1510 (1186-1960) seconds: local surgeons alone and 1600 (1152-2296) seconds for those under remote instructor supervision, including expert intervention time. There was no significant difference (p = 0.86). The mean error count was 0.92 (0-3) for local surgeons and 0.42 (0-2) with remote instructors. Image quality and operability questionnaires found no significant differences. Results communication companies A, B, and C: the A/B combination incurred 0.17 (0-1) presses of the environment change switch, B/C had 0, and C/A received 0.67 (0-3), showing no significant difference among provider combinations. Combining multiple communication lines guarantees communication redundancy and enables robotic telementoring with enhanced communication security.

Effects of communication delay in the dual cockpit remote robotic surgery system.

PURPOSE: To evaluate the impact of dual cockpit telesurgery on proctors and operators, and acceptable levels of processing delay for video compression and restoration. METHODS: Eight medical advisors and eight trainee surgeons, one highly skilled per group, performed gastrectomy, rectal resection, cholecystectomy, and bleeding tasks on pigs. Using the Medicaroid surgical robot hinotori™, simulated delay times (0 ms, 50 ms, 100 ms, 150 ms, and 200 ms) were inserted mid-surgery to evaluate the tolerance level. Operative times and dual cockpit switching times were measured subjectively using 5-point scale questionnaires (mSUS [modified System Usability Scale], and Robot Usability Score). RESULTS: No significant difference was observed in operative times between proctors and operators (proctor: p = 0.247, operator: p = 0.608) nor in switching times to the dual cockpit mode (p = 0.248). For each survey setting, proctors tended to give lower ratings to delays of ≥ 150 ms. No marked difference was observed in the operator evaluations. On the postoperative questionnaires, there were no marked differences in the mSUS or Robot Usability Score between the proctors and operators (mSUS: p = 0.779, Robot Usability Score: p = 0.261). CONCLUSION: Telesurgery using a dual cockpit with hinotori™ is practical and has little impact on surgical procedures.

Tele-robotic distal gastrectomy with lymph node dissection on a cadaver.

The purpose of this study is to evaluate the performance of tele-robotic distal gastrectomy (tele-RDG) with lymph node dissection (LND) using a novel Japanese-made surgical robot hinotori™ (Medicaroid, Kobe, Japan) in a cadaver with a presumptive gastric cancer. The Cadaveric Anatomy and Surgical Training Laboratory (CAST-Lab.) at Hokkaido University and Kushiro City General Hospital (KCGH) are connected by a guaranteed type line (1 Gbps), and the distance between the two facilities is 250 km. A patient cart was installed at CAST-Lab, and a surgeon cockpit was installed at KCGH. Tele-RDG with D2 LND was performed on an adult human cadaver. In all surgical processes, the communication environment was stable without image degradation, and the mean round trip time was 40 milliseconds (36.5-55 milliseconds). For tele-RDG with D2 LND, the operation time was 199 minutes without any technical problems. Tele-RDG using hinotori™ was feasible and similar to local robotic RDG.

Field experiment of a telesurgery system using a surgical robot with haptic feedback.

PURPOSE: To verify the usefulness of haptic feedback in telesurgery and improve the safety of telerobotic surgery. METHODS: The surgeon's console was installed at two sites (Fukuoka and Beppu; 140 km apart), and the patient cart was installed in Fukuoka. During the experiment, the surgeon was blinded to the haptic feedback levels and asked to grasp the intestinal tract in an animal model. The surgeon then performed the tasks at each location. RESULTS: No marked differences in task accuracy or average grasping force were observed between the surgeon locations. However, the average task completion time was significantly longer, and the system usability scale (SUS) was significantly lower rating for remote operations than for local ones. No marked differences in task accuracy or task completion time were observed between the haptic feedback levels. However, with haptic feedback, the organ was grasped with a significantly weaker force than that without it. Furthermore, with haptic feedback, experienced surgeons in robotic surgery tended to perform an equivalent task with weaker grasping forces than inexperienced surgeons. CONCLUSION: The haptic feedback function is a tool that allows the surgeon to perform surgery with an appropriate grasping force, both on site and remotely. Improved safety is necessary in telesurgery; haptic feedback will thus be an essential technology in robotic telesurgery going forward.

Evolution of Treatment Outcomes and Prognostic Factors in Esophageal Cancer Surgery: A Retrospective Analysis of 1500 Consecutive Esophagostomies.

Objective: To clarify the surgical outcomes of esophagectomy in Japan and comprehensively evaluate trends over time. It is important to analyze data from a large number of consecutive patients from a single institution. Methods: We evaluated the treatment outcomes, complications, and prognosis of 1500 consecutive patients who underwent esophagectomy during 5 periods: group A (n = 284), 1964-1984; group B (n = 345), 1985-1993; group C (n = 253), 1994-2002; group D (n = 297), 2003-2012; and group E (n = 321), 2013-March 2020. Results: The incidences of squamous cell carcinoma and adenocarcinoma were 93.8% and 3.3%, respectively. The proportion of adenocarcinoma cases has gradually increased over time. The in-hospital mortality rates for groups A, B, C, D, and E were 12%, 4.6%, 1.2%, 2.9%, and 1.5%, respectively. Group A had a significantly higher mortality rate than the other groups (P < 0.0001). Three-year survival rates were 22.2%, 47.8%, 53.4%, 69.9%, and 72.6% in groups A-E, respectively, 5-year survival rates were 17.2%, 41.3%, 49.2%, 63.9%, and 68.4%, respectively (P < 0.0001, group A vs groups D and E). The prognosis improved over time. Multivariate analysis revealed that depth of invasion, lymph node metastasis, the extent of lymph node resection, curative resection, pulmonary complications, and anastomotic leakage were significant independent prognostic factors. However, for recent surgeries (groups D and E), only the depth of invasion, lymph node metastasis, and curative resection were significant independent prognostic factors. Conclusions: Valuable changes in background and prognostic factors occurred over time. These findings will help optimize esophageal cancer management and improve patient outcomes.

Esophagectomy for esophageal stricture with systemic sclerosis: a case report.

BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disease characterized by frequent esophageal involvement. However, there are few reports on esophagectomy for esophageal strictures associated with SSc. Herein, we present a case of successful treatment of an esophageal stricture associated with SSc through subtotal esophagectomy. CASE PRESENTATION: A 53-year-old female patient was diagnosed with SSc, interstitial pneumonia, and gastroesophageal reflux disease (GERD). The patient developed an esophageal ulcer and benign stricture that required a subtotal esophagectomy 10 years after the diagnosis. Histopathological findings revealed thinning of the muscle layer, a characteristic feature of SSc. The patient was free of dysphagia or regurgitation. CONCLUSIONS: An esophagectomy is a valuable option for treating esophageal strictures in SSc. Therefore, surgical approaches should be established for patients with SSc.