Background: The Senhance Digital Laparoscopy System (Asensus Surgical Inc, Morrisville, NC, United States), which was introduced for the first time in Japan by our hospital, is a new surgical assistive robot following the da Vinci Surgical System. We herein report the short-term outcomes of 55 colorectal cancer surgery cases using this system at our hospital to assess the feasibility and safety of our procedures. Materials and Methods:We retrospectively reviewed the patient backgrounds and surgical outcomes of 55 patients who underwent Senhanceassisted laparoscopic colorectal cancer surgery. Results: The median age was 71 years. There were 31 males and 24 females, and the median body mass index was 23.1 kg/m 2 . Fifteen patients had a history of abdominal surgery. The most common surgical technique was ileocecal resection (18 cases, 32.7%), followed by high anterior resection (11 cases, 20.0%). D2 or D3 dissection was performed in each operation, and D3 dissection was performed in 41 cases (74.5%). The median operative time was 240 minutes, the median blood loss was 5 mL, there were no intraoperative complications, and there were no cases of intraoperative blood transfusion. The median postoperative hospital stay was 7 days, which was comparable to conventional laparoscopic surgery. Postoperative complications of grade 2 or higher in the Clavien-Dindo classification were observed in two cases. Conclusion:The short-term results of 55 colorectal cancer surgery cases using the Senhance Digital Laparoscopy System were excellent and the system was introduced and surgery was safely performed.

Objective To identify risk factors for lymph node metastasis and postoperative recurrence of pT1 colorectal cancer by clinicopathological study of surgically resected cases. Methods In 801 patients with pT1 colorectal cancer who underwent surgical resection with lymph node dissection between April 2007 and January 2021, we evaluated clinicopathological factors (age, gender, BMI, serum CEA level, tumor localization, additional resection after endoscopic treatment, operation time, blood loss, histological type, tumor size, vascular invasion, and central lymph node dissection). We performed univariate and multivariate analyses to examine risk factors for lymph node metastasis. We also examined risk factors for recurrence in 583 patients up to December 2017. Results Lymph node metastasis was observed in 100/801 patients (12.5%). Multivariate analysis of lymph node metastasis showed that patients with positive lymphatic invasion (odds ratio 2.57, 95% CI 1.62-4.04, P < .0001), positive venous invasion (odds ratio 2.31, 95% CI 1.48-3.61, P = .0002), and histologically poorly differentiated type (odds ratio 4.54, 95% CI 1.35-15.2, P = .014) were identified as risk factors. Postoperative recurrence was observed in 18/580 patients (3.1%). Risk factors for postoperative recurrence were also examined, including preoperative endoscopic treatment (odds ratio 3.59, 95% CI 1.18-10.9, P = .024), positive venous invasion (odds ratio 3.63, 95% CI 1.22-10.8, P = .021), positive lymph node metastasis (odds ratio 4.91, 95% CI 1.10-21.8, P = .037) were extracted as risk factors. Discussion In this study, venous invasion, lymphatic invasion, and histologically poorly differentiated type were identified as risk factors for lymph node metastasis in T1 colorectal cancer, and positive venous invasion, positive lymph node metastasis, and preoperative endoscopic treatment were identified as risk factors for recurrence. We hope that large prospective study will lead to the development of a more specific treatment strategy, including endoscopic treatment and additional surgical resection.

Background/Aim: Locally advanced colorectal cancer (LACC) has poor long-term outcomes. Our hypothesis was that the pathological tumor depth would affect postoperative outcomes in patients who underwent multivisceral resection with clear margins (R0). The aim of this study was to analyze short- and long-term outcomes in patients who underwent multivisceral resection for LACC, comparing between T3 and T4 stages. Patients and Methods: This was a propensity score-matched, retrospective study. All 8,764 consecutive patients who underwent surgery for colorectal cancer between April 2007 and January 2021 at the Saitama Medical University International Medical Center were screened; 572 underwent multivisceral resection for LACC. We compared the T3 and T4 groups to evaluate outcomes. Results: The 5-year disease-free survival (DFS) rates did not significantly differ between the two groups (hazard ratio=1.344, 95% confidence interval=0.638-2.907, p=0.33). The 5-year overall survival (OS) rates were significantly worse for the T4 group than for the T3 group (hazard ratio=3.162, 95% confidence interval=1.077-11.44), p=0.037). To determine the association between American Society of Anesthesiologists (ASA) score, transfusion, pathological T and OS, we performed univariate and multivariate analyses. ASA, transfusion, and pathological T-stage were associated with worse OS in univariate analysis (T4 vs. T3, respectively). Conclusion: Our study showed that postoperative complications and DFS of the T4 group were similar to those of the T3 group of locally advanced colorectal cancer treated with laparoscopic multivisceral resection. However, OS was worse in the T4 group compared with the T3 group. Multivariate risk factors for poor OS were ASA>2, transfusion, and T4 stage.

Purpose: Local advanced colorectal cancer (LACC) has poor long-term outcomes. Our hypothesis was that the depth of pathological findings would affect postoperative outcomes in patients who underwent multivisceral resection (MVR) resulting in clear margins (R0). The aim of this study was to analyze short- and long-term outcomes in patients who underwent MVR for LACC between T3 and T4 stages.Methods: This was a propensity score-matched (PSM) retrospective study. All 8,764 consecutive patients who underwent surgery for colorectal cancer between April-2007 and January- 2021 at the Saitama Medical University International Medical Center were screened. 572 underwent MVR for LACC. We compared the T3 and T4 groups to evaluate outcomes.Results: The 5-year disease-free survival (DFS) rates did not significantly differ between the two groups (HR 1.344 95% CI (0.638–-2.907), P=0.33). The 5-year overall survival (OS) rates were significantly worse for the T4 group than for the T3 group (HR 3.162 95% CI (1.077–-11.44), P=0.037).To determine the association between American Society of Anesthesiologists (ASA) score, transfusion, pathological T and OS, we performed univariate and multivariate analyses. ASA, transfusion, and pathological T were associated with worse OS in univariate analysis (T3 vs. T4, respectively).Conclusion: Our study showed that the postoperative complications and DFS of the T4 group were similar to those of the T3 group. However, OS was worse in the T4 group compared with T3 group. Multivariate risk factors were ASA>2, transfusion, and, T4.