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.

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.

Artificial Intelligence-Based Prediction of Recurrence after Curative Resection for Colorectal Cancer from Digital Pathological Images.

BACKGROUND: To develop an artificial intelligence-based model to predict recurrence after curative resection for stage I-III colorectal cancer from digitized pathological slides. PATIENTS AND METHODS: In this retrospective study, 471 consecutive patients who underwent curative resection for stage I-III colorectal cancer at our institution from 2004 to 2015 were enrolled, and 512 randomly selected tiles from digitally scanned images of hematoxylin and eosin-stained tumor tissue sections were used to train a convolutional neural network. Five-fold cross-validation was used to validate the model. The association between recurrence and the model's output scores were analyzed in the test cohorts. RESULTS: The area under the receiver operating characteristic curve of the cross-validation was 0.7245 [95% confidence interval (CI) 0.6707-0.7783; P < 0.0001]. The score successfully classified patients into those with better and worse recurrence free survival (P < 0.0001). Multivariate analysis revealed that a high score was significantly associated with worse recurrence free survival [odds ratio (OR) 1.857; 95% CI 1.248-2.805; P = 0.0021], which was independent from other predictive factors: male sex (P = 0.0238), rectal cancer (P = 0.0396), preoperative abnormal carcinoembryonic antigen (CEA) level (P = 0.0216), pathological T3/T4 stage (P = 0.0162), and pathological positive lymph node metastasis (P < 0.0001). CONCLUSIONS: The artificial intelligence-based prediction model discriminated patients with a high risk of recurrence. This approach could help decision-makers consider the benefits of adjuvant chemotherapy.

Telesurgery and telesurgical support using a double-surgeon cockpit system allowing manipulation from two locations.

BACKGROUND: Although several studies on telesurgery have been reported globally, a clinically applicable technique has not yet been developed. As part of a telesurgical study series conducted by the Japan Surgical Society, this study describes the first application of a double-surgeon cockpit system to telesurgery. METHODS: Surgeon cockpits were installed at a local site and a remote site 140 km away. Three healthy pigs weighing between 26 and 29 kg were selected for surgery. Non-specialized surgeons performed emergency hemostasis, cholecystectomy, and renal vein ligation with remote assistance using the double-surgeon cockpits and specialized surgeons performed actual telesurgery. Additionally, the impact of adding internet protocol security (IPsec) encryption to the internet protocol-virtual private network (IP-VPN) line on communication was evaluated to address clinical security concerns. RESULTS: The average time required for remote emergency hemostasis with the double-surgeon cockpit system was 10.64 s. A non-specialized surgeon could safely perform cholecystectomy or renal vein ligation with remote assistance. Global Evaluative Assessment of Robotic Skills and System Usability Scale scores were higher for telesurgical support-assisted surgery by a non-specialized surgeon using the double-surgeon cockpits than for telesurgery performed by a specialized surgeon without the double-cockpit system. Adding IPsec encryption to the IP-VPN did not have a significant impact on communication. CONCLUSION: Telesurgical support through our double-surgeon cockpit system is feasible as first step toward clinical telesurgery.

Impact of a Long Linear Staplers on the Incidence of Stricture after Triangulating Esophagogastric Anastomosis.

BACKGROUND: Various techniques have been reported for esophagogastric anastomosis to prevent anastomotic leakage. Recently, not only postoperative anastomotic leakage but also anastomotic stricture is considered important because stricture contributes to the patient's postoperative quality of life. However, the best procedure for anastomosis has not been established. MATERIALS AND METHODS: The authors divided 101 patients with thoracic or abdominal esophageal cancer who underwent cervical triangulating esophagogastric anastomosis using a linear stapler between May 2017 and May 2020 into 2 groups: surgery with a short (45 mm) linear stapler (SS group, n=59) or a long (60 mm) stapler (LS group, n=42). The frequencies of anastomotic leakage and stricture were compared between the 2 groups. RESULTS: The incidence of anastomotic leakage and stricture without leakage were significantly lower in the LS versus SS group (respectively: leakage: 15% vs. 0%, P=0.01; stricture: 36% vs. 7%, P=0.01). A short linear stapler and anastomotic leakage were independent risk factors for anastomotic stricture in the multivariate analysis (short stapler: odds ratio, 3.27; 95% confidence interval, 1.08-9.9; P=0.03; anastomotic leakage: odds ratio, 2.78; 95% confidence interval, 1.02-8.5; P=0.04). CONCLUSION: A long linear stapler is preferable for cervical triangulating esophagogastric anastomosis.

Quadruple gastrointestinal cancer with discordance of mismatch repair protein deficiency and microsatellite instability suggesting Lynch syndrome.

A 65-year-old woman with prior personal and family histories of cancer was admitted to our hospital for quadruple cancer. Preoperative endoscopy revealed a type 0-II gastric cancer (GC; gastric body), advanced type-II colon cancer (ascending colon), and early-stage recto-sigmoid colon cancers. We diagnosed her with Lynch syndrome (LS) per Amsterdam criteria, and performed distal gastrectomy, ileocecal resection and high anterior resection. Her pathological diagnoses were GC: well-to-poorly differentiated adenocarcinoma (AD, por2 > tub2) with signet-ring cells, ypT1b SM2; ascending colon cancer: AD with focal mucin products (tub2 > muc), SS; sigmoid colon cancer: AD (tub1), M; recto-sigmoid cancer: AD (tub1 > tub2), SM. Immunohistochemical tests revealed that all cancers lacked the MLH1/PMS2 protein. However, the three colon cancers were found to have high microsatellite instability (MSI); the GC was microsatellite stable (MSS). No recurrence or other cancers were observed for 30 months after surgery without adjuvant chemotherapy. As patients with LS may also develop MSS cancers, we should check for MSI in all LS cancers for proper treatment.

Extended total gastrectomy after nivolumab for unresectable multivisceral invasive gastric cancer.

BACKGROUND: Chemotherapy has been considered the main treatment for stage IV gastric cancer (GC). However, advances in chemotherapy have provided new clinical approaches, permitting conversion surgery with the aim of R0 resection after resolving unresectability issues. CASE PRESENTATION: A 70-year-old man with gastric cancer invading the pancreatic tail and spleen and with periaortic lymph-node enlargement was admitted to our hospital. After 24 courses of nivolumab as third-line chemotherapy, periaortic lymph-node enlargement was resolved, and conversion surgery was planned. Intraoperatively, we found no peritoneal metastasis, but the distal pancreas, splenic hilum, and transverse colon were adhered to the gastric body. Therefore, we performed D2 total gastrectomy with distal pancreatosplenectomy and partial transverse colectomy. The pathological diagnosis was type III moderately differentiated tubular adenocarcinoma (tub2) with signet ring cells, stage ypT1b (SM), ly0, and v0. The pathological proximal and distal tumor margins were negative. One lymph-node metastasis was observed (No. 4d; 1/23). Postoperatively, no recurrence was observed over 7 months, without adjuvant chemotherapy. CONCLUSIONS: Nivolumab may allow R0 resection in patients with unresectable gastric cancer. Conversion surgery should be considered even after third-line nivolumab treatment.

A rare case of esophageal adenocarcinoma with urinary bladder metastasis.

A 75-year-old man was admitted to our hospital for treatment of esophageal cancer (EC) in March 2017. Esophagogastroduodenoscopy revealed Barrett's esophagus and superficial, distal EC (type 0-IIc). Tumor biopsy showed esophageal adenocarcinoma. Computed tomography revealed no lymph node metastasis but did reveal a 19-mm tumor on the right side of the urinary bladder. Bladder cancer (BC) was also suspected, and the patient underwent endoscopic submucosal dissection for EC and transurethral resection of the bladder tumor. The pathological diagnosis of EC was moderately to poorly differentiated adenocarcinoma (tub2), pT1b (SM), ly0, v0. The pathological horizontal margin was negative and the vertical margin was positive. Additional esophagectomy and lymph node dissection were indicated for curability. Esophagectomy was difficult because the patient had severe cardiovascular disease, so follow-up observation was adopted. BC was classified as urothelial carcinoma Ta, ly0, v0. After 32 months, multiple tumors were found in the bladder, and BC recurrence was suspected. Transurethral resection of the bladder was performed again for seven tumors, and pathological diagnosis was poorly differentiated adenocarcinoma (tub2). The immunohistochemical features matched those of EC. We diagnosed EC metastasis in the urinary bladder. Bladder adenocarcinoma is difficult to distinguish from metastasis from other organs, especially the upper gastrointestinal tract, and cytomorphological features and appropriate clinical history are required.

Successful Conversion Surgery Following Chylous Ascites After Nivolumab for Advanced Gastric Cancer.

CASE REPORT: A 75-year-old man who underwent nivolumab as the third-line chemotherapy for advanced gastric cancer had chylous ascites (CA) after the primary tumor shrank remarkably. Total parenteral nutrition and subcutaneous octreotide were initiated, and CA disappeared. Nivolumab was continued for a total of 23 courses. Computed tomography showed lymph node swelling; however, staging laparoscopy showed that peritoneal metastasis had disappeared. Therefore, conversion surgery and distal gastrectomy with D1+ dissection were performed. RESULTS: The pathological diagnosis was type IV, poorly differentiated adenocarcinoma (por2) with signet ring cells, ypT2 (muscularis propria), without lymphatic or venous invasion, and no involvement of the proximal and distal margins. After the operation, no recurrence was observed over 7 months with no adjuvant chemotherapy. CONCLUSION: Nivolumab has the potential to lead to R0 resection for patients with peritoneal carcinomatosis gastric cancer. To our knowledge, this is the first report of successful conversion surgery after nivolumab-related chylous ascites.

Mesenteric venous thrombosis as a rare complication of decompression sickness.

BACKGROUND: Decompression sickness (DCS) induced by extravascular and intravascular gas bubbles during decompression can present with varying manifestations, such as joint pain, numbness, cutaneous symptoms, and cardiopulmonary dysfunction. However, mesenteric venous thrombosis (MVT) is a rare complication of DCS. To the best of our knowledge, only a few cases have been reported, and surgical cases of MVT secondary to DCS have not yet been reported. CASE PRESENTATION: A 59-year-old man who was a fisherman and recreational diver dived to a depth of 100 feet. After diving, he noted abdominal and postcervical pain and visited a community hospital. Computed tomography (CT) revealed a large amount of intravenous gas, so he was diagnosed with DCS. He was then transferred to a previous hospital, where hyperbaric oxygen therapy (HBOT) was performed. HBOT reduced the amount of venous gas, but his abdominal pain worsened, so he was transferred to our hospital. CT showed pneumatosis cystoides intestinalis. Because of the possibility of intestinal necrosis, a laparoscopic examination was performed, which revealed necrosis of the transverse colon. We therefore performed a transverse colon resection. He was discharged 36 days after the surgery and followed an uneventful postoperative course. CONCLUSIONS: DCS is likely to cause MVT. If intestinal necrosis is suspected, a laparoscopic examination may be useful for determining the diagnosis and treatment. MVT should be included as a differential diagnosis of abdominal pain that persists after HBOT.

True brachial artery aneurysm after arteriovenous fistula closure following renal transplantation: a case report and literature review.

BACKGROUND: A brachial artery aneurysm (BAA) is a rare condition accounting for 5% of all peripheral arterial aneurysms. More cases of true BAAs after arteriovenous fistula (AVF) closure have been reported in the past two decades. CASE PRESENTATION: A 60-year-old man who underwent AVF closure after renal transplantation had a true BAA on his left elbow that had grown within the past 6 months. We successfully performed an open repair with end-to-end anastomosis. No complications occurred for 1 year. CONCLUSIONS: High flow due to AVF and some collateral factors such as the use of steroids and immunosuppressants after renal transplantation, arteriosclerosis, and chronic mechanical stimulation might contribute to BAA formation.

Rapidly Progressive Glomerulonephritis with Delayed Appearance of Anti-Glomerular Basement Membrane Antibody Successfully Treated with Multiple Courses of Steroid Pulse Therapy.

Patients with anti-glomerular basement membrane (GBM) antibody glomerulonephritis typically exhibit rapidly progressive glomerulonephritis (RPGN). The renal outcome as well as the prognosis of this disease is worse than other forms of RPGN such as those from microscopic polyangiitis. Therefore, early therapeutic intervention is essential to improve its prognosis. One month before referral to our hospital, a 54-year-old female attended another hospital because of macrohematuria. At that time, she had proteinuria and macrohematuria with normal renal function, was negative for anti-GBM antibodies, and was diagnosed with chronic glomerulonephritis. A month later when she was admitted to our hospital, she showed renal insufficiency and was positive for anti-GBM antibodies. Immediately after recognizing the anti-GBM antibody status, plasma exchange and the first course of steroid pulse therapy was started. After 5 days of therapy, renal biopsy confirmed severe crescentic glomerulonephritis in which all the observed glomeruli were involved with cellular crescents. Despite this, she survived without end-stage renal disease after three courses of steroid pulse therapy and seven sessions of plasma exchange. This favorable outcome reflects the repeated analysis of anti-GBM antibodies within a very short period and the rapid therapeutic intervention in addition to the intensive immunosuppressive therapies.