Fatal pulmonary embolism after surgery for small intestinal necrosis caused by idiopathic portal vein thrombosis: a case report.

BACKGROUND: Portal vein thrombosis (PVT) and venous thromboembolism (VTE) both result from partial or complete occlusion of a blood vessel by a blood clot. The prognosis of PVT is generally good; however, PVT with VTE, including pulmonary embolism (PE), has a high mortality rate. We report here a case of PE after surgery for small intestinal necrosis caused by idiopathic PVT. CASE PRESENTATION: A 69-year-old female attended our hospital with a chief complaint of upper abdominal discomfort, and was diagnosed with necrosis of the small intestine as a result of unexplained PVT. She underwent partial resection of the small intestine. On the second postoperative day, she suffered from respiratory distress and went into cardiopulmonary arrest. The patient recovered following cardiopulmonary resuscitation, but PE was detected. Extracorporeal veno-arterial cardiopulmonary resuscitation and anticoagulation therapy were initiated immediately and the thrombus was aspirated as much as possible. Two days later, extracorporeal veno-arterial cardiopulmonary resuscitation was withdrawn and anticoagulation therapy was continued. The patient subsequently recovered with no neurological damage and was discharged on day 26 after the above procedure. CONCLUSIONS: Idiopathic PVT is often associated with VTE, and a prompt diagnosis and intervention may result in a good prognosis.

Spatial and single-cell colocalisation analysis reveals MDK-mediated immunosuppressive environment with regulatory T cells in colorectal carcinogenesis.

BACKGROUND: Cell-cell interaction factors that facilitate the progression of adenoma to sporadic colorectal cancer (CRC) remain unclear, thereby hindering patient survival. METHODS: We performed spatial transcriptomics on five early CRC cases, which included adenoma and carcinoma, and one advanced CRC. To elucidate cell-cell interactions within the tumour microenvironment (TME), we investigated the colocalisation network at single-cell resolution using a deep generative model for colocalisation analysis, combined with a single-cell transcriptome, and assessed the clinical significance in CRC patients. FINDINGS: CRC cells colocalised with regulatory T cells (Tregs) at the adenoma-carcinoma interface. At early-stage carcinogenesis, cell-cell interaction inference between colocalised adenoma and cancer epithelial cells and Tregs based on the spatial distribution of single cells highlighted midkine (MDK) as a prominent signalling molecule sent from tumour epithelial cells to Tregs. Interaction between MDK-high CRC cells and SPP1+ macrophages and stromal cells proved to be the mechanism underlying immunosuppression in the TME. Additionally, we identified syndecan4 (SDC4) as a receptor for MDK associated with Treg colocalisation. Finally, clinical analysis using CRC datasets indicated that increased MDK/SDC4 levels correlated with poor overall survival in CRC patients. INTERPRETATION: MDK is involved in the immune tolerance shown by Tregs to tumour growth. MDK-mediated formation of the TME could be a potential target for early diagnosis and treatment of CRC. FUNDING: Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Science Research; OITA Cancer Research Foundation; AMED under Grant Number; Japan Science and Technology Agency (JST); Takeda Science Foundation; The Princess Takamatsu Cancer Research Fund.

Implementable assay for monitoring minimum residual disease after radical treatment for colorectal cancer.

Considering the cost and invasiveness of monitoring postoperative minimal residual disease (MRD) of colorectal cancer (CRC) after adjuvant chemoradiotherapy (ACT), we developed a favorable approach based on methylated circulating tumor DNA to detect MRD after radical resection. Analyzing the public database, we identified the methylated promoter regions of the genes FGD5, GPC6, and MSC. Using digital polymerase chain reaction (dPCR), we termed the "amplicon of methylated sites using a specific enzyme" assay as "AMUSE." We examined 180 and 114 pre- and postoperative serial plasma samples from 28 recurrent and 19 recurrence-free pathological stage III CRC patients, respectively. The results showed 22 AMUSE-positive of 28 recurrent patients (sensitivity, 78.6%) and 17 AMUSE-negative of 19 recurrence-free patients (specificity, 89.5%). AMUSE predicted recurrence 208 days before conventional diagnosis using radiological imaging. Regarding ACT evaluation by the reactive response, 19 AMUSE-positive patients during their second or third blood samples showed a significantly poorer prognosis than the other patients (p = 9E-04). The AMUSE assay stratified four groups by the altered patterns of tumor burden postoperatively. Interestingly, only 34.8% of cases tested AMUSE-negative during ACT treatment, indicating eligibility for ACT. The AMUSE assay addresses the clinical need for accurate MRD monitoring with universal applicability, minimal invasiveness, and cost-effectiveness, thereby enabling the timely detection of recurrences. This assay can effectively evaluate the efficacy of ACT in patients with stage III CRC following curative resection. Our study strongly recommends reevaluating the clinical application of ACT using the AMUSE assay.

Tumor suppressive role of the epigenetic master regulator BRD3 in colorectal cancer.

Bromodomain and extraterminal domain (BET) family proteins are epigenetic master regulators of gene expression via recognition of acetylated histones and recruitment of transcription factors and co-activators to chromatin. Hence, BET family proteins have emerged as promising therapeutic targets in cancer. In this study, we examined the functional role of bromodomain containing 3 (BRD3), a BET family protein, in colorectal cancer (CRC). In vitro and vivo analyses using BRD3-knockdown or BRD3-overexpressing CRC cells showed that BRD3 suppressed tumor growth and cell cycle G1/S transition and induced p21 expression. Clinical analysis of CRC datasets from our hospital or The Cancer Genome Atlas revealed that BET family genes, including BRD3, were overexpressed in tumor tissues. In immunohistochemical analyses, BRD3 was observed mainly in the nucleus of CRC cells. According to single-cell RNA sequencing in untreated CRC tissues, BRD3 was highly expressed in malignant epithelial cells, and cell cycle checkpoint-related pathways were enriched in the epithelial cells with high BRD3 expression. Spatial transcriptomic and single-cell RNA sequencing analyses of CRC tissues showed that BRD3 expression was positively associated with high p21 expression. Furthermore, overexpression of BRD3 combined with knockdown of, a driver gene in the BRD family, showed strong inhibition of CRC cells in vitro. In conclusion, we demonstrated a novel tumor suppressive role of BRD3 that inhibits tumor growth by cell cycle inhibition in part via induction of p21 expression. BRD3 activation might be a novel therapeutic approach for CRC.

A rare case of liver regenerative and non-neoplastic lesion resembling a well-differentiated hepatocellular carcinoma.

BACKGROUND: Nodular regenerative hyperplasia (NRH) is a rare disease that presents pathologically as diffuse hepatic nodules without fibrous septa. It is believed to be caused by vasculopathy against a background of various systemic diseases, such as hematologic, autoimmune, and drug-induced diseases, with various symptoms. In spite of the recent imaging advances, various atypical cases of nodular lesions are observed in daily clinical practice. Cases that do not completely meet these criteria are referred to as -like or -similar lesions in clinical situations, making it difficult to understand their pathogenesis. We present a case in which two hepatic nodular lesions were noted and difficult to differentiate from malignancy preoperatively. The lesions were laparoscopically resected and a pathological diagnosis with non-neoplastic liver regenerative nodules resembling NRH was made. CASE PRESENTATION: A 49-year-old man with no alcohol or drug intake and no past medical history was identified as having liver tumors on screening examination without any symptoms. Contrast-enhanced computed tomography (CT) showed two hepatic tumors; approximately 2-cm tumors at S7 and S8. Gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) revealed fat inclusions in their contents. Ethoxybenzyl (EOB) uptake was also observed during the hepatobiliary phase. Based on preoperative examinations, we suspected well-differentiated hepatocellular carcinoma (HCC) and performed laparoscopic S7/8 partial resection for these lesions. Macroscopically, the resected specimens showed a non-cirrhotic yellowish-cut surface containing brownish, ill-defined lesions with irregular borders. Microscopically, these lesions showed zonal necrosis, congestion, and aggregation of hemosiderin-laden macrophages around the central vein. In these areas, the fatty deposition of hepatocytes was lower than that in the surrounding background hepatocytes. Histopathologically, neither neoplastic nor hyperplastic lesions were observed, and he was diagnosed as regenerative hepatic change with centrilobular necrosis. CONCLUSIONS: Considering the pathological results, these lesions were thought to be a type of NRH-like lesion with possible hepatic vessel disorder. However, the lesion's cause and classification was difficult to determine. The accumulation of these regenerative changes accompanying fatty liver is needed to clarify the mechanism and its clinical significance.

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.

Real-time telementoring with 3D drawing annotation in robotic surgery.

BACKGROUND: In telementoring, differences in teaching methods affect local surgeons' comprehension. Because the object to be operated on is a three-dimensional (3D) structure, voice or 2D annotation may not be sufficient to convey the instructor's intention. In this study, we examined the usefulness of telementoring using 3D drawing annotations in robotic surgery. METHODS: Kyushu University and Beppu Hospital are located 140 km apart, and the study was conducted using a Saroa™ surgical robot by RIVERFIELD Inc. using a commercial guarantee network on optical fiber. Twenty medical students performed vertical mattress suturing using a swine intestinal tract under surgical guidance at the Center for Advanced Medical Innovation Kyushu University. Surgical guidance was provided by Beppu Hospital using voice, 2D, and 3D drawing annotations. All robot operations were performed using 3D images, and only the annotations were independently switched between voice and 2D and 3D images. The operation time, needle movement, and performance were also evaluated. RESULTS: The 3D annotation group tended to have a shorter working time than the control group (25.6 ± 63.2 vs. - 36.7 ± 65.4 min, P = 0.06). The 3D annotation group had fewer retries than the control group (1.3 ± 1.7 vs. - 1.1 ± 0.7, P = 0.006), and there was a tendency for fewer needle drops (0.4 ± 0.7 vs. - 0.5 ± 0.9, P = 0.06). The 3D annotation group scored significantly higher than the control group on the Global Evaluate Assessment of Robot Skills (16.8 ± 2.0 vs. 22.8 ± 2.4, P = 0.04). The 3D annotation group also scored higher than the voice (13.4 ± 1.2) and 2D annotation (16.2 ± 1.8) groups (3D vs. voice: P = 0.03, 3D vs. 2D: P = 0.03). CONCLUSION: Telementoring using 3D drawing annotation was shown to provide good comprehension and a smooth operation for local surgeons.

Subclonal accumulation of immune escape mechanisms in microsatellite instability-high colorectal cancers.

BACKGROUND: Intratumor heterogeneity (ITH) in microsatellite instability-high (MSI-H) colorectal cancer (CRC) has been poorly studied. We aimed to clarify how the ITH of MSI-H CRCs is generated in cancer evolution and how immune selective pressure affects ITH. METHODS: We reanalyzed public whole-exome sequencing data on 246 MSI-H CRCs. In addition, we performed a multi-region analysis from 6 MSI-H CRCs. To verify the process of subclonal immune escape accumulation, a novel computational model of cancer evolution under immune pressure was developed. RESULTS: Our analysis presented the enrichment of functional genomic alterations in antigen-presentation machinery (APM). Associative analysis of neoantigens indicated the generation of immune escape mechanisms via HLA alterations. Multiregion analysis revealed the clonal acquisition of driver mutations and subclonal accumulation of APM defects in MSI-H CRCs. Examination of variant allele frequencies demonstrated that subclonal mutations tend to be subjected to selective sweep. Computational simulations of tumour progression with the interaction of immune cells successfully verified the subclonal accumulation of immune escape mutations and suggested the efficacy of early initiation of an immune checkpoint inhibitor (ICI) -based treatment. CONCLUSIONS: Our results demonstrate the heterogeneous acquisition of immune escape mechanisms in MSI-H CRCs by Darwinian selection, providing novel insights into ICI-based treatment strategies.

Successful multidisciplinary treatment with complete response to atezolizumab plus bevacizumab in a 90-year-old patient with hepatocellular carcinoma recurrence.

Atezolizumab plus bevacizumab is the first-line regimen in Japan for hepatocellular carcinoma following the results of the IMbrave 150 trial. However, the safety and efficiency of atezolizumab plus bevacizumab in older patients, especially in the oldest-old patients aged over 80 years, have not been thoroughly studied and is still controversial. Eighteen months ago, a 90-year-old woman underwent a laparoscopic hepatectomy (S6) for her primary hepatocellular carcinoma (S6, 2 cm). Nine months after the first surgery, she received transcatheter arterial chemoembolization treatment for solitary hepatocellular carcinoma recurrence (S8, 2 cm). The subsequent recurrence (S3, 1 cm; S5, 2 cm; S8, 1 cm) was uncovered by radiological assessment 1 year after transcatheter arterial chemoembolization treatment. We then initiated chemotherapy treatment with lenvatinib at 8 mg daily. Despite reducing the lenvatinib dosage, the adverse event of severe fatigue and asitia did not resolve; therefore, the regimen of atezolizumab + bevacizumab combination therapy was changed to be started. After the first 2 months, tumor regression was observed on computed tomography; the patient tolerated the atezolizumab + bevacizumab combination regimen over 8 months for 10 cycles without any adverse effects. She finally showed a complete response; no recurrence developed 1 year after the complete response. Therefore, older adult patients may benefit highly from atezolizumab plus bevacizumab with appropriate patient selection.

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.

Dynamic Changes in Peripheral Systemic Immunity Markers During Chemotherapy in HER2-negative Advanced Breast Cancer.

BACKGROUND/AIM: The immune system has a pivotal role in modulating the response to chemotherapy in breast cancer (BC). However, the immune status during chemotherapy remains unclear. We evaluated the sequential changes in peripheral systemic immunity markers in BC patients treated with various chemotherapeutic agents. MATERIALS AND METHODS: We examined the correlation between the peripheral systemic immunity markers, neutrophil-to-lymphocyte ratio (NLR), absolute lymphocyte count (ALC) and the local cytolytic activity (CYT) score obtained by quantitative reverse-transcription polymerase chain reaction of 84 preoperative BC patients. Next, we observed the sequential changes in the peripheral systemic immunity markers during treatment with four anticancer drugs: oral 5-fluorouracil derivative; S-1, epirubicin plus cyclophosphamide; paclitaxel plus the anti-vascular endothelial growth factor antibody bevacizumab, and eribulin in 172 HER2-negative advanced BC patients. Finally, we examined the correlation between the changes in the peripheral systemic immunity markers, time to treatment failure (TTF) and progression-free survival (PFS). RESULTS: A negative correlation was found between ALC and NLR. ALC-low and NLR-high cases were positively associated with CYT score-low cases. The ratio of ALC-increase and NLR-decrease varies depending on the anticancer drugs used. The responder group (TTF ≥3 months) had a higher NLR-decrease ratio than the nonresponder group (TTF <3 months). Patients with a high NLR-decrease ratio showed higher PFS. CONCLUSION: The change in ALC or NLR varies according to the anticancer drugs, suggesting differential immunomodulatory effects of the drugs. Furthermore, the change in NLR reflects the therapeutic efficacy of chemotherapy in advanced BC.

Identification of serum microRNAs as potential diagnostic biomarkers for detecting precancerous lesions of gastric cancer.

Aim: Gastric mucosal changes associated with chronic gastritis are known to be precancerous lesions of gastric cancer. We aimed to identify individuals with a high risk of gastric cancer by detection of microRNAs (miRNA) in the blood as biomarkers. Methods: Of 1206 individuals screened, 144 who were positive for Helicobacter pylori (H. pylori) by the serum antibody test and who underwent endoscopy were the subjects of this study. For the gross assessment of mucosal inflammation, we applied the Kimura-Takemoto classification, in which normal mucosa was defined as grade 0, and atrophy was categorized as grade 1 (C-1 and C-2), grade 2 (C-3 and O-1), and grade 3 (O-2 and O-3). Serum samples were divided into two phases and used for miRNA microarray profiling. We compared the expression of miRNAs in grade 3 mucosa and other grades. Expression in gastric cancer was confirmed with TCGA data. Results: miR-196b-3p was significantly upregulated, and miR-92a-2-5p was downregulated (P < .05 and q < 0.2). TCGA data showed a high expression of miR-196b-3p in gastric cancer cases (P < .001). Comparing grade 3 and the others, the area under the receiver operating characteristic curve using the detected miRNAs was as high as about 0.7. Furthermore, the combination of miRNAs resulted in higher accuracy. In terms of the significance of the combinatory mRNAs, the combination of three miRNAs (miR-196b-3p, miR-92a-2-5p, and miR-6791-3p) revealed high sensitivity and specificity, with the area under the curve exceeding 0.8. Conclusion: The identified combinatory miRNAs may represent promising biomarkers of precancerous lesions in gastric cancer.

Rab27b, a Regulator of Exosome Secretion, Is Associated With Peritoneal Metastases in Gastric Cancer.

BACKGROUND/AIM: Peritoneal metastasis (PM) of gastric cancer (GC) leads to poor clinical outcomes. Tumor-derived exosomes promote metastasis via communication between tumor cells and host cells. In this study, we investigated the effect of Rab27, which is required for exosome secretion, on the PM of GC. MATERIALS AND METHODS: We established a stable knockdown of two Rab27 homologs, Rab27a and Rab27b, in human GC cells (58As9) with a high potential of PM. We examined the level of exosome secretion from Rab27-knockdown 58As9 cells by Western blotting and the ability of Rab27b knockdown to suppress PM in 58As9 cells using a mouse xenograft model. In vitro proliferation and invasion assays were performed in the Rab27b-knockdown cells. Next, Rab27b expression was evaluated in human GC tissues by immunohistochemistry. Finally, we assessed the clinicopathological and prognostic significance of Rab27b expression by RT-qPCR in both our and other TCGA datasets of GC. RESULTS: Rab27a and Rab27b knockdown in 58As9 cells decreased the secretion of exosomes, characterized by the endocytic marker CD63. Rab27b knockdown decreased PM in vivo without affecting the in vitro proliferation or invasion ability of 58As9 cells. In human GC tissues, Rab27b was overexpressed in tumor cells. The overall and recurrence-free survival rates were significantly lower in GC patients with high compared to low Rab27b mRNA expression in our and other TCGA datasets. CONCLUSION: Rab27b expression potentially serves as a poor prognostic biomarker, possibly affecting PM via exosome secretion from GC cells.

Clinicopathological features of appendiceal goblet cell adenocarcinoma in Japan: a multicenter retrospective study.

PURPOSE: In the 5th edition of the World Health Organization classification, appendiceal goblet cell adenocarcinoma (GCA) is categorized separately from neuroendocrine tumors and other appendiceal adenocarcinomas. We clarified the clinicopathological characteristics of Japanese appendiceal GCA. METHODS: We designed a retrospective multicenter cohort study and retrieved the data of patients with appendiceal neoplasms and histologically diagnosed appendiceal goblet cell carcinoid (GCC) treated from January 2000 to December 2017 in Japan. The available GCC slides were reviewed and diagnosed with a new grading system of GCA. RESULTS: A total of 922 patients from 43 institutions were enrolled; of these, 32 cases were patients with GCC (3.5%), and 20 cases were ultimately analyzed. The 5-year survival rate was 61.4% (95% confidence interval: 27.4-83.2), and the median survival time was 93.1 months. For peritoneal metastasis, regional lymph node metastasis was a significant factor (p = 0.04), and Grade 3 was a potential factor (p = 0.07). No peritoneal metastasis was observed in either T1/2 patients (n = 2) or Grade 1 patients (n = 4). We were unable to detect any significant factors associated with regional lymph node metastasis. CONCLUSION: For peritoneal metastasis, regional lymph node metastasis was a significant factor, and Grade 3 was a potential factor.

Molecular and clinicopathological differences between depressed and protruded T2 colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) can be classified into four consensus molecular subtypes (CMS) according to genomic aberrations and gene expression profiles. CMS is expected to be useful in predicting prognosis and selecting chemotherapy regimens. However, there are still no reports on the relationship between the morphology and CMS. METHODS: This retrospective study included 55 subjects with T2 CRC undergoing surgical resection, of whom 30 had the depressed type and 25 the protruded type. In the classification of the CMS, we first defined cases with deficient mismatch repair as CMS1. And then, CMS2/3 and CMS4 were classified using an online classifier developed by Trinh et al. The staining intensity of CDX2, HTR2B, FRMD6, ZEB1, and KER and the percentage contents of CDX2, FRMD6, and KER are input into the classifier to obtain automatic output classifying the specimen as CMS2/3 or CMS4. RESULTS: According to the results yielded by the online classifier, of the 30 depressed-type cases, 15 (50%) were classified as CMS2/3 and 15 (50%) as CMS4. Of the 25 protruded-type cases, 3 (12%) were classified as CMS1 and 22 (88%) as CMS2/3. All of the T2 CRCs classified as CMS4 were depressed CRCs. More malignant pathological findings such as lymphatic invasion were associated with the depressed rather than protruded T2 CRC cases. CONCLUSIONS: Depressed-type T2 CRC had a significant association with CMS4, showing more malignant pathological findings such as lymphatic invasion than the protruded-type, which could explain the reported association between CMS4 CRC and poor prognosis.

Influence of Robotic Rectal Resection Versus Laparoscopic Rectal Resection on Postoperative Ileus: A Single-center Experience.

AIM: This study was performed to clarify the relationship between robotic rectal resection and postoperative ileus (POI) by comparing robotic surgery with laparoscopic surgery. MATERIALS AND METHODS: We retrospectively reviewed 238 patients who underwent robotic (n=41) or laparoscopic (n=197) rectal resection for rectal cancer in our institution from January 2013 to June 2020. First, we compared the background factors and short-term surgical outcomes between robotic and laparoscopic surgery. Next, we investigated the postoperative complications of robotic and laparoscopic rectal resection. Finally, we identified the risk factors for POI following rectal cancer resection. RESULTS: The percentages of patients with an Rb tumor location, treatment by abdominoperitoneal resection/intersphincteric resection/low anterior resection, a temporary diverting ileostomy, and a long operation time were significantly higher in robotic than laparoscopic surgery ( P <0.0001, P =0.0002, P =0.0078, and P =0.0001, respectively). There was no significant difference in any individual postoperative complication between robotic and laparoscopic surgery. Risk factors for POI were male sex ( P =0.0078), neoadjuvant chemoradiotherapy ( P =0.0007), an Rb tumor location ( P =0.0005), treatment by abdominoperitoneal resection/intersphincteric resection/low anterior resection ( P =0.0044), a temporary diverting ileostomy ( P <0.0001), and operation time of ≥240 minutes ( P =0.0024). Notably, robotic surgery was not a risk factor for POI following rectal resection relative to laparoscopic surgery. CONCLUSION: Although patients who underwent robotic surgery had more risk factors for POI, the risk of POI was similar between robotic and laparoscopic rectal resection.

Characteristics of anal canal cancer in Japan.

Anal canal cancer (ACC) has been reported to be an uncommon cancer in Japan, as in the USA, Europe, and Australia. This retrospective multi-institutional study was conducted to clarify the characteristics of ACC in Japan. First, the histological ACC type cases treated between 1991 and 2015 were collected. A detailed analysis of the characteristics of anal canal squamous cell carcinoma (SCC) cases was then conducted. The results of the histological types revealed that of the 1781 ACC cases, 435 cases (24.4%) including seven cases of adenosquamous cell carcinomas were SCC and 1260 cases (70.7%) were adenocarcinoma. However, the most common histological type reported in the USA, Europe, and Australia is SCC. Most ACC cases are adenocarcinomas and there is a low incidence of SCC in Japan which is different from the above-mentioned countries. Moreover, we reclassified T4 into the following two groups based on tumor size: T4a (tumor diameter of 5 cm or less) and T4b (tumor diameter of more than 5 cm). The results of the TNM classification of SCC revealed that the hazard ratio (HR) to T1 of T2, T3, T4a, and T4b was 2.45, 2.28, 2.89, and 4.97, respectively. As T4b cases had a worse prognosis than T4a cases, we propose that T4 for anal canal SCC in Japan be subclassified into T4a and T4b.

Clinical impact of the triple-layered circular stapler for reducing the anastomotic leakage in rectal cancer surgery: Porcine model and multicenter retrospective cohort analysis.

Aim: To investigate the impact of the triple-layered circular stapler compared with the double-layered circular stapler on anastomotic leakage after rectal cancer surgery. Methods: The bursting pressure was compared between porcine ileocolic anastomoses created using a double- or triple-layered stapler. We also retrospectively analyzed the incidence of severe anastomotic leakage in 194 patients who underwent colorectal anastomosis using a double- or triple-layered circular stapler during rectal cancer resection performed in two cancer centers between January 2015 and April 2021. Results: In the porcine model, the bursting pressure was higher in anastomoses created using the triple-layered stapler than the double-layered stapler (end-to-end anastomosis: 26.4 ± 6.2 mm Hg vs 14.5 ± 4.3 mm Hg, P = .0031; side-to-side anastomosis: 27.7 ± 5.0 mm Hg vs 18.0 ± 2.9 mm Hg, P = .0275). Intersectional leakage occurred in 41% and 83% of anastomoses created using the triple- or double-layered stapler, respectively (P = .0821). In the clinical cohort, the double- and triple-layered stapler was used in 153 and 41 patients, respectively. The incidence of anastomotic leakage was lower for anastomoses created using the triple-layered stapler vs the double-layered stapler (0.0% vs 5.8%, P = .0362). In multivariate analysis, the factors independently associated with a lower incidence of anastomotic leakage were female sex (odds ratio: 0.16, 95% confidence interval: 0.01-0.90, P = .0354) and triple-layered stapler usage (odds ratio: 0.00, 95% confidence interval: 0.00-0.96, P = .0465). Conclusion: Anastomoses created using a triple-layered circular stapler had high bursting pressure, which might contribute to a lower incidence of anastomotic leakage after rectal cancer surgery.

The effects of ARID1A mutations on colorectal cancer and associations with PD-L1 expression by stromal cells.

BACKGROUND: ARID1A is a component of the SWI/SNF complex, which controls the accessibility of proteins to DNA. ARID1A mutations are frequently observed in colorectal cancers (CRCs) and have been reported to be associated with high mutational burden and tumor PD-L1 expression in vitro. AIM: To clarify the role of ARID1A mutation in CRC. METHOD AND RESULTS: We used next generation sequencing (NGS) and immunohistochemistry on clinically obtained samples. A total of 201 CRC tissues from Niigata University and Niigata Center Hospital were processed by NGS using the CANCERPLEX panel. Immunohistochemistry for ARID1A, PD-L1, MLH1, and MSH2 was performed on 66 propensity-matched (33 microsatellite instability-high [MSI-H] and 33 microsatellite-stable [MSS]) cases among 499 cases from Kyushu University. TCGA data were downloaded from cBioPortal. NGS showed significantly more mutations in ARID1A mutated CRCs (p = 0.01), and the trend was stronger for right-sided CRCs than left-sided. TCGA data confirmed these findings (p < 0.01). BRAF V600E and ATM mutations were also found at higher frequencies. Immunohistochemistry showed that 30% of MSI-H CRCs had ARID1A loss, while this was true in only 6% of MSS CRCs. In both MSI-H and MSS, PD-L1 expression by stromal cells was enhanced in the ARID1A-mutant groups (90% vs 39% in MSI-H, 100% vs 26% in MSS). CONCLUSION: We found a higher mutational burden in ARID1A-mutant CRCs, and IHC study showed that ARID1A loss was correlated with high PD-L1 expression in stromal cells regardless of MSI status. These data support the idea that mutant ARID1A is a potential biomarker for CRCs.

Clinical significance of signal regulatory protein alpha (SIRPα) expression in esophageal squamous cell carcinoma.

Signal regulatory protein alpha (SIRPα) is a type I transmembrane protein that inhibits macrophage phagocytosis of tumor cells upon interaction with CD47, and the CD47-SIRPα pathway acts as an immune checkpoint factor in cancers. This study aims to clarify the clinical significance of SIRPα expression in esophageal squamous cell carcinoma (ESCC). First, we assessed SIRPα expression using RNA sequencing data of 95 ESCC tissues from The Cancer Genome Atlas (TCGA) and immunohistochemical analytic data from our cohort of 131 patients with ESCC. Next, we investigated the correlation of SIRPα expression with clinicopathological factors, patient survival, infiltration of tumor immune cells, and expression of programmed cell death-ligand 1 (PD-L1). Overall survival was significantly poorer with high SIRPα expression than with low expression in both TCGA and our patient cohort (P < .001 and P = .027, respectively). High SIRPα expression was associated with greater depth of tumor invasion (P = .0017). Expression of SIRPα was also significantly correlated with the tumor infiltration of M1 macrophages, M2 macrophages, CD8+ T cells, and PD-L1 expression (P < .001, P < .001, P = .03, and P < .001, respectively). Moreover, patients with SIRPα/PD-L1 coexpression tended to have a worse prognosis than patients with expression of either protein alone or neither. Taken together, SIRPα indicates poor prognosis in ESCC, possibly through inhibiting macrophage phagocytosis of tumor cells and inducing suppression of antitumor immunity. Signal regulatory protein alpha should be considered as a potential therapeutic target in ESCC, especially if combined with PD-1-PD-L1 blockade.