Real-time detection of active bleeding in laparoscopic colectomy using artificial intelligence

BACKGROUND

Most intraoperative adverse events (iAEs) result from surgeons' errors, and bleeding is the majority of iAEs. Recognizing active bleeding timely is important to ensure safe surgery, and artificial intelligence (AI) has great potential for detecting active bleeding and providing real-time surgical support. This study aimed to develop a real-time AI model to detect active intraoperative bleeding.

METHODS

We extracted 27 surgical videos from a nationwide multi-institutional surgical video database in Japan and divided them at the patient level into three sets: training (n = 21), validation (n = 3), and testing (n = 3). We subsequently extracted the bleeding scenes and labeled distinctively active bleeding and blood pooling frame by frame. We used pre-trained YOLOv7_6w and developed a model to learn both active bleeding and blood pooling. The Average Precision at an Intersection over Union threshold of 0.5 (AP.50) for active bleeding and frames per second (FPS) were quantified. In addition, we conducted two 5-point Likert scales (5 = Excellent, 4 = Good, 3 = Fair, 2 = Poor, and 1 = Fail) questionnaires about sensitivity (the sensitivity score) and number of overdetection areas (the overdetection score) to investigate the surgeons' assessment.

RESULTS

We annotated 34,117 images of 254 bleeding events. The AP.50 for active bleeding in the developed model was 0.574 and the FPS was 48.5. Twenty surgeons answered two questionnaires, indicating a sensitivity score of 4.92 and an overdetection score of 4.62 for the model.

CONCLUSIONS

We developed an AI model to detect active bleeding, achieving real-time processing speed. Our AI model can be used to provide real-time surgical support.

Midesophageal diverticulum with elevated intrabolus pressure: a case report

BACKGROUND

Esophageal diverticulum is commonly associated with esophageal motility disorders, which can be diagnosed using high-resolution manometry (HRM) according to the Chicago classification. Although midesophageal diverticulum (M-ED) is associated with inflammatory processes, esophageal motility disorders have been recently identified as an etiology of M-ED.

CASE PRESENTATION

We present the case of a patient with M-ED and elevated intrabolus pressure (IBP), which did not meet the criteria for esophageal motility disorders according to the Chicago classification. A 71-year-old man presented with gradually worsening dysphagia for two years and was diagnosed as having an 8-cm-long M-ED and multiple small diverticula in lower esophagus. HRM revealed a median integrated relaxation pressure of 14.6 mmHg, a distal latency of 6.4 s, and an average maximum IBP of 35.7 mmHg. He underwent thoracoscopic resection of the M-ED and myotomy, which successfully alleviated the symptoms and reduced the intrabolus pressure to normal levels.

CONCLUSIONS

It is important to recognize the esophageal diverticulum pathology with HRM findings even in cases where the results may not meet the Chicago classification and to include myotomy based on the results.

A case of laparoscopic lymphadenectomy for adenocarcinoma of unknown primary incidentally detected as a solitary enlarged lymph node along the common hepatic artery

BACKGROUND

Even in cancer of unknown primary (CUP), which is rare clinical condition, solitary anterosuperior lymph node (LN) along the common hepatic artery (No.8a LN) enlargement diagnosed as metastatic adenocarcinoma has never been reported.

CASE PRESENTATION

A 68-year-old Japanese male, with a history of early gastric cancer that had been completely treated by endoscopic submucosal dissection 26 years ago, was detected a single enlarged nodule along the common hepatic artery, No.8a LN, incidentally by computed tomography performed for monitoring of interstitial pneumonia. Endoscopic ultra-sound-guided fine needle aspiration revealed that this nodule was adenocarcinoma suggestive of metastasis, but other imaging studies, including upper and lower gastrointestinal endoscopy, positron emission tomography, and ultrasonography did not detect any primary cancer. We have finally diagnosed as the LN metastasis of CUP and performed laparoscopic lymphadenectomy for this tumor. The tumor was approximately 5 cm in size, was in close proximity to the pancreas, and involved part of the right gastric artery and vein. LNs in the No.5 and No.8a areas, including this tumor, were dissected laparoscopically, and radical resection was achieved. The patient had no postoperative complication and was discharged on postoperative day 10. Immunohistopathological findings revealed that the tumor was poorly differentiated adenocarcinoma, and different from the histology of gastric cancer resected 26 years ago, although the tumor was suggestive of gastrointestinal origin. Imaging studies performed 2 and 6 months after discharge also did not reveal a primary site.

CONCLUSION

We reported a case of solitary No.8a LN adenocarcinoma of CUP. For diagnostic and therapeutic purposes, radical resection is recommended for single enlarged intra-abdominal LN of CUP.

Utility of articulating instruments as an alternative to robotic devices in laparoscopic right hemicolectomy

Laparoscopic complete mesocolic excision with central vessel ligation has been widely accepted for its oncological benefits in colon cancer surgery. However, laparoscopic right hemicolectomy involves a risk for vascular injury during dissection around the surgical trunk. This technical difficulty has been attributed to the limited movement of conventional laparoscopic forceps. Although robotic devices can overcome the restricted motion of laparoscopic devices, they are not yet widely used. The ArtiSential is an articulating laparoscopic instrument that has a two-joint end-effector that enables a wide range of motion precisely reflecting the surgeon's finger movements, and is designed to compensate for the drawbacks of conventional laparoscopic tools. The present study demonstrated the utility of articulating instruments in laparoscopic right hemicolectomy by comparing the authors' laparoscopic procedures, using articulating instruments, with robotic procedures. Articulating laparoscopic instruments can be successfully maneuvered in virtually the same manner as robotic devices and, as such, represent a viable alternative to robotic surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13691-024-00654-w.

Anterior versus posterior mediastinal reconstruction after esophagectomy in esophageal cancer patients: a systematic review and meta-analysis

PURPOSE

Esophagectomy is the primary surgical treatment for esophageal cancer, although other treatment approaches are often incorporated, including preoperative chemotherapy and chemoradiotherapy. The two major routes of esophageal reconstruction after esophagectomy are the anterior mediastinal (retrosternal, heterotopic) and posterior mediastinal (prevertebral, orthotopic) routes. However, which of these two routes of reconstruction is the most appropriate remains controversial. This systematic review aimed to compare the efficacy and safety of anterior mediastinal reconstruction with those of posterior mediastinal reconstruction after esophagectomy in esophageal cancer.

METHODS

In January 2022, a literature search of the CENTRAL, MEDLINE, and EMBASE databases was conducted to identify all published and unpublished randomized controlled trials, regardless of language. Eight studies were included for quantitative synthesis.

RESULTS

Postoperative death (9/129 and 4/125, risk ratio [RR]: 2.07, 95% confidence interval [CI]: 0.65-6.64) and incidence of anastomotic leak (24/208 and 26/208, RR: 0.95, 95% CI: 0.56-1.62) were not significantly different between the two mediastinal reconstructions. We could not perform a meta-analysis for quality of life, loss of body weight, or postoperative hospital stay due to data limitations.

CONCLUSION

Overall, there was low-quality evidence to suggest that the outcomes of the anterior and posterior mediastinal routes of reconstruction are not significantly different in patients with esophageal cancer.

Prediction for oxaliplatin-induced liver injury using patient-derived liver organoids

BACKGROUND

Liver injury associated with oxaliplatin (L-OHP)-based chemotherapy can significantly impact the treatment outcomes of patients with colorectal cancer liver metastases, especially when combined with surgery. To date, no definitive biomarker that can predict the risk of liver injury has been identified. This study aimed to investigate whether organoids can be used as tools to predict the risk of liver injury.

METHODS

We examined the relationship between the clinical signs of L-OHP-induced liver injury and the responses of patient-derived liver organoids in vitro. Organoids were established from noncancerous liver tissues obtained from 10 patients who underwent L-OHP-based chemotherapy and hepatectomy for colorectal cancer.

RESULTS

Organoids cultured in a galactose differentiation medium, which can activate the mitochondria of organoids, showed sensitivity to L-OHP cytotoxicity, which was significantly related to clinical liver toxicity induced by L-OHP treatment. Organoids from patients who presented with a high-grade liver injury to the L-OHP regimen showed an obvious increase in mitochondrial superoxide levels and a significant decrease in mitochondrial membrane potential with L-OHP exposure. L-OHP-induced mitochondrial oxidative stress was not observed in the organoids from patients with low-grade liver injury.

CONCLUSIONS

These results suggested that L-OHP-induced liver injury may be caused by mitochondrial oxidative damage. Furthermore, patient-derived liver organoids may be used to assess susceptibility to L-OHP-induced liver injury in individual patients.

Paneth-like cells produced from OLFM4+ stem cells support OLFM4+ stem cell growth in advanced colorectal cancer

Tumor tissues consist of heterogeneous cells that originate from stem cells; however, their cell fate determination program remains incompletely understood. Using patient-derived organoids established from patients with advanced colorectal cancer (CRC), we evaluated the potential of olfactomedin 4 (OLFM4)+ stem cells to produce a bifurcated lineage of progenies with absorptive and secretory properties. In the early phases of organoid reconstruction, OLFM4+ cells preferentially gave rise to secretory cells. Additionally, we found that Paneth-like cells, which do not exist in the normal colon, were induced in response to Notch signaling inhibition. Video recordings of single OLFM4+ cells revealed that organoids containing Paneth-like cells were effectively propagated and that their selective ablation led to organoid collapse. In tumor tissues, Paneth-like cells were identified only in the region where tumor cells lost cell adhesion. These findings indicate that Paneth-like cells are directly produced by OLFM4+ stem cells and that their interaction contributes to tumor formation by providing niche factors. This study reveals the importance of the cell fate specification program for building a complete tumor cellular ecosystem, which might be targeted with novel therapeutics.

Impact of the coronavirus disease 2019 pandemic on gastric and colorectal cancer surgeries: a multicenter epidemiologic study from the Kinki region of Japan

The coronavirus disease 2019 pandemic affected cancer surgeries and advanced cancer diagnoses; however, the trends in patient characteristics in medical institutions during this time, and the surgical approaches used are unclear. We investigated the impact of the pandemic on gastric and colorectal cancer surgeries in the Kinki region of Japan. We grouped 1688 gastric and 3493 colorectal cancer surgeries into three periods: "pre-pandemic" (April 2019-March 2020), "pandemic 1" (April 2020-March 2021), and "pandemic 2" (April 2021-September 2021), to investigate changes in the number of surgeries, patient characteristics, surgical approaches, and cancer progression after surgery. Gastric and colorectal cancer surgeries decreased from the pre-pandemic levels, by 20% and 4%, respectively, in pandemic 1, and by 31% and 19%, respectively, in pandemic 2. This decrease had not recovered to pre-pandemic levels by September, 2021. Patient characteristics, surgical approaches, and cancer progression of gastric and colorectal surgeries did not change remarkably as a result of the coronavirus disease 2019 pandemic.

Lineage tracing of T cell differentiation from T-iPSC by 2D feeder-free culture and 3D organoid culture

Introduction

T cells induced from induced pluripotent stem cells(iPSCs) derived from antigen-specific T cells (T-iPS-T cells) are an attractive tool for T cell immunotherapy. The induction of cytotoxic T-iPS-T cells is well established in feeder-free condition for the aim of off-the-shelf production, however, the induction of helper T-iPS-T cells remains challenging.

Methods

We analyzed T-iPS-T cells matured in 3D organoid culture at different steps in the culture process at the single-cell level. T-iPS-T cell datasets were merged with an available human thymocyte dataset based in single-cell RNA sequencing (scRNA-seq). Particularly, we searched for genes crucial for generation CD4+ T-iPS-T cells by comparing T-iPS-T cells established in 2D feeder-free or 3D organoid culture.

Results

The scRNA-seq data indicated that T-iPS-T cells are similar to T cells transitioning to human thymocytes, with SELENOW, GIMAP4, 7, SATB1, SALMF1, IL7R, SYTL2, S100A11, STAT1, IFITM1, LZTFL1 and SOX4 identified as candidate genes for the 2D feeder-free induction of CD4+ T-iPS-T cells.

Discussion

This study provides single cell transcriptome datasets of iPS-T cells and leads to further analysis for CD4+ T cell generation from T-iPSCs.

Downregulation of osteoprotegerin in colorectal cancer cells promotes liver metastasis via activating tumor-associated macrophage

Osteoprotegerin (OPG) is a secreted cytokine that functions as a decoy receptor for receptor activator of nuclear factor kappa-B (RANK) ligand (RANKL). Anti-RANKL treatment for bone metastasis has been widely accepted for solid tumors. However, the mechanism of OPG-RANKL-RANK signaling in systemic colorectal cancer (CRC) metastasis remains unclear. In this study, we investigated the relevance and function of OPG expression in CRC liver metastasis. First, we performed in silico analysis using The Cancer Genome Atlas public database and found that lower OPG expression in CRC was associated with poor overall survival. Immunohistochemistry analyses using resected specimen from patients with CRC in our institute confirmed the result. Patient-matched primary CRC and liver metastases showed a significant downregulation of OPG expression in metastatic lesions. In CRC cell lines, OPG expression did not suppress cell proliferation and migration. However, OPG expression inhibited macrophage migration by suppressing the RANKL-RANK pathway. Moreover, in vivo mouse liver metastasis models showed that OPG expression in CRC cells suppressed liver metastases. In addition, treatment with an anti-RANKL neutralizing antibody also suppressed liver metastases. These results showed that downregulation of OPG expression in CRC cells promotes liver metastasis by activating tumor-associated macrophage, which can become a candidate for targeted therapy with anti-RANKL neutralizing antibody for CRC liver metastasis.

Factors Associated With Postoperative Decisional Regret in Patients Undergoing Gastrointestinal Cancer Surgery: A Prospective Cohort Study

BACKGROUND

Surgery is recommended as the first-line treatment option to cure resectable gastrointestinal (GI) cancer. However, patients occasionally feel postoperative regret after surgery. To date, it is not clear which factors are associated with patient regret after GI cancer surgery. The aim of this study was to investigate factors related to postoperative decision regret in patients undergoing surgery for GI cancer.

METHODS

The present prospective study used questionnaires to analyze postoperative decision regret in patients undergoing GI cancer surgery in our institution between February and July 2020. Decision regret that patients felt after surgery was quantitatively measured using the decision regret scale (DRS). Multivariable linear regression models were used to examine factors related to postoperative decision regret.

RESULTS

Among 70 patients analyzed, the median (interquartile range) DRS score was 10.0 (.0-25.0). Multivariable analysis showed that preoperative Trust in Physician Scale score (partial regression coefficient (B) = -.77; 95% confidence interval (CI) = -1.13 to -.41; P < .001) and postoperative complications (B = 9.17; 95% CI = 2.20 to 16.15; P = .0011) were significantly associated with DRS score.

DISCUSSION

Preoperative trust in physician and postoperative complications were significantly associated with postoperative decision regret in patients undergoing surgery for GI cancer. Although patients may regret their choice of surgery when postoperative complications occur, trust in their physician may help reduce feelings of regret.

Employment Status of Patients With Colorectal Cancer After Surgery: A Multicenter Prospective Cohort Study in Japan

BACKGROUND

Because of improved survival rates, patients with colorectal cancer may try to return to work. Many countries, however, have limited knowledge of the employment status of these patients.

OBJECTIVE

To explore the employment status of patients with colorectal cancer after surgery in Japan and the risk factors affecting the same.

DESIGN

This is a prospective multicenter cohort study that used self-administered questionnaires. Patients were recruited from June 2019 to August 2020 and were followed up for 12 months after surgery.

SETTING

Six community hospitals and 1 university hospital in Japan.

PATIENTS

Patients with clinical stages I to III colorectal cancer, employed at the time of diagnosis.

INTERVENTIONS

Patients who underwent surgical resection between June 2019 and August 2020.

MAIN OUTCOME MEASUREMENTS

The time it takes patients to return to work after surgery and the proportion of working patients 12 months after surgery were collected using self-administered questionnaires.

RESULTS

A total of 129 patients were included in the analyses. The median time to return-to-work was 1.1 months, and the proportion of working patients at 12 months after surgery was 79%. Risk factors for delayed return-to-work after surgery were an advanced tumor stage, stoma, severe postoperative complications, shorter years of service at the workplace, and lower willingness to return-to-work. Risk factors for not working 12 months after surgery were stoma, lower willingness to return-to-work, nonregular employee status, lower income, national health insurance, and no private medical insurance.

LIMITATIONS

This study is limited by its short-term follow-up and small sample size.

CONCLUSIONS

This study revealed that Japanese patients with stages I to III colorectal cancer found favorable employment outcomes in the 12 months after surgery. These results may help health care providers better understand the employment status of patients with colorectal cancer and encourage them to consider returning to work after surgery.

SITUACIN LABORAL DE LOS PACIENTES CON CNCER COLORRECTAL DESPUS DE LA CIRUGA UN ESTUDIO DE COHORTE PROSPECTIVO MULTICNTRICO EN JAPN

ANTECEDENTES:Debido a las mejores tasas de supervivencia, los pacientes con cáncer colorrectal pueden intentar volver al trabajo. Muchos países, sin embargo, tienen un conocimiento limitado de su situación laboral.OBJETIVO:Explorar la situación laboral de los pacientes con cáncer colorrectal después de la cirugía en Japón y los factores de riesgo que afectan a la misma.DISEÑO:Este es un estudio prospectivo de cohortes multicéntrico que utiliza cuestionarios autoadministrados. Los pacientes fueron reclutados desde junio de 2019 hasta agosto de 2020 y fueron seguidos durante 12 meses después de la cirugía.ENTORNO CLINICO:Seis hospitales comunitarios y un hospital universitario en Japón.PACIENTES:Pacientes con estadios clínicos I-III de cáncer colorrectal, trabajando en el momento del diagnóstico.INTERVENCIONES:Pacientes que recibieron resección quirúrgica desde junio de 2019 hasta agosto de 2020.PRINCIPALES MEDIDAS DE RESULTADO:El tiempo que tardan los pacientes en volver al trabajo después de la cirugía y la proporción de pacientes que trabajan 12 meses después de la cirugía se recogieron mediante cuestionarios autoadministrados.RESULTADOS:Un total de 129 pacientes fueron incluidos en los análisis. La mediana de tiempo de reincorporación al trabajo fue de 1,1 meses y la proporción de pacientes que trabajaban a los 12 meses de la cirugía fue del 79%. Los factores de riesgo para el retraso en el regreso al trabajo después de la cirugía fueron un estadio avanzado del tumor, estoma, complicaciones postoperatorias graves, menos años de servicio en el lugar de trabajo y menor disposición para volver al trabajo. Los factores de riesgo para no trabajar 12 meses después de la cirugía fueron estoma, menor voluntad de volver al trabajo, condición de empleado no regular, ingresos más bajos, seguro nacional de salud y la falta de seguro médico privado.LIMITACIONES:Este estudio está limitado por su seguimiento a corto plazo y tamaño de muestra pequeño.CONCLUSIONES:Este estudio reveló que los pacientes japoneses con cáncer colorrectal en estadios I-III obtuvieron resultados laborales favorables en los 12 meses posteriores a la cirugía. Estos resultados pueden ayudar a los proveedores de atención médica a comprender mejor la situación laboral de los pacientes con cáncer colorrectal y alentarlos a considerar regresar al trabajo después de la cirugía. (Traducción- Dr. Francisco M. Abarca-Rendon ).

Analysis of the characteristics and outcomes of patients with pseudomyxoma peritonei of appendiceal origin treated with curative-intent surgery

BACKGROUND

There are no previous studies on pseudomyxoma peritonei regarding the details of surgical procedures included in cytoreductive surgery and quantitative evaluation for peritoneal metastases by region in the abdominal cavity. This study aimed to describe the characteristics and procedural details involved in cytoreductive surgery, and survival outcomes of patients with pseudomyxoma peritonei originating from appendiceal mucinous neoplasm, and identify differences in the difficulty of cytoreductive surgery based on tumor location.

METHODS

Patient characteristics and survival outcomes were studied through a retrospective review. The complete cytoreduction rate (i), the 5-year survival rate for patients with complete cytoreduction (ii), and an index as a complement (i × ii × 100) were described for patients who had tumors larger than 50 mm in one of the 13 regions of the abdominal cavity.

RESULTS

A total of 989 patients were treated with curative-intent cytoreductive surgery. The median peritoneal cancer index was 18 (interquartile range, 6-29), with complete cytoreduction achieved in 702 patients (71%); the major complication rate was 17%. The median overall survival was 92.9 months, compared to 53.8 months for patients who underwent total gastrectomy and 30.4 months for those who underwent total colectomy. In the 13 abdominal regions, the index scores indicating cytoreduction difficulty were categorized into three risk groups: upper and mid-abdominal (>20), lateral abdominal (10-20), and small bowel (<10).

CONCLUSIONS

Cytoreductive surgery offered favorable survival outcomes, even in cases involving total gastrectomy. The difficulty of achieving complete cytoreduction varied across abdominal regions and was classified into three levels.

Identification of complications requiring interventions after gastrointestinal cancer surgery from real-world data: An external validation study

Background

Recently, real-world data have been recognized to have a significant role for research and quality improvement worldwide. The decision on the existence or nonexistence of postoperative complications is complex in clinical practice. This multicenter validation study aimed to evaluate the accuracy of identification of patients who underwent gastrointestinal (GI) cancer surgery and extraction of postoperative complications from Japanese administrative claims data.

Methods

We compared data extracted from both the Diagnosis Procedure Combination (DPC) and chart review of patients who underwent GI cancer surgery from April 2016 to March 2019. Using data of 658 patients at Kyoto University Hospital, we developed algorithms for the extraction of patients and postoperative complications requiring interventions, which included an invasive procedure, reoperation, mechanical ventilation, hemodialysis, intensive care unit management, and in-hospital mortality. The accuracy of the algorithms was externally validated using the data of 1708 patients at two other hospitals.

Results

In the overall validation set, 1694 of 1708 eligible patients were correctly extracted by DPC (sensitivity 0.992 and positive predictive value 0.992). All postoperative complications requiring interventions had a sensitivity of >0.798 and a specificity of almost 1.000. The overall sensitivity and specificity of Clavien-Dindo ≥grade IIIb complications was 1.000 and 0.995, respectively.

Conclusion

Patients undergoing GI cancer surgery and postoperative complications requiring interventions can be accurately identified using the real-world data. This multicenter external validation study may contribute to future research on hospital quality improvement or to a large-scale comparison study among nationwide hospitals using real-world data.

Management of Patients Receiving Antiplatelet Therapy During Gastroenterological Surgery: A Multicenter Prospective Cohort Study (GSATT)

OBJECTIVE

This study aimed to evaluate the effect of continuing preoperative aspirin monotherapy on surgical outcomes in patients receiving antiplatelet therapy (APT).

SUMMARY BACKGROUND DATA

The effectiveness of continuing preoperative aspirin monotherapy in patients undergoing APT in preventing thromboembolic consequences is mostly unknown.

METHODS

This prospective multicenter cohort study on the Safety and Feasibility of Gastroenterological Surgery in Patients Undergoing Antithrombotic Therapy (GSATT study) conducted at 14 clinical centers enrolled and screened patients between October 2019 and December 2021. The participants (n=1,170) were assigned to the continued APT group, discontinued APT group, or non-APT group, and the surgical outcomes of each group were compared. Propensity score matching was performed between the continued and discontinued APT groups to investigate the effect of continuing preoperative aspirin therapy on thromboembolic complications.

RESULTS

The rate of thromboembolic complications in the continued APT group was substantially lower than that in the non-APT or discontinued APT groups (0.5% vs. 2.6% vs. 2.9%; P=0.027). Multivariate investigation of the entire cohort revealed that discontinuation of APT (P<0.001) and chronic anticoagulant use (P<0.001) were independent risk factors for postoperative thromboembolism. The post-matching evaluation demonstrated that the rates of thromboembolic complications were significantly different between the continued and discontinued APT groups (0.6% vs. 3.3%; P=0.012).

CONCLUSIONS

APT discontinuation following elective gastroenterological surgery increases the risk of thromboembolic consequences, whereas continuing preoperative aspirin greatly reduces this risk. The continuation of preoperative aspirin therapy in APT-received patients is considered one of the best alternatives for preventing thromboembolism during elective gastroenterological surgery.

Mouse methylation profiles for leukocyte cell types, and estimation of leukocyte fractions in inflamed gastrointestinal DNA samples

Precise analysis of tissue DNA and RNA samples is often hampered by contaminating non-target cells whose amounts are highly variable. DNA methylation profiles are specific to cell types, and can be utilized for assessment of the fraction of such contaminating non-target cells. Here, we aimed 1) to identify methylation profiles specific to multiple types of mouse leukocytes, and 2) to estimate the fraction of leukocytes infiltrating inflamed tissues using DNA samples. First, genome-wide DNA methylation analysis was conducted for three myeloid-lineage cells and four lymphoid-lineage cells isolated by fluorescence-activated cell sorting after magnetic-activated cell sorting from leukocytes in the spleen. Clustering analysis using CpG sites within enhancers separated the three myeloid-lineage cells and four lymphoid-lineage cells while that using promoter CpG islands (TSS200CGIs) did not. Among the 266,108 CpG sites analyzed, one CpG site was specifically hypermethylated (β value ≥ 0.7) in B cells, and four, seven, 183, and 34 CpG sites were specifically hypomethylated (β value < 0.2) in CD4+ T cells, CD8+ T cells, B cells, and NK cells, respectively. Importantly, cell type-specific hypomethylated CpG sites were located at genes involved in cell type-specific biological functions. Then, marker CpG sites to estimate the leukocyte fraction in a tissue with leukocyte infiltration were selected, and an estimation algorithm was established. The fractions of infiltrating leukocytes were estimated to be 1.6-12.4% in the stomach (n = 10) with Helicobacter pylori-induced inflammation and 1.5-4.3% in the colon with dextran sulfate sodium-induced colitis (n = 4), and the fractions were highly correlated with those estimated histologically using Cd45-stained tissue sections [R = 0.811 (p = 0.004)]. These results showed that mouse methylation profiles at CpG sites within enhancers reflected leukocyte cell lineages, and the use of marker CpG sites successfully estimated the leukocyte fraction in inflamed gastric and colon tissues.

Total gastrectomy as a risk factor for postoperative loss of skeletal muscle in minimally invasive surgery for patients with gastric cancer

PURPOSE

Loss of skeletal muscle mass after gastrectomy for gastric cancer leads to decreased quality of life and poor postoperative survival. However, few studies have examined the postoperative loss of skeletal muscle mass following minimally invasive gastrectomy. This study investigated the impact of minimally invasive total gastrectomy (MI-TG) on changes in skeletal muscle mass during the early postoperative period.

METHODS

Patients who underwent MI-TG or minimally invasive distal or proximal gastrectomy (MI-nonTG) for cStage I-III gastric cancer were retrospectively analyzed (n = 58 vs. 182). Their body composition was measured before surgery and 2 months after surgery. Multivariable linear regression analysis was performed to clarify the impact of the surgical procedure on skeletal muscle index changes using clinically relevant covariates.

RESULTS

Skeletal muscle mass decreased more in the MI-TG group than in the MI-nonTG group (median [interquartile range]; -5.9% [-10.6, -3.7] vs -4.5% [-7.3, -1.9], P = 0.004). In multivariable linear regression analysis using clinically relevant covariates, MI-TG was an independent risk factor for postoperative loss of skeletal muscle mass (coefficient - 2.6%, 95% CI -4.5 to -0.68, P = 0.008).

CONCLUSIONS

Total gastrectomy was a risk factor for loss of skeletal muscle mass during the early postoperative period. If oncologically feasible, proximal or distal gastrectomy with a small remnant stomach should be considered.

Integrative analysis of cancer dependency data and comprehensive phosphoproteomics data revealed the EPHA2-PARD3 axis as a cancer vulnerability in KRAS-mutant colorectal cancer

Colorectal cancer (CRC), a common malignant tumour of the gastrointestinal tract, is a life-threatening cancer worldwide. Mutations in KRAS and BRAF, the major driver mutation subtypes in CRC, activate the RAS pathway, contribute to tumorigenesis in CRC and are being investigated as potential therapeutic targets. Despite recent advances in clinical trials targeting KRASG12C or RAS downstream signalling molecules for KRAS-mutant CRC, there is a lack of effective therapeutic interventions. Therefore, understanding the unique molecular characteristics of KRAS-mutant CRC is essential for identifying molecular targets and developing novel therapeutic interventions. We obtained in-depth proteomics and phosphoproteomics quantitative data for over 7900 proteins and 38 700 phosphorylation sites in cells from 35 CRC cell lines and performed informatic analyses, including proteomics-based coexpression analysis and correlation analysis between phosphoproteomics data and cancer dependency scores of the corresponding phosphoproteins. Our results revealed novel dysregulated protein-protein associations enriched specifically in KRAS-mutant cells. Our phosphoproteomics analysis revealed activation of EPHA2 kinase and downstream tight junction signalling in KRAS-mutant cells. Furthermore, the results implicate the phosphorylation site Y378 in the tight junction protein PARD3 as a cancer vulnerability in KRAS-mutant cells. Together, our large-scale phosphoproteomics and proteomics data across 35 steady-state CRC cell lines represent a valuable resource for understanding the molecular characteristics of oncogenic mutations. Our approach to predicting cancer dependency from phosphoproteomics data identified the EPHA2-PARD3 axis as a cancer vulnerability in KRAS-mutant CRC.

THBS1-producing tumor-infiltrating monocyte-like cells contribute to immunosuppression and metastasis in colorectal cancer

Mesenchymal activation, characterized by dense stromal infiltration of immune and mesenchymal cells, fuels the aggressiveness of colorectal cancers (CRC), driving progression and metastasis. Targetable molecules in the tumor microenvironment (TME) need to be identified to improve the outcome in CRC patients with this aggressive phenotype. This study reports a positive link between high thrombospondin-1 (THBS1) expression and mesenchymal characteristics, immunosuppression, and unfavorable CRC prognosis. Bone marrow-derived monocyte-like cells recruited by CXCL12 are the primary source of THBS1, which contributes to the development of metastasis by inducing cytotoxic T-cell exhaustion and impairing vascularization. Furthermore, in orthotopically generated CRC models in male mice, THBS1 loss in the TME renders tumors partially sensitive to immune checkpoint inhibitors and anti-cancer drugs. Our study establishes THBS1 as a potential biomarker for identifying mesenchymal CRC and as a critical suppressor of antitumor immunity that contributes to the progression of this malignancy with a poor prognosis.

Inhibition of the bone morphogenetic protein pathway suppresses tumor growth through downregulation of epidermal growth factor receptor in MEK/ERK-dependent colorectal cancer

The bone morphogenetic protein (BMP) pathway promotes differentiation and induces apoptosis in normal colorectal epithelial cells. However, its role in colorectal cancer (CRC) is controversial, where it can act as context-dependent tumor promoter or tumor suppressor. Here we have found that CRC cells reside in a BMP-rich environment based on curation of two publicly available RNA-sequencing databases. Suppression of BMP using a specific BMP inhibitor, LDN193189, suppresses the growth of select CRC organoids. Colorectal cancer organoids treated with LDN193189 showed a decrease in epidermal growth factor receptor, which was mediated by protein degradation induced by leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1) expression. Among 18 molecularly characterized CRC organoids, suppression of growth by BMP inhibition correlated with induction of LRIG1 gene expression. Notably, knockdown of LRIG1 in organoids diminished the growth-suppressive effect of LDN193189. Furthermore, in CRC organoids, which are susceptible to growth suppression by LDN193189, simultaneous treatment with LDN193189 and trametinib, an FDA-approved MEK inhibitor, resulted in cooperative growth inhibition both in vitro and in vivo. Taken together, the simultaneous inhibition of BMP and MEK could be a novel treatment option in CRC cases, and evaluating in vitro growth suppression and LRIG1 induction by BMP inhibition using patient-derived organoids could offer functional biomarkers for predicting potential responders to this regimen.

Impact of laparoscopic surgery on short-term and long-term outcomes in elderly obese patients with colon cancer

Background

Laparoscopic surgery is reported to be useful in obese or elderly patients with colon cancer, who are at increased risk of postoperative complications because of comorbidities and physical decline. However, its usefulness is less clear in patients who are both elderly and obese and may be at high risk of complications.

Methods

Data for obese patients (body mass index ≥25) who underwent laparoscopic or open surgery for stage II or III colon cancer between January 2009 and December 2013 were collected by the Japan Society of Laparoscopic Colorectal Surgery. Surgical outcomes, postoperative complications, and relapse-free survival (RFS) were compared between patients who underwent open surgery and those who underwent laparoscopic surgery according to whether they were elderly (≥70 y) or nonelderly (<70 y).

Results

Data of 1549 patients (elderly, n = 598; nonelderly, n = 951) satisfied the selection criteria for analysis. Length of stay was shorter and surgical wound infection was less common in elderly obese patients who underwent laparoscopic surgery than in those underwent open surgery. There were no significant between-group differences in overall complications, anastomotic leakage, ileus/small bowel obstruction, or RFS. There were also no significant differences in RFS after laparoscopic surgery according to patient age.

Conclusion

Laparoscopic surgery is safe in elderly obese patients with colon cancer and does not worsen their prognosis. There was no significant difference in the effectiveness of laparoscopic surgery between obese patients who were elderly and those who were nonelderly.

Postoperative recurrence in locally advanced rectal cancer: how does neoadjuvant treatment affect recurrence pattern?

BACKGROUND

The treatment strategy for locally advanced rectal cancer (LARC) has recently expanded from total mesorectal excision to additional neoadjuvant chemoradiotherapy (nCRT) and/or systemic chemotherapy (NAC). Data on disease recurrence after each treatment strategy are limited.

METHODS

Clinical stage II to III rectal cancer patients who underwent curative surgery between July 2005 and February 2021 were analyzed. The cumulative incidence and site of first recurrence were assessed. The median follow-up duration was 4.6 years.

RESULTS

Among the 332 patients, we performed nCRT and NAC in 15.4% (N=51) and 14.8% (N=49), respectively. The overall recurrence rate was 23.5% (N=78). Although several differences in tumor stage or location were observed, there was no significant difference in the rate among the surgery alone (N=54, 23.3%), nCRT (N=11, 21.6%), and NAC (N=13, 26.5%) groups. In this cohort, the local recurrence rate (18.4%) was higher than the rate of distant metastasis in the NAC group (14.3%). All patients with recurrence in the nCRT group had distant metastases (N=11: one patient had distant and local recurrences simultaneously). For pathological stage 0-I, the recurrence rate was higher in the nCRT and NAC groups than in the surgery-alone group (nCRT, 10.0%; NAC, 15.4%; and surgery-alone, 2.0%). Curative-intent resection of distant-only recurrences significantly improved patients' overall survival (hazard ratio [95% confidence interval], 0.34 [0.14-0.84]), which was consistent even when stratified according to neoadjuvant treatment. Regardless of neoadjuvant treatment, >80% of recurrences occurred in the first 2.2 years, and 98.7% within 5 years after surgery.

CONCLUSION

Regardless of neoadjuvant treatment, detecting distant metastases with intensive surveillance, particularly in the first 2 years after surgery, is important. Also, even if neoadjuvant treatment can downstage LARC to pathological stage 0-I, careful follow-up is needed.

Postoperative complications and prognosis based on type of surgery in ulcerative colitis patients with colorectal cancer: A multicenter observational study of data from the Japanese Society for Cancer of the Colon and Rectum

Background

Patients with ulcerative colitis are reported to be at increased risk of colorectal cancer and are also at high risk of postoperative complications. However, the incidence of postoperative complications in these patients and how the type of surgery performed affects prognosis are not well understood.

Methods

Data collected by the Japanese Society for Cancer of the Colon and Rectum on ulcerative colitis patients with colorectal cancer between January 1983 and December 2020 were analyzed according to whether total colorectal resection was performed with ileoanal anastomosis (IAA), ileoanal canal anastomosis (IACA), or permanent stoma creation. The incidence of postoperative complications and the prognosis for each surgical technique were investigated.

Results

The incidence of overall complications was not significantly different among the IAA, IACA, and stoma groups (32.7%, 32.3%, and 37.7%, respectively; p = 0.510). The incidence of infectious complications was significantly higher in the stoma group (21.2%) than in the IAA (12.9%) and IACA (14.6%) groups (p = 0.048); however, the noninfectious complication rate was lower in the stoma group (13.7%) than in the IAA (21.1%) and IACA (16.2%) groups (p = 0.088). Five-year relapse-free survival was higher in patients without complications than in those with complications in the IACA group (92.8% vs. 75.2%; p = 0.041) and the stoma group (78.1% vs. 71.2%, p = 0.333) but not in the IAA group (90.3% vs. 90.0%, p = 0.888).

Conclusion

The risks of infectious and noninfectious complications differed according to the type of surgical technique used. Postoperative complications worsened prognosis.

Novel and efficient method for culturing patient-derived gastric cancer stem cells

Experimental techniques for patient-derived cancer stem-cell organoids/spheroids can be powerful diagnostic tools for personalized chemotherapy. However, establishing their cultures from gastric cancer remains challenging due to low culture efficiency and cumbersome methods. To propagate gastric cancer cells as highly proliferative stem-cell spheroids in vitro, we initially used a similar method to that for colorectal cancer stem cells, which, unfortunately, resulted in a low success rate (25%, 18 of 71 cases). We scrutinized the protocol and found that the unsuccessful cases were largely caused by the paucity of cancer stem cells in the sampled tissues as well as insufficient culture media. To overcome these obstacles, we extensively revised our sample collection protocol and culture conditions. We then investigated the following second cohort and, consequently, achieved a significantly higher success rate (88%, 29 of 33 cases). One of the key improvements included new sampling procedures for tumor tissues from wider and deeper areas of gastric cancer specimens, which allowed securing cancer stem cells more reproducibly. Additionally, we embedded tumor epithelial pieces separately in both Matrigel and collagen type-I as their preference to the extracellular matrix was different depending on the tumors. We also added a low concentration of Wnt ligands to the culture, which helped the growth of occasional Wnt-responsive gastric cancer stem-cell spheroids without allowing proliferation of the normal gastric epithelial stem cells. This newly improved spheroid culture method may facilitate further studies, including personalized drug-sensitivity tests prior to drug therapy.

What can surgeons do to prevent job leave soon after cancer diagnosis? A brief report on colorectal cancer survivors in Japan

PURPOSE

Colorectal cancer is one of the most diagnosed cancers in Japan and the number of cancer survivors has increased. Work-related issues of cancer survivors have been investigated in relation to occupational health, and sufficient evidence in clinical practice is needed to support this. This study aimed to obtain the relevant information, intending to support the employment of patients with colorectal cancer for clinical settings.

METHODS

We conducted a prospective, multicenter cohort study, which included patients who underwent surgery with clinical stage I-III colorectal cancer. An electronic survey was used at the time of hospital admission to collect the patients' occupational information, including job resignation soon after cancer diagnosis. A cross-sectional analysis was performed to evaluate the patients' employment situations.

RESULTS

Of 129 eligible patients, 46 (36%) were female. Thirty-nine (30%) were self-employed and 72 (56%) worked at small-sized workplaces, which are not obliged to have occupational physicians. Most patients (89%) expressed their desire to return to work, but eight patients (6%) left their jobs soon after being diagnosed with colorectal cancer before undergoing surgery for several reasons stemming from worries about future treatment and its consequences. Multivariable analyses indicated that nonregular employees and the self-employed might be at a disadvantage in keeping their job at diagnosis.

CONCLUSION

Surgeons should address work-related issues for survivorship, which begins at cancer diagnosis and, when available, collaborate with occupational physicians while being mindful that patients working at smaller companies do not have immediate access to occupational physicians.

Abstract 978: Genomic characterization and risk stratification of colorectal cancer

Introduction: Adjuvant chemotherapy (ACT) has a key role in the treatment of high-risk colorectal cancer (CRC) patients to prevent post surgical recurrence. However, the efficacy of ACT is offset by the development of complication such as peripheral neuropathy, which leads to compromised quality of life, while ACT is expected to prevent tumor recurrence in only 5% and 20% in Stage2 and 3 patients, respectively. Thus, there is an urgent need to develop a biomarker that accurately predicts the effect of ACT and therefore helps guide ACT eligibility.

Methods: We enrolled a total of 3,023 cases with CRC, for whom targeted-capture sequencing was performed that covered 169 known or putative driver genes and 1,660 polymorphoic sites to detect somatic mutations and copy number alterations (CNAs), respectively. RNA sequencing was also performed to detect driver gene fusions and to profile gene expression. We identified, through univariate analysis, gene mutations/CNAs as well as clinical parameters using those cases who did not received ACT to establish a model that predict time to recurrence (TTR) using the Cox proportional hazard modelling. Thereafter, the model was applied to those who did receive ACT to assess the impact of the model in the prediction of TTR.

Results: We identified a total of 32145 mutations and/or 44511 CNAs in 2970 (98%) out of 3,023 cases. Mutations were found in 55 driver genes, including 15 previously unknown drivers, such as MAP2K1, AKT1, and TCF7. According to the number of mutations, 278 casese were classified as hypermutated cases. The remaining ‘non-hypermutated cases’ (n=2692) were classified into APC-mutated, RNF43/ZNRF3-mutated, CTNNB1-mutated, RSPO-fusion(+) and other Wnt-mutation(−) cases. The TTR prediction model was constructed by repeating Cox regression 1000 times using randomly selected 80% of the non-hypermutated cases and variables identified in univariate analysis. Adopting those variables selected in &gt;70% models, we established the final model including both genetic (mutations/CNAs) and clinical variables, based on which we classified patients into 4 risk groups, low/intermediate/high/very-high. Finally, by applying the classification to those who received ACT, we demonstrated that 18% of Stage2 and the majority of Stage3 cases with high/very-high risks were predicted to benefit from ACT, whereas most of the Stage2 and as many as 19% of Stage3 cases received ACT with no significant improvement of TTR. Approximately 5% of Stage1 cases belonged to the high-risk category and potentially benefit from ACT.

Conclusions: On the basis of large-scale genotyping of clinically well-annotated CRC cases, we proposed molecular classification of CRC and established a model that enabled prediction of TTR and risk stratification, which was successfully used to identify cases who benefited (within Stage 2/3 cases) or will benefit (in Stage1 cases) from ACT to prolong TTR.

Citation Format: Yoshikage Inoue, Nobuyuki Kakiuchi, Kenichi Yoshida, Yasuhito Nanya, Yasuhide Takeuchi, Yuichi Shiraishi, Kenichi Chiba, Tetusichi Yoshizato, Hiroko Tanaka, Satoshi Nagayama, Kazutaka Obama, Satoru Miyano, Seishi Ogawa. Genomic characterization and risk stratification of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 978.

Robotic gastrectomy for gastric cancer: systematic review and future directions

BACKGROUND

Robotic gastrectomy (RG) using the da Vinci Surgical System for gastric cancer was approved for national medical insurance coverage in Japan in April 2018, and its number has been rapidly increasing since then.

AIM

We reviewed and compared current evidence on RG and conventional laparoscopic gastrectomy (LG) to identify the differences in surgical outcomes.

METHODS

Three independent reviewers systematically reviewed the data collected from a comprehensive literature search by an independent organization, focusing on the following nine endpoints: mortality, morbidity, operative time, estimated blood loss volume, length of postoperative hospital stay, long-term oncologic outcome, quality of life, learning curve, and cost.

RESULTS

Compared to LG, RG has lower intraoperative blood loss volume, shorter length of hospital stay, and shorter learning curve, but both procedures have similar mortality. Contrarily, its disadvantages include longer procedural time and higher costs. Although the morbidity rate and long-term outcomes are almost comparable, RG showed superior potentials. Currently, the outcomes of RG are considered comparable to or better than LG.

CONCLUSION

RG might be applicable to all gastric cancer patients who fulfill the indication of LG at institutions that meet specific criteria and are approved to claim the National Health Insurance costs for the use of the surgical robot in Japan.

Total pelvic exenteration for mucinous adenocarcinoma arising from an implantation cyst 26 years after surgery for rectal cancer

A 47-year-old man underwent low anterior resection for rectal cancer and was surveilled for 5 years without metastasis. Twenty-four years later, the patient developed an implantation cyst at the anastomotic site. Two years after the diagnosis, colonoscopy revealed a disintegrated area in the lesion, and pathological examination of the biopsy specimen revealed adenocarcinoma. Due to the suspicion of invasion into the surrounding organs, the patient underwent laparoscopic total pelvic exenteration after neoadjuvant chemoradiotherapy. A transabdominal and transperineal endoscopic approach was used for safe en bloc excision of the tumor. Pathological examination of the specimen confirmed mucinous adenocarcinoma arising from the implantation cyst. Although an implantation cyst is considered benign, it is important to suspect malignant transformation when its appearance changes. For the accurate diagnosis of implantation cysts, surgeons, endoscopists, and radiologists should be aware of this disease.

Long-term results of a phase 2 study of neoadjuvant chemotherapy with molecularly targeted agents for locally advanced rectal cancer

BACKGROUND

We previously reported the feasibility and efficacy of neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer. Here, we report the results of a long-term follow-up study.

METHODS

This was a multi-institutional, prospective phase 2 study of patients with locally advanced rectal cancer. Patients received neoadjuvant chemotherapy with molecularly targeted agents before undergoing total mesorectal excision. Six cycles of modified FOLFOX (mFOLFOX6) with bevacizumab were administered to KRAS-mutant patients, and mFOLFOX6 with cetuximab was administered to KRAS-wild-type patients. Here, we report the secondary end points of overall survival, relapse-free survival, and local recurrence rate.

RESULTS

Sixty patients were enrolled in this study. R0 resection was achieved in 98.3% (59/60) patients, and pathological complete response was achieved in 16.7% (10/60) patients. After a median follow-up of 5.4 years, the 5 year overall survival was 81.6%, the 5 year relapse-free survival was 71.7%, and the 5 year local recurrence rate was 12.6%. None of the patients who achieved pathological complete response developed recurrence within 5 years.

CONCLUSIONS

The use of molecularly targeted agents in the neoadjuvant setting for locally advanced rectal cancer has an acceptable prognosis.

Differential involvement of LUBAC-mediated linear ubiquitination in intestinal epithelial cells and macrophages during intestinal inflammation

Disruption of the intestinal epithelial barrier and dysregulation of macrophages are major factors contributing to the pathogenesis of inflammatory bowel diseases (IBDs). Activation of NF-κB and cell death are involved in maintaining intestinal homeostasis in a cell type-dependent manner. Although both are regulated by linear ubiquitin chain assembly complex (LUBAC)-mediated linear ubiquitination, the physiological relevance of linear ubiquitination to intestinal inflammation remains unexplored. Here, we used two experimental mouse models of IBD (intraperitoneal LPS and oral dextran sodium sulfate [DSS] administration) to examine the role of linear ubiquitination in intestinal epithelial cells (IECs) and macrophages during intestinal inflammation. We did this by deleting the linear ubiquitination activity of LUBAC specifically from IECs or macrophages. Upon LPS administration, loss of ligase activity in IECs induced mucosal inflammation and augmented IEC death. LPS-mediated death of LUBAC-defective IECs was triggered by TNF. IEC death was rescued by an anti-TNF antibody, and TNF (but not LPS) induced apoptosis of organoids derived from LUBAC-defective IECs. However, augmented TNF-mediated IEC death did not overtly affect the severity of colitis after DSS administration. By contrast, defective LUBAC ligase activity in macrophages ameliorated DSS-induced colitis by attenuating both infiltration of macrophages and expression of inflammatory cytokines. Decreased production of macrophage chemoattractant MCP-1/CCL2, as well as pro-inflammatory IL-6 and TNF, occurred through impaired activation of NF-κB and ERK via loss of ligase activity in macrophages. Taken together, these results indicate that both intraperitoneal LPS and oral DSS administrations are beneficial for evaluating epithelial integrity under inflammatory conditions, as well as macrophage functions in the event of an epithelial barrier breach. The data clarify the cell-specific roles of linear ubiquitination as a critical regulator of TNF-mediated epithelial integrity and macrophage pro-inflammatory responses during intestinal inflammation. © 2022 The Pathological Society of Great Britain and Ireland.

Comparison of Minimally Invasive Surgery with Open Surgery for Remnant Gastric Cancer: A Multi-institutional Cohort Study

BACKGROUND

Despite growing evidence of the effectiveness of minimally invasive surgery (MIS) for primary gastric cancer, MIS for remnant gastric cancer (RGC) remains controversial due to the rarity of the disease. This study aimed to evaluate the surgical and oncological outcomes of MIS for radical resection of RGC.

PATIENTS AND METHODS

Patients with RGC who underwent surgery between 2005 and 2020 at 17 institutions were included, and a propensity score matching analysis was performed to compare the short- and long-term outcomes of MIS with open surgery.

RESULTS

A total of 327 patients were included in this study and 186 patients were analyzed after matching. The risk ratios for overall and severe complications were 0.76 [95% confidence interval (CI): 0.45, 1.27] and 0.65 (95% CI: 0.32, 1.29), respectively. The MIS group had significantly less blood loss [mean difference (MD), -409 mL; 95% CI: -538, -281] and a shorter hospital stay (MD, -6.5 days; 95% CI: -13.1, 0.1) than the open surgery group. The median follow-up duration of this cohort was 4.6 years, and the 3-year overall survival were 77.9% and 76.2% in the MIS and open surgery groups, respectively [hazard ratio (HR), 0.78; 95% CI: 0.45, 1.36]. The 3-year relapse-free survival were 71.9% and 62.2% in the MIS and open surgery groups, respectively (HR, 0.71; 95% CI: 0.44, 1.16).

CONCLUSIONS

MIS for RGC showed favorable short- and long-term outcomes compared to open surgery. MIS is a promising option for radical surgery for RGC.

Routine decompression by nasogastric tube after oesophagectomy for oesophageal cancer

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the effects of routine nasogastric decompression as compared to no nasogastric decompression after oesophagectomy. In the case of routine decompression, we will also aim to assess the effects of early versus late removal of the nasogastric tube.

Efficacious Combination Drug Treatment for Colorectal Cancer that Overcomes Resistance to KRAS G12C Inhibitors

Recent advances in combinatorial chemistry led to the discovery of inhibitors targeting the KRAS G12C mutant protein. However, efficacy of its monotherapy on colorectal cancer (CRC) is limited. Thus, effective combination drugs should be explored for applicable CRC patients to fully benefit from the KRAS G12C inhibitor treatment. Here we employed a patient-derived CRC stem cell (PD-CRC-SC) spheroid culture and demonstrated that three-drug combination of inhibitors against KRAS G12C, EGFR, and FGFR synergistically suppressed the growth of CRC cells carrying the KRAS G12C mutation. Likewise, combination of KRAS G12C and SHP2 inhibitors was also effective. Importantly, activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway in heregulin-responsive CRC cells canceled out the effect of KRAS G12C inhibition, which was largely overcome by PI3K inhibitors. These results reveal that evaluating efficacy of combination therapies with PD-CRC-SC spheroids can be a promising strategy to find the best regimen for individual CRC patients.

Advantages of minimally invasive surgery for remnant gastric cancer: A multi-institutional cohort study

357

Background: Remnant gastric cancer (RGC) is defined as a cancer arising in the remnant stomach after initial gastrectomy, regardless of the previous disease or surgical procedure. Despite growing evidence of the effectiveness of minimally invasive surgery (MIS) for primary gastric cancer, MIS for RGC remains controversial due to the rarity of the disease. This study aimed to evaluate the surgical and oncological outcomes of MIS for radical resection of RGC. Methods: We collected the data of patients with RGC who underwent surgery with curative intent between 2005 and 2020 from 17 institutions in Japan, and performed a propensity score (PS) matching analysis to compare the short- and long-term outcomes of MIS with open surgery. Results: A total of 327 patients were included in this study and 186 patients were analyzed after matching. The risk ratios for overall and severe complications were 0.76 (95% confidence interval [CI]: 0.45–1.27) and 0.65 (95% CI: 0.32–1.29), respectively. The MIS group had significantly less blood loss (50 ml vs. 361 ml, P<0.001) and a shorter hospital stay (13 days vs. 16 days, P=0.009) than the open surgery group, while the operative time was longer in the MIS group (344 min vs. 273 min, P<0.001). The median follow-up duration of this cohort was 4.6 years, and the 3-year overall survival rates were 77.9% in the MIS group and 76.2% in the open surgery group (hazard ratio [HR], 0.78; 95% CI: 0.45–1.36). The 3-year relapse-free survival rates were 71.9% in the MIS group and 62.2% in the open surgery group (HR, 0.71; 95% CI: 0.44–1.16). Locoregional recurrence occurred in three patients (3.2%) in the MIS group and four patients (4.3%) in the open surgery group. There were also no differences in the other patterns of recurrence between the groups. Conclusions: MIS for RGC showed favorable short- and long-term outcomes compared to open surgery. MIS is a promising option for radical surgery for RGC.

Timing of real-time indocyanine green fluorescence visualization for lymph node dissection during laparoscopic colon cancer surgery

PURPOSE

Although numerous studies have highlighted the potential value of indocyanine green (ICG) imaging in lymph node dissection of cancer surgery, its efficacy and optimal method remain to be clarified. This study aimed to investigate how lymphatic flow observation via ICG fluorescence could contribute to colon cancer surgery.

METHODS

From October 2018 to March 2021, a total of 56 patients with colon cancer who underwent laparoscopic complete mesocolic excision with intraoperative ICG imaging were analyzed. Lymphatic flow was examined at the following time points following ICG injection: within 5 min, 30-60 min, and over 60 min. We also evaluated the distribution of ICG fluorescence per each vascular pedicle.

RESULTS

Lymphatic flow was observed within 5 min following ICG injection in 6 cases (10.7%), and at 30-60 min following ICG injection in 43 cases (76.8%). ICG-stained vascular pedicles were variable especially in hepatic flexural, transverse, and splenic flexural colon cancer. Lymph node metastases were observed in 14 cases. Although metastatic lymph nodes were present only in the area along the ICG-stained vascular pedicles in 12 of the 14 cases, two patients exhibited lymph node metastasis in areas along the ICG-unstained vascular pedicles. ICG fluorescence was observed outside the standard range of lymph node dissection in 9 cases (20.9%: 9/43). Although addition of the proposed resection areas was made in 8 of these 9 cases, there was no pathologically positive lymph node.

CONCLUSION

Real-time ICG fluorescence imaging of lymph nodes may improve the performance of laparoscopic colon cancer surgery, although its oncological benefit is not yet clear.

Distinct but interchangeable subpopulations of colorectal cancer cells with different growth fates and drug sensitivity

Dynamic changes in cell properties lead to intratumor heterogeneity; however, the mechanisms of nongenetic cellular plasticity remain elusive. When the fate of each cell from colorectal cancer organoids was tracked through a clonogenic growth assay, the cells showed a wide range of growth ability even within the clonal organoids, consisting of distinct subpopulations; the cells generating large spheroids and the cells generating small spheroids. The cells from the small spheroids generated only small spheroids (S-pattern), while the cells from the large spheroids generated both small and large spheroids (D-pattern), both of which were tumorigenic. Transition from the S-pattern to the D-pattern occurred by various extrinsic triggers, in which Notch signaling and Musashi-1 played a key role. The S-pattern spheroids were resistant to chemotherapy and transited to the D-pattern upon drug treatment through Notch signaling. As the transition is linked to the drug resistance, it can be a therapeutic target.

Neutrophil Extracellular Traps Promote Metastases of Colorectal Cancers through Activation of ERK Signaling by Releasing Neutrophil Elastase

Neutrophil extracellular traps (NETs) play important roles in host immunity, as there is increasing evidence of their contribution to the progression of several types of cancers even though their role in colorectal cancers (CRCs) remains unclear. To investigate the clinical relevance of NETs in CRCs, we examined the expression of citrullinated histone H3 using immunohistochemistry and preoperative serum myeloperoxidase-DNA complexes in CRC patients using an enzyme-linked immunosorbent assay. High expression of intratumoral or systemic NETs was found to correlate with poor relapse-free survival (RFS), for which it is an independent prognostic factor. In vitro investigations of CRC cells (HCT116, HT29) revealed that NETs did not affect their proliferation but did promote the migration of CRC cells mediated by neutrophil elastase (NE) released during NETosis to increase extracellular signal-regulated kinase (ERK) activity. In vivo experiments using nude mice (KSN/slc) revealed that NE inhibition suppressed liver metastases in CRC cells, although it did not affect the growth of subcutaneously implanted tumors. Taken together, these results suggest that NET formation correlates with poor prognoses of patients with CRC and that the inhibition of NE could be a potential therapy for CRC metastases.

Single-incision laparoscopic partial cecectomy for appendiceal mucocele in a patient with porphyria photosensitivity

Erythropoietic protoporphyria (EPP) is a rare hereditary subtype of cutaneous porphyria characterized by photosensitivity. Increased exposure to light irradiation may precipitate acute liver failure, and surgical light-induced intestinal burns and perforations are known to occur. We report a case of EPP in a patient who underwent laparoscopic partial cecectomy for appendiceal mucocele. A 55-year-old man with EPP was presented for treatment of appendiceal mucocele. A light test using two types of laparoscopes (Companies O and S) was performed preoperatively. Light from the laparoscope manufactured by Company O caused photosensitivity; this effect was not observed with light from the laparoscope manufactured by Company S. Therefore, we performed laparoscopic partial cecectomy through a single umbilical incision using the laparoscope from Company S. Except for the incision site, the patient's skin was completely covered using surgical drapes. No intra- or postoperative complications were observed. Histopathological examination of the resected specimen revealed a low-grade appendiceal mucinous neoplasm.

Comparison of Cytoreductive Surgery and Resection of Isolated Peritoneal Metastases in Patients with Peritoneal Metastases from Colorectal Cancer: A Retrospective Study

Objectives

This study aimed to compare the short and long-term outcomes of cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy and resection of isolated peritoneal metastases in patients with peritoneal metastases from colorectal cancer in Japan.

Methods

We included patients who had undergone surgery for peritoneal metastases from colorectal cancer between 2013 and 2019. Data were retrieved from a prospectively maintained multi-institutional database and retrospective chart review. Patients were classified into cytoreductive surgery and resection of isolated peritoneal metastases groups based on the surgery they had undergone.

Results

A total of 413 patients were eligible for analysis (257 and 156 patients in the cytoreductive surgery and resection of isolated peritoneal metastases groups, respectively). There was no significant difference in overall survival (hazard ratio and 95% confidence intervals, 1.27 [0.81, 2.00]). Six cases (2.3%) of postoperative mortality were observed in the cytoreductive surgery group, whereas none were observed in the resection of the isolated peritoneal metastases group. Cases of postoperative complications were significantly higher in the cytoreductive surgery group (risk ratio 2.02 [1.18, 2.48]) than those in the resection of isolated peritoneal metastases group. Among patients with a high peritoneal cancer index (6 points or higher), the complete resection rate was 115/157 (73%) and 15/44 (34%) in the cytoreductive surgery and the resection of isolated peritoneal metastases groups, respectively.

Conclusions

Cytoreductive surgery was not superior in providing long-term survival benefits for colorectal cancer peritoneal metastases; however, cytoreductive surgery provided a higher complete resection rate even in patients with a high peritoneal cancer index (6 points or higher).

Big insulin-like growth factor 2-producing multiple solitary fibrous tumors treated with debulking surgery: A case report

BACKGROUND

Non-islet cell tumor hypoglycemia (NICTH) is a rare paraneoplastic syndrome caused by a tumor-producing high molecular weight form of insulin-like growth factor 2 (IGF2) known as big IGF2. The only curative treatment for this condition is surgical resection of the responsible tumors. However, this may not be feasible in cases with multiple metastases at diagnosis of NICTH, and no standard treatment strategy for multiple tumors has been established. The effects of pharmacological therapies including somatostatin analogs are often inefficient and remain difficult to predict.

CASE DESCRIPTION

A 68-year-old man was admitted to our hospital due to impaired consciousness and severe hypoglycemia. His medical history included diagnosis of a left temporal solitary fibrous tumor (SFT) at the age of 48 years, after which local recurrent and metastatic tumors were repeatedly resected. Four years before admission, multiple intraabdominal and subcutaneous tumors were detected and, being asymptomatic, were managed conservatively. Laboratory exam on admission demonstrated hypoglycemia accompanied with low serum insulin and IGF1 levels. Computed tomography (CT) scan revealed multiple intraabdominal and subcutaneous tumors increasing in size. Serum big IGF2 was detected on immunoblot analysis, and he was diagnosed as NICTH. In addition, tumor uptake was observed on ⁶⁸Ga-labelled 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-d-Phe¹-Tyr³-octreotide positron emission tomography/CT (DOTATOC-PET/CT). Since larger tumor is more suspicious about responsible producibility of big IGF2, we planned to resect large ones preferentially and reduce the amounts of residual tumors. Debulking surgery was performed by removing eleven intraabdominal tumors; the hypoglycemia was then completely corrected. Histological analyses revealed the resected tumors to be metastases of SFT having somatostatin receptor 2 expression. In immunoblot analysis, the resected tumors were found to be positive for big IGF2; serum big IGF2 was undetectable after surgery.

CONCLUSION

We present a case of NICTH with multiple metastatic SFTs. We strategically performed debulking surgery, which led to remission of hypoglycemia. This result demonstrates a pioneering practical solution for NICTH cases with multiple tumors. In addition, in cases of SFTs presenting with NICTH, positivity of DOTATOC-PET/CT as well as single-dose administration of octreotide may be predictive of the efficacy of somatostatin-based therapy.

A large-scale targeted proteomics of plasma extracellular vesicles shows utility for prognosis prediction subtyping in colorectal cancer

PURPOSE

The pathogenesis of cancers depends on the molecular background of each individual patient. Therefore, verifying as many biomarkers as possible and clarifying their relationships with each disease status would be very valuable. We performed a large-scale targeted proteomics analysis of plasma extracellular vesicles (EVs) that may affect tumor progression and/or therapeutic resistance.

EXPERIMENTAL DESIGN

Plasma EVs from 59 were collected patients with colorectal cancer (CRC) and 59 healthy controls (HC) in cohort 1, and 150 patients with CRC in cohort 2 for the large-scale targeted proteomics analysis of 457 proteins as candidate CRC markers. The Mann-Whitney-Wilcoxon test and random forest model were applied in cohort 1 to select promising markers. Consensus clustering was applied to classify patients with CRC in cohort 2. The Kaplan-Meier method and Cox regression analysis were performed to identify potential molecular factors contributing to the overall survival (OS) of patients.

RESULTS

In the analysis of cohort 1, 99 proteins were associated with CRC. The analysis of cohort 2 revealed two clusters showing significant differences in OS (p = 0.017). Twelve proteins, including alpha-1-acid glycoprotein 1 (ORM1), were suggested to be associated with the identified CRC subtypes, and ORM1 was shown to significantly contribute to OS, suggesting that ORM1 might be one of the factors closely related to the OS.

CONCLUSIONS

The study identified two novel subtypes of CRC, which exhibit differences in OS, as well as important biomarker proteins that are closely related to the identified subtypes. Liquid biopsy assessment with targeted proteomics analysis was proposed to be crucial for predicting the CRC prognosis.