松本 志郎

Abstract Background Osteopenia reflects frailty and has been shown to be associated with outcomes in cancer patients. This study was undertaken to examine whether osteopenia is an independent prognostic factor in patients with esophageal cancer after resection. Methods A total of 214 patients who underwent surgery for esophageal cancer were analyzed retrospectively. Bone mineral density (BMD) of the 11th thoracic vertebra was measured by computed tomography scan, and patients classified into osteopenia and normal BMD groups with BMD <160 Hounsfield units as the cutoff. Clinicopathological data and prognosis were analyzed. Results The 5‐year survival rate was 55.4% for the osteopenia group and 74.7% for the normal BMD group with a significantly worse prognosis in the osteopenia group (p = 0.0080). In multivariable analysis, osteopenia was a significant independent risk factor associated with overall survival (hazard ratio [HR] 1.90, 95% confidence interval [CI] 1.27–3.34, and p = 0.0151) along with R1/2 resection (HR 3.02, 95% CI 1.71–5.18, and p = 0.0002). Conclusion In patients with esophageal cancer undergoing resection, osteopenia may be a surrogate marker for frailty and an independent predictor of prognosis.

BACKGROUND: Adjuvant nivolumab therapy has become the standard therapy for patients with localized advanced esophageal cancer with non-pathological complete response after neoadjuvant chemoradiotherapy followed by curative surgery. However, the necessity of this therapy for patients after neoadjuvant chemotherapy (NAC) with docetaxel, cisplatin, and 5-fluorouracil (DCF) regimen followed by surgery is unclear, and the prognosis of grouping based on the presence or absence of pathological tumor and lymph node findings has not been analyzed. Therefore, our study aimed to address these questions. METHODS: This retrospective cohort study included patients with cT1N1-3M0 and cT2-3N0-3M0 esophageal cancer according to the Japanese Classification of Esophageal Cancer, 11th edition, who received NAC with DCF followed by curative surgery between 2008 and 2020 at Jichi Medical University Hospital. We divided patients with ypT0-3N0-3M0 into four histological groups, namely ypT0N0, ypT+N0, ypT0N+, and ypT+N+, and we evaluated overall survival as the primary outcome and the prognostic relationship of lymph node metastasis as the secondary outcome. RESULTS: A total of 101 patients were included in this study. Kaplan-Meier analysis showed that the curves of the ypT0N0 and ypT+N0 groups were almost identical, while they differed from the other two groups. The hazard ratio of ypN+ was 4.44 (95% confidence interval: 2.03-9.71; P<0.001). CONCLUSIONS: The prognosis of the ypT+N0 group after NAC with DCF followed by surgery was similar to that of pathological complete remission. Grouping patients according to pathological lymph node status is a reasonable predictor of prognosis.

INTRODUCTION: An eyeglass gaze camera and a skeletal coordinate camera without sensors attached to the operator's body were used to monitor gaze and movement during a simulated surgical procedure. These new devices have the potential to change skill assessment for laparoscopic surgery. The suitability of these devices for skill assessment was investigated. MATERIAL AND METHODS: Six medical students, six intermediate surgeons, and four experts performed suturing tasks in a dry box. The tip positions of the instruments were identified from video recordings. Performance was evaluated based on instrument movement, gaze, and skeletal coordination. RESULTS: Task performance time and skeletal coordinates were not significantly different among skill levels. The total movement distance of the right instrument was significantly different depending on the skill level. The SD of the gaze coordinates was significantly different depending on skill level and was less for experts. The expert's gaze stayed in a small area with little blurring. CONCLUSIONS: The SD of gaze point coordinates correlates with laparoscopic surgical skill level. These devices may facilitate objective intraoperative skill evaluation in future studies.

In this study, the relationship between gaze patterns, task duration, and years of experience, which are commonly used to define and evaluate expert surgeons in laparoscopic surgery, was identified. Ten surgeons with 1-28 years of experience and six inexperienced students were included. Subjects used forceps to repeat the task of suturing a suture pad. Each subject wore an eye-marking recorder, and gaze points were recorded and analyzed. No significant relationship between task duration and gaze pattern was observed. However, there was a significant relationship between a surgeon's years of experience and the percentage of time spent gazing at the forceps. Subjects with more years of experience operated without looking at the forceps and fixed their gaze on the operational target. Therefore, when analyzing laparoscopic gazing patterns, it may be more appropriate to define an "expert" based on the years of experience rather than task duration.

BACKGROUND: Despite recent progress in systemic chemotherapy, the prognosis of patients with peritoneal metastases from gastric cancer is still poor. Efficacious intraperitoneal and systemic combination chemotherapy regimens to treat patients with peritoneal metastases have recently been developed. CASE PRESENTATION: A 74-year-old man with gastric cancer T4b (transverse mesocolon) N3 M1 (peritoneum) received combination chemotherapy with intraperitoneal administration of paclitaxel, intravenous oxaliplatin, and oral S-1. Eight courses of combined chemotherapy had remarkable anti-tumor effects on the primary lesion, lymph node metastases, and peritoneal metastases. Total gastrectomy with regional lymph node dissection was performed. Pathological examination revealed no viable tumor cells in the resected specimens. After gastrectomy, the patient received 25 courses of the same chemotherapy without oxaliplatin and has no evidence of recurrence 24 months later. DISCUSSION: Therapeutic approaches including systemic chemotherapy, extended resection, and heated intraperitoneal chemotherapy have been used to treat patients with peritoneal metastases. Repeat therapy with intraperitoneal paclitaxel has been used recently. Intraperitoneal administration of paclitaxel results in prolonged retention in the peritoneal cavity with effects against peritoneal metastases. Repeated administration of paclitaxel does not cause adhesions in the peritoneal cavity. When combination chemotherapy is effective, salvage gastrectomy is a promising option with minimal morbidity and mortality. CONCLUSION: Combined chemotherapy with intraperitoneal paclitaxel and systemic chemotherapy followed by gastrectomy is a promising strategy for patients with advanced gastric cancer and peritoneal metastases.

INTRODUCTION: Gastric adenocarcinomas with low grade atypia may be difficult to diagnose as gastric cancer by preoperative biopsy. We report an extremely well-differentiated adenocarcinoma (EWDA) of the stomach which appeared like a submucosal tumor diagnosed by preoperative endoscopic submucosal dissection. PRESENTATION OF CASE: A 70-year-old male was referred with a 3-month history of a submucosal-appearing lesion in the gastric wall found on endoscopy. Biopsies of the lesion were performed and were inconclusive for neoplasia. Endoscopic ultrasonography showed a low echoic tumor growing into the fourth layer of the gastric wall. It was difficult to identify the tumor by repeat biopsy. Endoscopic submucosal dissection of the lesion was performed and revealed adenocarcinoma, and laparoscopic total gastrectomy was performed. Histopathologic evaluation showed that the tumor was stage IIA (T3N0M0). There is no recurrence 12 months after resection. DISCUSSION: Gastric EWDAs are rare lesions, accounting for 0.6% of all gastric cancers. It is difficult to diagnose gastric EWDA especially if it appears like a submucosal tumor. This lesion was finally diagnosed by endoscopic submucosal dissection. CONCLUSION: Endoscopic submucosal dissection may facilitate establishing the preoperative diagnosis of a tumor thought to be a gastric EWDA based on its endoscopic appearance and pathological findings.

Gastrointestinal stromal tumors (GIST) in patients under 18 years of age are classified as pediatric GIST. Pediatric GIST are extremely rare, and there are no reports of laparoscopic-endoscopic cooperative surgery for these lesions. We report the use of non-exposed endoscopic wall-inversion surgery as a laparoscopic-endoscopic cooperative surgery-related procedure for the treatment of a pediatric GIST. The case involved a 17-year-old male patient who presented with anemia and was found to have a bleeding gastric tumor. The tumor was resected transorally using the non-exposed endoscopic wall-inversion surgery technique. No gene mutation of c-Kit or Platelet-Derived Growth Factor Receptor α (PDGFRα) was found, and the final pathological diagnosis was epithelial-type GIST due to a succinate dehydrogenase abnormality. Follow-up included a CT scan every 4 months. No recurrence has occurred to date.

INTRODUCTION: Gastric hyperplastic polyps are common stomach lesion and these polyps are generally benign. However, they can undergo malignant transformation. Most reported cases of malignant transformation of gastric hyperplastic polyps have been to well or moderately differentiated adenocarcinoma, and those transformed into poorly differentiated adenocarcinoma are extremely rare. No case has been reported that has changed to diffuse type adenocarcinoma with lymphatic invasion. PRESENTATION OF CASE: A 48-year-old woman presented with worsening anemia. A polyp was seen in the gastric cardia seven years prior to presentation. Helicobacter pylori infection was also found at that time. She underwent upper gastrointestinal endoscopy and biopsy of the polyp revealed signet ring cell carcinoma. Total gastrectomy was performed due to concern about possible invasion into the submucosal layer and there was no evidence of distant metastases. Histologic examination revealed both poorly differentiated adenocarcinoma and signet ring cell carcinoma surrounded by hyperplastic epithelium at the head of the polyp. Lymphatic invasion was also found, and malignant cells were limited to the mucosa. DISCUSSION: Gastric hyperplastic polyps are commonly associated with chronic gastritis which is related to Helicobacter pylori infections. Gastric hyperplastic polyps are generally benign and rarely undergo malignant transformation to adenocarcinoma with differentiated histology. The gastric hyperplastic polyp in this patient transformed to poorly differentiated adenocarcinoma with lymphatic invasion. CONCLUSION: Even small polyps may become poorly differentiated adenocarcinoma with invasion, so close follow-up or endoscopic resection are recommended as well as eradication of Helico Pylori infection when appropriate.

Many types of immune cells appear in peritoneal cavity after abdominal surgery. In patients who underwent laparotomy due to gastric cancer, peritoneal lavages were obtained before and after surgical procedure. Cells were recovered from intermediate layer after Ficoll-Hypaque centrifugation and analyzed for phenotypes and functions, especially focused on low density neutrophils (LDN). The number of CD66b (+) LDN with mature phenotype was markedly elevated in postoperative as compared with preoperative lavages. Short term culture of the purified LDN produced many threadlike structures positive for SYTOX, nucleic acid staining, as well as histone and myeloperoxidase, suggesting the NETs formation. Human gastric cancer cells, MKN45, OCUM-1 and NUGC-4, were selectively attached on the NETs, which was totally abolished by the pretreatment of DNAse I. Intraperitoneal (IP) co-transfer of the LDN with MKN45 in nude mice strongly augments the metastasis formation on peritoneum, which was strongly suppressed by the following IP administration of DNAse I. Many NETs-like structures were detected on the surface of human omental tissue resected by gastrectomy. NETs on peritoneal surface can assist the clustering and growth of free tumor cells disseminated in abdomen. Disruption of the NETs by DNAse might be useful to prevent the peritoneal recurrence after abdominal surgery.