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Purpose: This study aimed to identify cases in which lateral lymph node (LLN) dissection (LLND) can be excluded by clarifying preoperative factors, including an evaluation of the middle rectal artery (MRA), associated with LLN metastasis., Methods: Fifty-five consecutive patients who underwent preoperative positron emission tomography-computed tomography (PET/CT) and total mesorectal excision with LLND for rectal cancer were included. We retrospectively investigated the preoperative clinical factors associated with pathological LLN (pLLN) metastasis. We analyzed the regions of pLLN metastasis using MRA., Results: pLLN metastasis occurred in 13 (23.6%) patients. According to a multivariate analysis, clinical LLN (cLLN) metastasis based on short-axis size and LLN status based on PET/CT were independent preoperative factors of pLLN metastasis. The negative predictive value (NPV) was high (97.1%) in patients evaluated as negative based on PET/CT and cLLN short-axis size. MRA was detected in 24 patients (43.6%) using contrast-enhanced CT, and there was a significant relationship between pLLN metastasis and the presence of MRA. pLLN metastasis in the internal iliac region but not in the obturator region was significantly correlated with the presence of MRA., Conclusion: Combined cLLN metastasis based on short-axis size and PET/CT showed a higher NPV, suggesting this to be a useful method for identifying cases in which LLND can be excluded., Competing Interests: Declarations. Conflict of interest: The authors declare no conflicts of Interests for this article., (© 2024. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.)

The "bystander effect" is a transmission phenomenon mediating communication from target to non-target cells, as well as cell-to-cell interactions between neighboring and distantly located cells. In this narrative review, we describe the fundamental and clinical significance of the bystander effect with respect to cell-to-cell interactions in carcinogenesis, therapeutic response, and tissue regeneration. In carcinogenesis, the bystander effect mediates communications between tumor microenvironments and non-malignant epithelial cells and has been suggested to impact heterogeneous tumorigenic cells in tumors and cancerized fields. In therapeutic response, the bystander effect mediates communications between drug-sensitive and drug-resistant cells and may transmit both drug efficacy and resistance. Therefore, control of therapeutic response transmission via the bystander effect might offer a promising future cancer treatment. Finally, in tissue regeneration, circulating cells and stromal cells may differentiate into various cells for the purpose of tissue regeneration under direction of the bystander effect arising from surrounding cells in a defective space. We hope that the findings we present will promote the development of innovative cancer therapies and tissue regeneration methodologies from the viewpoint of cell-to-cell interactions through the bystander effect., (© 2022. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.)

Purpose: Anticancer drugs for double cancers are selected based on their therapeutic effects on the target cancer, but there are insufficient data on the effects of anticancer drugs on comorbid cancer. We investigated the effect of chemotherapy on comorbid cancer in patients with simultaneous double cancers., Methods: The subjects of this retrospective study were 51 patients with simultaneous double cancers at the time of receiving systemic chemotherapy. We evaluated the types of anticancer drugs used for double cancers, the therapeutic effects on targeted and comorbid cancers, and prognoses., Results: Disease control was achieved for 90.9% of the target cancers and 90.7% of the comorbid cancers. The prognosis was significantly better when the disease was controlled, not only in the target cancer but also in the comorbid cancer., Conclusion: Physicians treating double cancers should develop treatment strategies focusing not only on the treatment for advanced cancer, but also on the course of comorbidities and the therapeutic effects of anticancer drugs. This study is important because it presents new possibilities to expand the indications for anticancer drugs, while allowing unnecessary clinical research to be avoided., (© 2022. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.)

Purpose: Flipped learning has been applied in various fields, including medical professional education. E-learning is compatible with flipped learning; however, it is considered to be unsuitable for providing training on surgical techniques. In this study, we retrospectively examined the ligation performance of online students who underwent training with flipped learning incorporated into e-learning., Methods: We conducted a retrospective study of the ligation practices of online students at the Department of General Surgery from March 2020 to June 2021. The subjects included 134 fourth- and fifth-year medical students from Gunma University School of Medicine. We conducted mid-term checks on the 8th day of practice and an examination on the 19th day. Two instructors independently evaluated and calculated scores using the original Global Rating Scale of Gunma University. We also conducted a questionnaire survey on the ligation practice of online students., Results: The total average score of the three tasks was 12.4 for Instructor 1 and 12.0 for Instructor 2. All students had a passing score. The questionnaire survey showed that 70% of the students were trained in ligation at the time of the first evaluation., Conclusions: Our online training materials and training methods enabled the acquisition of ligation skills by students who had not previously received ligation training., (© 2022. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.)

Laparoscopic esophagojejunostomy is a challenging procedure because of its technical difficulty. We herein report a new method involving circular-stapled anastomosis using a hand-sewn suture with four stay-sutures and evaluate its outcomes. Esophagojejunostomy using this method was performed in 36 consecutive patients with clinical stage I gastric cancer at the authors' institutions. The key feature of our procedure was the placement of four full-thickness stay-sutures to anchor the esophageal stump prior to the hand-sewn purse-string suture. The median operation time and mean anvil fixation time were 315.5 and 21.9 min, respectively. The mortality rate was 0%, although anastomotic leakage following esophagojejunostomy was observed in 1 patient (2.8%), and anastomotic stenosis was observed in another patient (2.8%). Intracorporeal esophagojejunostomy using the four stay-sutures method appears to be safe and feasible. We believe that this method enables hand-sewn purse-string suturing to be performed more easily.

Purpose: Surgical site infections (SSI) are a common complication of gastrointestinal tract surgery. In this study, we explored the correlation between the anastomosis method and the incidence of SSI., Methods: A total of 110 patients underwent ileocecal resection or right hemicolectomy for the excision of colon cancer. Two methods (open and closed, 28 and 82 patients, respectively) of functional end-to-end anastomosis were adopted., Results: Increased perioperative blood loss (p = 0.029214), a longer hospital stay (p = 0.026668) and the development of SSI (p = 0.000181) were significantly correlated with the open method. There was no correlation between SSI and the body mass index, or between SSI and the length of the surgery or diabetes mellitus. However, patients that developed SSI tended to be obese., Conclusion: The open method was associated with a higher incidence of SSI. Therefore, it is necessary to consider potential contamination of the surgical field at the time of anastomosis to reduce the incidence of SSI.

Purpose: Nonspecific esophageal motility disorder (NEMD) is a vague category that includes patients with poorly defined contraction abnormalities observed during esophageal manometry. This study investigated the therapeutic effects of the video-assisted thoracoscopic surgery (VATS) approach using long myotomy and fundopexy for NEMD., Methods: The VATS approach using myotomy and fundopexy was performed for 4 patients of NEMD between 2005 and 2008. A total of 4 patients with NEMD that underwent treatment at our institution were analyzed retrospectively., Results: The patients included 2 males and 2 females with a median age of 48 years (range 21-74 years). The median duration of NEMD symptoms was 58 months (range 4-108 months). Dysphagia was a primary symptom in all patients. Chest pain was a primary symptom in 3 of 4 patients (75 %). Treatment with medication was attempted before the operation. The median operative time was 344.5 min (range 210-476 min). The median time before starting oral feeding was 2.5 days (range 2-22 days). All patients achieved a significant improvement of their previous condition., Conclusions: The VATS approach using myotomy and fundopexy for NEMD is a good treatment in cases resistant to medication and balloon dilation.

Barrett's esophagus (BE) is the premalignant lesion from which esophageal adenocarcinoma near the esophagogastric junction arises. The management of BE and the treatment of Barrett's esophageal adenocarcinoma (BEA) are important clinical issues in Europe and the United States. As the Helicobacter pylori infection rate in Japan is decreasing in the younger population, the incidence of BE and adenocarcinoma arising from BE may start increasing. Thus, we review the current status of BEA and its management. Magnifying endoscopy with narrow-band imaging is important for diagnosing dysplasia arising from BE. In Japan, adenocarcinoma arising from BE is managed the same way as squamous cell carcinoma in the same location. Strategies to prevent BEA may include medication such as non-steroidal anti-inflammatory drugs and proton pump inhibitors, and anti-reflux surgery. Understanding the pathophysiology of BE will help to reduce the incidence of BEA.

Esophageal cancer is a common malignancy with a striking variation in geographical distribution; a reflection of exposure to specific environmental factors, which are still poorly defined. We discuss the recent progress made in the investigation of the molecular biology of esophageal cancer, addressing the topics of genetic alterations, methylation, overexpression of molecules thought to cause malignant transformation, carcinogenesis, invasion, and metastasis. We review six aspects of the research literature on esophageal cancer: epidemiology and etiology, epidermal growth factor receptor and related growth factor receptors, cell cycle regulatory proteins, transforming growth factor-beta/Smad proteins, mismatch repair genes, and other genes. This article provides a conceptual basis for evaluating studies on the molecular mechanism of esophageal carcinogenesis and for devising therapeutic and preventive strategies based on molecular biology. We hope that in the near future, the clinical outcome of patients with esophageal carcinoma will be improved by a better understanding of the basic mechanisms of carcinogenesis.