Comparison of Risk Factors for Locally Advanced Lower Rectal Cancer Recurrence Evaluated by Magnetic Resonance Imaging and Pathological Factors Analysed by Longitudinal Slicing Method

BACKGROUND/AIM

We compared the risk factors for locally advanced lower rectal cancer (LALRC) recurrence evaluated by preoperative magnetic resonance imaging (MRI) and pathological factors analysed via the longitudinal slicing method to identify high risk groups for recurrence.

PATIENTS AND METHODS

This retrospective single-institution cohort study analysed 45 consecutive patients who underwent curative surgery for LALRC. Data were analysed by an experienced radiologist and pathologist.

RESULTS

Final preoperative extramural venous invasion (EMVI) and extramural depth of invasion (EMD) determined via MRI were significantly associated with EMVI and EMD determined via pathological analysis. The log-rank test for disease-free survival based on initial preoperative factors showed significantly poor prognoses for circumferential resection margin (CRM)-positive, EMVI-positive, and EMD-positive patients.

CONCLUSION

Final preoperative EMVI and EMD determined via MRI correlated with pathological EMVI and EMD, especially in patients who did not undergo preoperative treatment. CRM, EMVI, and EMD determined via preoperative MRI were significant risk factors for recurrence.

Risk Factors for Postoperative Liver Enzyme Elevation After Laparoscopic Gastrectomy for Gastric Cancer

BACKGROUND/AIM

Laparoscopic gastrectomy (LG) is more frequently associated with postoperative liver enzyme elevation (PLEE) than open gastrectomy in phase III clinical trials for Japanese gastric cancer patients. The aim of this study was to determine the risk factors for PLEE after LG for gastric cancer.

PATIENTS AND METHODS

This study enrolled 153 consecutive patients with gastric cancer who underwent LG. The patient characteristics, the liver retraction method [silicone disc (SD) or Nathanson liver retractor (NLR)], and perioperative outcomes were compared between patients with and without PLEE.

RESULTS

PLEE was observed in 26 patients (17%). The patients with PLEE exhibited longer operative times (p=0.005) and more frequent use of the NLR for liver retraction (p=0.022). In the multivariate analysis, liver retraction using the NLR (p=0.003) and aberrant left hepatic artery (ALHA) ligation (p=0.042) were independent risk factors of PLEE.

CONCLUSION

Liver retraction with the SD during LG was shown to be the safer method that is less likely to cause postoperative liver dysfunction. ALHA preservation may contribute to avoiding postoperative liver dysfunction.

Impact of the Hepatic Branch of the Vagus Nerve Transection in Laparoscopic Sleeve Gastrectomy for Patients with Obesity and Type 2 Diabetes Mellitus

BACKGROUND

An increase in gastroesophageal reflux disease (GERD) after laparoscopic sleeve gastrectomy (LSG) has been reported, and concomitant hiatal hernia repair (HHR) during LSG is expected to reduce the incidence of post-LSG GERD. In HHR, the hepatic branch of the vagus nerve is anatomically transected. Recent experimental animal models suggest that vagotomy may affect glycemic control and weight loss through a neuroendocrine response.

OBJECTIVES

To examine whether LSG with/without hepatic branch vagotomy (HV) has a clinical impact on glycemic control in patients with obesity and type 2 diabetes mellitus (T2DM). Furthermore, the impact on weight loss and post-LSG GERD were evaluated.

METHODS

A total of 204 Japanese patients with obesity and T2DM, who underwent LSG and completed 1-year follow-up, were retrospectively analyzed. Operative outcomes, weight loss, glycemic, and GERD-related parameters were compared between the LSG/HHR/HV group (n = 89) and the LSG group (n = 115).

RESULTS

There was no significant difference in the background factors in terms of anthropometric and T2DM-related parameters between the groups. The median operation times in the LSG/HHR/HV and LSG groups were 133 and 124 minutes, respectively (p = 0.236). At 1 year, the diabetes remission rate, HbA1c, fasting glucose, and C-peptide levels were all comparable between the groups. The weight loss effect was also comparable. The patients in the LSG/HHR/HV group achieved significant improvement and prevention of GERD and hiatus hernia (p < 0.001).

CONCLUSION

HV does not appear to have a clinical impact on glycemic control and weight loss. Concomitant HHR with LSG serves to reduce post-LSG GERD.

Measurement of the 2νββ Decay Half-Life of ^{130}Te with CUORE

We measured two-neutrino double beta decay of ^{130}Te using an exposure of 300.7 kg yr accumulated with the CUORE detector. Using a Bayesian analysis to fit simulated spectra to experimental data, it was possible to disentangle all the major background sources and precisely measure the two-neutrino contribution. The half-life is in agreement with past measurements with a strongly reduced uncertainty: T_{1/2}^{2ν}=7.71_{-0.06}^{+0.08}(stat)_{-0.15}^{+0.12}(syst)×10^{20}  yr. This measurement is the most precise determination of the ^{130}Te 2νββ decay half-life to date.

Resistance to Preoperative Oral Care Is Associated With Postoperative Pneumonia After Oesophageal Cancer Surgery

BACKGROUND/AIM

Postoperative pneumonia is a serious complication of major oesophageal surgery. We aimed to clarify the association between the degree of improvement in oral hygiene by perioperative oral care and postoperative pneumonia in oesophageal cancer patients.

PATIENTS AND METHODS

Oesophageal cancer patients (n=129) who underwent esophagectomy received perioperative oral care. Their oral hygiene was evaluated using the Oral Assessment Guide (OAG). The relationship between perioperative OAG scores and postoperative complications was analysed.

RESULTS

The average OAG scores before starting oral care, pre-operation, and post-operation were 11.0±1.7, 9.1±1.5, and 11.2±3.0, respectively (p<0.001). An increase in preoperative OAG scores was independently associated with postoperative pneumonia on multivariate analysis (p=0.027).

CONCLUSION

Preoperative oral care improves oral hygiene in patients undergoing oesophageal cancer surgery. No improvement in oral hygiene despite preoperative oral care was an independent predictor of postoperative pneumonia.

Diagnostic Immunostaining and Tumor Markers Predict the Prognosis of Esophageal Neuroendocrine Cell Carcinoma Patients

BACKGROUND

Esophageal neuroendocrine carcinoma (ENEC) has a poor prognosis, and predicting the prognosis by examining various markers may contribute to the determination of treatment strategies. Therefore, a multiple-institution retrospective study was performed to identify biomarkers using diagnostic immunohistochemistry and serum tumor markers that predict the prognosis of patients with ENEC.

METHODS

The results of immunohistochemical examination and serum tumor markers were extracted from the data of 141 ENEC patients at 39 institutions certified by the Japan Esophageal Society. The study then examined correlations between these data and prognosis or treatment effects.

RESULTS

The ENEC patients with positively for all expression of synaptophysin (Syn), chromogranin A (CgA), and CD56 had a significantly worse prognosis than the patients with other expression patterns. Additionally, surgery and chemoradiotherapy were significantly more effective treatments than chemotherapy for the patients who were not positive for all expressions of Syn, CgA, and CD56. In terms of serum tumor markers, the patients with a high neuron-specific enolase (NSE) value had a significantly worse prognosis than the patients with a normal NSE value, and complete response (CR) cases treated with chemotherapy were significantly fewer in the high-NSE group. The results of multivariate analysis demonstrated that high NSE levels were an independent poor prognostic factor for esophageal endocrine cell carcinoma.

CONCLUSION

This study showed that positivity for all expressions of Syn, CgA, and CD56, and a high NSE value were significantly worse prognostic factors for ENEC patients than other expression patterns and may be important prognostic biomarkers of ENEC.

Concurrent Chemoradiotherapy With Docetaxel, Cisplatin, and 5-Fluorouracil (DCF-RT) vs. Cisplatin and 5-Fluorouracil (CF-RT) for Patients With Unresectable Locally Advanced Esophageal Cancer in a Real-world Clinical Setting

BACKGROUND/AIM

We compared the outcome of docetaxel, cisplatin, and 5-fluorouracil as combination chemoradiotherapy (DCF-RT) for unresectable locally advanced thoracic esophageal cancer (EC) with that of cisplatin (CDDP) and 5-fluorouracil (5-FU) as combination chemoradiotherapy (CF-RT) in clinical settings.

PATIENTS AND METHODS

Seventy-three patients with unresectable locally advanced thoracic EC were included in this study. CF (n=38) consisted of intravenous CDDP at 70 mg/m² (day 1) and 5-FU at 700 mg/m² (days 1 to 4), repeated every four weeks for two cycles. DCF (n=35) consisted of intravenous docetaxel at 50 mg/m² (day 1), CDDP at 60 mg/m² (day 1), and 5-FU at 600 mg/m² (days 1 to 4), repeated every four weeks for two cycles. Patients were irradiated with 60 Gy in 30 fractions.

RESULTS

The overall complete response (CR) rate of DCF-RT was significantly higher than that of CF-RT (36.7% vs. 3.7%, p=0.003). The 3-year overall survival (OS) rate of DCF-RT was significantly higher than that of CF-RT (32.8% vs. 8.5%, p<0.001).

CONCLUSION

DCF-RT demonstrated a higher CR rate and OS for unresectable locally advanced thoracic EC than CF-RT.

From Stress to Psychopathology: Relationship with Self-Reassurance and Self-Criticism in Czech University Students

Psychological stress has become a major concern, potentially leading to diverse health problems including psychopathology such as depression and anxiety. Transactional Model of Stress and Coping is an established model, conceptualizing stressful experiences via person–environment relationship. This cross-sectional study aimed to explore the pathway from stress to depression/anxiety, with a focus on self-criticism (inadequate-self and hated-self) and self-reassurance (reassured-self) in Czech students who suffered from high prevalence of mental health problems. Convenience sample of 119 undergraduates completed the Depression Anxiety and Stress Scale-21 and the Forms of the Self-Criticizing/Attacking & Self-Reassuring Scale. Correlation and path analyses were conducted. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines were used to aid an accurate and complete report of the study. Depression, anxiety, and stress were positively associated with inadequate-self and hated-self while negatively associated with reassured-self. Both inadequate-self and hated-self partially mediated the stress–depression and stress–anxiety relationships, whereas reassured-self only partially mediated the stress–depression relationship. Inadequate-self had greater impact on the stress–depression/anxiety pathways than hated-self and reassured-self. Findings indicate that clinical treatment may benefit from targeting the feelings of inadequacy to prevent stress progressing to psychopathology. This is particularly relevant as stress levels are rising globally. Our findings offer developments to the Transactional Model, and help practitioners and educators identify solutions to protect mental health of Czech university students.

Low level of stromal lectin-like oxidized LDL receptor 1 and CD8+ cytotoxic T-lymphocytes indicate poor prognosis of colorectal cancer

Background

Lectin‐like oxidized LDL receptor‐1 (LOX‐1) has been identified as a new marker for functional myeloid‐derived suppressor cells (MDSCs) that exhibit an immunosuppressive phenotype in the tumor microenvironment (TME). However, the role of LOX‐1⁺ cells in the TME of colorectal cancer (CRC) remains unknown.

Aim

This study aimed to determine the expression and significance of LOX‐1 in the TME of clinical CRC specimens.

Methods and results

We performed immunohistochemical and genetic analyses of LOX‐1, CD8, KRAS, and BRAF in 128 resected CRC specimens and determined the expression of IFN‐γ and IL‐10 using real‐time reverse transcription‐polymerase chain reaction. We analyzed the correlation between LOX‐1, TME factors, gene alteration, clinicopathological factors, and disease prognosis. The co‐expression pattern of LOX‐1, hematopoietic markers, and a fibroblast marker was evaluated using multiplex immunofluorescence staining. Low stromal LOX‐1 expression and low intratumoral CD8⁺ cytotoxic T‐lymphocyte (CTL) status correlated with poor prognosis. Moreover, stromal LOX‐1‐low/CD8⁺ CTL‐low status was the most important independent prognostic factor of poor overall survival. Most of the LOX‐1⁺ stromal cells were positive for CD163⁺, indicating they were CD163⁺ M2 macrophages.

Conclusions

The MDSC marker, LOX‐1, was mainly expressed by M2 macrophages in CRC tissues. LOX‐1⁺ macrophages and CD8⁺ CTLs may serve as useful biomarkers for predicting the prognosis of CRC.

Bowel obstruction due to Chlamydia trachomatis: a case report and review of literature

Background

Chlamydial infection is a difficult-to-diagnose type of sexually transmitted disease that occurs mainly in young people. We report a case of bowel obstruction caused by intrapelvic adhesions formed by chlamydial infection.

Case presentation

This patient was a 23-year-old woman who had been suffering from acute abdominal pain. She had been previously treated several times for intrapelvic abscesses and had a history of chlamydial infection. Endometriosis was thought to be the cause of her pelvic abscess based on endoscopic findings. Computed tomography demonstrated a small bowel obstruction caused by a pelvic abscess. However, the diagnosis could not be confirmed. She underwent laparoscopic surgery and was diagnosed with bowel obstruction due to adhesion of chlamydial infection based on the intraoperative findings and Chlamydia trachomatis antibody test. She was discharged 5 days after surgery.

Conclusions

It is necessary to consider the possibility of chlamydial infection as a cause for lower abdominal pain and unexplained bowel obstruction in female patients.

Robustness of daily dose for each beam angle and accumulated dose for inter-fractional anatomical changes in passive carbon-ion radiotherapy for pancreatic cancer: Bone matching versus tumor matching

PURPOSE

We aimed to assess the robustness of accumulated dose distributions for inter-fractional changes in passive carbon-ion radiotherapy for pancreatic cancer.

METHODS

Ninety-five daily CT image sets acquired after the treatment of eight patients with pancreatic cancer were used in this prospective study. Dose distributions with treatment beam fields were recalculated for bone matching (BM) and tumor matching (TM) positions on all daily CT images, the accumulated doses being calculated using deformable image registration methods. The prescribed dose was 55.2 Gy (relative biological effectiveness [RBE]) in 12 fractions. Dose volume parameters of V95 (%) for CTV and GTV, and D2cc (Gy(RBE)) for the stomach and duodenum were evaluated.

RESULTS

The medians (range) of CTV V95 (%) were 91.9 (86.1-100.0), 80.5 (56.1-90.6), and 86.4 (72.5-96.5) for the Plan, accumulated with BM and TM, respectively; GTV values (%) were 98.0 (85.7-100.0), 93.3 (65.7-99.9), and 96.2 (84.8-100.0), respectively. There were significant differences between all combinations apart from the Plan and TM for both targets. The values of stomach D2cc (Gy(RBE)) were 36.0 (16.9-43.4), 36.7 (17.9-45.0), and 35.2 (16.8-43.5), respectively; duodenum values (Gy(RBE)) were 25.2 (21.3-40.3), 30.1 (23.3-48.6), and 28.3 (20.4-50.6), respectively. There was a significant difference between the Plan and BM for duodenum only.

CONCLUSIONS

TM is recommended over BM because it can achieve higher target dose coverage than BM. Nevertheless, it is not enough in some cases. Further technical improvements are necessary to improve the target dose coverage.

Outcomes of surgical treatment in patients with anorectal fistula cancer

Background

No standard treatment for anorectal fistula cancer, such as multidisciplinary therapy, has been established due to the rarity of the disease. Herein, we investigated patients with cancer associated with anorectal fistula who underwent surgery to clarify the clinicopathological characteristics and to propose future perspectives for treatment strategies.

Case presentation

Seven patients with cancer associated with anorectal fistula who underwent rectal amputation in our institute were analyzed with regard to clinical characteristics, pathological findings, surgical results, and prognosis. Four cases had Crohn's disease as an underlying cause. All seven cases were diagnosed as advanced stage. Preoperative [¹⁸F]-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography/computed tomography (FDG-PET/CT) showed abnormal FDG accumulation in six cases including four mucinous adenocarcinomas. Three cases that received preoperative hyperthermo-chemoradiotherapy achieved pathological R0 resection. Postoperative recurrence was observed in four cases including three with Crohn's disease and one resulting in death.

Conclusions

Anorectal fistula cancer is rare and difficult to be diagnosed at early stages. Mucinous adenocarcinoma associated with anorectal fistula tends to exhibit abnormal FDG accumulation by FDG-PET/CT unlike common colorectal mucinous adenocarcinoma. Preoperative hyperthermo-chemoradiotherapy may be effective in obtaining pathological complete resection.

Utility of Thermography of Reconstructed Gastric Conduit for Predicting Postoperative Anastomotic Leakage After Esophagectomy for Esophageal Cancer

BACKGROUND AND AIM

Anastomotic leakage, the most common major complication after esophagectomy, is an important early postoperative complication that results in reoperation, delayed discharge, and psychological and financial distress. The current study focused on gastric conduit blood flow and investigated the relationship between gastric conduit temperature and anastomotic leakage.

PATIENTS AND METHODS

Between July 2015 and December 2017, a total of 51 patients aged 38 to 84 years who underwent esophagectomy followed by esophagogastric anastomosis with gastric conduit reconstruction were enrolled. Thermography was then used to measure the temperature of the intact stomach and gastric conduit before anastomosis.

RESULTS

The temperature of the planned site of gastric conduit anastomosis was significantly inversely correlated with anastomotic leakage, with the receiver operator characteristic curve showing a cutoff point of 27.6°C for predicting anastomotic leakage.

CONCLUSION

The temperature of the planned gastric tube anastomosis line should be kept at 27.6°C or higher to reduce anastomotic leakage.

Impact of neutrophil-lymphocyte ratio, Glasgow Prognostic Score, and postoperative decrease in psoas muscle index on recurrence after curative gastrectomy

Aim : We investigated whether preoperative or postoperative inflammatory markers and psoas muscle index (PMI), and their change after surgery, could predict postoperative recurrence in gastric cancer (GC). Methods : Thirty-five patients who underwent curative gastrectomy for pStage II and III GC were retrospectively reviewed. The relationship between neutrophil-lymphocyte ratio (NLR), prognostic nutritional index (PNI), Glasgow Prognostic Score (GPS), and PMI, as well as postoperative recurrence, was analyzed presurgery and at 6 months after surgery. Results : In the preoperative data, there was a significant association between postoperative recurrence and high NLR, low total protein, low albumin, low PNI, and high GPS. In the data from 6 months after surgery, there was a significant association between postoperative recurrence and high NLR, high C-reactive protein, and high GPS. The reduction in PMI at 6 months after surgery relative to preoperative data was significantly greater in the cases with recurrence than in those without recurrence. No patients whose PMI increased compared with presurgery had recurrence. Conclusions : The postoperative reduction in PMI at 6 months after surgery relative to presurgery could be a predictive marker of recurrence after curative gastrectomy for patients with pStage II and III GC. J. Med. Invest. 68 : 119-124, February, 2021.

A case of colorectal large cell neuroendocrine carcinoma accompanied by disseminated peritoneal leiomyomatosis

Background

Neuroendocrine carcinomas (NECs) of the colon are among the rarest types of colorectal cancers. Among these, large cell type neuroendocrine carcinoma (LCNEC) is particularly rare. Colorectal NEC is an aggressive disease, and there are few reports of long-term survivors. Here, we report a case of LCNEC accompanied by disseminated peritoneal leiomyomatosis that was difficult to diagnose.

Case presentation

The case involves a 62-year-old female found to be positive for fecal occult blood by medical examination. An endoscopy revealed a tumor in the ascending colon, and the biopsy revealed poorly differentiated cancer. Abnormal FDG accumulation with peritoneal thickening was visible on 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET) and suspected to be peritoneal dissemination. Laparoscopic ileocecal resection was performed for the tumor of the ascending colon with abdominal wall invasion. At that time, numerous intra-abdominal nodules were observed, indicating peritoneal dissemination. The pathological diagnosis of the primary lesion was LCNEC, and the patient requested to undergo total peritoneal resection. After one course of chemotherapy with irinotecan plus cisplatin, she underwent total peritoneal resection, uterine annex resection, left inguinal lymph node resection, and intra-abdominal hyperthermic intraperitoneal chemotherapy with mitomycin C. Because a postoperative pathological examination revealed that the intra-abdominal nodules were leiomyomas, we diagnosed the patient with disseminated peritoneal leiomyomatosis. The left inguinal lymph node was diagnosed with a metastatic tumor. In summary, the final diagnosis was LCNEC in the ascending colon with inguinal lymph node metastasis. Postoperative chemotherapy has been administered to date. She is currently 18 months post-primary surgery and 15 months post-peritonectomy without apparent recurrence or metastatic findings.

Conclusion

We experienced a case of Stage IVa colorectal LCNEC accompanied by disseminated peritoneal leiomyomatosis. Although the prognosis is generally poor, multidisciplinary treatment for advanced colorectal LCNEC may result in a favorable outcome for some patients. If peritoneal dissemination is suspected during operation, sampling of the nodule to confirm the pathological diagnosis is advisable.

Comparative Analysis of Immunoinflammatory and Nutritional Measures in Surgically Resected Esophageal Cancer: A Single-center Retrospective Study

BACKGROUND/AIM

Several immunoinflammatory and nutritional measures have been reported to be good prognostic indicators for esophageal cancer (EC). However, the association between those markers and the postoperative survival of EC patients remains unclear due to varying study designs and treatment strategies. The aim of this study was to compare the significance of preoperative immunoinflammatory and nutritional measures in patients with EC.

PATIENTS AND METHODS

One hundred and five patients with EC who underwent McKeown esophagectomy with gastric tube reconstruction without neoadjuvant therapy between 2006 and 2014 were included in this study. The prognostic values of preoperative modified Glasgow prognostic score (mGPS), controlling nutritional status (CONUT) score, prognostic nutritional index (PNI), C-reactive protein (CRP)-to-albumin ratio (CAR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) were investigated using univariate and multivariate survival analyses.

RESULTS

Multivariate analysis revealed that CAR and pathological stage are independent prognostic factors for overall survival (OS). CAR was significantly associated with more advanced pathological stage as both a subject and a continuous variable.

CONCLUSION

Preoperative CAR was an independent prognostic factor for the OS of EC patients who underwent McKeown esophagectomy. The tumor-stage related increase in CAR demonstrated that a high CAR is associated with tumor progression in EC patients.

Postoperative hemodynamic changes for predicting anastomotic leakage after esophagectomy in patients with esophageal cancer using the FloTrac system

Background : Anastomotic leakage after esophagectomy is significantly associated with more severe complications, such as sepsis and mortality. Early prediction for anastomotic leakage is usually difficult and needs to be treated rapidly. In the current study, we investigated the correlation between hemodynamic and several complications after esophagectomy in patients with esophageal cancer, using the FloTrac system. Materials and Methods : Between April 2013 and December 2014, 39 patients with a mean age of 66.6 ± 8.9 years underwent postoperative supervision using the FloTrac sensor / Vigileo monitoring system after curative surgery for esophageal cancer. We retrospectively evaluated the association between the number of aberrant cardiac index (CI) along with stroke volume variability (SVV) values and clinicopathological parameters of postoperative complications in this report. Results : There were significant positive correlations between the number of aberrant values of CI along with SVV and depth of invasion during pathological stage. Concerning major postoperative complications, there was a significant positive correlation between the number of aberrant values of CI and anastomotic leakage. Discussion: The hemodynamic change by employing the FloTrac system could predicts the complication of anastomotic leakage after esophagectomy. Adequate management of hemodynamic stability by utilizing it will reduce the complications of anastomotic leakage. J. Med. Invest. 67 : 240-245, August, 2020.

Pathophysiology of Vomiting and Esophageal Perforation in Boerhaave's Syndrome

BACKGROUND AND AIMS

Boerhaave's syndrome, involving esophagus rupture, is considered a pathological response to vomiting that may occur just before perforation. However, the mechanism of vomiting and occurrence of this disease have not been clearly demonstrated.

METHODS

We identified patients with esophageal perforation between 1995 and 2017 and reviewed endoscopic findings at retching during upper gastrointestinal endoscopy. Finally, we proposed a theory for the underlying pathological mechanism.

RESULTS

We retrospectively investigated 10 patients with esophageal perforation between 1995 and 2017. All patients presented after vomiting associated with large volumes of food and alcohol intake. Nine were treated by primary closure of the perforation and drainage of the thoracic cavity, and one was conservatively treated. In all cases, the perforations were longitudinal tears (1-4 cm) and located in the left of the esophagus, just above the gastric cardia.

CONCLUSIONS

We hypothesize that vomiting occurred by retrograde propagation of gastrointestinal motor contraction from the jejunum to the gastric antrum, followed by prolapse of the gastric fornix mucosal into the esophagus. Subsequent esophageal perforation probably resulted from excessive prolapse due to strong contraction and destruction of the muscularis mucosa of the left side of abdominal esophagus, with longitudinal stretching of the whole left esophageal wall due to traction. We also propose that Boerhaave's syndrome is defined as "post-emetic esophageal perforation" to ensure broader recognition and more expedient diagnosis and treatment. Remaining conditions without any definite causes may be labeled "idiopathic" or "spontaneous" rupture of the esophagus.

Role of PD-L1 Expression during the Progression of Submucosal Gastric Cancer

INTRODUCTION

Programmed death-ligand 1 (PD-L1) expression is a prognostic marker for gastric cancer that correlates with tumor diameter and depth of penetration. But the role of PD-L1 and mechanism(s) employed in the initial phase of invasion in early gastric cancer is yet to be understood.

OBJECTIVE

This study aims to elucidate the role of PD-L1 during the progression of gastric cancer, specifically invading the submucosa beyond the lamina muscularis mucosa.

METHODS

Using 107 patients with pathological submucosal gastric cancer, we determined the expression of PD-L1 based on the staining of the cell membrane or cytoplasm of tumor cells in the central and invasive front of the tumor. Samples were categorized into 3 groups based on the intensity of PD-L1 expression. CD8+ lymphocytes expressing PD-1 and CD163+ macrophages were used to determine the number of cell nuclei at the invasive front, similar to PD-L1. CMTM6 levels were determined and used to stratify samples into 3 groups.

RESULTS

PD-L1 expression was higher in the invasive front (26.2%) than in the central portion of the tumors (7.4%; p < 0.001). Moreover, lymphatic and vascular invasion were more frequently observed in samples with high levels of PD-L1 (lymphatic invasion: 60.7 vs. 35.4%, p = 0.0026, and vascular invasion: 39.3 vs. 16.5%, p = 0.0018). There was no correlation between PD-L1 expression and the levels of PD-1, CD8, CD163, and CMTM6.

CONCLUSIONS

PD-L1-expressing cancer cells at the invasive front of gastric cancer influence the initial stages of tumor invasion and lymphovascular permeation in early-stage gastric cancers. Immune checkpoint signaling may be the driving force in the invasive front during the invasion of the submucosa beyond the lamina muscularis mucosa.

IR super-resolution imaging of avian feather keratins detected by using vibrational sum-frequency generation

IR super-resolution imaging of the cross section of the rachis of an avian feather was carried out by using a vibrational sum-frequency generation (VSFG) detected IR microscope with a sub-micrometer spatial resolution. In the YYX polarization combination, we clearly observed strong signals in the entire region of the rachis at the amide I vibration of β-keratin. On the other hand, the signal disappears from most of the cross section in the XXY polarization combination. Because the VSFG imaging detects the signal only from the interface, we conclude that the interfacial deflection inside of a rachis was detected.

Skin Dose Reduction by Layer-Stacking Irradiation in Carbon Ion Radiotherapy for Parotid Tumors

Background: Layer-stacking irradiation (LSI) results in the accumulation of multiple small spread-out Bragg peaks along the beam direction. Although the superiority of LSI to conventional passive irradiation (CPI) regarding normal tissue sparing is theoretically evident, the clinical benefit of LSI has not been demonstrated. Here, we compared LSI with CPI using the same treatment planning-computed tomography images used for carbon ion radiotherapy (CIRT).

Methods: Twenty-one parotid tumors were analyzed. The clinical target volume (CTV) 1 and CTV2 encompassed the parotid grand and the tumor, respectively. CTV1 and CTV2 received 36 Gy (RBE: relative biological effectiveness) in nine fractions and 64 Gy (RBE) in 16 fractions, respectively, using either LSI or CPI. CTV coverage was assessed by DX%, which is the dose covering at least X% of the target volume. Skin dose was assessed by SX, which is the skin surface area receiving at least X Gy (RBE).

Results: For CTV1 and CTV2, there were no significant differences in D2% between LSI and CPI. D50% and D98% were slightly higher for CPI; however, the absolute difference between the two methods was <3%. S10–S60 (in increments of 10) were significantly lower for LSI than for CPI (P < 0.001 for all parameters). LSI was associated with a significant trend toward dose reduction at the skin area irradiated with a higher dose by CPI (P < 0.001).

Conclusions: LSI achieved better skin sparing than CPI without sacrificing target volume coverage in parotid tumor patients.

Role of surgery in multidisciplinary treatment strategies for locally advanced esophageal squamous cell carcinoma

We reviewed the current status and future perspectives regarding the role of surgery in multidisciplinary treatment strategies for locally advanced esophageal squamous cell carcinoma (ESCC). The treatment and management of ESCC have been improved by dramatic advances in diagnostic techniques and the development of surgery, chemotherapy, radiotherapy, and immunotherapy. The current standard treatment for locally advanced ESCC is preoperative chemotherapy followed by surgery in Japan, whereas preoperative chemoradiotherapy is a globally recommended approach. Differences of recognition regarding the role for surgery between Japan and many Western countries may have created peculiar preferences for preoperative therapy. The clinical significance of conversion strategy and salvage surgery for patients with ESCC should be further evaluated in terms of curability and safety. Although strategies to identify patients who would benefit from preoperative therapy are strongly required to avoid performing unnecessary treatment, it remains difficult to predict the efficacy of preoperative therapy prior to treatment. Prospective clinical trials and basic research to identify predictive biomarkers for response to chemotherapy, radiotherapy, and immunotherapy are needed to promote the development of multidisciplinary treatment strategies for patients with ESCC.