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A bstract Plahte identities are monodromy relations between open string scattering amplitudes at tree level derived from the Koba-Nielsen formula. We represent these identities by polygons in the complex plane. These diagrams make manifest the appearance of sign changes and singularities in the analytic continuation of amplitudes. They provide a geometric expression of the KLT relations between closed and open string amplitudes. We also connect the diagrams to the BCFW on-shell recursion relations and generalise them to complex momenta resulting in a relation between the complex phases of partial amplitudes.

The current standard surgical procedure for proximal gastric and gastroesophageal junction (P/GEJ) cancers with limited esophageal involvement is total gastrectomy (TG). TG is associated with impaired appetite and weight loss due to decreased levels of ghrelin (a “hunger hormone” secreted by the stomach) and with anemia due to intrinsic factor loss and vitamin B12 malabsorption. Theoretically, proximal gastrectomy (PG) with an anti-reflux technique such as double-tract reconstruction (DTR) can improve quality of life (QoL) by preserving gastric function. 1 A recent Japanese prospective GEJ adenocarcinoma study reported a low incidence of lymph node metastases at peripyloric stations, 2 indicating the oncological safety of PG for GEJ adenocarcinoma regardless of tumor stage. As a result, PG is increasingly performed in South Korea and Japan, although the QoL benefit of PG over TG remains unknown. 3 , 4 We have performed PG with DTR in select cases with satisfying short-term outcomes. In this video, we introduce our technique for robotic PG with DTR. The presented case is a 75-year-old woman with GEJ adenocarcinoma that showed an excellent response to preoperative chemoradiation therapy. The patient underwent robotic PG with DTR. Fluorescent sentinel lymphatic mapping was performed by injecting indocyanine green solution (total of 2 ml, at four quadrants around the tumor at submucosal space) via endoscopy at the beginning of the operation. It showed absence of sentinel lymphatic flow to peripyloric lymph nodes, which were thus considered safe to preserve. Pathologic examination confirmed a complete response. The patient’s recovery was favorable, and she reported satisfaction with her QoL and good appetite, though some intermittent bloating after eating. PG with DTR has theoretical disadvantages including incomplete lymph node removal, which may result in recurrence; therefore, PG should be carefully performed for P/GEJ cancers with low risk of perigastric lymph node metastases, such as cT1 tumors or GEJ tumors with limited gastric involvement. 2 In addition, delayed gastric emptying of the remnant stomach can cause upper gastrointestinal symptoms such as reflux and bloating. The QoL benefits of PG with DTR must be demonstrated before encouraging its use in the USA and other countries. International collaboration is warranted to test the benefits and safety of PG, and the effective use of sentinel lymphatic mapping, to standardize the surgical care of patients with P/GEJ cancers.

Background Few studies have focused on palliative surgery in patients with advanced gastroesophageal junction (GEJ) or gastric cancer. We sought to evaluate clinical observational outcomes following palliative surgery in this population. Patients and Methods Patients with GEJ or gastric cancer who underwent palliative surgery (1/2010–11/2022) were identified. The primary outcomes were symptom improvement, ability to tolerate an oral diet, discharge to home, 30 “good days” without hospitalization, and receipt of systemic treatment. Postoperative outcomes and survival were secondarily evaluated. Results Among 93 patients, the median age was 59 (IQR 47–68) years, and the median Eastern Cooperative Oncology Group Performance Status (ECOG-PS) was 1 (range 0–3). The most frequent indication for palliative surgery was primary tumor obstruction [75 (81%) patients]. The most common procedures were feeding tube placement in 60 (65%) and intestinal bypass in 15 (16%) patients. A total of 75 (81%) patients experienced symptom improvement. Of these, 19 (25%) developed recurrent and 49 (65%) developed new symptoms. ECOG-PS was significantly associated with symptom-free time. Among those who underwent a bypass, resection, or ostomy creation for malignant obstruction, 16 (80%) tolerated an oral diet. Postoperatively, 87 (94%) were discharged home, 72 (77%) had 30 good days, and 64 (69%) received systemic treatment. Postoperative complications occurred in 35 (38%) patients, and 7 (8%) died within 30 days. The median survival time was 7.7 (95% CI 6.4–10.40) months. Conclusions Patients with incurable GEJ or gastric cancer can benefit from palliative surgery. Prognosis and performance status should inform goals-of-care discussions and patient selection for surgical palliation.

Minimally invasive surgery techniques have evolved remarkably over the past few decades in the field of surgical oncology, including robotic techniques for gastric malignancies. Bedside surgical assistance is often limited by operating table space or surgeon availability. Operating surgeons need to understand such limitations in robotic surgery assistance and how to maximize the effective use of the inactive 4th robotic arm (i.e., determine “where to park the 4th arm”) to obtain adequate exposure of the surgical field during robotic gastrectomy. In this video, we demonstrate how we perform robotic total gastrectomy, with a focus on how we effectively utilize the 4th robotic arm to achieve adequate exposure of the surgical field. Achieving excellent exposure of the surgical field is of paramount importance during robotic total gastrectomy for gastric cancer, and the effective use of the 4th robotic arm is extremely important for improving the safety and oncologic quality of robotic total gastrectomy.

The prognosis of appendiceal goblet cell carcinoid tumors (GCTs) is believed to be intermediate between appendiceal adenocarcinomas and conventional carcinoid tumors. However, GCTs can have mixed morphologic patterns, with variable amount of adenocarcinoma. To evaluate the behavior of GCTs and related entities with variable components of adenocarcinoma. We classified 74 cases of appendiceal tumors into 3 groups: group 1, GCTs or GCTs with less than 25% adenocarcinoma; group 2, GCTs with 25% to 50% adenocarcinoma; group 3, GCTs with more than 50% adenocarcinoma; and a comparison group of 68 adenocarcinomas without a GCT component (group 4). Well-differentiated mucinous adenocarcinomas were excluded. Clinicopathologic features and follow-up were obtained from computerized medical records and the US Social Security Death Index. Of the 142 tumors studied, 23 tumors (16%) were classified as group 1; 27 (19%) as group 2; 24 (17%) as group 3; and 68 (48%) as group 4. Staging and survival differed significantly among these groups. Among 140 patients (99%) with available staging data, stages II, III, and IV were present in 87%, 4%, and 4% of patients in group 1 patients; 67%, 7%, and 22% of patients in group 2; 29%, 4%, and 67% of patients in group 3; and 19%, 6%, and 75% of patients in group 4, respectively (P = .01). Mean (SD) overall survival was 83.8 (34.6), 60.6 (30.3), 45.6 (39.7), and 33.6 (27.6) months for groups 1, 2, 3, and 4, respectively (P = .01). By multivariate analysis, only stage and tumor category were independent predictors of overall survival. Our data highlight the importance of subclassifying the proportion of adenocarcinoma in appendiceal tumors with GCT morphology because that finding reflects disease stage and affects survival.

Background Serum prealbumin has long been used as a marker of nutritional status. However, prealbumin is a negative acute phase reactant influenced by several non-nutritional-related factors including surgery, infection, and cancer. An increasing prealbumin has been correlated with a positive nitrogen balance in general surgery patients receiving parenteral nutrition (PN) with 88% specificity and 70% sensitivity. To date, no trial has evaluated the effect of concurrent cancer and surgery on the value of prealbumin in predicting nitrogen balance. Methods This study is a concurrent retrospective design of post-operative patients (≥ 19 years of age) identified by the nutrition support service who received PN for ≥ 5 days, had a baseline and follow-up serum prealbumin and C-reactive Protein (CRP) measured, as well as a 24-h urinary urea nitrogen (UUN) performed between days 5–10 of PN. Exclusion criteria include anuric renal failure, Child–Pugh Class C liver failure, pregnancy, and corticosteroid use. Prealbumin was correlated to nitrogen balance, measuring sensitivity, specificity, and negative and positive predictive values. Information was collected regarding patient demographics and presence or absence of metastatic cancer. Results Thirty patients were identified and evaluated for this study from December 1st, 2010 to July 15th, 2011. Patients included in the study had a mean age of 57 years old (range 20–82), 53% male, with a mean weight of 84 kg (range 42–140) and body mass index (BMI) of 29 kg/m 2 (range 14.9–56.8). The mean daily caloric dose of PN per actual body weight was 21 kcal/kg (range 10–34) and the mean daily protein dose was 1.4 g/kg (range 1–2). Forty seven percent of patients were obese (BMI > 30 kg/m 2 ) and were prescribed high-protein hypocaloric PN. The most common indication for PN was post-operative ileus (23/30 patients). 24-h urine collection for UUN was performed on average of day 8 after PN initiation (range 5–10 days). Nitrogen balance as calculated from 24-h UUN was positive in 17/30 patients. A positive prealbumin change of greater than 2.8 mg/dL was found to have a statistically significant association with positive nitrogen balance ( p  = 0.02). At the cut off level of positive 2.8 mg/dL, the likelihood of a positive nitrogen balance had a sensitivity of 82% (95% confidence interval (CI) 64–100%); specificity of 62% (95% CI 35–88%); positive predictive value of 74% (95% CI 54–93%); negative predictive value of 73% (95% CI 46–99%). No absolute value for prealbumin level (e.g., > 20  mg/dL) was found to be a significant predictor of positive nitrogen balance. CRP levels at initiation of PN were significantly elevated with a mean level of 147 mg/dL. Conclusion These results indicate a positive change in serum prealbumin (> 2.8 mg/dL) has sufficient sensitivity (82%) to predict positive changes in nitrogen balance in the surgical oncology population. However, the low specificity (62%) makes it less useful in predicting a negative nitrogen balance. Absolute prealbumin levels were greatly affected by inflammation, as evidenced by CRP levels, and single values were not useful in predicting positive nitrogen balance. Clinical relevancy Positive changes in serum prealbumin levels have previously been associated with a positive nitrogen balance (NB) in surgical patients receiving parenteral nutrition (PN); however, it is unclear if this is true in oncologic surgery patients. This study highlights how changing levels of serum prealbumin and C-reactive protein correlates to NB for cancer patients in the post-operative period requiring PN. Changes in prealbumin levels from baseline showed sufficient sensitivity, but not specificity to utilize routinely for predicting NB in this population.

A bstract We study contact interactions for long world-lines on a curved surface, focusing on the average number of times two world-lines intersect as a function of their end-points. The result can be used to extend the concept of path-ordering, as employed in the Wilson loop, from a closed curve into the interior of a surface spanning the curve. Taking this surface as a string world-sheet yields a generalisation of the string contact interaction previously used to represent the Abelian Wilson loop as a tensionless string. We also describe a supersymmetric generalisation.

Background We sought to determine the sites of recurrence and identify predicting factors for recurrence and survival in patients who underwent gastrectomy for adenocarcinoma at an institution where preoperative therapy is commonly used for advanced gastric cancer. Methods We collected clinicopathologic data and sites of recurrence from a prospectively maintained database of patients who underwent potentially curative resection of gastric or gastroesophageal adenocarcinoma at our institution in 1995–2014, and we assessed associations between these characteristics and recurrence patterns and survival. Results We identified 488 patients who underwent R0 resection of localized gastric cancer. The median age was 63 years (interquartile range 53–71 years), and 60% were male. The most common T and N categories, per endoscopic ultrasonography, were T3 (58%) and N0 (61%). Preoperative treatment was used in 61% of patients. A total of 125 (26%) patients experienced recurrence during follow-up. Recurrences were locoregional in 19 patients (15%), peritoneal in 61 (49%), and nonperitoneal distant in 67 (54%). The peritoneum also was the most common organ of recurrence (49%), followed by the liver (21%). The median time from primary resection to recurrence was 2.7 years for locoregional, 1.3 years for peritoneal, and 0.6 years for nonperitoneal distant recurrence ( p  = 0.01). Median overall survival was markedly shorter after peritoneal and nonperitoneal distant recurrences than after locoregional recurrences. Conclusions The peritoneum was a common site of recurrence after curative resection of gastric cancer and was associated with poor survival. Prophylactic treatment targeting the peritoneal cavity might improve survival of advanced gastric cancer.

Background This study aimed to identify the yield of staging laparoscopy with peritoneal lavage cytology for gastric cancer patients and to track it over time. Methods The medical records of patients with gastric or gastroesophageal adenocarcinoma who underwent pretreatment staging laparoscopy at the authors’ institution from 1995 to 2012 were reviewed. The yield of laparoscopy was defined as the proportion of patients who had positive findings on laparoscopy, including those with macroscopic carcinomatosis, positive cytology, or other clinically important findings. To compare the yield of laparoscopy over time, the patients were divided into three 6-year ranges based on the date of diagnosis. Associations between clinicopathologic factors and peritoneal disease were examined using uni- and multivariate analyses. Results The study included 711 patients. Among these patients, 43.5 % had gastroesophageal junction tumors, 72.9 % had poorly differentiated adenocarcinoma, and 53 % had signet ring cell morphology. Endoscopic ultrasound had most commonly identified T3 (83.9 %) and N-positive (66.4 %) tumors. At laparoscopy, 148 (20.8 %) patients had been found to have macroscopic peritoneal carcinomatosis. Among 514 macroscopically negative patients who underwent peritoneal lavage cytologic analysis, 68 (13.2 %) had positive cytology results for malignancy. The total laparoscopy yield was 36 %, which did not change over time ( p = 0.58). Multivariate analysis demonstrated that positive cytology or carcinomatosis was associated with poorly differentiated histology, linitis plastica, and equivocal computed tomography findings. Conclusions Laparoscopy remains a useful staging procedure to evaluate for peritoneal spread when treatment or surgery is considered, even with the current availability of high-quality imaging.