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Abstract We developed and validated a new staging system that includes metabolic information from pretreatment [18F]Fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) for predicting disease-specific survival (DSS) in gastric cancer (GC) patients. Overall, 731 GC patients undergoing preoperative [18F]FDG PET/CT were enrolled and divided into the training (n = 543) and validation (n = 188) cohorts. A metabolic score (MS) was developed by combining the maximum standardized uptake value (SUVmax) of the primary tumor (T_SUVmax) and metastatic lymph node (N_SUVmax). A new staging system incorporating the MS and tumor-node-metastasis (TNM) stage was developed using conditional inference tree analysis. The MS was stratified as follows: score 1 (T_SUVmax ≤ 4.5 and N_SUVmax ≤ 1.9), score 2 (T_SUVmax > 4.5 and N_SUVmax ≤ 1.9), score 3 (T_SUVmax ≤ 4.5 and N_SUVmax > 1.9), and score 4 (T_SUVmax > 4.5 and N_SUVmax > 1.9) in the training cohort. The new staging system yielded five risk categories: category I (TNM I, II and MS 1), category II (TNM I, II and MS 2), category III (TNM I, II and MS ≥ 3), category IV (TNM III, IV and MS ≤ 3), and category V (TNM III, IV and MS 4) in the training cohort. DSS differed significantly between both staging systems; the new staging system showed better prognostic performance in both training and validation cohorts. The MS was an independent prognostic factor for DSS, and discriminatory power of the new staging system for DSS was better than that of the conventional TNM staging system alone.

Abstract Biliary strictures can have several benign or malignant causes. We attempted to determine the usefulness of establishing a diagnosis using self-expandable metal stents (SEMS) in a prospective series of patients with suspected malignant biliary obstruction. Data of patients who underwent SEMS removal from August 2016 to December 2019 were collected. During this period, 55 patients underwent endobiliary biopsy and SEMS insertion and removal. Fifty-five consecutive patients (mean age, 69 years; range 53–90 years) were enrolled, and of these, 37 were male and 18 were female. A final diagnosis was established using biopsy specimens in 37 cases (67.3%) and surgical specimens in 6 cases (10.9%), with 12 cases (21.8%) diagnosed on radiological follow-up. The final diagnoses included malignancy in 34 cases (61.8%) and benign stricture in 21 cases (38.2%). Endobiliary biopsy had a sensitivity and specificity of 44.1% and 95.2%, whereas SEMS cytology had a sensitivity and specificity of 52.9% and 100%, respectively. Combining endobiliary biopsy and/or SEMS cytology yielded a sensitivity and specificity of 73.5% and 95.2%, respectively. (1) The use of biopsy results alone as a diagnostic tool yielded an area under the receiver operating characteristic curve (AUC) of 0.70 (0.60–0.79). (2) The addition of SEMS to the biopsy results yielded an AUC of 0.86 (0.78–0.94). (3) The addition of CA 19–9 levels to the biopsy results yielded an AUC of 0.81 (0.71–0.94). (4) Combining the endobiliary biopsy results, SEMS tissues, and CA 19–9 levels yielded the best diagnostic accuracy, with an AUC of 0.90 (0.83–0.98). Detection of biliary obstruction using the combination strategy was better than the diagnostic results based on biopsy alone according to recent 3-year data. Our study suggested that SEMS removal could help establish a diagnosis of suspected malignant biliary obstruction.