Artificial Intelligence for Assessment of Endotracheal Tube Position on Chest Radiographs: Validation in Patients From Two Institutions.

BACKGROUND. Timely and accurate interpretation of chest radiographs obtained to evaluate endotracheal tube (ETT) position is important for facilitating prompt adjustment if needed. OBJECTIVE. The purpose of our study was to evaluate the performance of a deep learning (DL)-based artificial intelligence (AI) system for detecting ETT presence and position on chest radiographs in three patient samples from two different institutions. METHODS. This retrospective study included 539 chest radiographs obtained immediately after ETT insertion from January 1 to March 31, 2020, in 505 patients (293 men, 212 women; mean age, 63 years) from institution A (sample A); 637 chest radiographs obtained from January 1 to January 3, 2020, in 302 patients (157 men, 145 women; mean age, 66 years) in the ICU (with or without an ETT) from institution A (sample B); and 546 chest radiographs obtained from January 1 to January 20, 2020, in 83 patients (54 men, 29 women; mean age, 70 years) in the ICU (with or without an ETT) from institution B (sample C). A commercial DL-based AI system was used to identify ETT presence and measure ETT tip-to-carina distance (TCD). The reference standard for proper ETT position was TCD between greater than 3 cm and less than 7 cm, determined by human readers. Critical ETT position was separately defined as ETT tip below the carina or TCD of 1 cm or less. ROC analysis was performed. RESULTS. AI had sensitivity and specificity for identification of ETT presence of 100.0% and 98.7% (sample B) and 99.2% and 94.5% (sample C). AI had sensitivity and specificity for identification of improper ETT position of 72.5% and 92.0% (sample A), 78.9% and 100.0% (sample B), and 83.7% and 99.1% (sample C). At a threshold y-axis TCD of 2 cm or less, AI had sensitivity and specificity for critical ETT position of 100.0% and 96.7% (sample A), 100.0% and 100.0% (sample B), and 100.0% and 99.2% (sample C). CONCLUSION. AI identified improperly positioned ETTs on chest radiographs obtained after ETT insertion as well as on chest radiographs obtained of patients in the ICU at two institutions. CLINICAL IMPACT. Automated AI identification of improper ETT position on chest radiographs may allow earlier repositioning and thereby reduce complications.

Identification of maximal tumor size associated with negligible lymph node metastasis for endoscopic submucosal dissection of undifferentiated-type early gastric cancer.

BACKGROUND AND AIMS: When treating undifferentiated-type early gastric cancer (UD-EGC) that is limited to the mucosa (clinically T1a), endoscopic submucosal dissection (ESD) can be considered if the tumor is 2 cm or less and is not ulcerated. However, there is insufficient evidence to determine the relationships between tumor size and oncological safety of ESD in UD-EGC. METHODS: The pathology reports of Korean patients who were diagnosed with UD-EGC (n = 5286) were retrospectively reviewed. The cumulative incidence of lymph node metastasis (LNM) according to tumor size was evaluated in subgroups. The tumor-size cut-off was identified as the upper limit of the 95% confidence interval (CI) of cumulative LNM incidence that did not exceed 1.0%. RESULTS: We identified 1516 patients with non-ulcerated T1a tumors ≤2 cm in size. Among patients without lymphatic invasion, 1.5% (95% CI 0.91-2.16%) had LNM. In patients with poorly differentiated tubular adenocarcinoma (PD), LNM increased from 0 to 0.74% based on a tumor size of 1.0 cm. Regardless of tumor size, smaller percentages of undifferentiated-type (UD) and poorly cohesive carcinoma (PCC) patients experienced LNM than did those with PD. In non-ulcerated mucosal cancer without lymphatic invasion and tumor size ≤0.9 cm, no LNM was observed in patients with UD (95% CI 0-0.53%), PCC (95% CI 0-0.59%), or PD (95% CI 0-0.86%) histologic type. CONCLUSION: In patients diagnosed with non-ulcerated T1a UD-EGC, ESD can be performed if the tumor size is 0.9 cm or less, regardless of histologic type.

Predictive Value of KLASS-02-QC Assessment Score on KLASS-02 Surgical Outcomes: Validation of Surgeon Quality Control and Standardization for D2 Lymphadenectomy.

OBJECTIVE: The aim of this study was to audit the 22 items and assessed each item's predictive value on surgical outcomes. BACKGROUND: The KLASS-02 trial revealed that the oncologic outcomes of laparoscopic distal gastrectomy are not inferior to open distal gastrectomy in patients with advanced gastric cancer. The surgeons participating in this trial were chosen based on the assessment scores from the KLASS-02-QC trial, which used 22 items for standardization of D2 lymphadenectomy and quality control. METHODS: We reviewed proficiency scores (PSs) for 22 items for 20 surgeons who participated in KLASS-02. The surgeons were divided into 2 groups according to PS, and the perioperative outcomes of 924 patients enrolled in KLASS-02 were compared between groups. Each item's predictive value for perioperative outcome was then assessed using multivariable regression models. RESULTS: Of the total 924 patients, 529 were operated on by high-score surgeons (high PS) and 395 were operated on by low-score surgeons (low-PS). High-PS group had less intraoperative blood loss, longer operation times, and fewer complications, major complications, reoperations, and shorter first flatus and hospital stay than low-PS group ( P =0.006, P <0.001, P <0.001, P <0.001, P =0.042, P =0.013, and P <0.001, respectively). Some items used in KLASS-02-QC predicted perioperative outcomes, such as intraoperative blood loss, major complications, reoperation, and hospital stay. CONCLUSIONS: Although this study only analyzed data associated with qualified surgeons, the 22 items effectively assessed the surgeons based on PS. A high score was associated with longer operation times, but better perioperative outcomes.

Standard follow-up after curative surgery for advanced gastric cancer: secondary analysis of a multicentre randomized clinical trial (KLASS-02).

BACKGROUND: The benefit of regular follow-up after curative resection for gastric cancer is controversial as there is no evidence that it will improve survival. This study assessed whether regular follow-up leads to improved survival in patients after surgery for gastric cancer. METHODS: A secondary analysis was undertaken of patients who participated in an RCT of laparoscopic versus open distal gastrectomy for advanced gastric cancer between November 2011 and April 2015. Depending on whether patients were compliant with the initial trial follow-up protocol or not, they were analysed as having had either regular or irregular follow-up. Clinicopathological characteristics, recurrence patterns, detection, treatments, and survival were compared between the groups. RESULTS: The regular and irregular follow-up groups comprised 712 and 263 patients respectively. Disease recurrence within 36 months was more common in the regular group than in the irregular group (17.0 versus 11.4 per cent; P = 0.041). Recurrence patterns did not differ between the groups. The 3-year recurrence-free survival rate was worse in the regular than in the irregular group (81.2 versus 86.5 per cent; P = 0.031). However, the 5-year overall survival rate was comparable (84.5 versus 87.5 per cent respectively; P = 0.160). Multivariable analysis revealed that type of follow-up was not an independent factor affecting 5-year overall survival. CONCLUSION: Regular follow-up after radical gastrectomy was not associated with improved overall survival.

Determining the precise extent of sentinel basins during laparoscopic gastrectomy for early gastric cancer.

PURPOSE: By analyzing sentinel basin dissection (SBD) data from the SEntinel Node ORIented Tailored Approach (SENORITA) trial, we sought to determine the precise extent of the sentinel basin (SB) without a tracer. MATERIALS AND METHODS: This study investigated SB length in patients (n = 25) who underwent laparoscopic SBD for early gastric cancer (EGC) in the SENORITA trial. SB length along the greater curvature (GC) and lesser curvature (LC) was measured intraoperatively before performing SBD. RESULTS: In all 25 cases, along the LC of the stomach, the lengths of the SB were 3.7 cm [2.0-5.0] (median [min-max]) proximally and 3.0 cm [2.3-5.5] distally; along the GC side, the lengths of the SB were 6.8 cm [3.5-11.0] proximally and 7.0 cm [3.8-9.5] distally from the tumors. The SB length at the GC or LC side was not significantly different between subgroups categorized by tumor depth, size, and longitudinal location. When tumors were located at the anterior wall of the stomach, the length of the proximal SB (10.0 cm [9.0-11.0]) at the GC side was the longest. In cases with several sentinel lymph nodes (SLNs), the lengths of the SB at the GC side were significantly longer than those with fewer SLNs. However, the lengths of the SB were similar on the LC side regardless of the number of SLNs. CONCLUSIONS: This pilot study had some limitations of a small number of enrolled patients, the lack of research on the specific station of SLNs, and the inaccurate indication for sentinel node navigation surgery (SNNS) without tracer. Nevertheless, the present study which reported the extents of SBs might be the first step towards simplifying procedures in laparoscopic SNNS for stomach preservation in EGC.

Clinicopathologic and genomic characteristics of mucinous gastric adenocarcinoma.

BACKGROUND: Mucinous gastric adenocarcinoma (MGC) is a rare but distinctive histologic subtype of gastric cancer (GC). The clinico-pathologic and genomic characteristics of MGC have not been well evaluated. METHODS: We collected individual data from five cohorts targeting the microsatellite instability (MSI) of GC (n = 5089) to evaluate the clinico-pathologic characteristics of MGC. In addition, public genomic databases were used for genomic analysis. The characteristics of MGC were compared with those of non-mucinous GC (NMGC). RESULTS: MGC (n = 158, 3.1%) showed distinctive characteristics in terms of age, sex, and TNM stage compared to NMGC (n = 4931). MGC was frequently associated with MSI-high (OR: 2.24, 95% confidence interval [CI] 1.44-3.40, p < 0.001), while mutually exclusive to the Epstein-Barr virus type. The prognosis of MGC was better than that of NMGC (adj.HR: 0.731, 95% CI 0.556-0.962, p = 0.025). There was no clear benefit from postoperative chemotherapy in MGC. TP53 was the main driver mutation in the MGC without recurrent variants. MGC was related to high expression of GPR120 and B3GNT6 and moderate regulation of epithelial-mesenchymal transition (EMT)-up signature with a high EMT-down signature, and those characteristics was related to favorable prognosis of GC (log-rank p = 0.044, p < 0.001, p < 0.001, respectively). MSI-H of MGC was associated with low cancer-associate fibroblasts but high CD274 (PD-L1) expression compared to microsatellite stable MGC, suggesting that immune checkpoint inhibitors may be useful for the MSI-H of MGC. CONCLUSION: MGC could be a surrogate for performing MSI but not the EBV test in GC. Further, its genetic characteristics lead to a favorable prognosis for MGC.

A preoperative risk prediction model for high malignancy potential gastrointestinal stromal tumors of the stomach.

BACKGROUND: Gastric gastrointestinal stromal tumors (GISTs) exhibit various degrees of aggression and malignant potential. However, no systematic preoperative evaluation strategy to predict the malignancy potential of gastric GISTs has yet been developed. This study aimed to develop a reliable and easy-to-use preoperative risk-scoring model for predicting high malignancy potential (HMP) gastric GISTs. METHODS: The data of 542 patients with pathologically confirmed gastric GISTs who underwent resection were reviewed. Multivariate logistic regression analysis was used to identify significant predictors of HMP. The risk-scoring system (RSS) was based on the predictive factors for HMP, and its performance was validated using a split-sample approach. RESULTS: A total of 239 of 542 (44.1%) surgically resected gastric GISTs had HMP. Multivariate analysis demonstrated that tumor size, location, and surface changes were independent risk factors for HMP. Based on the accordant regression coefficients, the presence of surface ulceration was assigned 1 point. Tumor sizes of 4-6 cm and > 6 cm were assigned 2 and 5 points, respectively. Two points were assigned to cardia or fundus locations. A score of 3 points was the optimal cut-off value for HMP prediction. HMP were found in 19.8% and 82.7% of the low and high-risk groups of the RSS, respectively. The area under the receiver-operating characteristic curve for predicting HMP was 0.81 (95% confidence interval (CI) 0.75-0.86). Discrimination was good after validation (0.75, 95% CI 0.69-0.81). CONCLUSION: This simple RSS could be useful for predicting the malignancy potential of gastric GISTs and may aid preoperative clinical decision making to ensure optimal treatment.

Adjuvant Chemotherapy vs. Surgery Alone for pT3N0M0 Gastric Cancer.

BACKGROUND: As both the role and clinical application of adjuvant chemotherapy (CTx) for pT3N0M0 gastric cancer after curative gastrectomy have fluctuated chronologically, the oncological benefit of adjuvant CTx in patients should be elucidated. METHODS: Between 2000 and 2018, 1083 patients underwent radical gastrectomy for pT3N0M0 gastric cancer and were subsequently divided into two groups: the surgery-alone group (n = 471) and the adjuvant CTx group (n = 612). Chronological changes in adjuvant CTx and various chemotherapeutic regimens were evaluated and disease-free survival was compared between the two groups. Risk factors for tumor recurrence were also analyzed. RESULTS: The proportion of patients in the surgery-alone group was more than 60% until 2001, whereas in the CTx group this increased to over 80%, especially after publication of the American Joint Committee on Cancer (AJCC) 7th edition staging manual. The main chemotherapeutic agents were tegafur-uracil (UFT) and 5-fluorouracil with leucovorin until 2008, whereas tegafur/gimeracil/oteracil (TS-1) has been the main agent since 2009. The 5-year disease-free survival was 89.2% in the surgery-alone group and 89.9% in the CTx group, which was not significantly different (p = 0.694). In multivariate analysis, larger tumor size (≥ 4.5 cm) and venous invasion were significant risk factors for tumor recurrence. In addition, adjuvant CTx did not improve the oncological outcome, even in the large tumor size group (p = 0.760) and the venous invasion group (p = 0.753). CONCLUSIONS: As adjuvant CTx did not show any oncological benefit in pT3N0M0 gastric cancer in this large-scale study, it might be unnecessary for these patients after curative gastrectomy.

Microsatellite Instability and Effectiveness of Adjuvant Treatment in pT1N1 Gastric Cancer: A Multicohort Study.

BACKGROUND: Microsatellite status is a prognostic biomarker in advanced gastric cancer. This retrospective study aimed to investigate the usefulness of microsatellite status in predicting prognosis and response to adjuvant treatment in pT1N1 gastric cancer. PATIENTS AND METHODS: Among 875 patients who underwent radical gastrectomy for pT1N1 gastric cancer at two tertiary hospitals, 838 with available microsatellite instability (MSI) data were included and classified into two groups according to microsatellite status: microsatellite stable (MSS) and MSI-high (MSI-H). Recurrence-free survival rate and risk factors for tumor recurrence were analyzed. RESULTS: Of 838 gastric cancer patients, 100 (11.9%) were MSI-H and 307 (36.6%) received adjuvant treatment. During median follow-up of 70 months, 42 (5.0%) patients experienced gastric cancer recurrence; hematogenous recurrences were the most common (45.2%). Recurrence-free survival was similar in the MSS and MSI-H groups (p = 0.27), and adjuvant treatment did not show an oncological benefit over surgery alone for pT1N1 gastric cancer (p = 0.53). On univariate analysis, age, operation period, and Lauren classification were significantly associated with tumor recurrence, while adjuvant treatment and MSI status were not associated with tumor recurrence. On multivariate analysis, MSI status was not associated with tumor recurrence, and adjuvant treatment worsened the tumor recurrence risk [hazard ratio (HR) 2.373, 95% confidence interval (CI) 1.125-5.006, p = 0.023). CONCLUSION: MSI status may not be a prognostic factor for tumor recurrence or a predictor of response to adjuvant treatment in pT1N1 gastric cancer patients. Considering that the effect of adjuvant treatment to decrease the risk of tumor recurrence is not clear, it may not be indicated in pT1N1 patients.

Single patient classifier as a prognostic biomarker in pT1N1 gastric cancer: Results from two large Korean cohorts.

OBJECTIVE: Benefits of adjuvant treatment in pT1N1 gastric cancer (GC) remain controversial. Additionally, an effective biomarker for early GC is the need of the hour. The prognostic and predictive roles of single patient classifier (SPC) were validated in stage II/III GC. In this study, we aimed to elucidate the role of SPC as a biomarker for pT1N1 GC. METHODS: The present retrospective biomarker study (NCT03485105) enrolled patients treated for pT1N1 GC between 1996 and 2012 from two large hospitals (the Y cohort and S cohort). For SPC, mRNA expression of four classifier genes (GZMB, WARS, SFRP4 and CDX1) were evaluated by real-time reverse transcription-polymerase chain reaction assay. The SPC was revised targeting pT1 stages and the prognosis was stratified as high- and low-risk group by the expression of SFRP4, a representative epithelial-mesenchymal transition marker. RESULTS: SPC was evaluated in 875 patients (n=391 and 484 in the Y and S cohorts, respectively). Among 864 patients whose SPC result was available, 41 (4.7%) patients experience GC recurrence. According to revised SPC, 254 (29.4%) patients were classified as high risk [123 (31.5%) and 131 (27.1%) in the Y and S cohorts, respectively]. The high risk was related to frequent recurrence in both Y and S cohort (log-rank P=0.023, P<0.001, respectively), while there was no difference byGZMB and WARS expression. Multivariable analyses of the overall-cohort confirmed the high risk of revised SPC as a significant prognostic factor [hazard ratio (HR): 4.402 (2.293-8.449), P<0.001] of GC. A significant difference was not detected by SPC in the prognosis of patients in the presence and absence of adjuvant treatment (log-rank P=0.670). CONCLUSIONS: The present study revealed the revised SPC as a prognostic biomarker of pT1N1 GC and suggested the use of the revised SPC for early-stage GC as like stage II/III.

Nomogram to predict lymph node metastasis in patients with early gastric cancer: a useful clinical tool to reduce gastrectomy after endoscopic resection.

BACKGROUND: The indications for endoscopic dissection have been expanded to improve the quality of life of patients with early gastric cancer (EGC). This study aimed to develop a nomogram to predict the status of lymph node metastasis with the aim of avoiding unnecessary gastrectomies. METHODS: We reviewed the clinicopathological data of 10 579 patients who underwent curative resection for EGC. The nomogram was developed by multivariate analysis and was evaluated by external validation. Overall, disease-free and recurrence-free survival were compared between the gastrectomy group of 6641 patients and the endoscopic dissection group of 999 patients to show the efficacy of the nomogram. RESULTS: Multivariate analyses revealed that age, tumor size, lymphatic invasion, depth of invasion, and histologic differentiation were all significant prognostic factors for lymph node metastasis. The nomogram had good discriminatory performance, with a concordance index of 0.846. This was supported by the external validation point of 0.813. For patients with low risk of lymph node metastasis on the nomogram (≤ 3 % of the provisional value in this study), the endoscopic dissection and gastrectomy groups had comparable rates of overall (P = 0.32), disease-free (P = 0.47), and recurrence-free (P = 0.09) survival. CONCLUSIONS: We developed and validated a nomogram that predicts the risk of lymph node metastasis in EGC based on a large database. This precision nomogram is useful to avoid unnecessary gastrectomy after endoscopic dissection, which may ultimately improve the quality of life of patients with EGC.

Bridging genomics and phenomics of gastric carcinoma.

Genetic alterations are the starting point leading to numerous changes in clinical and pathologic features (phenotypes) of individual cancers; however, their inter-relationships in gastric cancers (GC) are unclear. We performed massive parallel sequencing of 381 cancer-related genes and compared the results with clinical and pathologic findings in 330 GC. High tumor mutation burden (TMB) accounted for 11% of GC (n = 37) and all 19 MSI-H GCs were high TMB. High TMB was significantly more frequent in intestinal-type by Lauren, tumor with higher host cellular immune response, earlier AJCC stage and favorable prognosis. The most significantly mutated genes were TP53 (54%), ARID1A (23%), CDH1 (22%), PIK3CA (12%), RNF43 (10%) and KRAS (9%). For receptor tyrosine kinases, amplifications detected by immunohistochemistry were higher than sequencing (HER2, 9.1% vs. 5.8%; EGFR, 11.2% vs. 6.1%; FGFR2, 4.6% vs. 3.9%, c-MET, 3.4% vs. 0.9%). PTEN protein loss (22%) correlated well with underlying PTEN alterations while ATM loss (27%) was not significantly correlated with genetic alterations of ATM. p53 protein expression predicted alterations of TP53 with high sensitivity (97.8%) and low (15.9%) specificity. The poorly cohesive histology/CDH1-mutant GC subgroup showed the worst survival (p < 0.001). PD-L1 expression was significantly associated with MSI-H, MLH1 loss, ATM loss, MET positivity, higher host immune response, and genetic alterations of ARID1A, BRD3, PIK3CA, KRAS, MAP3K13, CDH2, PTEN and ESR1. The merged clinical, pathology and genomics of GC provide a better understanding of GC and new insights into the treatment of GC.

Short-term Outcomes of a Multicenter Randomized Controlled Trial Comparing Laparoscopic Distal Gastrectomy With D2 Lymphadenectomy to Open Distal Gastrectomy for Locally Advanced Gastric Cancer (KLASS-02-RCT).

OBJECTIVE: The aim of the study was to evaluate the short-term outcomes of KLASS-02-RCT, a multicenter randomized controlled trial comparing laparoscopic distal gastrectomy (LDG) with D2 lymphadenectomy with open distal gastrectomy (ODG). SUMMARY BACKGROUND DATA: Although several benefits of laparoscopic gastric cancer surgery have been reported, strong evidence is still limited, especially in locally advanced gastric cancer which requires extensive lymph node dissection. METHODS: Enrollment criteria included histologically confirmed cT2-4a and N0-1 gastric adenocarcinoma. Thirty-day morbidity, 90-day mortality, postoperative pain, and recovery were compared between LDG and ODG groups. RESULTS: A total of 1050 patients were randomly assigned to LDG (n = 526) or ODG group (n = 524) between November 2011 and April 2015. After excluding patients who received bypass or no surgery, 1011 patients were analyzed as actual treatment group. Mean number of totally retrieved lymph nodes was similar in both groups (LDG = 46.6 vs ODG = 47.4, P = 0.451). Early morbidity rate was significantly lower after LDG (16.6%) than after ODG (24.1%; P = 0.003). Postoperative analgesics use and patients' reported pain score were significantly lower after LDG. First day of flatus was earlier after LDG (3.5 vs 3.7 d, P = 0.025) and postoperative hospital stay was shorter in LDG group (8.1 vs 9.3 d, P = 0.005). Ninety days' mortality rate was similar in both groups (LDG = 0.4% vs ODG = 0.6%, P = 0.682). CONCLUSIONS: Laparoscopic distal gastrectomy with D2 lymphadenectomy for locally advanced gastric cancer shows benefits in terms of lower complication rate, faster recovery, and less pain compared with open surgery.

Prognostic Impact of Increased Perioperative Platelet Count in Gastric Cancer Patients.

BACKGROUND: Solid tumors are a common cause of secondary (reactive) thrombocytosis, a paraneoplastic syndrome that is also a prognostic factor for various cancers. However, cutoff values for platelet count specific to gastric cancer and their prognostic roles are unknown. METHODS: We retrospectively analyzed records of 4643 patients with gastric cancer who underwent radical surgery from 2007 to 2010. The minimum P-value approach was used with the log-rank test to determine the optimal prognosis predicting threshold for preoperative platelet count. Change in perioperative platelet count over time was evaluated with a generalized estimating equation. Clinicopathologic features and prognostic significance were analyzed according to platelet count. RESULTS: Thrombocytosis prevalence (platelet count ≥40 × 104/µL) was 1.6% (75 of 4643 patients). The platelet count cutoff value with the lowest P-value was ≥25.5 × 104/µL, and patients with higher platelet count had more advanced disease. Multivariate analysis showed that cutoff value was an independent prognostic factor of overall survival (hazard ratio 1.19, 95% confidence interval 1.03-1.37, P = 0.017). Patients who underwent adjuvant chemotherapy (n = 1300) and had a greater than 10% increase in platelet count at postoperative 1 y compared to before surgery had significantly poorer overall survival (hazard ratio 1.65, 95% confidence interval 1.11-2.45, P = 0.013). CONCLUSIONS: Elevated preoperative platelet count (≥25.5 × 104/µL) and increased platelet count (≥10%) at postoperative 1 y in an adjuvant chemotherapy group were unfavorable prognostic factors. Platelet count could be a cost-effective biomarker for screening and monitoring patients with unfavorable survival outcomes.

A prediction model for lymph node metastasis in early-stage gastric cancer: Toward tailored lymphadenectomy.

BACKGROUND: The aim of this study was to develop a prediction model for the presence and location of lymph node metastasis (LNM) in early gastric cancer. METHOD: We reviewed medical records of 4 929 patients who underwent radical gastrectomy for early gastric cancer. Variables of age, sex, lymphatic invasion, depth of invasion, location, gross type, differentiation, and tumor size were analyzed. Logistic regression analysis was used to determine independent predictors of LNM at each LN station. RESULT: Overall incidence of LNM was 9.1% (448/4 929 patients). For the presence of LNM, risk factors of age, sex, lymphatic invasion, depth of invasion, anatomical part, gross ulceration, size, and tumor differentiation were significantly associated with LNM. The area under the curve (AUC) for predicting LNM after validation was 0.834 for the test set. For the location of LNM, age, sex, lymphatic invasion, depth of invasion, anatomical part, circumferential portion, gross type, differentiation, and tumor size were significantly associated with LNM. The AUC of each LN station was favorable with the test set. CONCLUSION: Predicting the location of metastatic LNs appeared to be possible in patients with early gastric cancer.

A comparison of short-term postoperative outcomes including nutritional status between gastrectomy with simultaneous cholecystectomy and gastrectomy only in patients with gastric cancer.

OBJECTIVE: We aimed to evaluate the effect of simultaneous cholecystectomy on the short-term postoperative outcomes and nutritional status in patients with gastric cancer. METHODS: We retrospectively reviewed data from 4,820 patients with gastric cancer who underwent gastrectomy from January 2011 to December 2016. Patients who underwent only gastrectomy (N=4,578) were matched to those who underwent simultaneous cholecystectomy during gastrectomy (N=242) at a 1:1 ratio using propensity score matching analysis. The nutritional status and inflammatory responses preoperatively and postoperatively and postoperative outcomes were compared between the groups. RESULTS: The simultaneous cholecystectomy group showed more intraoperative blood loss and a longer operative time than the gastrectomy only group [150.0 (100.0, 200.0) mL vs. 100.0 (100.0, 200.0) mL, P=0.006; 176.0 (150.0, 210.0) min vs. 155.0 (128.0, 188.0) min, P<0.001, respectively]. Intraoperative event rate, postoperative complication rate, and postoperative recovery did not differ between the groups. All parameters including body weight, the hemoglobin level, absolute lymphocyte count, total protein level, albumin level, fasting glucose level, and prognostic nutritional index excluding the cholesterol level were not significantly different between the groups, and their changing patterns were similar. Although the cholesterol level was significantly lower in the simultaneous cholecystectomy group than in the gastrectomy only group at all follow-up points, the mean value of the decreased cholesterol level was within normal range. CONCLUSIONS: In gastric cancer patients with gallbladder disease, simultaneous cholecystectomy is safe and not associated with additional nutritional loss.

Adjuvant Chemotherapy Versus Chemoradiotherapy Versus Surgery Alone for Early Gastric Cancer with One or Two Lymph Node Metastasis.

BACKGROUND: Limited studies exist comparing clinical outcomes by adjuvant treatment for pT1N1 gastric cancer. This study compared the disease-free survival (DFS) of patients with pT1N1 gastric cancer according to the type of adjuvant treatment-surgery alone, chemotherapy (CTx), and chemoradiotherapy (CCRTx)-and evaluated risk factors for tumor recurrence. METHODS: Between 1995 and 2015, 738 patients underwent radical gastrectomy for pT1N1 gastric cancer and were divided into three groups: surgery alone (n = 355), CTx (n = 214), and CCRTx (n = 169). Chronological changes in adjuvant treatment type and chemotherapeutic regimens were evaluated and DFS was compared. Risk factors for tumor recurrence were analyzed. RESULTS: The proportion of patients who underwent surgery alone was more than 50% until 2001, and the proportion of those who had either CTx or CCRTx was more than 50% from 2002 to 2011, after which the proportion who underwent surgery alone increased again. The main chemotherapeutic agent was 5-fluorouracil with leucovorin. The 5-year DFS was 96.5% in the surgery-alone group, 96.0% in the CTx group, and 95.8% in the CCRTx group (no significant difference). The various chemotherapeutic regimens did not show differences in DFS. In univariate and multivariate analyses, adjuvant CTx and CCRTx showed no beneficial effect with regard to tumor recurrence. CONCLUSIONS: Because adjuvant CTx and CCRTx did not show any benefit with regard to tumor recurrence, these treatment strategies might be unnecessary for pT1N1 gastric cancer after gastrectomy. Further studies are necessary to reveal pT1N1 gastric cancer patient subgroups who might benefit from adjuvant treatments.

Factors Associated With Host Immune Response and Number of Lymph Nodes: A Large Retrospective Cohort Study.

BACKGROUND: The host immune response (HIR) against tumor cells is one of the key players in antitumor activities. However, the relationship between HIR and regional lymph nodes (LN) and their impacts on prognosis have not been studied. METHODS: This study analyzed HIR and clinicopathologic factors for 8819 consecutive gastric cancer patients who underwent gastrectomy and D2 LN dissection. The findings confirmed Epstein-Barr virus (EBV) with Epstein-Barr encoding region in situ hybridization, HIR grading (G1, G2, and G3), LN numbers classified into seven groups, and performed ordinal regression analysis. RESULTS: The mean number of LNs was 41. A higher degree of HIR was significantly associated with male sex, EBV+, non-intestinal histology by Lauren classification, earlier American Joint Committee on Cancer (AJCC) stage, and greater number of LNs (P < 0.001). Female gender, younger age (< 60 years), EBV+, non-intestinal histology, higher HIR grade (G2 and G3), larger tumor size, and deeper invasion depth were significantly related to a higher number of LNs, with an odds ratio greater than 1. In cancer-specific survival analyses, EBV+, younger age, higher HIR grade (G3), and increased number of LNs were independent prognostic factors in addition to AJCC stage. CONCLUSIONS: The HIR was associated with increased number of LNs was a significant favorable prognosticator.

Lymphovascular invasion and lymph node metastasis rates in papillary adenocarcinoma of the stomach: implications for endoscopic resection.

BACKGROUND: Current Japanese gastric cancer treatment guidelines recommend the same endoscopic resection criteria for papillary early gastric cancer (EGC) and well-differentiated (WD) or moderately differentiated (MD) EGC. To evaluate the appropriateness of this recommendation, we compared the clinicopathological characteristics of papillary EGC with those of WD, MD, poorly differentiated (PD), and signet ring cell (SRC) EGC. METHODS: A total of 6710 patients who underwent radical gastrectomy for EGC were included. Clinicopathological characteristics of papillary EGC were retrospectively reviewed and compared with those in other EGC subtypes. RESULTS: Papillary EGC accounted for 1.9% (130/6710) of total cases. Patients with papillary EGC were older and showed a male predominance compared to patients with PD or SRC EGC. Papillary EGCs showed significantly higher submucosal and lymphovascular invasion rates than WD or MD EGC or PD or SRC EGC. However, the LN metastasis rate of papillary EGC was comparable to or lower than that in other EGC subtypes. LN metastasis rates in mucosal cancers were 1.5%, 1.1%, and 4.0%, and those in submucosal cancers were 9.4%, 11.9%, and 17.6% for papillary EGC, WD or MD EGC, and PD or SRC EGC, respectively. In multivariate analysis, lymphatic invasion and PD or SRC histology were the strongest risk factors for LN metastasis. Among 63 papillary EGC that met the curative endoscopic resection criteria, no case showed LN metastasis. CONCLUSIONS: Endoscopic resection can be indicated for papillary EGC according to current guidelines. Given a considerable lymphovascular invasion rate, careful histological evaluation is required after endoscopic resection for papillary EGC.

Comparison of Long-Term Outcomes After Non-curative Endoscopic Resection in Older Patients with Early Gastric Cancer.

BACKGROUND: Limited data exist that describe the long-term outcomes from additional surgery following non-curative endoscopic resection (ER) of early gastric cancer (EGC) in older people. This study aimed to determine the appropriate treatment strategy for these patients. METHODS: We analyzed data from 2895 patients who underwent ER for EGC, of whom 451 (15.6%) had non-curative resections followed by curative surgery or surveillance only. Of these patients, 138 were older (aged ≥70 years). We compared the long-term outcomes of the different treatment strategies in the older patients with non-curative resections for EGC, and the outcomes of each treatment strategy, with those in younger patients. RESULTS: The older patients underwent curative resections, non-curative resections with surgery, or non-curative resections with surveillance, and the 5-year disease-specific survival (DSS) rates were 100, 100, and 73%, respectively. There was a trend toward significance for DSS in favor of the non-curative resections with surgery group compared with the non-curative resections with surveillance-only group (p = 0.069). Among those who did not undergo additional surgery, the older patients had worse DSS than the younger patients, and patients who underwent additional surgery had better DSS, irrespective of their ages. Multivariable analysis adjusted for other-cause mortality generated similar results. Overall survival and recurrence-free survival did not differ according to treatment strategy, and perioperative morbidity and mortality did not differ significantly according to age. CONCLUSIONS: In older patients with non-curatively resected EGC, additional surgery demonstrated a trend toward better DSS, and perioperative complications did not increase significantly.