Two-Port Minimally Invasive Nephro-Laparoscopic Retroperitoneal Debridement for Pancreatic Necrosis.

Walled-off necrosis (WON) occurs in approximately 20% of patients with necrotizing pancreatitis. Infection occurs in approximately 30% of necrosis patients, and despite advances in management, infected necrosis still confers a high mortality between 30 and 40%. While sterile necrosis requires drainage only for cases of symptom relief or "persistent unwellness," prompt intervention is critical for infected necrosis. Several management strategies exist depending on the location and anatomy of the necrosum. In particular, retroperitoneal collections away from the stomach are typically managed with a step-up approach that begins with percutaneous drain placement. While a minority of patients skirt further intervention, the majority require formal debridement at some point via the existing drain tract. These debridement techniques include video-assisted retroperitoneal debridement (VARD) through a flank incision or minimally invasive retroperitoneal pancreatic (MIRP) necrosectomy under continuous irrigation with a nephroscope. While effective, both debridement strategies have drawbacks: for VARD, the flank incision is prone to infections and hernia while MIRP debridements are tedious and often require repeat operative trips. To overcome these pitfalls, we describe a novel two-trocar minimally invasive hybrid nephro-laparoscopic retroperitoneal debridement technique for an efficient retroperitoneal pancreatic necrosectomy.

Revascularization techniques for complete portomesenteric venous occlusion in patients undergoing pancreatic resection.

INTRODUCTION: Pancreatic pathologies causing portomesenteric occlusion complicate extirpative pancreatic resection due to portomesenteric hypertension and collateral venous drainage. METHODS: Patients with portomesenteric occlusion undergoing pancreatectomy were identified between 2007 and 2020 at Stanford University Hospital. Demographic and clinical data, technique and perioperative factors, and post-operative outcomes were analyzed. RESULTS: Of twenty-seven (27) patients undergoing venous revascularization during pancreatectomy, most (15) were for pancreatic neuroendocrine tumor. Occlusions occurred mostly at the portosplenic confluence (15). Median occlusion length was 4.0 cm [3.1-5.8]. Regarding revascularization strategy, mesocaval shunting was used in 11 patients, in-line venous revascularization with internal jugular conduit in three patients, traditional venous resection and reconstruction in 9 patients, and thrombectomy in two patients. Median cohort operative time and estimated blood loss were 522 min [433-638] and 1000 mL [700-2500], respectively. Median length of stay was 10 days [8-14.5] with overall readmission rate of 37%. Significant complications occurred in 44% of patients despite only one (4%) perioperative mortality. DISCUSSION: Despite the technical complexity for managing portomesenteric occlusions, early revascularization strategies including mesocaval shunting or in-line venous revascularization are feasible and facilitate a safe pancreatic resection for surgically fit patients.

Utilization of parenteral nutrition in major gastrointestinal surgery: An opportunity for quality improvement.

BACKGROUND & AIMS: Parenteral nutrition (PN) is commonly utilized to support patients in the perioperative period of major gastrointestinal (GI) surgeries. This study sought to evaluate PN utilization based on malnutrition status and duration of PN use in a single academic institution to evaluate baseline ASPEN recommendation concordance and identify opportunities for quality improvement. METHODS: Patients who had undergone major GI surgical oncology operations and received PN were identified over six months. The medical charts were reviewed for clinicopathologic variables, nutrition status, and the initiation and duration of PN. The cohort was stratified by PN recommendation concordance, and intergroup comparisons were made to identify factors associated with non-concordant utilization of PN. RESULTS: Eighty-one patients were identified, 38.3% of patients were initiated on PN due to dysmotility. Other indications were: intra-abdominal leak (27.2%), mechanical obstruction (18.5%), and failure to thrive (16.0%). Non-concordant PN utilization was identified in 67.9% (55/81) of patients. The most frequent reason for non-concordance was initiation outside the recommended time frame due to severity of malnutrition; well-nourished patients started "too soon" accounted for 29.0% (16/55), and 61.8% started "too late," most of whom were moderately or severely malnourished (34/55). In 16.0% (13/81) of the overall cohort, PN was administered for fewer than five days. CONCLUSIONS: PN use during the perioperative period surrounding major GI oncologic operations is clinically nuanced and frequently not concordant with established ASPEN recommendations. Quality improvement efforts should focus on reducing delayed PN initiation for nutritionally at-risk patients without increasing premature PN use in well-nourished patients.

Therapeutic Efficacy of Temsirolimus in a Patient-derived Model of Metastatic Fibrolamellar Hepatocellular Carcinoma.

BACKGROUND/AIM: Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare tumor presenting in younger patients without chronic liver disease. Up to 80-100% develop recurrent disease, necessitating additional surgery or systemic treatment. Systemic options and pre-clinical treatment studies are lacking. We previously described patient-derived xenograft (PDX) development, allowing for pre-clinical studies. Herein, we develop FLHCC PDX models and utilize these to define tumor characteristics and determine the efficacy of systemic agents. MATERIALS AND METHODS: Primary and lymph node metastatic tumor tissues were obtained at the time of FLHCC resection in two patients. Tumor lysates were screened for protein upregulation. Cell lines were generated from metastatic and primary tumor tissue. The viability of the cell lines was assessed after treatment with temsirolimus, gemcitabine/oxaliplatin, and FOLFIRINOX. Two PDX models were developed from metastatic tissue. For in vivo studies, tumor-bearing mice were treated with temsirolimus, FOLFIRINOX, and Gemcitabine/oxaliplatin. RESULTS: PDX models were successfully generated from metastatic FLHCC, which closely recapitulated the original tumor. Upregulation of mTOR was seen in metastatic tissue compared to primary tumors. Cell lines from metastatic tissue demonstrated significant sensitivity to temsirolimus. In vivo testing of PDX models demonstrated a significant response to single-agent temsirolimus with minimal toxicity. CONCLUSION: Herein, we demonstrate the feasibility of developing PDX models that closely recapitulate FLHCC. Upregulation of mTOR was seen in metastatic tissue compared to primary tissue. The efficacy of mTOR inhibition with temsirolimus treatment suggests that the upregulation of the mTOR pathway may be a significant mechanism for growth in metastatic lesions and a potential target for therapeutics.

Determinants, Costs, and Consequences of Common Bile Duct Injury Requiring Operative Repair Among Privately Insured Individuals in the United States, 2003-2020.

Objective: Characterize the determinants, all-cause mortality risk, and healthcare costs associated with common bile duct injury (CBDI) following cholecystectomy in a contemporary patient population. Background: Retrospective cohort study using nationwide patient-level commercial and Medicare Advantage claims data, 2003-2019. Beneficiaries ≥18 years who underwent cholecystectomy were identified using Current Procedure Terminology (CPT) codes. CBDI was defined by a second surgical procedure for repair within one year of cholecystectomy. Methods: We estimated the association of common surgical indications and comorbidities with risk of CBDI using logistic regression; the association between CBDI and all-cause mortality using Cox proportional hazards regression; and calculated average healthcare costs associated with CBDI repair. Results: Among 769,782 individuals with cholecystectomy, we identified 894 with CBDI (0.1%). CBDI was inversely associated with biliary colic (odds ratio [OR] = 0.82; 95% confidence interval [CI]: 0.71-0.94) and obesity (OR = 0.70, 95% CI: 0.59-0.84), but positively associated with pancreas disease (OR = 2.16, 95% CI: 1.92-2.43) and chronic liver disease (OR = 1.25, 95% CI: 1.05-1.49). In fully adjusted Cox models, CBDI was associated with increased all-cause mortality risk (hazard ratio = 1.57, 95% CI: 1.38-1.79). The same-day CBDI repair was associated with the lowest mean overall costs, with the highest mean overall costs for repair within 1 to 3 months. Conclusions: In this retrospective cohort study, calculated rates of CBDI are substantially lower than in prior large studies, perhaps reflecting quality-improvement initiatives over the past two decades. Yet, CBDI remains associated with increased all-cause mortality risks and significant healthcare costs. Patient-level characteristics may be important determinants of CBDI and warrant ongoing examination in future research.

Clinical features and postoperative survival in patients with sporadic versus multiple endocrine neoplasia type 1-related pancreatic neuroendocrine tumors: An international cohort study.

BACKGROUND: The optimal surgical management of pancreatic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1 is controversial. This study sought to compare clinicopathologic characteristics and outcomes of multiple endocrine neoplasia type 1-associated and sporadic pancreatic neuroendocrine tumors from a large multi-national database. METHODS: A multi-institutional, international database of patients with surgically resected pancreatic neuroendocrine tumors was analyzed. The cohort was divided into 2 groups: those with multiple endocrine neoplasia type 1 versus those with sporadic disease. Clinicopathologic comparisons were made. Overall and disease-free survival were analyzed. Propensity score matching was used to reduce bias. RESULTS: Of 651 patients included, 45 (6.9%) had multiple endocrine neoplasia type 1 and 606 sporadic pancreatic neuroendocrine tumors. Multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors were more common in younger patients and associated with multifocal disease at the time of surgery and higher T-stage. Lymph node involvement and the presence of metastasis were similar. Total pancreatectomy rate was 5-fold higher in the multiple endocrine neoplasia type 1 cohort. Median survival did not differ (disease-free survival 126 months multiple endocrine neoplasia type 1 vs 198 months sporadic, P > .5). After matching, survival remained similar (overall survival not reached in either cohort, disease-free survival 126 months multiple endocrine neoplasia type 1 vs 198 months sporadic, P > .5). Equivalence in overall survival and disease-free survival persisted even when patients who underwent subtotal and total pancreatectomy were excluded. CONCLUSION: Multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors are more common in younger patients and are associated with multifocality and higher T-stage. Survival for patients with multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors is comparable to those with sporadic pancreatic neuroendocrine tumors, even in the absence of radical pancreatectomy. Consideration should be given to parenchymal-sparing surgery to preserve pancreatic function.

More Than an ERAS Pathway is Needed to Meet Target Length of Stay After Pancreaticoduodenectomy.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) protocols have been successfully instituted for pancreaticoduodenectomy (PD). This study evaluates reasons patients fail to meet length of stay (LOS) and areas for pathway improvement. MATERIALS AND METHODS: A multidisciplinary team developed and implemented an ERAS protocol for open PD in 2017. The study includes a medical record review of all patients who were perioperatively managed with the ERAS protocol and failed to meet LOS after PD procedures. Target LOS was defined as 7 d. RESULTS: From 2017 to 2020, 44% (93 of 213) of patients using ERAS protocol after PD procedures failed to meet target LOS. The most common reason to fail target LOS was ileus or delayed gastric emptying (47 of 93, LOS 11). Additional reasons included work-up of leukocytosis or pancreatic leak (17 of 93, LOS 14), additional "night" of observation (14 of 93, LOS 8), and orthostatic hypotension (3 of 93, LOS 10). Of these additional 46 patients, 19 patients underwent computed tomography (on or after POD 7) and only four patients received additional inpatient intervention. CONCLUSIONS: The most common reason for PD pathway failure included slow return of gastrointestinal function, a known complication after PD. The remaining patients were often kept for observation without additional intervention. This group represents an actionable cohort to target for improving LOS through surgeon awareness rather than protocol modification.

Perception versus reality: A National Cohort Analysis of the surgery-first approach for resectable pancreatic cancer.

INTRODUCTION: Although surgical resection is necessary, it is not sufficient for long-term survival in pancreatic ductal adenocarcinoma (PDAC). We sought to evaluate survival after up-front surgery (UFS) in anatomically resectable PDAC in the context of three critical factors: (A) margin status; (B) CA19-9; and (C) receipt of adjuvant chemotherapy. METHODS: The National Cancer Data Base (2010-2015) was reviewed for clinically resectable (stage 0/I/II) PDAC patients. Surgical margins, pre-operative CA19-9, and receipt of adjuvant chemotherapy were evaluated. Patient overall survival was stratified based on these factors and their respective combinations. Outcomes after UFS were compared to equivalently staged patients after neoadjuvant chemotherapy on an intention-to-treat (ITT) basis. RESULTS: Twelve thousand and eighty-nine patients were included (n = 9197 UFS, n = 2892 ITT neoadjuvant). In the UFS cohort, only 20.4% had all three factors (median OS = 31.2 months). Nearly 1/3rd (32.7%) of UFS patients had none or only one factor with concomitant worst survival (median OS = 14.7 months). Survival after UFS decreased with each failing factor (two factors: 23 months, one factor: 15.5 months, no factors: 7.9 months) and this persisted after adjustment. Overall survival was superior in the ITT-neoadjuvant cohort (27.9 vs. 22 months) to UFS. CONCLUSION: Despite the perceived benefit of UFS, only 1-in-5 UFS patients actually realize maximal survival when known factors highly associated with outcomes are assessed. Patients are proportionally more likely to do worst, rather than best after UFS treatment. Similarly staged patients undergoing ITT-neoadjuvant therapy achieve survival superior to the majority of UFS patients. Patients and providers should be aware of the false perception of 'optimal' survival benefit with UFS in anatomically resectable PDAC.

Regional lymph node sampling in hepatoma resection: insight into prognosis.

BACKGROUND: The importance of regional lymph node sampling (LNS) during resection of hepatocellular carcinoma (HCC) is poorly understood. This study sought to ameliorate this knowledge gap through a nationwide population-based analysis. METHODS: Patients who underwent liver resection (LR) for HCC were identified from Surveillance, Epidemiology and End Results (SEER-18) database (2003-2015). Cohort-based clinicopathologic comparisons were made based on completion of regional LNS. Propensity-score matching reduced bias. Overall and disease-specific survival (OS/DSS) were analyzed. RESULTS: Among 5395 patients, 835 (15.4%) underwent regional LNS. Patients undergoing LNS had larger tumors (7.0vs4.8 cm) and higher T-stage (30.9 vs. 17.6% T3+, both p < 0.001). Node-positive rate was 12.0%. Median OS (50 months for both) and DSS (28 vs. 29 months) were similar between cohorts, but node-positive patients had decreased OS/DSS (20/16 months, p < 0.01). Matched patients undergoing LNS had equivalent OS (46 vs. 43 months, p = 0.869) and DSS (27 vs. 29 months, p = 0.306) to non-LNS patients. The prognostic impact of node positivity persisted after matching (OS/DSS 24/19 months, p < 0.01). Overall disease-specific mortality were both independently elevated (overall HR 1.71-unmatched, 1.56-matched, p < 0.01; disease-specific HR 1.40-unmatched, p < 0.01, 1.25-matched, p = 0.09). CONCLUSION: Regional LNS is seldom performed during resection for HCC, but it provides useful prognostic information. As the era of adjuvant therapy for HCC begins, surgeons should increasingly consider performing regional LNS to facilitate optimal multidisciplinary management.

Laparoscopic hepatic lobectomy for symptomatic polycystic liver disease.

BACKGROUND: Laparoscopic fenestration has largely replaced open fenestration of liver cysts. However, most hepatectomies for polycystic liver disease (PCLD) are performed open. Outcomes data on laparoscopic hepatectomy for PCLD are lacking. METHODS: Patients who underwent surgery for PCLD at a single institution between 2010 and 2019 were reviewed and grouped by operative approach. Pre- and post-operative volumes were calculated for patients who underwent resection. Primary outcomes were: volume reduction, re-admission and postoperative complications. RESULTS: Twenty-six patients were treated for PCLD: 13 laparoscopic fenestration, nine laparoscopic hepatectomy, three open hepatectomy and one liver transplantation. Median length of stay for patients after laparoscopic resection was 3 days (IQR 2-3). The only complication was post-operative atrial fibrillation in one patient. There were no readmissions. Overall volume reduction was 51% (range 22-69) for all resections, 32% (range 22-46) after open resection and 56% (range 39-69) after laparoscopic resection. CONCLUSION: Volume reduction achieved through laparoscopic approach exceeded open volume reduction at this institution and is comparable to volume reduction in previously published open resection series. Adequate volume reduction can be accomplished by laparoscopic means with acceptable postoperative morbidity.

Challenges of Modeling Outcomes for Surgical Infections: A Word of Caution.

Background: We developed a novel analytic tool for colorectal deep organ/space surgical site infections (C-OSI) prediction utilizing both institutional and extra-institutional American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) data. Methods: Elective colorectal resections (2006-2014) were included. The primary end point was C-OSI rate. A Bayesian-Probit regression model with multiple imputation (BPMI) via Dirichlet process handled missing data. The baseline model for comparison was a multivariable logistic regression model (generalized linear model; GLM) with indicator parameters for missing data and stepwise variable selection. Out-of-sample performance was evaluated with receiver operating characteristic (ROC) analysis of 10-fold cross-validated samples. Results: Among 2,376 resections, C-OSI rate was 4.6% (n = 108). The BPMI model identified (n = 57; 56% sensitivity) of these patients, when set at a threshold leading to 80% specificity (approximately a 20% false alarm rate). The BPMI model produced an area under the curve (AUC) = 0.78 via 10-fold cross- validation demonstrating high predictive accuracy. In contrast, the traditional GLM approach produced an AUC = 0.71 and a corresponding sensitivity of 0.47 at 80% specificity, both of which were statstically significant differences. In addition, when the model was built utilizing extra-institutional data via inclusion of all (non-Mayo Clinic) patients in ACS-NSQIP, C-OSI prediction was less accurate with AUC = 0.74 and sensitivity of 0.47 (i.e., a 19% relative performance decrease) when applied to patients at our institution. Conclusions: Although the statistical methodology associated with the BPMI model provides advantages over conventional handling of missing data, the tool should be built with data specific to the individual institution to optimize performance.

Emergent pancreatectomy for neoplastic disease: outcomes analysis of 534 ACS-NSQIP patients.

BACKGROUND: While emergent pancreatic resection for trauma has been previously described, no large contemporary investigations into the frequency, indications, and outcomes of emergent pancreatectomy (EP) secondary to complications of neoplastic disease exist. Modern perioperative outcomes data are currently unknown. METHODS: ACS-NSQIP was reviewed for all non-traumatic pancreatic resections (DP - distal pancreatectomy, PD - pancreaticoduodenectomy, or TP- total pancreatectomy) in patients with pancreatico-biliary or duodenal-ampullary neoplasms from 2005 to 2013. Patients treated for complications of pancreatitis were specifically excluded. Emergent operation was defined as NSQIP criteria for emergent case and one of the following: ASA Class 5, preoperative ventilator dependency, preoperative SIRS, sepsis, or septic shock, or requirement of > 4 units RBCs in 72 h prior to resection. Chi-square tests, Fisher's exact tests were performed to compare postoperative outcomes between emergent and elective cases as well as between pancreatectomy types. RESULTS: Of 21,452 patients who underwent pancreatectomy for neoplastic indications, we identified 534 (2.5%) patients who underwent emergent resection. Preoperative systemic sepsis (66.3%) and bleeding (17.9%) were most common indications for emergent operation. PD was performed in 409 (77%) patients, DP in 115 (21%), and TP in 10 (2%) patients. Overall major morbidity was significantly higher (46.1% vs. 25.6%, p < 0.001) for emergent vs. elective operations. Emergent operations resulted in increased transfusion rates (47.6% vs. 23.4%, p < 0.001), return to OR (14.0% vs. 5.6%, p < 0.001), organ-space infection (14.6 vs. 10.5, p = 0.002), unplanned intubation (9.% vs. 4.1%, p < 0.001), pneumonia (9.6% vs. 4.2%, p < 0.001), length of stay (14 days vs. 8 days, p < 0.001), and discharge to skilled facility (31.1% vs. 13.9%). These differences persisted when stratified by pancreatic resection type. The 30-day operative mortality was higher in the emergent group (9.4%vs. 2.7%, p < 0.001) and highest for emergent TP (20%). CONCLUSION: Emergent pancreatic resection is markedly uncommon in the setting of neoplastic disease. Although these operations result in increased morbidity and mortality compared to elective resections, they can be life-saving in specific circumstances. The results of this large series of modern era national data may assist surgeons as well as patients and their families in making critical decisions in select cases of acutely complicated neoplastic disease.

Biliary tract cancer patient-derived xenografts: Surgeon impact on individualized medicine.

BACKGROUND & AIMS: Biliary tract tumors are uncommon but highly aggressive malignancies with poor survival outcomes. Due to their low incidence, research into effective therapeutics has been limited. Novel research platforms for pre-clinical studies are desperately needed. We sought to develop a patient-derived biliary tract cancer xenograft catalog. METHODS: With appropriate consent and approval, surplus malignant tissues were obtained from surgical resection or radiographic biopsy and implanted into immunocompromised mice. Mice were monitored for xenograft growth. Established xenografts were verified by a hepatobiliary pathologist. Xenograft characteristics were correlated with original patient/tumor characteristics and oncologic outcomes. A subset of xenografts were then genomically characterized using Mate Pair sequencing (MPseq). RESULTS: Between October 2013 and January 2018, 87 patients with histologically confirmed biliary tract carcinomas were enrolled. Of the 87 patients, 47 validated PDX models were successfully generated. The majority of the PDX models were created from surgical resection specimens (n = 44, 94%), which were more likely to successfully engraft when compared to radiologic biopsies (p = 0.03). Histologic recapitulation of original patient tumor morphology was observed in all xenografts. Successful engraftment was an independent predictor for worse recurrence-free survival. MPseq showed genetically diverse tumors with frequent alterations of CDKN2A, SMAD4, NRG1, TP53. Sequencing also identified worse survival in patients with tumors containing tetraploid genomes. CONCLUSIONS: This is the largest series of biliary tract cancer xenografts reported to date. Histologic and genomic analysis of patient-derived xenografts demonstrates accurate recapitulation of original tumor morphology with direct correlations to patient outcomes. Successful development of biliary cancer tumografts is feasible and may be used to direct subsequent therapy in high recurrence risk patients. LAY SUMMARY: Patient biliary tract tumors grown in immunocompromised mice are an invaluable resource in the treatment of biliary tract cancers. They can be used to guide individualized cancer treatment in high-risk patients.

Novel staging system using carbohydrate antigen (CA) 19-9 in extra-hepatic cholangiocarcinoma and its implications on overall survival.

BACKGROUND: CA19-9 elevation has shown to be associated with poor prognosis in extrahepatic cholangiocarcinoma (ECCA). However, the role of CA19-9 in staging of ECCA has not been evaluated. We hypothesized that CA19-9 elevation is a marker of aggressive biology in ECCA and that inclusion of CA19-9 in the staging system may improve overall survival (OS) discrimination. METHODS: Patients with ECCA whose CA19-9 levels, irrespective of surgical status, were reported to the National Cancer Database (2004-2015) were included. The patients were classified based on their CA19-9 levels and a new staging system was proposed. Net reclassification improvement (NRI) model was used to assess the predictive improvement in the proposed survival model as compared to AJCC-TNM staging. RESULTS: Of the 2100 patients included in the study, 626 (32%) and 1474 (68%) had normal and elevated CA19-9 levels (>38 U/ml), respectively. Median OS was lower among patients with elevated CA19-9 level compared to those with CA19-9 level ≤38 U/ml (8.5 vs 16 months, p < 0.01). On multivariate analysis, CA19-9 elevation independently predicted poor prognosis [HR:1.72 (1.46-2.02); p < 0.01] with similar impact as node-positivity, positive resection margins and non-receipt of chemotherapy. We developed a new staging system by incorporating CA19-9 into the 7th edition AJCC TNM staging system. NRI of 46% (95%CI: 39-57%) indicates that the new staging system is substantially effective at re-classifying events at 12 months as compared to AJCC 7th edition. CONCLUSION: Elevated CA19-9 was found to be an independent risk factor for mortality in ECCA and its inclusion in the proposed staging system improved OS discrimination.

Early-onset gastric cancer is a distinct disease with worrisome trends and oncogenic features.

BACKGROUND: Overall the incidence of gastric cancer is declining in the United States; however, the incidence of early-onset gastric cancer is increasing. We sought to elucidate clinical and genomic characteristics and risk factors for early-onset gastric cancer compared with late-onset gastric cancer. METHODS: We utilized the Surveillance, Epidemiology, and End Results database (1973-2015), the Behavioral Risk Factor Surveillance Survey, and The Cancer Genome Atlas to characterize early-onset gastric cancer. RESULTS: The incidence of early-onset gastric cancer increased during the study period and now comprises >30% of all gastric cancer in the United States. Early-onset gastric cancer was associated with higher grade (55.2 vs 46.9%), signet-ring cells (19.0 vs 10.4%), diffuse histology (25.7 vs 15.0%), and metastatic disease (49.5 vs 40.9%, all P < .01) compared with late-onset gastric cancer. Early-onset gastric cancer was more likely to be Epstein-Barr virus (7.7 vs 5.1%) or genomically stable (22.5 vs 8.1%) subtype, whereas late-onset gastric cancer was more likely to be microsatellite instability subtype (18.6 vs 5.6%; all P < .01). Risk factors for gastric cancer were less correlated with early-onset gastric cancer compared with late-onset gastric cancer. CONCLUSION: The incidence of early-onset gastric cancer has been steadily increasing in the United States, comprising >30% of new gastric cancer cases today. Early-onset gastric cancer is genetically and clinically distinct from traditional gastric cancer. Additional investigations are warranted to better understand this alarming phenomenon.