A Novel Microbiome Signature in Gastric Cancer: A Two Independent Cohort Retrospective Analysis

OBJECTIVE

The microbiome is hypothesized to have a significant impact on cancer development. In gastric cancer (GC), Helicobacter pylori is an established class I carcinogen. However, additional organisms in the intratumoral microbiome play an important role in GC pathogenesis and progression. In this study, we characterize the full spectrum of the microbes present within GC and identify distinctions among molecular subtypes.

METHODS

A microbiome bioinformatics pipeline that is generalizable across multiple next-generation sequencing platforms was developed. Microbial profiles for alpha diversity and enrichment were generated for 2 large, demographically distinct cohorts: (1) internal Memorial Sloan Kettering Cancer Center (MSKCC) and (2) The Cancer Genome Atlas (TCGA) cohorts. A total of 520 GC samples were compared with select tumor-adjacent nonmalignant samples. Microbiome differences among the GC molecular subtypes were identified.

RESULTS

Compared with nonmalignant samples, GC had significantly decreased microbial diversity in both MSKCC and TCGA cohorts ( P <0.05). Helicobacter , Lactobacillus , Streptococcus , Prevotella , and Bacteroides were significantly more enriched in GC samples when compared with nonmalignant tissue ( P <0.05). Microsatellite instability-high GC had distinct microbial enrichment compared with other GC molecular subtypes.

CONCLUSION

Distinct patterns of microbial diversity and species enrichment were identified in patients with GC. Given the varied spectrum of disease progression and treatment response of GC, understanding unique microbial signatures will provide the landscape to explore key microbial targets for therapy.

Outcomes and Molecular Features of Brain Metastasis in Gastroesophageal Adenocarcinoma

IMPORTANCE

Brain metastasis (BrM) in gastroesophageal adenocarcinoma (GEA) is a rare and poorly understood phenomenon associated with poor prognosis.

OBJECTIVES

To examine the clinical and genomic features of patients with BrM from GEA and evaluate factors associated with survival.

DESIGN, SETTING, AND PARTICIPANTS

In this single-institution retrospective cohort study, 68 patients with BrM from GEA diagnosed between January 1, 2008, and December 31, 2020, were identified via review of billing codes and imaging reports from the electronic medical record with follow-up through November 3, 2021. Genomic data were derived from the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets clinical sequencing platform.

EXPOSURES

Treatment with BrM resection and/or radiotherapy.

MAIN OUTCOMES AND MEASURES

Overall survival after BrM diagnosis.

RESULTS

Sixty-eight patients (median age at diagnosis, 57.4 years [IQR, 49.8-66.4 years]; 59 [86.8%] male; 55 [85.9%] White) participated in the study. A total of 57 (83.8%) had primary tumors in the distal esophagus or gastroesophageal junction. Median time from initial diagnosis to BrM diagnosis was 16.9 months (IQR, 8.5-27.7 months). Median survival from BrM diagnosis was 8.7 months (95% CI, 5.5-11.5 months). Overall survival was 35% (95% CI, 25%-48%) at 1 year and 24% (95% CI, 16%-37%) at 2 years. In a multivariable analysis, an Eastern Cooperative Oncology Group performance status of 2 or greater (hazard ratio [HR], 4.66; 95% CI, 1.47-14.70; P = .009) and lack of surgical or radiotherapeutic intervention (HR, 7.71; 95% CI, 2.01-29.60; P = .003) were associated with increased risk of all-cause mortality, whereas 3 or more extracranial sites of disease (HR, 1.85; 95% CI, 0.64-5.29; P = .25) and 4 or more BrMs (HR, 2.15; 95% CI, 0.93-4.98; P = .07) were not statistically significant. A total of 31 patients (45.6%) had ERBB2 (formerly HER2 or HER2/neu)-positive tumors, and alterations in ERBB2 were enriched in BrM relative to primary tumors (8 [47.1%] vs 7 [20.6%], P = .05), as were alterations in PTPRT (7 [41.2%] vs 4 [11.8%], P = .03).

CONCLUSIONS AND RELEVANCE

This study suggests that that a notable proportion of patients with BrM from GEA achieve survival exceeding 1 and 2 years from BrM diagnosis, a more favorable prognosis than previously reported. Good performance status and treatment with combination surgery and radiotherapy were associated with the best outcomes. ERBB2 positivity and amplification as well as PTPRT alterations were enriched in BrM tissue compared with primary tumors; therefore, further study should be pursued to identify whether these variables represent genomic risk factors for BrM development.

TERT Copy Number Alterations, Promoter Mutations and Rearrangements in Adrenocortical Carcinomas

Molecular characterization of adrenocortical carcinomas (ACC) by The Cancer Genome Atlas (TCGA) has highlighted a high prevalence of TERT alterations, which are associated with disease progression. Herein, 78 ACC were profiled using a combination of next generation sequencing (n = 76) and FISH (n = 9) to assess for TERT alterations. This data was combined with TCGA dataset (n = 91). A subset of borderline adrenocortical tumors (n = 5) and adrenocortical adenomas (n = 7) were also evaluated. The most common alteration involving the TERT gene involved gains/amplifications, seen in 22.2% (37/167) of cases. In contrast, "hotspot" promoter mutations (C > T promoter mutation at position -124, 7/167 cases, 4.2%) and promoter rearrangements (2/165, 1.2%) were rare. Recurrent co-alterations included 22q copy number losses seen in 24% (9/38) of cases. Although no significant differences were identified in cases with and without TERT alterations pertaining to age at presentation, tumor size, weight, laterality, mitotic index and Ki67 labeling, cases with TERT alterations showed worse outcomes. Metastatic behavior was seen in 70% (28/40) of cases with TERT alterations compared to 51.2% (65/127, p = 0.04) of cases that lacked these alterations. Two (of 5) borderline tumors showed amplifications and no TERT alterations were identified in 7 adenomas. In the borderline group, 0 (of 4) patients with available follow up had adverse outcomes. We found that TERT alterations in ACC predominantly involve gene amplifications, with a smaller subset harboring "hotspot" promoter mutations and rearrangements, and 70% of TERT-altered tumors are associated with metastases. Prospective studies are needed to validate the prognostic impact of these findings.

Phase II Trial Evaluating Esophageal Anastomotic Reinforcement with a Biologic, Degradable, Extracellular Matrix after Total Gastrectomy and Esophagectomy

BACKGROUND

A biologic, degradable extracellular matrix (ECM) has been shown to support esophageal tissue remodeling, which could reduce the risk of anastomotic leak following total gastrectomy and esophagectomy. We evaluated the safety and efficacy of reinforcing the anastomosis with ECM in reducing anastomotic leak as compared to a matched cohort.

STUDY DESIGN

In this single-center, nonrandomized phase II trial, gastric or esophageal adenocarcinoma patients undergoing total gastrectomy or esophagectomy were recruited from November 2013 through December 2018. ECM was surgically wrapped circumferentially around the anastomosis. Anastomotic leak was assessed clinically and by contrast study and defined as clinically significant if requiring invasive treatment (grade 3 or higher). Anastomotic stenosis, other adverse events, symptoms, and dysphagia score were collected by standardized forms at regular follow-up visits at approximately postoperative days (POD) 21 and 90. Patients receiving ECM were compared to a cohort matched for surgery type and age.

RESULTS

ECM placement was not feasible in 9 of 75 patients (12%), resulting in 66 patients receiving ECM. Total gastrectomy was performed in 50 patients (76%) and esophagectomy in 16 (24%). Clinically significant anastomotic leak was diagnosed in 6 of 66 patients (9.1%) (3/50 [6.0%] after gastrectomy, 3/16 [18.8%] after esophagectomy); this rate did not differ from that in the matched cohort (p = 0.57). Stenosis requiring invasive treatment occurred in 8 patients (12.5%), and 10 patients (15.6%) reported not being able to eat a normal diet at POD 90. No adverse events related to ECM were reported.

CONCLUSIONS

Esophageal anastomotic reinforcement after total gastrectomy or esophagectomy with a biologic, degradable ECM was mostly feasible and safe, but was not associated with a statistically significant decrease in anastomotic leak.

Gastric Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Gastric cancer is the third leading cause of cancer-related deaths worldwide. Over 95% of gastric cancers are adenocarcinomas, which are typically classified based on anatomic location and histologic type. Gastric cancer generally carries a poor prognosis because it is often diagnosed at an advanced stage. Systemic therapy can provide palliation, improved survival, and enhanced quality of life in patients with locally advanced or metastatic disease. The implementation of biomarker testing, especially analysis of HER2 status, microsatellite instability (MSI) status, and the expression of programmed death-ligand 1 (PD-L1), has had a significant impact on clinical practice and patient care. Targeted therapies including trastuzumab, nivolumab, and pembrolizumab have produced encouraging results in clinical trials for the treatment of patients with locally advanced or metastatic disease. Palliative management, which may include systemic therapy, chemoradiation, and/or best supportive care, is recommended for all patients with unresectable or metastatic cancer. Multidisciplinary team management is essential for all patients with localized gastric cancer. This selection from the NCCN Guidelines for Gastric Cancer focuses on the management of unresectable locally advanced, recurrent, or metastatic disease.

Genomic characterization of metastatic patterns from prospective clinical sequencing of 25,000 patients

Metastatic progression is the main cause of death in cancer patients, whereas the underlying genomic mechanisms driving metastasis remain largely unknown. Here, we assembled MSK-MET, a pan-cancer cohort of over 25,000 patients with metastatic diseases. By analyzing genomic and clinical data from this cohort, we identified associations between genomic alterations and patterns of metastatic dissemination across 50 tumor types. We found that chromosomal instability is strongly correlated with metastatic burden in some tumor types, including prostate adenocarcinoma, lung adenocarcinoma, and HR+/HER2+ breast ductal carcinoma, but not in others, including colorectal cancer and high-grade serous ovarian cancer, where copy-number alteration patterns may be established early in tumor development. We also identified somatic alterations associated with metastatic burden and specific target organs. Our data offer a valuable resource for the investigation of the biological basis for metastatic spread and highlight the complex role of chromosomal instability in cancer progression.

Brain metastasis in gastroesophageal adenocarcinoma: Outcomes and molecular features

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Background: Brain metastases (BrM) rarely occur in patients with metastatic gastroesophageal adenocarcinoma (GEA) and represent a unique therapeutic challenge. We describe the unique clinical, molecular, and genomic factors associated with mGEA cancer and BrM development in order to help guide future clinical management. Methods: Patients (pts) with GEA seen at Memorial Sloan Kettering Cancer Center (MSKCC) from 2008-2019 and who had consented for genomic tumor profiling with MSK-IMPACT, a capture-based next-generation sequencing platform that detects mutations, copy-number variations, and select fusions, were retrospectively identified. Clinical and pathologic characteristics were reviewed. BrM were identified via International Classification of Diseases (ICD) billing codes and electronic medical record problem lists, and then manually validated. Survival was calculated from the time of BrM diagnosis until date of death or last follow up and estimated using the Kaplan-Meier method. Results: Fifty pts with GEA metastatic to the brain were identified. Most pts were male (86%) and white (80%), with primary tumor of the esophagus/gastroesophageal junction (82%) and intestinal-type Lauren histology (90%). Twenty-three pts (46%) were HER2 positive (defined as IHC 2+/FISH+ or IHC 3+). Frequencies of PTEN (16%) and EGFR (22%) alterations in primary or metastatic sites were enriched in pts with BM compared to that seen across the MSKCC retrospective cohort and the GEA Cancer Genome Atlas (TCGA) cohort. The majority (68%) of pts had stage IV disease at initial diagnosis, and 4 pts were found to have BrM within 1 month (mo) of stage IV diagnosis, while 27 pts developed BrM during therapy. Median time to BrM diagnosis was 18.3 mos (IQR 11.5-28.9) and 15.1 mos from stage IV diagnosis (IQR 4.8-25.5). Median survival was 7.6 mos from BrM diagnosis and 15.6 (95% CI 10.0-NR, n = 19), 7.6 (95% CI 2.5-NR, n = 13), and 4.3 (95% CI 3.5-12.3, n = 18) mos for pts with 1, 2-3, or 4+ BrM, respectively. Conclusions: GEA pts with BrM had increased frequency of HER2 positivity, as well as PTEN and EGFR alterations, compared to GEA pts overall historically. Further correlation between BrM development, molecular characteristics, and survival in a larger cohort will be presented.

Defining and Targeting Esophagogastric Cancer Genomic Subsets With Patient-Derived Xenografts

PURPOSE

Comprehensive genomic profiling has defined key oncogenic drivers and distinct molecular subtypes in esophagogastric cancer; however, the number of clinically actionable alterations remains limited. To establish preclinical models for testing genomically driven therapeutic strategies, we generated and characterized a large collection of esophagogastric cancer patient-derived xenografts (PDXs).

MATERIALS AND METHODS

We established a biobank of 98 esophagogastric cancer PDX models derived from primary tumors and metastases. Clinicopathologic features of each PDX and the corresponding patient sample were annotated, including stage at diagnosis, treatment history, histology, and biomarker profile. To identify oncogenic DNA alterations, we analyzed and compared targeted sequencing performed on PDX and parent tumor pairs. We conducted xenotrials in genomically defined models with oncogenic drivers.

RESULTS

From April 2010 to June 2019, we implanted 276 patient tumors, of which 98 successfully engrafted (35.5%). This collection is enriched for PDXs derived from patients with human epidermal growth factor receptor 2-positive esophagogastric adenocarcinoma (62 models, 63%), the majority of which were refractory to standard therapies including trastuzumab. Factors positively correlating with engraftment included advanced stage, metastatic origin, intestinal-type histology, and human epidermal growth factor receptor 2-positivity. Mutations in TP53 and alterations in receptor tyrosine kinases (ERBB2 and EGFR), RAS/PI3K pathway genes, cell-cycle mediators (CDKN2A and CCNE1), and CDH1 were the predominant oncogenic drivers, recapitulating clinical tumor sequencing. We observed antitumor activity with rational combination strategies in models established from treatment-refractory disease.

CONCLUSION

The Memorial Sloan Kettering Cancer Center PDX collection recapitulates the heterogeneity of esophagogastric cancer and is a powerful resource to investigate mechanisms driving tumor progression, identify predictive biomarkers, and develop therapeutic strategies for molecularly defined subsets of esophagogastric cancer.

Distinct differences in genomic profile of gastric and gastroesophageal junction adenocarcinoma

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Background: Gastroesophageal junction cancer (GEJC) and gastric cancer (GC) are frequently studied together as one disease. Genomic profiles between the two disease sites have not been well characterized. We aimed to characterize molecular differences between the two disease sites. Methods: We collected data between January 2010 and December 2019 from a prospectively maintained database of GEJC and GC at our center. GEJC was defined according to the Siewert type 1 to 3 classification. Patients who underwent surgical resection and had MSK-IMPACT (MSK-Integrated Mutation Profiling of Actionable Cancer Targets) sequencing performed on their primary tumor were included in this analysis. Results: Two hundred and seventy-four samples were analyzed; 156 (56.9%) GEJC and 118 (43.1%) GC patients. Regarding molecular subtypes, the GEJC group had a higher frequency of chromosomally instable tumors compared to the GC cohort (55.1% vs. 25.4%, p < 0.001). The fraction of genome altered (FGA) was significantly higher in the GEJC group (p < 0.001). TP53 (75.3% vs. 31.9%, p < 0.001, q < 0.001), CDKN2A (17.1% vs. 4.3%, p = 0.002, q = 0.02), and MDM2 (6.8% vs. 0%, p = 0.007, q = 0.033) were more frequently altered in the GEJC group, whereas CDH1 (2.7% vs. 9.6%, p = 0.037, q = 0.118) and RHOA (0% vs. 6.4%, p = 0.003, q = 0.02) were more frequently altered in the GC group. The GEJC group also had a higher frequency of alterations in the cell cycle pathway compared to the GC patients (36.3% vs. 11.7%, p < 0.001, q < 0.001). Conclusions: There are distinct differences in genomic profiles between GEJC and GC with a higher frequency of mutations in TP53, CDKN2A, MDM2, and cell cycle pathway in the GEJC patients, that may have potential implications in evaluating optimal treatment strategies with targeted therapy.

Enhanced PAtient Clinical Streamlining (EPACS): Quality Initiative to Improve Healthcare for New Surgical Outpatient Visits

Purpose

For patients who select a specialty hospital for cancer treatment, the wait time until the initial consultation leaves patients anxious and delays treatment. To improve quality of care, we implemented an enhanced patient clinical streamlining (EPACS) process that establishes an early connection and coordinates care before the first surgical outpatient visit at our specialty cancer center.

Methods

During a pre-visit EPACS phone call to new patients, an advanced practice provider (APP) collected medical history and ordered work-up tests or consultations if feasible. First visit cancellation rate, number of patients who started treatment, time to start of treatment, and satisfaction by the care team and patient were compared between patients treated with versus without EPACS.

Results

Among 5062 consecutive new patients, 720 (14%) received an EPACS call and 4342 did not (86%); work-up was ordered pre-visit in 34% and 16%, respectively. Fewer EPACS patients cancelled the first visit (4.6% vs. 12%, p < 0.001), more started treatment (55% vs. 50%, p = 0.037), and their time to treatment was shorter, but not significantly (median 17 vs. 19 days, p = 0.086). Patient interaction was considered to be improved by EPACS by 17 of 17 APPs and 14 of 16 surgeons, and outpatient clinic efficiency by 14 of 17 APPs and 13 of 16 surgeons. EPACS reduced anxiety and increased preparedness for the first visit in 29 of 31 patients.

Conclusions

EPACS improved effectiveness, timeliness, and physician and patient satisfaction with health care at our cancer center.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-021-11126-3.

Prognosis after neoadjuvant chemoradiation or chemotherapy for locally advanced gastro-oesophageal junctional adenocarcinoma

BACKGROUND

Trials typically group cancers of the gastro-oesophageal junction (GOJ) with oesophageal or gastric cancer when studying neoadjuvant chemoradiation and perioperative chemotherapy, so the results may not be fully applicable to GOJ cancer. Because optimal neoadjuvant treatment for GOJ cancer remains controversial, outcomes with neoadjuvant chemoradiation versus chemotherapy for locally advanced GOJ adenocarcinoma were compared retrospectively.

METHODS

Data were collected from all patients who underwent neoadjuvant treatment followed by surgery for adenocarcinoma located at the GOJ at a single high-volume institution between 2002 and 2017. Postoperative major complications and mortality were compared between groups using Fisher's exact test. Overall survival (OS) and disease-free survival (DFS) were assessed by log rank test and multivariable Cox regression analyses. Cumulative incidence functions were used to estimate recurrence, and groups were compared using Gray's test.

RESULTS

Of 775 patients, 650 had neoadjuvant chemoradiation and 125 had chemotherapy. These groups were comparable in terms of clinical tumour and lymph node categories, although the chemoradiation group had greater proportions of white men, complete pathological response to chemotherapy, and smaller proportions of diffuse cancer, poor differentiation, and neurovascular invasion. Postoperative major complications (20.0 versus 17.6 per cent) and 30-day mortality (1.7 versus 1.6 per cent) were not significantly different between the chemoradiation and chemotherapy groups. After adjustment, type of therapy (chemoradiation versus chemotherapy) was not significantly associated with OS (hazard ratio (HR) 1.26, 95 per cent c.i. 0.96 to 1.67) or DFS (HR 1.27, 0.98 to 1.64). Type of recurrence (local, regional, or distant) did not differ after neoadjuvant chemoradiation versus chemotherapy.

CONCLUSION

In patients undergoing surgical resection for locally advanced adenocarcinoma of the GOJ, OS and DFS did not differ significantly between patients who had neoadjuvant chemoradiation compared with chemotherapy.

Prevalence of Germline Alterations on Targeted Tumor-Normal Sequencing of Esophagogastric Cancer

Importance

Among patients with esophagogastric cancers, only individuals who present with known features of heritable cancer syndromes are referred for genetic testing. Broader testing might identify additional patients with germline alterations.

Objectives

To examine the prevalence of likely pathogenic or pathogenic (LP/P) germline alterations among patients with esophagogastric cancer and to assess associations between germline variant prevalence and demographic and clinicopathologic features.

Design, Setting, and Participants

This cross-sectional study was performed at a tertiary referral cancer center from January 1, 2014, to December 31, 2019, in 515 patients with esophagogastric cancer who consented to tumor and blood sequencing.

Main Outcomes and Measures

Presence or absence of LP/P variants in up to 88 genes associated with cancer predisposition syndromes as identified by targeted sequencing (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets).

Results

Among 515 patients (median age, 59 years; range, 18-87 years; 368 [71.5%] male; 398 [77.3%] White), 243 (47.2%) had gastric cancer, 111 (21.6%) had gastroesophageal junction (GEJ) cancer, and 161 (31.3%) had esophageal cancer. A total of 48 patients with gastric cancer (19.8%), 16 (14.4%) with GEJ cancer, and 17 (10.6%) with esophageal cancer had LP/P germline variants. The number of LP/P variants in high- and moderate-penetrance genes was significantly higher in patients with gastric cancer (29 [11.9%]; 95% CI, 8.1%-16.7%) vs patients with esophageal cancer (8 [5.0%]; 95% CI, 2.2%-9.6%; P = .03), and the difference was greater for high-penetrance germline alterations in patients with gastric cancer (25 [10.3%]; 95% CI, 6.8%-14.8%) vs in patients with esophageal cancer (3 [1.9%]; 95% CI, 0.38%-5.3%; P = .001). The most frequent high- and moderate-penetrance LP/P alterations were in BRCA1/2 (14 [2.7%]), ATM (11 [2.1%]), CDH1 (6 [1.2%]), and MSH2 (4 [0.8%]). Those with early-onset disease (≤50 years of age at diagnosis) were more likely to harbor an LP/P germline variant (29 [21.0%]; 95% CI, 14.5%-28.8%) vs those with late-onset disease (patients >50 years of age at diagnosis) (52 [13.8%]; 95% CI, 10.5%-17.7%; P = .046). ATM LP/P variants occurred in 6 patients (4.3%; 95% CI, 1.6%-9.1%) with early-onset esophagogastric cancer vs 5 (1.3%; 95% CI, 0.4%-3.1%; P = .08) of those with late-onset esophagogastric cancer.

Conclusions and Relevance

These results suggest that pathogenic germline variants are enriched in gastric and early-onset esophagogastric cancer and that germline testing should be considered in these populations. The role of ATM alterations in esophagogastric cancer risk warrants further investigation.

Frequency of minimal residual disease as measured by ctDNA in mismatch repair deficient tumors following curative resection

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Background: Mismatch repair deficient (MMRd) tumors are highly sensitive to checkpoint blockade (CPB) in patients with metastatic disease regardless of tumor type. However, the efficacy of CPB in the adjuvant setting is unknown, especially since MMRd is considered a favorable biomarker for most resected tumor types. Circulating tumor DNA (ctDNA) could be used to screen for patients at high risk for recurrence following surgery or adjuvant chemotherapy and identify patients (pts) that would most benefit from CPB. Methods: To assess the frequency of ctDNA in the resected MMRd population, we prospectively screened pts with MMRd tumors who completed standard perioperative chemotherapy and surgery (NCT03832569). DNA from resected tumors and matched postoperative plasma was sequenced for the presence of somatic mutations. Patients were considered to have minimal residual disease (MRD) when mutations were identified in tumor and found to be identical to those in matched plasma DNA. Somatic tissue mutations were assessed using MSK-IMPACT and ctDNA was assessed using FoundationOne, Guardant360 or MSK-ACCESS. Results: A total of 86 pts were screened for the presence of MRD. These represented 7 tumor types with colorectal (63%), endometrial (16%) and esophagogastric (13%) being the most common. The majority of pts were stage III (49%). MRD was detected in 18% of cases (14 of 79). Among the MRD negative group (n=62), only one pt developed disease recurrence. Three samples failed ctDNA analysis for technical reasons. Conclusions: MRD was identified in 18% of resected MMRd tumors using ctDNA analysis, suggesting this to be a feasible tumor agnostic approach to test the efficacy of CPB in a pts at high-risk for recurrence. Future studies will assess the impact of CPB in MRD positive MMRd tumors.[Table: see text]

Association of Obesity with Worse Operative and Oncologic Outcomes for Patients Undergoing Gastric Cancer Resection

BACKGROUND

How obesity has an impact on operative and oncologic outcomes for gastric cancer patients is unclear, and the influence of obesity on response to neoadjuvant chemotherapy (NAC) has not been evaluated.

METHODS

Patients who underwent curative gastrectomy for primary gastric cancer between 2000 and 2018 were retrospectively identified. After stratification for NAC, operative morbidity, mortality, overall survival (OS), and disease-specific survival (DSS) were compared among three body mass index (BMI) categories: normal BMI (< 25 kg/m²), mild obesity (25-35 kg/m²), and severe obesity (≥ 35 kg/m²).

RESULTS

During the study period, 984 patients underwent upfront surgery, and 484 patients received NAC. Tumor stage did not differ among the BMI groups. However, the rates of pathologic response to NAC were significantly lower for the patients with severe obesity (10% vs 40%; p < 0.001). Overall complications were more frequent among the obese patients (44.3% for obese vs 24.9% for normal BMI, p < 0.001). Intraabdominal infections were also more frequent in obese patients (13.9% for obese vs 4.7% for normal BMI, p = 0.001). In the upfront surgery cohort, according to the BMI, OS and DSS did not differ, whereas in the NAC cohort, severe obesity was independently associated with worse OS [hazard ratio (HR) 1.87; 95% confidence interval (CI) 1.01-3.48; p = 0.047] and disease-specific survival (DSS) (HR 2.08; 95% CI 1.07-4.05; p = 0.031).

CONCLUSION

For the gastric cancer patients undergoing curative gastrectomy, obesity was associated with significantly lower rates of pathologic response to NAC and more postoperative complications, as well as shorter OS and DSS for the patients receiving NAC.

Enhanced Recovery After Major Gastrectomy for Cancer

Enhanced recovery after surgery (ERAS) protocols have gained increasing popularity over the past 10 years, and its overarching objectives are to improve perioperative morbidity and reduce postoperative length of stay. Consensus guidelines from the ERAS Society specific to major gastrectomy were published in 2014, however since that time, prospective and retrospective studies have expanded the collective evidence for both the content and efficacy of ERAS pathways for gastrectomy. This objective of this review was to summarize recent data pertinent to the preoperative, perioperative, and postoperative management of gastrectomy patients along an ERAS pathway.

Comparison of Long- and Short-term Outcomes in 845 Open and Minimally Invasive Gastrectomies for Gastric Cancer in the United States

BACKGROUND

Few Western studies have evaluated the long-term oncologic outcomes of minimally invasive surgery (MIS) approaches to gastrectomy for gastric cancer. This study aimed to compare the outcomes between minimally invasive and open gastrectomies and between laparoscopic and robotic gastrectomies at a high-volume cancer center in the United States.

METHODS

The study analyzed data for all patients undergoing curative gastrectomy for gastric adenocarcinoma from January 2007 to June 2017. Postoperative complications and disease-specific survival (DSS) were compared between surgical approaches.

RESULTS

The median follow-up period for the 845 patients in this study was 38.5 months. The stage-stratified 5-year DSS did not differ significantly between open surgery (n = 534) and MIS (n = 311). The MIS approach resulted in significantly fewer complications, as confirmed by adjusted comparison (odds ratio [OR], 0.70; range, 0.49-1.00; p = 0.049). After adjustment, the two groups did not differ in terms of DSS (hazard ratio [HR], 0.83; range, 0.55-1.25; p = 0.362). The robotic operations (n = 190) had fewer conversions to open procedure (p = 0.010), a shorter operative time (212 vs 240 min; p < 0.001), more dissected nodes (27 vs 22; p < 0.001), fewer Clavien-Dindo grade ≥3 complications (5.8% vs 13.2%; p = 0.023), and a shorter postoperative stay (5 vs 6 days; p = 0.045) than the laparoscopic operations (n = 121). The DSS rate did not differ between the laparoscopic and robotic groups.

CONCLUSION

The study findings demonstrated the long-term survival and oncologic equivalency of MIS gastrectomy and the open approach in a Western cohort, supporting the use of MIS at centers that have adequate experience with appropriately selected patients.

Outcomes of Neoadjuvant Chemotherapy for Clinical Stages 2 and 3 Gastric Cancer Patients: Analysis of Timing and Site of Recurrence

BACKGROUND

This study aimed to analyze timing and sites of recurrence for patients receiving neoadjuvant chemotherapy for gastric cancer. Neoadjuvant chemotherapy followed by surgical resection is the standard treatment for locally advanced gastric cancer in the West, but limited information exists as to timing and patterns of recurrence in this setting.

METHODS

Patients with clinical stage 2 or 3 gastric cancer treated with neoadjuvant chemotherapy followed by curative-intent resection between January 2000 and December 2015 were analyzed for 5-year recurrence-free survival (RFS) as well as timing and site of recurrence.

RESULTS

Among 312 identified patients, 121 (38.8%) experienced recurrence during a median follow-up period of 46 months. The overall 5-year RFS rate was 58.9%, with RFS rates of 95.8% for ypT0N0, 81% for ypStage 1, 77.4% for ypStage 2, and 22.9% for ypStage 3. The first site of recurrence was peritoneal for 49.6%, distant (not peritoneal) for 45.5%, and locoregional for 11.6% of the patients. The majority of the recurrences (84.3%) occurred within 2 years. Multivariate analysis showed that ypT4 status was an independent predictor for recurrence within 1 year after surgery (odds ratio, 2.58; 95% confidence interval, 1.10-6.08; p = 0.030).

CONCLUSIONS

The majority of the recurrences for patients with clinical stage 2 or 3 gastric cancer who received neoadjuvant chemotherapy and underwent curative resection occurred within 2 years. After neoadjuvant chemotherapy, pathologic T stage was a useful risk predictor for early recurrence.

Indications for Total Gastrectomy in CDH1 Mutation Carriers and Outcomes of Risk-Reducing Minimally Invasive and Open Gastrectomies

Importance

CDH1 variants are increasingly identified on commercially available multigene panel tests, calling for data to inform counseling of individuals without a family history of gastric cancer.

Objectives

To assess association between CDH1 variant pathogenicity or family history of gastric or lobular breast cancer and identification of signet ring cell cancer and to describe outcomes of risk-reducing minimally invasive and open total gastrectomy.

Design, Setting, and Participants

This cohort study was performed from January 1, 2006, to January 1, 2020, in 181 patients with CDH1 germline variants from a single institution.

Interventions

Genetic counseling, esophagogastroduodenoscopy, and possible total gastrectomy.

Main Outcomes and Measures

CDH1 variant classification, family cancer history, findings of signet ring cell carcinoma at esophagogastroduodenoscopy and surgery, postoperative events and weight changes, and follow-up.

Results

Of 181 individuals with CDH1 germline variants (mean [SD] age at time of testing, 44 [15] years; 126 [70%] female), 165 harbored a pathogenic or likely pathogenic variant. Of these patients, 101 underwent open (n = 58) or minimally invasive (n = 43) total gastrectomy. Anastomotic leaks that required drainage were infrequent (n = 3), and median long-term weight loss was 20% (interquartile range [IQR], 10%-23%). In those undergoing minimally invasive operations, more lymph nodes were retrieved (median, 28 [IQR, 20-34] vs 15 [IQR, 9-19]; P < .001) and the hospital stay was 1 day shorter (median, 6 [IQR, 5-7] vs 7 [IQR, 6-7] days; P = .04). Signet ring cell cancer was identified in the surgical specimens of 85 of 95 patients (89%) with a family history of gastric cancer and 4 of 6 patients (67%) who lacked a family history. Among the latter 6 patients, 4 had a personal or family history of lobular breast cancer, including 2 with signet ring cell cancer. Of the 16 patients with pathogenic or likely pathogenic CDH1 variants who presented with locally advanced or metastatic gastric cancer, 3 (19%) had no family history of gastric cancer or personal or family history of lobular breast cancer.

Conclusions and Relevance

Total gastrectomy may be warranted for patients with pathogenic or likely pathogenic CDH1 variants and a family history of gastric or lobular breast cancer and may be appropriate for those without a family history. A minimally invasive approach is feasible and may be preferred for selected patients.

The interaction between microsatellite instability high (MSI-high) gastric cancer and chemotherapy on survival

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Background: Subgroup analysis of trials data suggested a favorable prognostic role for microsatellite instability high (MSI-high) status in resectable gastric cancer, but a lack of survival benefit from neoadjuvant/adjuvant chemotherapy; questioning current standard of care for MSI-high locally advanced gastric cancer. To help guide treatment decision making, we retrospectively studied the interaction between MSI status and chemotherapy on survival in a single institution. Methods: All clinically advanced (tumor stage 3-4 or positive lymph nodes) gastric cancer patients that underwent gastrectomy between 2000-2018 with MSI status available from immunohistochemistry (IHC, deficient mismatch repair protein expression (dMMR) vs proficient (pMMR)) or DNA next generation sequencing testing (NGS, MSI-high vs low/stable (MSS)) were included. Clinicopathological characteristics and overall survival (OS) was compared between patients with neoadjuvant/adjuvant chemotherapy and without, stratified for MSI status, by Kaplan-Meier and Cox regression analysis. Results: From a total of 1,844 clinically advanced patients with resection, MSI status was available in 559 as determined by IHC in 420, NGS in 88, and both in 51 with a concordance rate of 50/51 (98%). Tumors were dMMR/MSI-high in 84 (15%) and pMMR/MSS in 475 (85%). Patients with dMMR/MSI-high tumors were more often older, female, and had distal tumors with intestinal subtype. Neoadjuvant and/or adjuvant chemotherapy was administered in 53 (63%) in the dMMR/MSI-high group and 367 (77%) in the pMMR/MSS (p = 0.006). Median (interquartile range) time of follow-up was 32 (19-57) months. In the total cohort, OS after 3 years was 82% in the dMMR/MSI-high and 59% in pMMR/MSS (p < 0.001). In the patients with neoadjuvant/adjuvant chemotherapy only, the dMMR/MSI-high had improved OS (3-years OS: 80% vs 60%, p = 0.001), and after adjustment for age and clinical tumor stage in multivariable analysis, dMMR/MSI-high status was associated with improved OS (HR 0.38 95%CI 0.22-0.68). In the dMMR/MSI-high group only, 3-year OS was 80% with chemotherapy vs 86% without (p = 0.374), and chemotherapy was not associated with a difference in OS after multivariable analysis (HR 1.03 95%CI 0.40-2.66). In case of neoadjuvant chemotherapy, grade 1 pathological response ( > 90%) was observed in 1/41 (2.4%) of the dMMR/MSI-high tumors vs 43/278 (16%) of the pMMR/MSS tumors respectively (p = 0.026). Conclusions: The incidence of MSI-high tumors in our cohort of clinically locally advanced, resectable, gastric cancers was 15%. Patients with MSI-high tumors had worse pathological treatment response to neoadjuvant chemotherapy, but better OS, compared to microsatellite stable tumors. However, in patients with MSI-high tumors, OS was not altered by neoadjuvant/adjuvant chemotherapy. We recommend assessing MSI status in locally advanced gastric cancer.

Clinical and molecular characteristics of early-onset versus average-onset esophagogastric cancer

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Background: While the rate of esophagogastric (EG) cancer is declining, early onset (EO) gastric cancer prior to age 50 is rising. It is unknown whether EO-EG cancer represents a distinct entity. This study investigates the clinical and molecular characteristics of EO compared with average onset (AO)-EG cancers. Methods: We reviewed clinical and molecular features of gastric (G), esophageal (E) and gastroesophageal junction (GEJ) cancer in patients treated at MSKCC between 2005 and 2018. We defined early onset as age < 49, based on the age cutoff for urgent endoscopy referral. Clinical symptoms at diagnosis, primary tumor location, histology, HER2 and MSI status and molecular alterations were compared using Fisher’s exact test. Benjamini-Hochberg method was used to decrease the false discovery rate. Results: We analyzed 738 pts with EG cancer (age < 49 n=151; age >50 n=587). Race and sex were different with more Asian (19% vs. 9%), fewer Caucasian (62% vs. 81%) ( P<0.001) and more female patients (40% vs. 29%, P=0.014) in the EO group. Time from symptom onset to diagnosis was longer in the EO group (median (IQR) 144 d (66-276) vs. 75 d (34-136), P=0.009), though stage did not differ ( P=0.49). Patients with EO-EG cancer had less weight loss ( P<0.001), but no other distinct presenting symptoms. Primary disease site was different with more gastric in the EO group (66% vs. 55%, P=0.04). Signet-ring histology was more common in the EO group (11% vs. 3%; P=0.0009). ERBB2 amp and MSI-H were similar, with a trend toward more MSI-H in the AO group (ERBB2 amp P=0.88, Q=0.830; MSI-H P=0.0157, Q=0.056). The most frequent somatic alterations were similar in EO vs. AO pts, including TP53 (68% vs. 70%, P=0.370, Q=0.825), CDH1 (15% vs. 11%, P=0.139, Q=0.825), RHOA (6% vs. 5%, P=0.395, Q=0.825). There was a trend toward more ARID1A (19% vs. 7%, P<0.01, Q=0.250) and FBWX7 (5% vs. 2%, P=139, Q=0.825) mutations in the AO group. Conclusions: Presenting symptoms, stage, histology, HER2 and MSI status are similar in patients with EO vs. AO-EG cancer. There is a trend in EO toward longer time to diagnosis, gastric primary site of disease, signet-ring histology and fewer ARID1A and FBWX7 mutations. Expanded clinical and molecular data will be presented. [Table: see text]

Genomic characterization of a comprehensive collection of esophagogastric cancer patient-derived xenografts

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Background: Large-scale sequencing has identified multiple oncogenic drivers and molecularly defined subsets in esophagogastric cancer. However, besides therapies for HER2-positive and microsatellite instability-high disease, few genomic biomarker-driven treatments are currently approved. Patient-derived xenografts (PDXs) have emerged as promising preclinical models that capture the heterogeneity and biology of human tumors. Therefore, we established a comprehensive collection of esophagogastric cancer PDXs and performed next-generation sequencing (NGS) to genomically characterize these models. Methods: Starting in 2010, we developed an ongoing program for generating esophagogastric cancer PDXs from fresh tumor specimens that are acquired from surgical resections or biopsies and implanted into NOD scid gamma (NSG) mice either subcutaneously into flanks or orthotopically into the gastric wall. We reviewed clinical and pathologic characteristics of patients from whom established PDXs were derived, including stage, histology, HER2 status and treatment history. To identify oncogenic DNA alterations, NGS was performed on PDX material using MSK-IMPACT, a capture-based NGS platform. Results: From April 2010 to August 2018, we implanted 270 tumor samples, of which 112 were successfully engrafted (41.4%) including 57 gastric adenocarcinomas, 25 gastroesophageal junction adenocarcinomas, 23 esophageal adenocarcinomas, 4 squamous cell carcinomas and 3 small cell/high-grade neuroendocrine tumors. PDXs were generated from both primary tumors (n = 67, 59.8%) and metastases (n = 45, 40.2%), with many PDXs established from patients with metastatic disease who had progressed on standard therapy (n = 50, 44.6%). In addition, a large number of PDXs were derived from patients initially diagnosed with HER2-positive esophagogastric adenocarcinoma (n = 68, 60.7%). NGS of these PDXs demonstrated frequent alterations in TP53, receptor tyrosine kinases ( ERBB2, EGFR), cell-cycle mediators ( CDK12, CCNE1, CCND3) and histone methyltransferases ( KMT2C, KMT2D), consistent with clinical sequencing. Conclusions: Comprehensive molecular profiling demonstrates that esophagogastric cancer PDXs recapitulate the genomic heterogeneity and tumor biology of patients. This panel represents one of the largest described collections of esophagogastric cancer PDXs and serves as a powerful platform to investigate mechanisms driving tumor growth and metastasis, identify predictive biomarkers for treatment responsiveness and develop novel genomically-driven therapeutic strategies.