Initial Experience Using Laparoscopic HIPEC for Gastric Cancer with Peritoneal Metastasis: Safety and Outcomes.

BACKGROUND: Peritoneal metastases (PM) develop in approximately 20% of patients with gastric cancer (GC). For selected patients, treatment of PM with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promising results. This report aims to describe the safety and perioperative outcomes of laparoscopic HIPEC for GC/PM. METHODS: This retrospective cohort study evaluated patients who had GC and PM treated with laparoscopic HIPEC (2018-2022). The HIPEC involved cisplatin and mitomycin C (MMC) or MMC alone. The primary end point was perioperative safety. RESULTS: The 22 patients in this study underwent 27 procedures. The mean age was 58 ± 13 years. All the patients were Eastern Cooperative Oncology Group (ECOG) 0 or 1 (55 and 45%, respectively). Five patients underwent a second laparoscopic HIPEC, with a median of 126 days (interquartile range [IQR], 117-166 days) between procedures. The median peritoneal carcinomatosis index (PCI) was 4 (IQR, 2-9), and the median hospital stay was 2 days (IQR, 1-3 days). No 30-day readmissions or complications occurred. Eight patients (36%) underwent gastrectomy (CRS ± HIPEC). After an average follow-up period of 11 months, 7 (32%) of the 22 patients were alive. The median overall survival was 11 months (IQR, 195-739 days) from the initial procedure and 19.3 months (IQR, 431-1204 days) from the diagnosis. CONCLUSIONS: Laparoscopic HIPEC appears to be safe with minimal perioperative complications. Approximately one third of the patients undergoing initial laparoscopic HIPEC ultimately proceeded to cytoreduction and gastrectomy. Preliminary survival data from this highly selected cohort suggest that the addition of laparoscopic HIPEC to systemic chemotherapy does not compromise other treatment options. These initial results suggest that laparoscopic HIPEC may offer benefit to patients with GC and PM and aid in the selection of patients who may benefit from curative-intent resection.

Induction Fluorouracil-Based Chemotherapy and PET-Adapted Consolidation Chemoradiation with Esophagectomy for High-Risk Gastroesophageal Adenocarcinoma.

Background: Neoadjuvant chemoradiation with esophagectomy is standard management for locally advanced esophageal adenocarcinoma. Induction chemotherapy with a tailored approach to chemoradiation based on metabolic response to therapy on PET was explored as an alternative strategy in the CALGB 80803 trial. We sought to describe real-world institutional experience implementing this approach outside of a clinical trial. Methods: Patients who were treated with induction fluorouracil-leucovorin-oxaliplatin (FOLFOX) or fluorouracil-leucovorin-oxaliplatin-docetaxel (FLOT) with tailored chemoradiation based on PET response and subsequent esophagectomy were identified from a prospectively maintained database. Primary outcomes were pathologic complete response (pCR) and overall survival (OS) following completion of all therapy. Results: There were 35 patients who completed induction chemotherapy, chemoradiation, and esophagectomy. Thirty-three completed restaging PET following induction chemotherapy with metabolic response seen in 76% (n = 25/33). The pCR rate was 31% (n = 11/35) and the ypN0 rate was 71% (n = 25/35). Among the patients who demonstrated metabolic response to induction FOLFOX/FLOT and subsequently continued fluorouracil-based chemoradiation, the pCR rate was 39% (n = 9/23). The rate of pathologically negative lymph nodes in this group was high (n = 19/23, 83%) with 100% R0 resection rate (n = 23/23). With the median follow-up of 43 months, the median OS was not reached for this group and was significantly longer than the OS for the remainder of the cohort (p = 0.027, p = 0.046 adjusted for clinical stage). Conclusions: Induction FOLFOX/FLOT chemotherapy with evaluation of sensitivity via metabolic response and tailored chemoradiation seems to lead to high pCR and ypN0 rates in high-risk patients with adenocarcinoma of the esophagus and GE junction. This approach in clinical practice seems to recapitulate encouraging results in clinical trials.

Surgical versus non-surgical management for patients with malignant bowel obstruction (S1316): a pragmatic comparative effectiveness trial.

BACKGROUND: Malignant small bowel obstruction has a poor prognosis and is associated with multiple related symptoms. The optimal treatment approach is often unclear. We aimed to compare surgical versus non-surgical management with the aim to determine the optimal approach for managing malignant bowel obstruction. METHODS: S1316 was a pragmatic comparative effectiveness trial done within the National Cancer Trials Network at 30 hospital and cancer research centres in the USA, Mexico, Peru, and Colombia. Participants had an intra-abdominal or retroperitoneal primary cancer confirmed via pathological report and malignant bowel disease; were aged 18 years or older with a Zubrod performance status 0-2 within 1 week before admission; had a surgical indication; and treatment equipoise. Participants were randomly assigned (1:1) to surgical or non-surgical treatment using a dynamic balancing algorithm, balancing on primary tumour type. Patients who declined consent for random assignment were offered a prospective observational patient choice pathway. The primary outcome was the number of days alive and out of the hospital (good days) at 91 days. Analyses were based on intention-to-treat linear, logistic, and Cox regression models combining data from both pathways and adjusting for potential confounders. Treatment complications were assessed in all analysed patients in the study. This completed study is registered with ClinicalTrials.gov, NCT02270450. FINDINGS: From May 11, 2015, to April 27, 2020, 221 patients were enrolled (143 [65%] were female and 78 [35%] were male). There were 199 evaluable participants: 49 in the randomised pathway (24 surgery and 25 non-surgery) and 150 in the patient choice pathway (58 surgery and 92 non-surgery). No difference was seen between surgery and non-surgery for the primary outcome of good days: mean 42·6 days (SD 32·2) in the randomised surgery group, 43·9 days (29·5) in the randomised non-surgery group, 54·8 days (27·0) in the patient choice surgery group, and 52·7 days (30·7) in the patient choice non-surgery group (adjusted mean difference 2·9 additional good days in surgical versus non-surgical treatment [95% CI -5·5 to 11·3]; p=0·50). During their initial hospital stay, six participants died, five due to cancer progression (four patients from the randomised pathway, two in each treatment group, and one from the patient choice pathway, in the surgery group) and one due to malignant bowel obstruction treatment complications (patient choice pathway, non-surgery). The most common grade 3-4 malignant bowel obstruction treatment complication was anaemia (three [6%] patients in the randomised pathway, all in the surgical group, and five [3%] patients in the patient choice pathway, four in the surgical group and one in the non-surgical group). INTERPRETATION: In our study, whether patients received a surgical or non-surgical treatment approach did not influence good days during the first 91 days after registration. These findings should inform treatment decisions for patients hospitalised with malignant bowel obstruction. FUNDING: Agency for Healthcare Research and Quality and the National Cancer Institute. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Long-term nutrition alterations after surgery for gastrointestinal cancers.

As surgical and adjuvant therapies for gastrointestinal (GI) cancers improve in safety and efficacy, extended survival in these diseases is becoming commonplace. Surgically induced nutrition alterations are common side effects of treatment and often debilitating. This review is intended for multidisciplinary teams to better understand the postoperative anatomy, physiology, and nutrition morbidity of GI cancer operations. We have arranged this paper by the anatomic and functional changes to the GI tract intrinsic to common cancer operations. Operation-specific long-term nutrition morbidity is detailed, along with the underlying pathophysiology. We have included the most common and effective interventions for the management of individual nutrition morbidities. Finally, we highlight the importance of a multidisciplinary approach to the evaluation and treatment of these patients over the oncologic surveillance period and beyond.

Tumor Regression Grade and Overall Survival following Gastrectomy with Preoperative Therapy for Gastric Cancer.

BACKGROUND: Pre-/perioperative chemotherapy is well-established for management of locoregional gastric cancer (LRGC). The American Joint Committee on Cancer advocates histopathologic assessment of tumor regression grade (TRG) but does not endorse a specific schema. We sought to examine the prognostic value of the recently revised National Comprehensive Cancer Network (NCCN) definition of TRG specifying TRG0 as no disease in primary tumor or lymph nodes. PATIENTS AND METHODS: Patients with clinical-stage T2+/N+/M0 LRGC receiving preoperative chemotherapy and curative-intent gastrectomy were identified (2000-2020). TRG using the current NCCN definition was retrospectively assigned. Factors associated with TRG were examined using ordinal logistic regression and overall survival (OS) was assessed using the Kaplan-Meier method and Cox regression. RESULTS: Among 117 patients, the most common chemotherapy regimen was epirubicin, cisplatin, plus fluorouracil or capecitabine (ECF/ECX) (n = 48, 41%), followed by folinic acid, fluorouracil, and oxaliplatin (FOLFOX) (n = 30, 26%), and fluorouracil, leucovorin, oxaliplatin, plus docetaxel (FLOT) (n = 13, 11%). TRG3 was the most common histopathologic response (n = 68, 58%), followed by TRG2 (n = 25, 21%), TRG1 (n = 18, 15%), and, lastly, TRG0 (n = 6, 5.1%). The only preoperative factor independently associated with lower TRG was gastroesophageal junction tumor location (OR 0.24, p = 0.012). Higher TRG was independently associated with worse OS in a stepwise fashion (HR 1.49, p = 0.026). Posttreatment pathologic lymph node status was the strongest prognostic factor (HR 1.93, p = 0.026). Independent prognostic value of TRG and ypT stage could not be shown due to substantial overlap. CONCLUSIONS: TRG using the contemporary NCCN definition is associated with OS in LRGC. TRG0 is uncommon but with excellent prognosis. ypN status is the strongest prognostic factor and the revised NCCN definition acknowledging this is appropriate.

Case presentation and panel discussion: Micronutrient therapy in critical illness.

Over the past decade, the use of supraphysiologic doses of micronutrients (also called metabolic resuscitation) in critically ill patients has gained significant attention. Building upon preclinical and observational human data, numerous randomized controlled trials have tested the impact of multiple micronutrients on various outcomes in critically ill patients. At the 2022 American Society for Parenteral and Enteral Nutrition Preconference Course, three world-renowned speakers delivered talks on the (1) overall role of micronutrients and, specifically, (2) selenium and vitamin C and (3) vitamin D and zinc in critically ill patients. Here, the case presentation and discussion from the postsession question and answer period are presented. The moderator for this session was Jose Pimiento, MD, and the speakers and panelists were Christian Stoppe, MD, Todd Rice, MD, and Daren Heyland, MD.

Overview of oxidative stress and the role of micronutrients in critical illness.

Inflammation and oxidative stress represent physiological response mechanisms to different types of stimuli and injury during critical illness. Its proper regulation is fundamental to cellular and organismal survival and are paramount to outcomes and recovery from critical illness. A proper maintenance of the delicate balance between inflammation, oxidative stress, and immune response is crucial for resolution from critical illness with important implications for patient outcome. The extent of inflammation and oxidative stress under normal conditions is limited by the antioxidant defense system of the human body, whereas the antioxidant capacity is commonly significantly compromised, and serum levels of micronutrients and vitamins significantly depleted in patients who are critically ill. Hence, the provision of antioxidants and anti-inflammatory nutrients may help to reduce the extent of oxidative stress and therefore improve clinical outcomes in patients who are critically ill. As existing evidence of the beneficial effects of antioxidant supplementation in patients who are critically ill is still unclear, actual findings about the most promising anti-inflammatory and antioxidative candidates selenium, vitamin C, zinc, and vitamin D will be discussed in this narrative review. The existing evidence provided so far demonstrates that several factors need to be considered to determine the efficacy of an antioxidant supplementation strategy in patients who are critically ill and indicates the need for adequately designed multicenter prospective randomized control trials to evaluate the clinical significance of different types and doses of micronutrients and vitamins in selected groups of patients with different types of critical illness.

Hospital Surgical Volume Is Poorly Correlated With Delivery of Multimodal Treatment for Localized Pancreatic Cancer: A National Retrospective Cohort Study.

Using Donabedian's quality of care model, this study assessed process (hospital multimodal treatment) and structure (hospital surgical case volume) measures to evaluate localized pancreatic cancer outcomes. Background: Treatment at high surgical volume hospitals has been shown to improve short-term outcomes. However, multimodal treatment-surgery and chemotherapy-is the standard of care yet only received by 35% of US patients and has not been examined at the hospital level. Methods: The National Cancer Database was used to identify a cohort of clinical stage I pancreatic cancer patients eligible for multimodal treatment from 2004 to 2016. Hospital multimodal treatment was defined as the number of patients receiving surgery and chemotherapy by the number of eligible patients per hospital. Descriptive statistics and survival analyses were conducted. Results: A total of 16,771 patients met inclusion criteria, of whom 68.0% received curative-intent surgery and 35.8% received multimodal treatment. There was poor correlation between hospital surgical volume and delivery of multimodal treatment (Spearman correlation 0.214; P < 0.001). Of patients cared for at the highest surgical volume hospitals, 18.8% and 52.1% were treated at hospitals with low (0%-25%) and moderate (>25%-50%) multimodal treatment delivery, respectively. Higher hospital multimodal treatment delivery was associated with improved overall survival. Discussion: Although the volume-outcome relationship for pancreatic cancer has demonstrated improved outcomes, this work identified poor correlation between hospital surgical volume and delivery of multimodal treatment. The role of care coordination in the delivery of multimodal treatment warrants further investigation as it is associated with improved survival for patients with localized pancreatic cancer.

Efficacy and safety of esophagectomy via left thoracic approach versus via right thoracic approach for middle and lower thoracic esophageal cancer: a multicenter randomized clinical trial (NST1501).

Background: Left thoracic approach (LTA) has been a favorable selection in surgical treatment for esophageal cancer (EC) patients in China before minimally invasive esophagectomy (MIE) is popular. This study aimed to demonstrate whether right thoracic approach (RTA) is superior to LTA in the surgical treatment of middle and lower thoracic esophageal squamous cell carcinoma (TESCC). Methods: Superiority clinical trial design was used for this multicenter randomized controlled two-parallel group study. Between April 2015 and December 2018, cT1b-3N0-1M0 TESCC patients from 14 centers were recruited and randomized by a central stratified block randomization program into LTA or RTA groups. All enrolled patients were followed up every three months after surgery. The software SPSS 20.0 and R 3.6.2. were used for statistical analysis. Efficacy and safety outcomes, 3-year overall survival (OS) and disease-free survival (DFS) were calculated and compared using the Kaplan-Meier method and the log-rank test. Results: A total of 861 patients without suspected upper mediastinal lymph nodes (umLN) were finally enrolled in the study after 95 ineligible patients were excluded. 833 cases (98.7%) were successfully followed up until June 1, 2020. Esophagectomies were performed via LTA in 453 cases, and via RTA in 408 cases. Compared with the LTA group, the RTA group required longer operating time (274.48±78.92 vs. 205.34±51.47 min, P<0.001); had more complications (33.8% vs. 26.3% P=0.016); harvested more lymph nodes (LNs) (23.61±10.09 vs. 21.92±10.26, P=0.015); achieved a significantly improved OS in stage IIIa patients (67.8% vs. 51.8%, P=0.022). The 3-year OS and DFS were 68.7% and 64.3% in LTA arm versus 71.3% and 63.7% in RTA arm (P=0.20; P=0.96). Conclusions: Esophagectomies via both LTA and RTA can achieve similar outcomes in middle or lower TESCC patients without suspected umLN. RTA is superior to LTA and recommended for the surgical treatment of more advanced stage TESCC due to more complete lymphadenectomy. Trial Registration: ClinicalTrials.gov NCT02448979.

Prophylactic Perioperative Antibiotics in Open Pancreaticoduodenectomy: When Less Is More and When It Is Not. A National Surgical Quality Improvement Program Propensity-Matched Analysis.

INTRODUCTION: We hypothesized that first-generation cephalosporins (G1CEP) provide adequate antimicrobial coverage for pancreaticoduodenectomy (PD) when no biliary stent is present but might be inferior to second-generation cephalosporins or broad-spectrum antibiotics (G2CEP/BS) in decreasing surgical-site infection (SSI) rates when a biliary stent is present. METHODS: The National Surgical Quality Improvement Program 2014-2019 was used to select patients who underwent elective open PD. We divided the population into no-stent versus stent groups based on the status of biliary drainage and then divided each group into G1CEP versus G2CEP/BS subgroups based on the choice of perioperative antibiotics. We matched the subgroups per a propensity score match and analyzed postoperative outcomes. RESULTS: Six thousand two hundred forty five cases of 39,779 were selected; 2821 in the no-stent (45.2%) versus 3424 (54.8%) in the stent group. G1CEP were the antibiotics of choice in 2653 (42.5%) versus G2CEP/BS in 3592 (57.5%) cases. In the no-stent group, we matched 1129 patients between G1CEP and G2CEP/BS. There was no difference in SSI-specific complications (20.3% versus 21.0%; P = 0.677), general infectious complications (25.7% versus 26.9%; P = 0.503), PD-specific complications, overall morbidity, length of stay, or mortality. In the stent group, we matched 1244 pairs. G2CEP/BS had fewer SSI-specific complications (19.9% versus 26.6%; P < 0.001), collections requiring drainage (9.6% versus 12.9%; P = 0.011), and general infectious complications (28.5% versus 34.1%; P = 0.002) but no difference in overall morbidity, mortality, length of stay, and readmission rates. CONCLUSIONS: G2CEP/BS are associated with reduced rates of SSI-specific and infectious complications in stented patients undergoing open elective PD. In patients without prior biliary drainage, G1CEP seems to provide adequate antimicrobial coverage.

Management of Malignant Small Bowel Obstruction: Is Intestinal Bypass Effective Palliation?

BACKGROUND/PURPOSE: Malignant small bowel obstruction (mSBO) is a common consequence of advanced malignancies. Surgical consultation is common, however data on the outcomes following an operation are lacking. We investigated a specific operative approach-intestinal bypass-to determine the outcomes associated with this intervention. METHODS: Patients with a preoperative diagnosis of mSBO who underwent intestinal bypass between 2015 and 2021 were included. Isolated colonic obstruction was excluded as was gastric outlet obstruction. Perioperative and postoperative outcomes were measured, including complications, overall survival, return to oral intake, and return to intended oncologic therapy. Patients were additionally grouped as to whether the operation was performed as elective or as inpatient. RESULTS: Overall, 55 patients were identified, with a mean age of 61.2 ± 14 years. The most common primary malignancy was colorectal cancer (65.5%) and 80% of patients had a preoperative diagnosis of metastatic disease. Small bowel to colon was the most common bypass procedure (51%). Severe complications occurred in 25.5% of patients with three in-hospital mortalities (5.5%). Survival rates at 30, 90, and 180 days were 91%, 80%, and 62%, respectively. The majority of patients were discharged to home (85.5%) and were tolerating an oral diet (74.6%). Twenty-seven patients (49.1%) returned to some form of oncologic treatment. CONCLUSIONS: Patients with mSBO face a potentially terminal condition. In this study, approximately 75% of patients who underwent intestinal bypass were able to regain the ability to eat, and 49% returned to oncologic therapy. Although retrospective, these data suggest the approach is efficacious for palliation of this difficult sequela of advanced cancer.

The effect of histologic grade on neoadjuvant treatment outcomes in esophageal cancer.

BACKGROUND AND OBJECTIVES: The gold standard for locoregional esophageal cancer (LEC) treatment includes preoperative chemoradiation and surgical resection, with possible perioperative or adjuvant systemic therapy. With few data associating histologic grade and prognosis in LEC patients receiving neoadjuvant chemoradiation followed by resection, we seek to evaluate this association. METHODS: Our institutional esophagectomy database between 1999 and 2019 was queried, selecting esophageal adenocarcinoma patients who completed neoadjuvant therapy (NAT), followed by esophagectomy. Propensity-score matching of low- and high-histologic grade groups was performed to assess survival metrics using initial clinical grade (cG) and final pathologic grade (pG). We performed a multivariable logistic regression to study predictors of pathologic complete response as a secondary objective. RESULTS: A total of 518 patients met the inclusion criteria. Kaplan-Meier analysis of the matched dataset showed no difference in initial or 5-year recurrence-free survival or overall survival (OS) between cG1 and cG2 versus cG3 based on original grade. When matched according to pG, cG1-2 had improved median survival parameters compared to cG3, with 5-year OS for cG1-2 of 45% versus 27% (p = 0.001). Higher pG, pathologic N stage, and poor response to NAT are predictors of poor survival. CONCLUSION: Patients with post-NAT pG1-2 demonstrated improved survival. Integrating histologic grade into postneoadjuvant staging may be warranted.

Evaluation of Tumor DNA Sequencing Results in Patients with Gastric and Gastroesophageal Junction Adenocarcinoma Stratified by TP53 Mutation Status.

BACKGROUND: Gastric cancer (GC) and gastroesophageal junction adenocarcinomas (GEJ) are molecularly diverse. TP53 is the most frequently altered gene with approximately 50% of patients harboring mutations. This qualitative study describes the distinct genomic alterations in GCs and GEJs stratified by TP53 mutation status. PATIENTS AND METHODS: Tumor DNA sequencing results of 324 genes from 3741 patients with GC and GEJ were obtained from Foundation Medicine. Association between gene mutation frequency and TP53 mutation status was examined using Fisher's exact test. Functional gene groupings representing molecular pathways suggested to be differentially mutated in TP53 wild-type (TP53WT) and TP53 mutant (TP53MUT) tumors were identified. The association of the frequency of tumors containing a gene mutation in the molecular pathways of interest and TP53 mutation status was assessed using Fisher's exact test with a P-value of <.01 deemed statistically significant for all analyses. RESULTS: TP53 mutations were noted in 61.6% of 2946 GCs and 81.4% of 795 GEJs (P < .001). Forty-nine genes had statistically different mutation frequencies in TP53WT vs. TP53MUT patients. TP53WT tumors more likely had mutations related to DNA mismatch repair, homologous recombination repair, DNA and histone methylation, Wnt/B-catenin, PI3K/Akt/mTOR, and chromatin remodeling complexes. TP53MUT tumors more likely had mutations related to fibroblast growth factor, epidermal growth factor receptor, other receptor tyrosine kinases, and cyclin and cyclin-dependent kinases. CONCLUSION: The mutational profiles of GCs and GEJs varied according to TP53 mutation status. These mutational differences can be used when designing future studies assessing the predictive ability of TP53 mutation status when targeting differentially affected molecular pathways.

A clinical nomogram for predicting tumor regression grade in esophageal squamous-cell carcinoma treated with immune neoadjuvant immunotherapy.

Background: There are various treatment options for esophageal squamous cell cancer. including surgery, peri-operative chemotherapy, and radiation. More recently, neoadjuvant immunotherapy has also been shown improve outcomes. In this study, we addressed the question, "Can we predict which patients with esophageal squamous cell cancer will benefit from neoadjuvant immunotherapy?". Methods: All patients with thoracic esophageal squamous-cell carcinoma (T2N+M0-T3-4N0/+M0) (according to the eighth edition of the National Comprehensive Cancer Network guidelines) who underwent immune neoadjuvant immunochemotherapy with programmed cell death protein 1 (PD-1) combined with paclitaxel plus cisplatin or nedaplatin in the Affiliated Cancer Hospital of Zhengzhou University, China, between November 2019 and August 2021 were included in this study. All patients underwent surgical resection. We developed a response [tumor regression grade (TRG)] prediction model using the least absolute shrinkage and selection operator (LASSO) regression incorporating factors associated with response. The accuracy of the prediction model was then validated. Results: We included 79 patients who underwent neoadjuvant immunotherapy combined with chemotherapy, aged 48-78 years (62.05±6.67), including 21 males and 58 females. There were five cases of immune-related pneumonia, of which three cases were diagnosed as immune-related pneumonia during the perioperative period, and one case of immune-related thyroid dysfunction changes. After LASSO regression, the factors that were independently associated with TRG were clinical T stage before neoadjuvant therapy, clinical N stage before neoadjuvant therapy, albumin level difference from before to after neoadjuvant therapy, white blood cell (WBC) count before neoadjuvant therapy, and T stage before surgery. We constructed a prediction model, plotted the nomogram, and verified its accuracy. Its Brier score was 0.13, its calibration slope was 0.98, and its C-index was 0.90 (95% CI: 0.82-0.97). Conclusions: Our prediction model can predict the likelihood of TRG in patients with esophageal squamous cell cancer after immunotherapy combined with neoadjuvant chemotherapy. Using this prediction model, we plan to conduct a subsequent neoadjuvant radiotherapy in patients with of TRG 2-3 patients with neoadjuvant radiotherapy.

Fundic gland polyps related to diverse aetiologies show subtle morphological differences: a multicentre retrospective study.

AIMS: Fundic gland polyps (FGPs) comprise 66% of all gastric polyps. Although they are usually non-syndromic, they may be associated with various syndromes, including familial adenomatous polyposis (FAP) or gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). We aimed to evaluate how histological features relate to distinct FGP subtypes. METHODS AND RESULTS: We performed a retrospective analysis of 118 FGPs from 109 patients for the architecture of fundic glands, microcyst lining, parietal cell hyperplasia and surface foveolar epithelial changes. Age, gender and history of FAP or GAPPS were collected. Based on combinations of histological features, three distinct patterns (A, B and C) of FGPs were delineated and correlated to the aetiologies. Non-syndromic FGPs were well-formed polyps composed of disordered fundic glands with intermediate-sized microcysts typically lined by a mixture of oxyntic and mucin-secreting cells (73%). Parietal cell hyperplasia (80%) and foveolar surface hyperplasia (78%) were common. FAP-associated cases demonstrated small microcysts that were predominantly lined by fundic epithelium (77%), with limited parietal cell hyperplasia (27%); foveolar hyperplasia was uncommon. GAPPS-related polyps were the largest, with prominent, mucin-secreting epithelium-lined microcysts (73%). Hyperproliferative aberrant pits were universally present, whereas parietal cell hyperplasia was uncommon. Pattern A was identified in most non-syndromic FGPs (74%) and in a minority of FAP-related FGPs (26%). The majority (82%) of FAP-related FGPs showed pattern B, but only 18% of non-syndromic FGPs did. Pattern C consisted exclusively of GAPPS-associated polyps. CONCLUSIONS: We conclude that, although FGPs share similar histomorphology, subtle differences exist between polyps of different aetiology. In the appropriate clinical setting, the recognition of these variations may help to consider syndromic aetiologies.