Textbook Neoadjuvant Outcome-Novel Composite Measure of Oncological Outcomes among Gastric Cancer Patients Undergoing Multimodal Treatment.

The incidence of gastric cancer (GC) is expected to increase to 1.77 million cases by 2040. To improve treatment outcomes, GC patients are increasingly treated with neoadjuvant chemotherapy (NAC) prior to curative-intent resection. Although NAC enhances locoregional control and comprehensive patient care, survival rates remain poor, and further investigations should establish outcomes assessment of current clinical pathways. Individually assessed parameters have served as benchmarks for treatment quality in the past decades. The Outcome4Medicine Consensus Conference underscores the inadequacy of isolated metrics, leading to increased recognition and adoption of composite measures. One of the most simple and comprehensive is the "All or None" method, which refers to an approach where a specific set of criteria must be fulfilled for an individual to achieve the overall measure. This narrative review aims to present the rationale for the implementation of a novel composite measure, Textbook Neoadjuvant Outcome (TNO). TNO integrates five objective and well-established components: Treatment Toxicity, Laboratory Tests, Imaging, Time to Surgery, and Nutrition. It represents a desired, multidisciplinary care and hospitalization of GC patients undergoing NAC to identify the treatment- and patient-related data required to establish high-quality oncological care further. A key strength of this narrative review is the clinical feasibility and research background supporting the implementation of the first and novel composite measure representing the "ideal" and holistic care among patients with locally advanced esophago-gastric junction (EGJ) and GC in the preoperative period after NAC. Further analysis will correlate clinical outcomes with the prognostic factors evaluated within the TNO framework.

International consensus on the management of metastatic gastric cancer: step by step in the foggy landscape : Bertinoro Workshop, November 2022.

BACKGROUND: Many gastric cancer patients in Western countries are diagnosed as metastatic with a median overall survival of less than twelve months using standard chemotherapy. Innovative treatments, like targeted therapy or immunotherapy, have recently proved to ameliorate prognosis, but a general agreement on managing oligometastatic disease has yet to be achieved. An international multi-disciplinary workshop was held in Bertinoro, Italy, in November 2022 to verify whether achieving a consensus on at least some topics was possible. METHODS: A two-round Delphi process was carried out, where participants were asked to answer 32 multiple-choice questions about CT, laparoscopic staging and biomarkers, systemic treatment for different localization, role and indication of palliative care. Consensus was established with at least a 67% agreement. RESULTS: The assembly agreed to define oligometastases as a "dynamic" disease which either regresses or remains stable in response to systemic treatment. In addition, the definition of oligometastases was restricted to the following sites: para-aortic nodal stations, liver, lung, and peritoneum, excluding bones. In detail, the following conditions should be considered as oligometastases: involvement of para-aortic stations, in particular 16a2 or 16b1; up to three technically resectable liver metastases; three unilateral or two bilateral lung metastases; peritoneal carcinomatosis with PCI ≤ 6. No consensus was achieved on how to classify positive cytology, which was considered as oligometastatic by 55% of participants only if converted to negative after chemotherapy. CONCLUSION: As assessed at the time of diagnosis, surgical treatment of oligometastases should aim at R0 curativity on the entire disease volume, including both the primary tumor and its metastases. Conversion surgery was defined as surgery on the residual volume of disease, which was initially not resectable for technical and/or oncological reasons but nevertheless responded to first-line treatment.

European clinical practice guidelines for the definition, diagnosis, and treatment of oligometastatic esophagogastric cancer (OMEC-4).

INTRODUCTION: The OligoMetastatic Esophagogastric Cancer (OMEC) project aims to provide clinical practice guidelines for the definition, diagnosis, and treatment of esophagogastric oligometastatic disease (OMD). METHODS: Guidelines were developed according to AGREE II and GRADE principles. Guidelines were based on a systematic review (OMEC-1), clinical case discussions (OMEC-2), and a Delphi consensus study (OMEC-3) by 49 European expert centers for esophagogastric cancer. OMEC identified patients for whom the term OMD is considered or could be considered. Disease-free interval (DFI) was defined as the time between primary tumor treatment and detection of OMD. RESULTS: Moderate to high quality of evidence was found (i.e. 1 randomized and 4 non-randomized phase II trials) resulting in moderate recommendations. OMD is considered in esophagogastric cancer patients with 1 organ with ≤ 3 metastases or 1 involved extra-regional lymph node station. In addition, OMD continues to be considered in patients with OMD without progression in number of metastases after systemic therapy. 18F-FDG PET/CT imaging is recommended for baseline staging and for restaging after systemic therapy when local treatment is considered. For patients with synchronous OMD or metachronous OMD and a DFI ≤ 2 years, recommended treatment consists of systemic therapy followed by restaging to assess suitability for local treatment. For patients with metachronous OMD and DFI > 2 years, upfront local treatment is additionally recommended. DISCUSSION: These multidisciplinary European clinical practice guidelines for the uniform definition, diagnosis and treatment of esophagogastric OMD can be used to standardize inclusion criteria in future clinical trials and to reduce variation in treatment.

Fashioning esophagogastric anastomosis in robotic Ivor-Lewis esophagectomy: a multicenter experience.

BACKGROUND: The aim of the present study is to compare outcomes of the robotic hand-sewn, linear- and circular-stapled techniques performed to create an intrathoracic esophagogastric anastomosis in patients who underwent Ivor-Lewis esophagectomy. METHODS: Patients who underwent a planned Ivor-Lewis esophagectomy were retrospectively analysed from prospectively maintained databases. Only patients who underwent a robotic thoracic approach with the creation of an intrathoracic esophagogastric anastomosis were included in the study. Patients were divided into three groups: hand-sewn-, circular stapled-, and linear-stapled anastomosis group. Demographic information and surgery-related data were extracted. The primary outcome was the rate of anastomotic leakages (AL) in the three groups. Moreover, the rate of grade A, B and C anastomotic leakage were evaluated. In addition, patients of each group were divided in subgroups according to the characteristics of anastomotic fashioning technique. RESULTS: Two hundred and thirty patients were enrolled in the study. No significant differences were found between the three groups about AL rate (p = 0.137). Considering the management of the AL for each of the three groups, no significant differences were found. Evaluating the correlation between AL rate and the characteristics of anastomotic fashioning technique, no significant differences were found. CONCLUSIONS: No standardized anastomotic fashioning technique has yet been generally accepted. This study could be considered a call to perform ad hoc high-quality studies involving high-volume centers for upper gastrointestinal surgery to evaluate what is the most advantageous anastomotic technique.

Influence of Tumor Stroma on the Aggressiveness of Poorly Cohesive Gastric Carcinoma.

Tumor-stroma crosstalk promotes the adaptation of cancer cells to the local microenvironment and sustains their growth. We assessed the quantitative and qualitative impact of intralesional stroma on clinic-pathological features and the prognosis of poorly cohesive gastric cancer (PCGC) variants. Tissue microarrays including 75 PCGC specimens were immunostained for cytokeratin 8/18 and α-smooth muscle actin to assess the relative proportion of neoplastic cells versus stromal components and the cases were subsequently divided into stroma-rich (SR) and stroma-poor (SP) tumors. Stromal status is significantly associated with the depth of tumor invasion. Patient survival rate was found to be higher in the SP compared to the SR tumor group and, hence, abundant stroma was identified as a significant risk factor in univariable analysis but had no independent prognostic impact. We also investigated the mRNA levels of KRT8 and the associated transcriptional signatures using the molecular data of 82 PCGC cases divided into KRT8-high and KRT8-low groups. KRT8-high tumors were enriched in proteins localized in the extracellular compartment and their expression levels correlated with longer survival in the KRT8-high group and shorter overall survival in the KRT8-low group. Comprehensively, we find that relative intralesional stromal content is a marker of aggressiveness in PCGC tumors and that extracellular proteins characterize functionally and clinically different PCGC subgroups.

Clinical predictors of postoperative complications in the context of enhanced recovery (ERAS) in patients with esophageal and gastric cancer.

The overall frequency of postoperative complications in patients with esophageal and gastric cancer diverges between studies. We evaluated the frequency and assessed the relationship between complications and demographic and clinical features. For this observational study, data were extracted from the ERAS Registry managed by the University of Verona, Italy. Patients were evaluated and compared for postoperative complications according to the consensus-based classification and the Clavien-Dindo scale. The study population was 877 patients: 346 (39.5%) with esophageal and 531 (60.5%) with gastric cancer; 492 (56.2%) reported one or more postoperative complications, 213 (61.6%) of those with esophageal and 279 (52.5%) of those with gastric cancer. When stratified by consensus-based classification, patients with esophageal cancer reported general postoperative complications more frequently (p < 0.001) than those with gastric cancer, but there was no difference in postoperative surgical complications between the two groups. Multiple logistic regression models revealed an association between postoperative complications and the Charlson Comorbidity Index (adjusted odds ratio [OR] 1.22; 95% confidence interval [CI] 1.08-1.36), operation time (adjusted OR, 1.08; 95% CI 1.00-1.15), and days to solid diet intake (adjusted OR, 1.39; 95% CI 1.20-1.59). Complications in patients with esophageal and gastric cancer are frequent, even in those treated according to ERAS principles, and are often associated with comorbidities, longer operative time, and longer time to solid diet intake.

The effect of aging on short- and long-term results after esophagectomy: an international multicenter retrospective analysis.

The optimal treatment for esophageal cancer in elderly patients is still debated and data on postoperative results are limited. This retrospective international study aims to clarify the impact of age on clinical and oncological outcomes after esophagectomy. All patients that underwent esophagectomy for cancer between 2007 and 2016 at two European high-volume Centers have been included in the study. Patients were divided into three groups according to their age: young-age group (YAG) (18-69), middle-age group (70-74) and old-age group (>74). Primary outcome was 5-year overall survival (OS), while secondary outcomes considered were 5-year disease free survival and disease related survival, 90-day morbidity and mortality, readmission rate and radicality. A total of 575 patients were included. No differences emerged in terms of morbidity and length of stay, while mortality increased with aging from 2% in YAG to 4.8% in old-aged (P = 0.003). Old-age patients had less neoadjuvant treatment (P < 0.001), a less aggressive mediastinal lymphadenectomy and presented a more advanced pathological stage. As expected, OS decreased significantly for older patients compared with the other two age groups (P = 0.044) but, on the other hand, disease free and disease related survival were comparable between the groups. Age itself should not be considered a contraindication to esophagectomy. Although in patients older than 75 years postoperative mortality is significantly increased, esophagectomy could be still an option in selected patients, favoring the use of minimally invasive techniques and enhanced recovery protocols.

Biological and targeting differences between the rare KRAS A146T and canonical KRAS mutants in gastric cancer models.

BACKGROUND: Gastric cancer (GC) is the third leading cause of cancer-related death worldwide, with a poor prognosis for patients with advanced disease. Since the oncogenic role of KRAS mutants has been poorly investigated in GC, this study aims to biochemically and biologically characterize different KRAS-mutated models and unravel differences among KRAS mutants in response to therapy. METHODS: Taking advantage of a proprietary, molecularly annotated platform of more than 200 GC PDXs (patient-derived xenografts), we identified KRAS-mutated PDXs, from which primary cell lines were established. The different mutants were challenged with KRAS downstream inhibitors in in vitro and in vivo experiments. RESULTS: Cells expressing the rare KRAS A146T mutant showed lower RAS-GTP levels compared to those bearing the canonical G12/13D mutations. Nevertheless, all the KRAS-mutated cells displayed KRAS addiction. Surprisingly, even if the GEF SOS1 is considered critical for the activation of KRAS A146T mutants, its abrogation did not significantly affect cell viability. From the pharmacologic point of view, Trametinib monotherapy was more effective in A146T than in G12D-mutated models, suggesting a vulnerability to MEK inhibition. However, in the presence of mutations in the PI3K pathway, more frequently co-occurrent in A146T models, the association of Trametinib and the AKT inhibitor MK-2206 was required to optimize the response. CONCLUSION: A deeper genomic and biological characterization of KRAS mutants might sustain the development of more efficient and long-lasting therapeutic options for patients harbouring KRAS-driven GC.

Clinical Features of Gastric Signet Ring Cell Cancer: Results from a Systematic Review and Meta-Analysis.

BACKGROUND: Conflicting results about the prognostic relevance of signet ring cell histology in gastric cancer have been reported. We aimed to perform a meta-analysis focusing on the clinicopathological features and prognosis of this subgroup of cancer compared with other histologies. METHODS: A systematic literature search in the PubMed database was conducted, including all publications up to 1 October 2021. A meta-analysis comparing the results of the studies was performed. RESULTS: A total of 2062 studies referring to gastric cancer with signet ring cell histology were identified, of which 262 studies reported on its relationship with clinical information. Of these, 74 were suitable to be included in the meta-analysis. A slightly lower risk of developing nodal metastases in signet ring cell tumours compared to other histotypes was found (especially to undifferentiated/poorly differentiated/mucinous and mixed histotypes); the lower risk was more evident in early and slightly increased in advanced gastric cancer. Survival tended to be better in early stage signet ring cell cancer compared to other histotypes; no differences were shown in advanced stages, and survival was poorer in metastatic patients. In the subgroup analysis, survival in signet ring cell cancer was slightly worse compared to non-signet ring cell cancer and differentiated/well-to-moderately differentiated adenocarcinoma. CONCLUSIONS: Most of the conflicting results in signet ring cell gastric cancer literature could be derived from the lack of standardisation in their classification and the comparison with the different subtypes of gastric cancer. There is a critical need to strive for a standardised classification system for gastric cancer, fostering clarity and coherence in the forthcoming research and clinical applications.

Major vessel resection for complete cytoreduction in primary advanced and recurrent ovarian malignancies: A case series and systematic review of the literature - pushing the boundaries in oncovascular surgery.

INTRODUCTION: Oncovascular surgery (the removal of major blood vessels infiltrated by cancer) is challenging but can be key to achieve complete cytoreduction in patient with advanced ovarian cancer. The aim of this study was to review the literature on oncovascular surgery in ovarian cancer and to report the details of all the cases performed at our institution. METHODS: We retrospectively reviewed the database of ovarian cancer patients who underwent debulking surgery at the Department of Obstetrics and Gynecology of Verona University between January 2021 and 2023. Patients with at least one major vessel resection during cytoreduction were identified. We then systematically review the literature searching Pubmed and Embase from inception to January 2023 to report all cases of surgery for ovarian cancer with concomitant major vessel resection. RESULTS: Five patients with advanced/recurrent ovarian cancer underwent major vascular resection at our institution. Vascular involvement was preoperatively identified in all cases and no case of vascular resection was performed after accidental injury. The major vessels removed were the inferior vena cava (n = 2), the common iliac veins (n = 2), the external iliac arteries (n = 2), the left common iliac artery (n = 1), and the left external iliac vein (n = 1). All patients underwent other non-gynecological cytoreductive procedures prior to vessel removal and had R0 obtained. Three (60%) patients experienced one or more postoperative complications. The literature search identified a total of seven cases of major vessels resection in ovarian cancer surgery. A single or multiple major vessels were removed in two (28.6%) and five (72.4%) cases, respectively. All the seven patients underwent vascular reconstruction. Four (57.1%) patients reported postoperative complications. Overall, 66.7% of the 12 total identified patients were free from disease at the last follow-up [median 15.5 months (range 5-25)]. CONCLUSIONS: Oncovascular surgery is feasible in selected patients with ovarian cancer, provided that a multidisciplinary approach with customized care is available.

VEGFA Status as a Predictive Marker of Therapy Outcome in Metastatic Gastric Cancer Patients Following Ramucirumab-Based Treatment.

Metastatic gastric cancer (mGC) often has a poor prognosis and may benefit from a few targeted therapies. Ramucirumab-based anti-angiogenic therapy targeting the VEGFR2 represents a milestone in the second-line treatment of mGC. Several studies on different cancers are focusing on the major VEGFR2 ligand status, meaning VEGFA gene copy number and protein overexpression, as a prognostic marker and predictor of response to anti-angiogenic therapy. Following this insight, our study aims to examine the role of VEGFA status as a predictive biomarker for the outcome of second-line therapy with Ramucirumab and paclitaxel in mGC patients. To this purpose, the copy number of the VEGFA gene, by fluorescence in situ hybridization experiments, and its expression in tumor tissue as well as the density of micro-vessels, by immunohistochemistry experiments, were assessed in samples derived from mGC patients. This analysis found that amplification of VEGFA concomitantly with VEGFA overexpression and overexpression of VEGFA with micro-vessels density are more represented in patients showing disease control during treatment with Ramucirumab. In addition, in the analyzed series, it was found that amplification was not always associated with overexpression of VEGFA, but overexpression of VEGFA correlates with high micro-vessel density. In conclusion, overexpression of VEGFA could emerge as a potential biomarker to predict the response to anti-angiogenic therapy.

Textbook Oncological Outcome in European GASTRODATA.

OBJECTIVE: To assess the rate of textbook outcome (TO) and textbook oncological outcome (TOO) in the European population based on the GASTRODATA registry. BACKGROUND: TO is a composite parameter assessing surgical quality and strongly correlates with improved overall survival. Following the standard of treatment for locally advanced gastric cancer, TOO was proposed as a quality and optimal multimodal treatment parameter. METHODS: TO was achieved when all the following criteria were met: no intraoperative complications, radical resection according to the surgeon, pR0 resection, retrieval of at least 15 lymph nodes, no severe postoperative complications, no reintervention, no admission to the intensive care unit, no prolonged length of stay, no postoperative mortality and no hospital readmission. TOO was defined as TO with the addition of perioperative chemotherapy compliance. RESULTS: Of the 2558 patients, 1700 were included in the analysis. TO was achieved in 1164 (68.5%) patients. The use of neoadjuvant chemotherapy [odds ratio (OR) = 1.33, 95% CI: 1.04-1.70] and D2 or D2+ lymphadenectomy (OR = 1.55, 95% CI: 1.15-2.10) had a positive impact on TO achievement. Older age (OR = 0.73, 95% CI: 0.54-0.94), pT3/4 (OR = 0.79, 95% CI: 0.63-0.99), ASA 3/4 (OR = 0.68, 95% CI: 0.54-0.86) and total gastrectomy (OR = 0.56, 95% CI: 0.45-0.70), had a negative impact on TO achievement. TOO was achieved in 388 (22.8%) patients. Older age (OR = 0.37, 95% CI: 0.27-0.53), pT3 or pT4 (OR = 0.52, 95% CI: 0.39-0.69), and ASA 3 or 4 (OR = 0.58, 95% CI: 0.43-0.79) had a negative impact on TOO achievement. CONCLUSIONS: Despite successively improved surgical outcomes, stage-appropriate chemotherapy in adherence to the current guidelines for multimodal treatment of gastric cancer remains poor. Further implementation of oncologic quality metrics should include greater emphasis on perioperative chemotherapy and adequate lymphadenectomy.

Bidirectional Approach with PIPAC and Systemic Chemotherapy for Patients with Synchronous Gastric Cancer Peritoneal Metastases (GCPM).

BACKGROUND: This study evaluated the efficacy of pressurized intraperitoneal aerosol chemotherapy (PIPAC) with systemic chemotherapy as a bidirectional approach for gastric cancer (GC) patients with synchronous peritoneal metastases (SPM). METHODS: A retrospective analysis of a prospective PIPAC database was queried for patients who underwent a bidirectional approach between October 2019 and April 2022 at two high-volume GC surgery units in Italy (Verona and Siena). Surgical and oncological outcomes were analyzed. RESULTS: Between October 2019 and April 2022, 74 PIPAC procedures in 42 consecutive patients with Eastern Cooperative Oncology Group performance status ≤2 were performed-32 patients treated in Verona and 10 in Siena. Twenty-seven patients (64%) were female and median age at first PIPAC was 60.5 years (I-III quartiles: 49-68 years). Median Peritoneal Cancer Index (PCI) was 16 (I-III quartiles: 8-26) and 25 patients (59%) had at least two PIPAC procedures. Major complications according to the Common Terminology Criteria for Adverse Events (CTCAE; 3 and 4) occurred in three (4%) procedures, and, according to the Clavien-Dindo classification (>3a), one (1%) severe complication occurred. There were no reoperations or deaths within 30 days. Median overall survival (mOS) from diagnosis was 19.6 months (range 14-24), and mOS from first PIPAC was 10.5 months (range 7-13). Excluding cases with very heavy metastatic peritoneal burden, with PCI from 2 to 26, treated with more than one PIPAC, mOS from diagnosis was 22 months (range 14-39). Eleven patients (26%) underwent curative-intent surgery after a bidirectional approach. R0 was achieved in nine (82%) patients and complete pathological response was obtained in three (27%) cases. CONCLUSIONS: Patient selection is associated with bidirectional approach efficacy and feasibility for SPM GC treatment, which may allow potentially curative surgical radicalization in highly selected cases.

Gastric Cancer (GC) with Peritoneal Metastases (PMs): An Overview of Italian PSM Oncoteam Evidence and Study Purposes.

Gastric cancer (GC) continues to be one of the leading types of malignancies worldwide, despite an ongoing decrease in incidence. It is the fifth most frequent type of cancer in the world and the fourth leading cause of cancer death. Peritoneal metastases (PMs) occur in 20-30% of cases during the natural history of the disease. Systemic chemotherapy (SC) is undoubtedly the standard of care for patients with GC and PMs. However, with the development of highly effective regimens (SC combined with intraperitoneal chemotherapy), significant tumor shrinkage has been observed in many patients with synchronous GC and PMs, allowing some to undergo curative resection "conversion surgery" with long-term survival. In recent years, there has been growing interest in intraperitoneal chemotherapy for PMs, because the reduced drug clearance associated with the peritoneal/plasma barrier allows for direct and prolonged drug exposure with less systemic toxicity. These procedures, along with other methods used for peritoneal surface malignancies (PSMs), can be used in GCs with PMs as neoadjuvant chemotherapy or adjuvant treatments after radical surgery or as palliative treatments delivered either laparoscopically or-more recently-as pressurized intraperitoneal aerosol chemotherapy. The great heterogeneity of patients with stage IV gastric cancer did not allow us to carry out a systemic review; therefore, we limited ourselves to providing readers with an overview to clarify the indications and outcomes of integrated treatments for GCs with PMs by analyzing reports from the international clinical literature and the specific experiences of our oncoteam.

BRCA2 Germline Mutations Identify Gastric Cancers Responsive to PARP Inhibitors.

Despite negative results of clinical trials conducted on the overall population of patients with gastric cancer, PARP inhibitor (PARPi) therapeutic strategy still might represent a window of opportunity for a subpopulation of patients with gastric cancer. An estimated 7% to 12% of gastric cancers exhibit a mutational signature associated with homologous recombination (HR) failure, suggesting that these patients could potentially benefit from PARPis. To analyze responsiveness of gastric cancer to PARPi, we exploited a gastroesophageal adenocarcinoma (GEA) platform of patient-derived xenografts (PDX) and PDX-derived primary cells and selected 10 PDXs with loss-of-function mutations in HR pathway genes. Cell viability assays and preclinical trials showed that olaparib treatment was effective in PDXs harboring BRCA2 germline mutations and somatic inactivation of the second allele. Olaparib responsive tumors were sensitive to oxaliplatin as well. Evaluation of HR deficiency (HRD) and mutational signatures efficiently stratified responder and nonresponder PDXs. A retrospective analysis on 57 patients with GEA showed that BRCA2 inactivating variants were associated with longer progression-free survival upon platinum-based regimens. Five of 7 patients with BRCA2 germline mutations carried the p.K3326* variant, classified as "benign." However, familial history of cancer, the absence of RAD51 foci in tumor cells, and a high HRD score suggest a deleterious effect of this mutation in gastric cancer. In conclusion, PARPis could represent an effective therapeutic option for BRCA2-mutated and/or high HRD score patients with GEA, including patients with familial intestinal gastric cancer. SIGNIFICANCE: PARP inhibition is a potential strategy for treating patients with gastric cancer with mutated BRCA2 or homologous repair deficiency, including patients with familial intestinal gastric cancer, for whom BRCA2 germline testing should be recommended.

Definition, diagnosis and treatment of oligometastatic oesophagogastric cancer: A Delphi consensus study in Europe.

BACKGROUND: Local treatment improves the outcomes for oligometastatic disease (OMD, i.e. an intermediate state between locoregional and widespread disseminated disease). However, consensus about the definition, diagnosis and treatment of oligometastatic oesophagogastric cancer is lacking. The aim of this study was to develop a multidisciplinary European consensus statement on the definition, diagnosis and treatment of oligometastatic oesophagogastric cancer. METHODS: In total, 65 specialists in the multidisciplinary treatment for oesophagogastric cancer from 49 expert centres across 16 European countries were requested to participate in this Delphi study. The consensus finding process consisted of a starting meeting, 2 online Delphi questionnaire rounds and an online consensus meeting. Input for Delphi questionnaires consisted of (1) a systematic review on definitions of oligometastatic oesophagogastric cancer and (2) a discussion of real-life clinical cases by multidisciplinary teams. Experts were asked to score each statement on a 5-point Likert scale. The agreement was scored to be either absent/poor (<50%), fair (50%-75%) or consensus (≥75%). RESULTS: A total of 48 experts participated in the starting meeting, both Delphi rounds, and the consensus meeting (overall response rate: 71%). OMD was considered in patients with metastatic oesophagogastric cancer limited to 1 organ with ≤3 metastases or 1 extra-regional lymph node station (consensus). In addition, OMD was considered in patients without progression at restaging after systemic therapy (consensus). For patients with synchronous or metachronous OMD with a disease-free interval ≤2 years, systemic therapy followed by restaging to consider local treatment was considered as treatment (consensus). For metachronous OMD with a disease-free interval >2 years, either upfront local treatment or systemic treatment followed by restaging was considered as treatment (fair agreement). CONCLUSION: The OMEC project has resulted in a multidisciplinary European consensus statement for the definition, diagnosis and treatment of oligometastatic oesophagogastric adenocarcinoma and squamous cell cancer. This can be used to standardise inclusion criteria for future clinical trials.