Background Postoperative complications frequently occur after gastrectomy for gastric cancer and are associated with poor clinical outcomes, such as mortality and reoperations. The aim of study was to identify the clinically most relevant complications after gastrectomy, using the population-attributable fraction (PAF). Methods Between 2011 and 2017, all patients who underwent potentially curative gastrectomy for gastric adenocarcinoma were included from the Dutch Upper GI Cancer Audit. Postoperative outcomes (morbidity, mortality, recovery and hospitalization) were evaluated. The prevalence of postoperative complications (e.g., anastomotic leakage and pneumonia) and of the study outcomes were calculated. The adjusted relative risk and Confidence Interval (CI) for each complication-outcome pair were calculated. Subsequently, the PAF was calculated, which represents the percentage of a given outcome occurring in the population, caused by individual complications, taking both the relative risk and the frequency in which a complication occurs into account. Results In total, 2176 patients were analyzed. Anastomotic leakage and pulmonary complications had the greatest overall impact on postoperative mortality (PAF 29.2% [95% CI 19.3–39.1] and 21.6% [95% CI 10.5–32.7], respectively) and prolonged hospitalization (PAF 12.9% [95% CI 9.7–16.0] and 14.7% [95% CI 11.0–18.8], respectively). Anastomotic leakage had the greatest overall impact on re-interventions (PAF 25.1% [95% CI 20.5–29.7]) and reoperations (PAF 30.3% [95% CI 24.3–36.3]). Intra-abdominal abscesses had the largest impact on readmissions (PAF 7.0% [95% CI 3.2–10.9]). Other complications only had a small effect on these outcomes. Conclusion Surgical improvement programs should focus on preventing or managing anastomotic leakage and pulmonary complications, since these complications have the greatest overall impact on clinical outcomes after gastrectomy.

Initial staging of gastric cancer consists of computed tomography (CT) and gastroscopy. In locally advanced (cT3–4) gastric cancer, fluorodeoxyglucose positron emission tomography with CT (FDG-PET/CT or PET) and staging laparoscopy (SL) may have a role in staging, but evidence is scarce. The aim of this study is to evaluate the impact and cost-effectiveness of PET and SL in addition to initial staging in patients with locally advanced gastric cancer. This prospective observational cohort study will include all patients with a surgically resectable, advanced gastric adenocarcinoma (cT3–4b, N0–3, M0), that are scheduled for treatment with curative intent after initial staging with gastroscopy and CT. The modalities to be investigated in this study is the addition of PET and SL. The primary outcome of this study is the proportion of patients in whom the PET or SL lead to a change in treatment strategy. Secondary outcome parameters are: diagnostic performance, morbidity and mortality, quality of life, and cost-effectiveness of these additional diagnostic modalities. The study recently started in August 2017 with a duration of 36 months. At least 239 patients need to be included in this study to demonstrate that the diagnostic modalities are break-even. Based on the annual number of gastrectomies in the participating centers, it is estimated that approximately 543 patients are included in this study. In this study, it is hypothesized that performing PET and SL for locally advanced gastric adenocarcinomas results in a change of treatment strategy in 27% of patients and an annual cost-reduction in the Netherlands of €916.438 in this patient group by reducing futile treatment. The results of this study may be applicable to all countries with comparable treatment algorithms and health care systems. NCT03208621 . This trial was registered prospectively on June 30, 2017.

Background: The role of ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG-PET/CT) and staging laparoscopy (SL) has increased in the preoperative staging of gastric cancer. Dutch national guidelines have recommended the use of FDG-PET/CT and SL for patients with locally advanced tumors since July 2016. Objective: The aim of this study was to evaluate the implementation of FDG-PET/CT and SL in The Netherlands. Methods: Between 2011 and 2018, all patients who underwent surgery for gastric cancer were included from the Dutch Upper GI Cancer Audit. The use of FDG-PET/CT and SL was evaluated before and after revision of the Dutch guidelines. Outcomes included the number of non-curative procedures (e.g. palliative and futile procedures) and the association of FDG-PET/CT and SL, with waiting times from diagnosis to the start of treatment. Results: A total of 3310 patients were analyzed. After July 2016, the use of FDG-PET/CT (23% vs. 61%; p < 0.001) and SL (21% vs. 58%; p < 0.001) increased. FDG-PET/CT was associated with additional waiting time to neoadjuvant therapy (4 days), as well as primary surgical treatment (20 days), and SL was associated with 8 additional days of waiting time to neoadjuvant therapy. Performing SL or both modalities consecutively in patients in whom it was indicated was not associated with the number of non-curative procedures. Conclusion: During implementation of FDG-PET/CT and SL after revision of the guidelines, both have increasingly been used in The Netherlands. The addition of these staging methods was associated with increased waiting time to treatment. The number of non-curative procedures did not differ after performing none, solely one, or both staging modalities.

Objectives: The aim of the study was to evaluate the current status of gastric cancer surgery worldwide and update the changes compared to a previous survey in 2014. Methods: A cross-sectional survey was sent to surgical members of the International Gastric Cancer Association, pilot centers of the World Organization for Specialized Studies on Diseases of the Esophagus, and the Australian and New Zealand Gastric and Oesophageal Surgeons Association in addition to participants of the 2019 International Gastric Cancer and European Society for Diseases of the Esophagus congresses. Topics addressed included hospital volume, staging, perioperative treatment, surgical approach, anastomotic techniques, lymphadenectomy, and palliative management. Results: Between June 2019 and January 2020, 165 respondents from 44 countries completed the survey. In total, 80% worked in a hospital performing >20 gastrectomies annually. Staging laparoscopy and 18F-fluorodeoxyglucose positron emission tomography with computed tomography were preferred by 68 and 26% for advanced cancer, and 90% offered perioperative chemo(radio)therapy to patients. For early cancer, a minimally invasive surgical approach was preferred by 65% for distal and by 50% for total gastrectomy. For advanced cancer, this was preferred by 39% for distal and by 33% for total gastrectomy. And 84% favored a stapled anastomosis, and 14% created a jejunal pouch as reconstruction during total gastrectomy. A D2 lymphadenectomy was preferred for distal as well as for total gastrectomy, in both early (62 and 71%) and advanced (84 and 89%) cancer. Conclusion: This international survey demonstrates that perioperative chemotherapy and a D2 lymphadenectomy have now become the preferred treatment for gastric cancer. A minimally invasive surgical approach has gained popularity.

Aim: To improve identification of peritoneal and distant metastases in locally advanced gastric cancer using [¹⁸F]FDG-PET radiomics. Methods: [¹⁸F]FDG-PET scans of 206 patients acquired in 16 different Dutch hospitals in the prospective multicentre PLASTIC-study were analysed. Tumours were delineated and 105 radiomic features were extracted. Three classification models were developed to identify peritoneal and distant metastases (incidence: 21%): a model with clinical variables, a model with radiomic features, and a clinicoradiomic model, combining clinical variables and radiomic features. A least absolute shrinkage and selection operator (LASSO) regression classifier was trained and evaluated in a 100-times repeated random split, stratified for the presence of peritoneal and distant metastases. To exclude features with high mutual correlations, redundancy filtering of the Pearson correlation matrix was performed (r = 0.9). Model performances were expressed by the area under the receiver operating characteristic curve (AUC). In addition, subgroup analyses based on Lauren classification were performed. Results: None of the models could identify metastases with low AUCs of 0.59, 0.51, and 0.56, for the clinical, radiomic, and clinicoradiomic model, respectively. Subgroup analysis of intestinal and mixed-type tumours resulted in low AUCs of 0.67 and 0.60 for the clinical and radiomic models, and a moderate AUC of 0.71 in the clinicoradiomic model. Subgroup analysis of diffuse-type tumours did not improve the classification performance. Conclusion: Overall, [¹⁸F]FDG-PET-based radiomics did not contribute to the preoperative identification of peritoneal and distant metastases in patients with locally advanced gastric carcinoma. In intestinal and mixed-type tumours, the classification performance of the clinical model slightly improved with the addition of radiomic features, but this slight improvement does not outweigh the laborious radiomic analysis.