Gastrectomy with or without omentectomy for gastric cancer: A systematic review and meta-analysis

Comparative assessment of the capability of machine learning-based radiomic models for predicting omental metastasis in locally advanced gastric cancer

The study aims to investigate the predictive capability of machine learning algorithms for omental metastasis in locally advanced gastric cancer (LAGC) and to compare the performance metrics of various machine learning predictive models. A retrospective collection of 478 pathologically confirmed LAGC patients was undertaken, encompassing both clinical features and arterial phase computed tomography images. Radiomic features were extracted using 3D Slicer software. Clinical and radiomic features were further filtered through lasso regression. Selected clinical and radiomic features were used to construct omental metastasis predictive models using support vector machine (SVM), decision tree (DT), random forest (RF), K-nearest neighbors (KNN), and logistic regression (LR). The models' performance metrics included accuracy, area under the curve (AUC) of the receiver operating characteristic curve, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). In the training cohort, the RF predictive model surpassed LR, SVM, DT, and KNN in terms of accuracy, AUC, sensitivity, specificity, PPV, and NPV. Compared to the other four predictive models, the RF model significantly improved PPV. In the test cohort, all five machine learning predictive models exhibited lower PPVs. The DT model demonstrated the most significant variation in performance metrics relative to the other models, with a sensitivity of 0.231 and specificity of 0.990. The LR-based predictive model had the lowest PPV at 0.210, compared to the other four models. In the external validation cohort, the performance metrics of the predictive models were generally consistent with those in the test cohort. The LR-based model for predicting omental metastasis exhibited a lower PPV. Among the machine learning algorithms, the RF predictive model demonstrated higher accuracy and improved PPV relative to LR, SVM, KNN, and DT models.

Does total omentectomy prevent peritoneal seeding for advanced gastric cancer with serosal invasion?

BACKGROUND

Radical gastrectomy is composed of gastrectomy, lymph node dissection, and omentectomy. Total omentectomy (TO) is expected to reduce the incidence of peritoneal recurrence. We aimed to investigate the necessity of TO for advanced gastric cancer (AGC) with serosal invasion.

METHODS

We retrospectively reviewed 310 patients who underwent radical gastrectomy with TO and 93 patients who underwent partial omentectomy (PO) for gastric cancer with serosal invasion between August, 2005 and December, 2017. Finally, 91 patients in the PO group and 91 in the TO group were enrolled based on a 1:1 propensity-score matching analysis. We evaluated surgical and oncological outcomes, including 5-year overall and recurrence-free survival rates.

RESULTS

There was no statistically significant difference between the two groups in postoperative complications. Recurrence sites showed similar patterns in both groups, including peritoneal recurrence (PO vs. TO, 18.7% vs. 28.6%; p = 0.188). Five-year overall survival was better in the PO group (p = 0.018), while 5-year recurrence-free survival was similar in both groups (p = 0.066).

CONCLUSION

TO might not be an essential part of preventing peritoneal recurrence for AGC with serosal invasion. PO could be considered a radical gastrectomy for T4a gastric cancer.

Safety and Efficacy of Partial Omentectomy in Laparoscopic Distal Gastrectomy for pT3-T4a Stage Gastric Cancer

Purpose

Partial omentectomy (PO) has been gradually applied in laparoscopic gastrectomy for gastric cancer (GC); however, its efficacy remains unclear. The purpose of this study was to assess the safety and efficacy of PO in laparoscopic distal gastrectomy for pT3-T4a stage GC.

Patients and Methods

From June 2019 to May 2021, 108 patients with pT3 or pT4a stage GC who underwent laparoscopic distal gastrectomy were retrospectively included and divided into the PO (n=58) and total omentectomy (TO, n=50) groups. The surgical outcomes, recurrence patterns and postoperative 2-year overall survival (OS) rates were compared between the PO and TO groups.

Results

The PO group showed a shorter operation time than the TO group (183.9±21.6 vs 197.6±22.7 min, p=0.002). Less intraoperative blood loss (155.3±113.0 vs 178.8±154.4 mL, p=0.336) and intraoperative complications (5.1% vs 12.0%, p=0.298) were also observed in the PO group than in the TO group, but the difference was not significant. The numbers of retrieved lymph nodes (LNs) and metastatic LNs, postoperative hospital stays and postoperative complications in the two groups were comparable (p>0.05). Moreover, the postoperative overall recurrence rates (25.9% vs 26.0%, p=0.987) and the 2-year OS rates (63.8% vs 65.4%, p=0.437) in the PO and TO groups were also comparable. TO was not an independent prognostic factor for GC patients (HR=0.806, p=0.443).

Conclusion

In laparoscopic distal gastrectomy, PO could provide better surgical outcomes and comparable oncological outcomes compared to TO for patients with pT3-T4a stage GC, suggesting that PO may be an acceptable surgical procedure for these patients.

Management of Gastric Cancer

Gastric adenocarcinoma is a complex disease that requires a thorough multidisciplinary approach for appropriate management. Management strategies vary in different regions of the world and have changed over time. In spite of improvements in chemotherapy and surgical techniques and an improvement in outcomes over the last several decades, overall survival remains low. The best outcomes are likely related to early detection, preoperative reduction of tumor burden with immunochemotherapy, consistent surgical technique for resection, and postoperative eradication of tumor cells. We aim to describe the management for gastric cancer, from the specifics of staging and imaging workup to the tenets of surgical resection and reconstruction as well as the adjuvant treatment strategies in this broad review of gastric cancer management.

Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Gastrectomy with or without Complete Omentectomy for Advanced Gastric Cancer: A Meta-Analysis

Background and Objectives: Surgery remains the only possible curative treatment for advanced gastric cancer (AGC). Peritoneal metastases are estimated to occur in approximately 55–60% AGC patients. Greater omentum is the most common metastatic area in AGC. At present, omentectomy alone or bursectomy are usually carried out during gastric cancer surgery. We performed a meta-analysis in order to evaluate long-term and short-term outcomes among AGC patients, who have undergone radical gastrectomy with or without complete omentectomy (CO). Materials and Methods: We performed a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Meta-analysis was performed by use of RevMan (Computer program) Version 5.4. Results: The eight included studies covered an approximately 20 years long study period (2000–2018). Almost all included studies were retrospective ones and originated from Asian countries. Meta-analysis indicated gastrectomy without CO as significantly associated with longer 3-year (RR: 0.94, 95% CI: 0.90–0.98, p = 0.005) and 5-year overall survivals (OS) (RR: 0.93, 95% CI: 0.88–0.98, p = 0.007). Moreover, we found longer operative time (MD: 24.00, 95% CI: −0.45–48.45, p = 0.05) and higher estimated blood loss (MD: 194.76, 95% CI: 96.40–293.13, p = 0.0001) in CO group. Conclusions: Non-complete omentectomy (NCO) group had a statistically greater rate in 3-year and 5-year OSs than the CO group, while the CO group had significantly longer operative time and higher estimated blood loss than the NCO group. Further randomized, possibly multi-center trials may turn out of paramount importance in confirming our results.