Introduction: The postoperative recurrence of gastric cancer (GC) has a significant impact on the overall prognosis of patients. Therefore, accurately predicting the postoperative recurrence of GC is crucial. Methods: This retrospective study gathered data from 2813 GC patients who underwent radical surgery between 2011 and 2017 at two medical centers. Follow-up was extended until May 2023, and cases were categorized as recurrent or nonrecurrent based on postoperative outcomes. Clinical pathological information and imaging data were collected for all patients. A new deep learning signature (DLS) was generated using pretreatment computed tomography images, based on a pretrained baseline (a customized Resnet50), for predicting postoperative recurrence. The deep learning fusion signature (DLFS) was created by combining the score of DLS with the weighted values of identified clinical features. The predictive performance of the model was evaluated based on discrimination, calibration, and clinical usefulness. Survival curves were plotted to investigate the differences between DLFS and prognosis. Results: In this study, 2813 patients with GC were recruited and allocated into training, internal validation, and external validation cohorts. The DLFS was developed and assessed for its capability in predicting the risk of postoperative recurrence. The DLFS exhibited excellent performance with AUCs of 0.833 (95% CI: 0.809–0.858) in the training set, 0.831 (95% CI: 0.792–0.871) in the internal validation set, and 0.859 (95% CI: 0.806–0.912) in the external validation set, along with satisfactory calibration across all cohorts (P>0.05). Furthermore, the DLFS model significantly outperformed both the clinical model and DLS (P<0.05). High-risk recurrent patients exhibit a significantly poorer prognosis compared to low-risk recurrent patients (P<0.05). Conclusions: The integrated model developed in this study, focusing on GC patients undergoing radical surgery, accurately identifies cases at high-risk of postoperative recurrence and highlights the potential of DLFS as a prognostic factor for GC patients.

Aim Postoperative adjuvant chemotherapy is known to enhance cure rates and is thus recommended for stages pII to pIII. However, specific guidelines for such treatment in elderly gastric cancer (GC) patients are currently lacking. This study examines the impact of adjuvant chemotherapy on the postoperative survival of these patients. Methods We reviewed a total of 7749 patients with GC who underwent radical gastrectomy at Zhejiang Cancer Hospital and Fujian Cancer Hospital from January 2007 to December 2019. We conducted univariate and multivariate Cox regression analyses to investigate the impact of clinicopathological factors on overall survival (OS) and cancer-specific survival (CSS) in these patients. Additionally, we created a meta-analysis forest plot and employed propensity score matching (PSM) to mitigate confounding bias. Results Age and adjuvant chemotherapy were independent risk factors for OS and CSS. Stratified analysis based on chemotherapy use revealed a statistically significant difference in OS and CSS between younger patients who did and did not receive adjuvant chemotherapy. In contrast, no significant differences in OS and CSS were observed between older patients with or without adjuvant chemotherapy. These findings remained consistent after propensity score matching (PSM). Conclusions Age and adjuvant chemotherapy are independent risk factors for OS and CSS in patients with stage II/III GC; for patients with stage II/III gastric cancer aged ≥ 75 years, shared decision-making should be made taking into account functional status and comorbidities, rather than conventional adjuvant chemotherapy.