Analysis of medium-term prognostic factors for laparoscopic radical resection of serosal infiltrating (pT4a) gastric cancer: a retrospective cohort study

To investigate the clinicopathological characteristics and factors influencing medium-term prognosis in patients with gastric cancer and serosal invasion (pT4a) following laparoscopic radical gastrectomy. In this retrospective study, 461 patients with pT4a gastric cancer who underwent laparoscopic D2 radical gastrectomy at The First Affiliated Hospital of Shandong Second Medical University (October 2019-December 2024) were analyzed. Survival was assessed by the Kaplan–Meier method; prognostic factors were identified using univariate and multivariate Cox regression. Poorly differentiated/undifferentiated adenocarcinoma comprised 76.8% of cases, and 63.8% were of the diffuse Lauren type. Median tumor diameter was 5.5 cm (58.2% >5 cm). Lymphovascular and perineural invasion were present in 88.7% and 92.4% of patients, respectively; tumor deposits were found in 10.7%. Overall lymph node metastasis rate was 84.8% (pN3a: 25.2%, pN3b: 19.5%). With a median follow-up of 26.0 months, median overall survival (OS) was 49.0 months and median disease-free survival (DFS) was 37.0 months. Multivariate analysis identified independent adverse prognostic factors for OS: age (HR = 1.03, 95% CI 1.01–1.04, P = 0.001), elevated CA19−9 (HR = 1.58, 95% CI 1.15–2.17, P = 0.004), tumor deposits (HR = 1.40, 95% CI 1.01–1.94, P = 0.045), Lauren classification (HR = 1.32, 95% CI 1.04–1.68, P = 0.022), total gastrectomy (vs. partial/subtotal; HR = 1.81, 95% CI 1.35–2.43, P < 0.001), and advanced pN stage (HR = 1.54, 95% CI 1.26–1.88, P < 0.001). For DFS, independent predictors were age, elevated CA19−9, tumor deposits, total gastrectomy, and pN stage (all P < 0.05). In this study cohort, patients with pT4a gastric cancer who underwent laparoscopic D2 radical resection achieved medium-term survival outcomes that are broadly comparable to those reported in historical open surgery cohorts. Age, elevated CA19−9, tumor deposits, Lauren classification(diffuse type), total gastrectomy, and advanced pN stage are independent adverse prognostic factors.