Adenocarcinoma of the esophagogastric junction (AEG) has distinct malignant features compared with other esophageal and gastric cancers. Its management is controversial and largely influenced by tumor location and esophageal involvement. Hence, understanding the clinicopathological characteristics and prognosis of AEG is essential for optimizing treatment strategies.To evaluate the prognosis and clinicopathological features of patients with AEG, providing insights for management strategies.This retrospective study analyzed cases with AEG admitted between January 2016 and December 2017. Patients meeting the inclusion criteria were categorized into three groups: Type E [tumors whose center was located within 5 cm above the esophagogastric junction (EGJ)]; Type Eg (tumors whose center was situated within 2 cm below the EGJ), with a 2-cm esophageal invasion; Type Ge (tumors whose center was situated within 2 cm below the EGJ, with an esophageal invasion of < 2 cm, based on tumor location and esophageal involvement. Then, clinicopathological characteristics and survival outcomes of the groups were compared to evaluate the predictive value of the American Joint Committee on Cancer/International Alliance against Cancer 8th edition gastric cancer and esophageal adenocarcinoma staging systems. Statistical analysis included survival analysis and Cox regression to assess prognostic factors.Totally, 153 patients with AEG were included (median follow up: 41.1 months; 22, 31, and 100 patients from type E, Eg, and Ge, respectively), with significant differences in maximum tumor length, esophageal involvement length, tumor type, pathology, differentiation, depth of invasion, and lymph node metastasis between the groups (P < 0.05). Lymph node metastasis rates at stations 1, 2, 3, and 7 were lower in type E than in Eg and Ge (P < 0.05). Survival rates for type E (45.5%) were significantly lower than those for Eg (48.4%) and Ge (73.0%) (P = 0.001). Type E tumors, vascular infiltration, T3-T4 invasion depth, and lymph node metastasis, were identified as independent prognostic factors (P < 0.05). The gastric cancer staging system outperformed the esophageal adenocarcinoma system for type Ge tumors.Clinicopathological characteristics and prognoses varied between the AEG groups, with type E demonstrating distinct features. The gastric cancer staging system more accurately predicted type Ge AEG prognosis, guiding clinical decision-making.©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.