Abstract
BACKGROUND/AIM: In the Japanese Classification of Gastric Carcinoma, T4a gastric cancer is defined as tumor invasion contiguous to the serosa or penetrating the serosa with exposure to the peritoneal cavity. The aim of this study was to assess the impact of T4a subclassification of gastric cancer on survival. PATIENTS AND METHODS: A total of 326 patients with T4a cancer who had undergone gastrectomy were enrolled. The T4a tumors were classified into two groups: serosa-contiguous or serosa-exposed. RESULTS: The serosa-exposed group had a significantly worse prognosis, and multivariate analysis identified the T4a subclass as an independent prognostic factor. Analysis of the risk factors for recurrence identified the T4a subclass as a significant risk factor for peritoneal recurrence in patients undergoing curative gastrectomy. CONCLUSION: The serosa-contiguous and serosa-exposed subgroups of T4a gastric cancer showed different biological behaviors. These groups may need to be treated as separate.