Prognostic significance of perinodal extension in gastric cancer

BACKGROUND: The grouping of patients who have a poor prognosis is important in determining a treatment strategy. The aim of this study was to investigate the clinicopathologic features and prognosis in patients with perinodal extension, with a focus on the difference of survival between homogenous groups. METHODS: This study included a total of 1,092 patients who underwent curative gastrectomy for gastric adenocarcinoma from 1997 to 2004 at the Department of Surgery, Yongdong Severance Hospital, Yonsei University College of Medicine. RESULTS: One hundred sixty-one patients had perinodal extension. The incidence of perinodal extension was positively correlated for T and N stages. Perinodal extension was identified as an independent prognostic factor and had more influence on survival than T and N stages. Patients who had nodal metastasis without serosal exposure and who had serosal exposure without nodal metastasis were selected as homogenous groups, and there was no difference of survival between these groups. However, when the nodal metastasis group was subdivided according to the perinodal extension, perinodal extension subgroup had significant poorer prognosis than no perinodal extension subgroup. CONCLUSIONS: The perinodal extension was the most important independent prognostic factor in gastric cancer, and should be included in the TNM gastric cancer staging system.