Histological mixed-type as an independent prognostic factor in stageⅠgastric carcinoma

AIM: To evaluate the clinicopathological features of mixed-type gastric cancer and their influence on prognosis of mixed-type stageⅠgastric cancer.METHODS: We analyzed 446 patients who underwent curative gastrectomy for stageⅠgastric cancer between 1999 and 2009. The patients were divided into two groups: those with differentiated or undifferentiated cancer(non-mixed-type, n = 333) and those with a mixture of differentiated and undifferentiated cancers(mixed-type, n = 113).RESULTS: The overall prevalence of mixed-type gastric cancer was 25.3%(113/446). Compared with patients with non-mixed-type gastric cancer, those with mixedtype gastric cancer tended to be older at onset(P = 0.1252) and have a higher incidence of lymph node metastasis(P = 0.1476). They also had significantly larger tumors(P < 0.0001), more aggressive lymphatic invasion(P = 0.0011), and deeper tumor invasion(P < 0.0001). In addition, they exhibited significantly worse overall survival rates than did patients with non-mixedtype gastric cancer(P = 0.0026). Furthermore, mixedtype gastric cancer was independently associated with a worse outcome in multivariate analysis [P = 0.0300, hazard ratio = 11.4(1.265-102.7)].CONCLUSION: Histological mixed-type of gastric cancer contributes to malignant outcomes and highlight its usefulness as a prognostic indicator in stageⅠgastric cancer.