Published online Jan 14, 2015. doi: 10.3748/wjg.v21.i2.549
Peer-review started: April 23, 2014
First decision: May 29, 2014
Revised: June 13, 2014
Accepted: July 30, 2014
Article in press: July 30, 2014
Published online: January 14, 2015
AIM: To evaluate the clinicopathological features of mixed-type gastric cancer and their influence on prognosis of mixed-type stage I gastric cancer.
METHODS: We analyzed 446 patients who underwent curative gastrectomy for stage I gastric 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 mixed-type 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-mixed-type gastric cancer (P = 0.0026). Furthermore, mixed-type 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 stage I gastric cancer.
Core tip: Little is known about the clinical outcome of the histological mixed-type gastric cancer, which consists of differentiated and undifferentiated components. We evaluated the clinicopathological features of this cancer and their influences on the prognosis of patients with mixed-type stage I gastric cancer.