Background:During the past several decades, changing pattern of gastric cancer(GC) in western countries and the increasing rate of early detection and overall survival has been reported.
Aim:To evaluate the time-related trends of tumor characteristics and postoperative survival for patients with GC in two large-volume centers of high incidence areas of southern China.
Methods:Based on meticulously collected data of 5327 patients surgically treated in the Department of Gastric and Pancreatic Surgery, Sun Yat-sen University Cancer Center and the Department of Gastric Surgery, Fujian Medical University Union Hospital, we analyzed the differences in clinicopathological features and postoperative survival for four consecutive periods:period 1(1991-1995);period 2(1996-2000);period 3(2001-2005)and period 4(2006-2010).
Results:The proportion of tumors within the gastric cardia/fundus decreased from 51% to 32.1% (P＜0.001).Size of tumor was becoming smaller over the study of periods (P=0.001),and the poorly differentiated tissue type increased from 47.8% to 68.9%(P=0.008).A diagnosis of early GC was made more prevalently gradually, from 7.2% to 15%(P＜0.001).The incidence of stage IA according to 7th edition AJCC/UICC classification significantly increased(P＜0.001). A surprisingly improvement was observed in the mean number of retrieved lymph nodes, ranging from 10.36 to 26.22(P＜0.001). However, the radical resection rate increased from 87.9% to 92.7% without a statistical significance. The overall 5-year survival rate was seen to improve steadily over the four periods, from 37.4% to 59.5%(P＜0.001). Multivariate analysis revealed that age, tumor location, histological type, tumor size, depth of invasion, lymphatic invasion, number of retrieved lymph nodes, radical resection and time periods were independent factors for determining the prognosis.
Conclusions:The patterns of GC location, histology and stage have changed during the observed period of time in our regions. The increasing early detection of patients with gastric cancer and more standardized surgical regimens, including routinely performed D2 lymphadenectomy, by experienced surgeons probably mainly result in the progress in overall survival.