Changing Trends In The Clinicopathological Features Of Gastric Cancer In Northwest China Over The Past 15 Years

Background and AimGastric cancer(GC)is the second most common disease in both incidence and mortality in China.It threatened the human health seriously.Over the past few decades,overall incidence rates for GC have been steadily declined worldwide,particularly in developed countries.However,some studies have shown that there has been a stable or an increasing trend in gastric cardia cancer(GCC)in many countries.Using the Lauren classification,a decline in the incidence of the intestinal carcinoma was found.In contrast,the incidence of diffuse type carcinoma has been significantly increasing,particularly the signet ring cell carcinoma.However,the changing trends of clinicopathological features of GC reported in each place has an obvious geographic variation.Signet ring cell carcinoma(SRC)is a special type of GC,and is classified into diffuse type by Lauren classification.With the characteristics of poorly differentiation,diffuse infiltrative growth,rapid progression,earlier metastasis,and the prognosis is quiet poor.However,whether it behaves progressively is still controversial.Some studies have shown that early SRC has a better prognosis other subtypes.Because of the clinical and endoscopy features in early GC with SRC is a pale,flat lesion that can easily be missed,leading to a low detection rate.To understand the changing trends of GC in Northwest China and the clinicopathological features of SRC can guide us make a more effective strategy to prevent and treat GC.Part 1 Changing trends in the clinicopathological characteristics of Gastric Cancer in Northwest China over the past 15 yearsObjective To analyze the clinicopathological characteristics of primary gastric cancer of the Northwest China over the past 15 years in order to explore its variation and development tendency.Methods The data of primary gastric cancer confirmed by pathology in our department were enrolled from January 2000 to December 2014,including demographic data,endoscopic results,surgical information and postoperative pathological results,etc.Patients were divided into three 5-year periods: group A(2000-2004),group B(2005-2009),group C(2010-2014).The gender,age,tumor location,TNM stage,Borrmann type,histological type,degree of differentiation and metastasis were analyzed retrospectively.Results A total of 5481 patients with primary gastric cancer were collected in this study,and 85.8% came from Northwest China.Group A 623,group B 1323,group C 3535.The mean age for gastric cancer was 57.17±11.41 years.Significant differences were noted in age,tumor location,clinical characteristics,diameter,TNM stage,lymph node metastasis and distant metastasis between three groups,while there were no difference in gender ratio.(1)Man-to-female ratio were 2.58:1,3.35:1 and 2.94:1 in three groups,respectively.The male-to-female did not changed significantly(P>0.05).The higher incidence was ≥61-years old in group A,but the 41-60 years old in group C.The average age of gastric cancer was decreased over the past 15 years(P<0.01).There was no significant change in the incidence of young patients between 3 groups(P>0.05).With the increase of age,the incidence rate of gastric cancer in female decreased.The gender in young age group was no significantly different.(2)The clinical symptoms of each group were abdominal pain,weight loss,anorexia,abdominal distension and acid reflux.The patients with early gastric cancer only a very slight symptoms such as abdominal pain.(3)The diameter of tumor was larger in group C than group A and B.(4)Over the 15-year period,gastric cancer in the antrum were still the most common site and had significantly increased,whereas the incidence of gastric cancer in the body had declined(P<0.05)and the gastric cardia cancer were keep stable(P>0.05).(5)In histological features,adenocarcinoma was still the main histological type and remained increasing trend,from 70.5% in groups A to 80.3% in group C.The increase is clearly in the poorly differentiated adenocarcinoma,which has increased from 46.5% in group A to 60.6% in group C.The incidence of mucinous adenocarcinoma and signet ring cell carcinoma had significantly declined(P<0.05)over the studied period.(6)The incidence of early gastric cancer shown a increasing trend between 2000 and 2014,from 8.2% to 18.1%(P<0.05).(7)An increasing trend of lymph node metastasis rate for group A,B,and C was 51.5%,58.4% and 66.5%,respectively.And a decreasing trend of distant metastasis rate for group A,B,and C was 9.6%,8.7%and 7.1%,respectively.Conclusion(1)The changing trends of gastric cancer in Northwest China were different from the western countries and other areas in China.When making the gastric cancer prevention and control strategy,we should consider the regional different characteristics.(2)The age of gastric cancer patients is showing a decreasing trend.This may prompt us to screening the high risk groups in Northwest China in a younger age.(3)There was a rising trend of gastric cancer in the antrum and a decreasing trend of gastric cancer in the body,whereas the incidence of gastric cardia cancer were stable during the study period.We should pay attention to the distal during gastroscopy for gastric cancer high risk groups in Northwest China.(4)Adenocarcinoma remain a higher incidence rate and keep increasing steadily while signet ring cell carcinoma showed a decreasing trend.This may suggests that the risk factors of gastric cancer in Northwest China may be different from other areas,and this need to futher discuss.(5)The incidence of early gastric cancer shown a rising trend,indicate that the detection rate of early gastric cancer in Northwest china has increased but is still lower than Japan and Korea.(6)There may have some selection bias because this is a single center study,so the results may only apply to the Northwest China.Part 2 Clinicopathological Characteristics Analysis of Gastric Signet Ring Cell CarcinomaObjective To analyze the clinicopathological characteristics of patients with signet ring cell carcinoma(SRC)in comparison with non-signet ring cell carcinoma(NSRC)of the stomach.Methods The clinicopathological characteristics were reviewed in 5481 patients of diagnosed with gastric cancer who received surgical resection and pathologically confirmed from January 2000 to December 2014 in Xijing hospital.The patients were divided into signet ring cell carcinoma(SRC)and non-signet ring cell carcinoma(NSRC),the clinicopathological data of two groups were analyzed.Results Significant differences were noted in age,gender,tumor location,TNM stage,invasion depth and lymph node metastasis between SRC and NSRC(P<0.05),while there was no difference in distant metastasis.(1)SRC was more prevalent in younger age(53.7vs.57.8 years,P<0.05)and female(37.2% vs.23.0%,P<0.05)patients than NSRC.(2)The most common sites were in gastric body and antrum,gastric cardia cancer was significantly less than NSRC(P<0.05).(3)The proportion of Ⅲ and Ⅳ stage in SRC was significantly higher than NSRC(59.2% vs.51.3%,P<0.05).4)SRC had a higher incidence of lymphatic metastasis than NSRC(68.0% vs.62.1%,P<0.05).The distant metastasis in SRC was not statistically different from NSRC.Conclusion Signet ring cell carcinoma happens more common in young females,Most carcinoma site located at middle and lower part of gastric body.Early SRC tends to occur higher lymph node metastasis.We should strength the ability to recognize the endoscopic features of early SRC,in order to improve the early diagnosis rate and prognosis of patients with SRC.