Clinicopathologic Features In Early Proximal Gastric Carcinomas Diagnosed With WHO 2010 Criteria In Chinese Patients

Background: The epidemiological and clinicopathologic features in early gastric carcinoma(EGC),and especially in proximal gastric carcinoma(PGC)remains poorly understood and endoscopic therapy has not been well established towards Chinese patients.7th edition of the UICC/AJCC TNM classification defines cancers up to 5cm distal to the junction as junctional tumours,as well as the increasingly applied classification proposed by Siewert et al.However,proximal gastric carcinoma in Chinese patients might not the same as "junctional" carcinoma seen in Western Caucasian patients.Aims: To investigate the difference of epidemiological and clinicopathologic features,lymphatic metastasis(LNM),and endoscopic characteristics between PGC and DGC,and find more evidence of the classification of proximal gastric carcinoma in Chinese patients.Methods: Guided with the WHO 2010 criteria,we investigated all consecutive gastric cancer resections performed in Nanjing,China,and identified 438 EGCs between 2005 and 2012.Among them,131 were PGCs and 307 were DGCs.All cases were followup.Median follow-up duration was 55 months(Range: 2-107).Risk factors of pathogenesis and LNM were identified by Logistic regression analysis.All prognosisrelated clinicopathologic features were identified by using one-way ANOVA test and Chi-square test or COX regression analysis when appropriate.A 15-point scoring model for LNM risk prediction was developed based on the independent risk factors of LNM and to facilitate the decision-making process on EGC resection.Results: Proportion of early PGCs in all EGC patients was significantly increased year by year(P<0.05).Advanced age(OR=9.83,P<0.01),personal cancer history(OR=5.09,P<0.05),high BMI(>24)(OR=2.79,P<0.01),and history of environmental toxin exposure(OR=2.31,P<0.05)were independent risk factors for PGC.In contrast,family cancer history(OR=2.34,P<0.01)and Helicobacter-pylori infection(OR=2.81,P<0.001)were independent risk factors for DGC.By endoscopy,PGCs showed protruding and elevated patterns in 61.9%,while depressed and excavated patterns in 33.6%,which were significantly different from those(32.6% and 64.5%)in DGCs.PGCs were significantly smaller(1.9 cm in average size,versus 2.2 cm in DGCs),invaded deeper(22.9% into SM2,versus 13% in DGCs),but had fewer(2.9%,versus 16.7% in DGCs)lymph node metastases.Papillary adenocarcinoma was significantly more frequent(32.1%,versus 12.1% in DGCs),as were mucinous and neuroendocrine carcinomas,carcinoma with lymphoid stroma(6.9%,versus 1.6% in DGCs);poorly cohesive carcinoma was significantly less frequent(5.3%,versus 35.8% in DGCs).LNM occurred in 49(12.9%)cases.Multivariate analysis identified female gender,DGC,poorly cohesive carcinoma,and lymphovascular invasion as independent risk factors.Risk of LNM was effectively stratified by the 15-point scoring model as minimal(0-3 points),high(4-7 points)and extremely high(?8 points)groups with excellent discriminatory power(AUROC 0.875),high sensitivity(94%),and moderate specificity(60%)when the cut-off value was set at 3.5 points.Conclusions: Independent risk factors and clinicopathologic features of PGC in Chinese patients were different from those of DGC or esophageal adenocarcinoma,supports PGC classified as a separate gastric carcinoma entity in Chinese population.Compared to DGCs,early PGCs feature smaller size,but fewer nodal metastases,and thus more suitable for endoscopic resection.