RESUMO
BACKGROUND: Many studies investigated the association between alcohol drinking and gastric cancer risk, but the results were controversial. We performed a meta-analysis of observational studies to explore the association. MATERIALS AND METHODS: We searched PubMed to identify the relevant studies that reported the association between alcohol drinking and gastric cancer risk up to December 31, 2016. We pooled relative risks (RRs) in random effects model and performed dose-response analysis to quantify the association. Cochran Q test and I2 analyses were used to evaluate the heterogeneity. Meta-regression, subgroup, sensitivity and publication bias analyses were also performed. RESULTS: 75 studies were included in our study. The pooled RR of high vs low total alcohol drinking was 1.25 (95% CI, 1.15-1.37, P < 0.001), and a nonlinear association was further observed. Subgroup analysis showed that alcohol drinking significantly associated with the risk of gastric noncardia cancer (RR, 1.19; 95% CI, 1.01-1.40, P = 0.033), but not with the risk of gastric cardia cancer (RR, 1.16; 95% CI, 0.98-1.39, P = 0.087). Notably, the pooled RRs of high vs low analyses were 1.13 (95% CI, 1.03-1.24, P = 0.012) for beer drinking, 1.22 (95% CI, 1.06-1.40, P = 0.005) for liquor drinking, and 0.99 (95% CI, 0.84-1.16, P = 0.857) for wine drinking. CONCLUSIONS: Our meta-analysis found a nonlinear association between alcohol drinking and gastric cancer risk, and heavy drinking level was strongly related to gastric cancer risk. Beer and liquor had significant positive associations with gastric cancer risk, while wine drinking would not increase gastric cancer risk. These results need to be verified in future research.
RESUMO
Insufficient number of examined lymph nodes (eLNs) was considered to increase significantly the risk of stage migration in gastric cancer patients. The aim of our study is to establish a nomogram predicting the overall survival (OS) for patients with an insufficient number of eLNs. A total of 872 gastric cancer patients with extended lymphadenectomies were assigned randomly (2:1) to the development cohort and the validation cohort. The nomogram was established based on the Cox regression model using the development cohort. The concordance index (C-index) was used to evaluate the discriminative ability. We also compared our model with two other staging systems. Using multivariate analysis, age, sex, tumor location, depth of invasion, macroscopic type, lymphovascular invasion, the number of eLNs, and metastatic lymph nodes were selected and incorporated into the nomogram. The C-index of the nomogram was 0.742 and 0.743 in development and validation cohorts, respectively, which were significantly superior to the C-indices (range 0.705-0.712, all P < 0.001) of American Joint Committee on Cancer (AJCC) seventh edition and lymph node ratio staging systems in both cohorts. We established a nomogram which could predict accurately OS for gastric cancer patients with insufficient number of eLNs.