Factors Predicting Lymph Node Metastasis in Intramucosal Gastric Cancer: A Systematic Review and Meta-analysis of 18 Studies: Presidential Poster

Abstract

Introduction: Gastric cancer restricted to the mucosa (T1a) is amenable to endoscopic management. However, this may only be considered curative in the absence of metastasis to lymph nodes. In this systematic review and meta-analysis, we sought to identify predictors of lymph node metastasis (LNM) in intramucosal gastric cancer. Methods: Using free text words and MeSH terms with and without Boolean operators, two reviewers independently performed a search of PubMed and Embase databases through April 2015 to identify studies that described clinicopathologic factors associated with lymph node metastasis in intramucosal gastric cancer. Dichotomous data for various risk factors was extracted from individual studies. Summary Odds Ratio (OR) with 95% confidence intervals (CI) was estimated using the random effects model for each risk factor included in the meta-analysis, and heterogeneity was measured using the inconsistency index (I2).Table 1: Characteristics of studies included along with an indication of data available in each studyTable 2: Pooled Odds Ratios (OR) with 95% confidence intervals (CI) for clinicopathologic factors predicting lymph nodal metastasisFigure 1Figure 2Figure 3Results: After reviewing 1173 abstracts, 18 studies which included a total of 7266 patients with intramucosal gastric cancer were identified and data was extracted. Meta-analysis was performed for association with age, sex, location and size of tumor, morphologic appearance, histology and lymphovascular invasion (LVI) after extraction of available data. Significant association was found between LNM and female sex, tumor size greater than 2 cm, presence of ulceration, undifferentiated histology and lymphovascular invasion. LVI was the strongest risk factor predicting LNM (pooled OR 26.08; 95% CI 16.74- 40.63), with moderate heterogeneity (p for Chi2= 0.04, I2= 43%) that that was lost after studies that included only undifferentiated cancer were excluded (Pooled OR 21.23; 95% CI 13.68- 32.95; P for Chi2 =0.33, I2= 12%). Conclusion: Female sex, tumor size greater than 2 cms, undifferentiated histology, presence of ulceration and lymphovascular invasion predict lymph nodal metastasis in intramucosal gastric cancer. Sentinel lymph node biopsy or lymph nodal dissection should be considered in these patients after endoscopic management.