Predicting lymph node metastases with endoscopic resection in cT2N0M0 oesophageal cancer: A systematic review and meta-analysis.

Background: Despite modern imaging modalities, staging of clinically staged T2N0M0 (cT2N0M0) oesophageal cancer is suboptimal, often leading to overtreatment. Endoscopic resection - the first-line therapy for early localised tumours - could be used to improve staging and to attain predictors of nodal upstaging enabling more stage-guided treatment decisions.
Objective: A systematic literature review and a meta-analysis were conducted to assess the prevalence and the pathological risk factors of lymph node metastases in cT2N0M0 oesophageal cancer.
Methods: Databases of PUBMED, EMBASE and Cochrane were searched for literature. The primary outcome was lymph node metastases determined after primary surgical resection.
Results: Nine studies with a total of 1650 cT2N0M0 patients were included. The prevalence of lymph node metastases was 43% (95% confidence interval: 35-50%) with heterogeneity being high across studies ( I ²  = 0.86, p  < 0.001). Factors potentially attainable by endoscopic resection and having a significant association with lymph node metastases were invasion depth, differentiation grade, tumour size, depth of invasion in the muscularis propria and lymphovascular invasion.
Conclusions: Clinical lymph node staging is inaccurate in almost half of cT2N0M0 oesophageal cancer. Endoscopic resection is a promising diagnostic modality that might even be a valid alternative to surgery in selected patients without high-risk features, but further evidence is warranted.