Systematic review and meta‐analysis of histopathological factors influencing the risk of lymph node metastasis in early colorectal cancer

Abstract

Aim: Lymph node (LN) metastases are present in up to 17% of early colorectal cancers (p T 1). Identification of associated histopathological factors would enable counselling of patients regarding this risk. Method: Pubmed and E mbase were employed utilizing the terms ‘early colorectal cancer’, ‘lymph node metastasis’, ‘submucosal invasion’, ‘lymphovascular invasion’, ‘tumour budding’ and ‘histological differentiation’. Analysis was performed using REVIEW MANAGER 5.1. Results: Twenty‐three cohort studies including 4510 patients were analysed. There was a significantly higher risk of LN metastasis with a depth of submucosal invasion > 1 mm than with lesser degrees of penetration (OR 3.87, 95% CI 1.50–10.00, P = 0.005). Lymphovascular invasion was significantly associated with LN metastasis (OR 4.81, 95% CI 3.14–7.37, P < 0.00001). Poorly differentiated tumours had a higher risk of LN metastasis compared with well or moderately differentiated tumours (OR 5.60, 95% CI 2.90–10.82, P < 0.00001). Tumour budding was found to be significantly associated with LN metastasis (OR 7.74, 95% CI 4.47–13.39, P < 0.001). Conclusion: Meta‐analysis of the current literature demonstrates that in early colorectal cancer a depth of submucosal invasion by the primary tumour of > 1 mm, lymphovascular invasion, poor differentiation and tumour budding are significantly associated with LN metastasis.