A liquid biopsy signature predicts lymph node metastases in T1 oesophageal squamous cell carcinoma: implications for precision treatment strategy

The treatment strategies for T1 oesophageal squamous cell carcinoma (ESCC) patients with or without lymph node metastasis (LNM) are different. Given the advantages of the minimally invasive, sensitive and real-time detection, liquid biopsy has become an important cancer diagnostic and prognostic tool.MiRNA array and small-RNA sequencing were performed. Then, 222 formalin-fixed and paraffin-embedded tumour samples and 229 pretreatment serum samples from T1 ESCC patients were used to verify and evaluate the results.We demonstrated that serum miR-20b-5p could predict LNM in T1 ESCC patients. The AUC for serum miR-20b-5p was higher (0.827) than those for lymphovascular invasion (LVI) (0.751, P = 0.2128), invasion depth (0.662, P = 0.0027) and tumour differentiation grade (0.634, P = 0.0019). A nomogram for predicting LNM with three independent significant predictors (miR-20b-5p, LVI and invasion depth) was constructed with a concordance index of 0.931. Serum miR-20b-5p was also significantly correlated with disease-free survival (P < 0.001). An algorithm of improved T1 ESCC treatment strategy after biopsy and/or after endoscopic resection based on serum miR-20b-5p level was constructed.This study suggests that serum miR-20b-5p is a potential biomarker for predicting LNM and can be helpful for precise clinical decision-making strategies and improve treatment outcomes for T1 ESCC patients.