Exploration of a new intrapapillary capillary loop classification in diagnosis of superficial esophageal squamous cell carcinoma staging: a meta-analysis and single-center study

Background and study aims Though intrapapillary capillary loops (IPCL) can be used to diagnose the staging of superficial esophageal squamous cell carcinoma (SESCC), the accuracy still remains controversial. Moreover, which IPCL classification is more suitable for clinical application is unclear. The aim was to evaluate the diagnostic performance of different IPCL classifications and to explore a new classification. Patients and methods A meta-analysis was conducted to compare the diagnostic efficiency of the three IPCL classifications for SESCC staging. STATA 12.0 software was used and bivariate mixed effects-model was applied for the meta-analysis. A new classification was developed based on the meta-analysis result. Then a single-center study was conducted for further validation analysis. Results Of the 2310 citations, 14 studies fulfilled our criteria. For epithelium (EP) and lamina propria mucosa (LPM) staging tumors, IPCL showed high diagnostic accuracy (Inoue: 87.17%, Arima: 98.71%, JES: 86.70%). For muscularis mucosa (MM) and submucosa (SM1), 23.12% were underestimated and the Japan Esophageal Society classification (JES) was better than Inoue (Accuracy: 75.48% VS 58.67%, P < 0.05). For >= SM2, 38.86% were underdiagnosed and the diagnostic accuracy of Arima classification was significantly higher than the other two (P < 0.05). Our study showed that the new criteria had higher diagnostic sensitivity than the widely used classification (JES) for differentiating >= SM2 staging cancer from EP-SM1 (0.77 VS 0.50, P < 0.05). Conclusions IPCL was valuable for diagnosing SESCC staging. However, >= MM would be underestimated easily. Our study revealed that the diagnostic sensitivity for >= SM2 staging tumors was significantly improved by the new standard.