Abstract 3293: Impact of the invasive depth on lymph node metastasis and survival in Chinese patients with esophageal squamous cell carcinoma

The lymph node metastasis (LNM) has been well recognized as one of the major risk factors affecting the survival of the patients with esophageal squamous cell carcinoma (ESCC). However, it is a dilemma to determine the LNM status before surgery. The invasive depth (T stage) of ESCC could be determined either with computed tomography or ultrasound endoscopy and may reflect the severity of LNM. Thus, the present study was designed to determine the impact of tumor invasive depth on LNM status and survival in ESCC patients with T1-4N0M0. The enrolled 30,514 ESCC patients in this study were from the ESCC database in Henan Key Laboratory for Esophageal Cancer Research of the First Affiliated Hospital, Zhengzhou University. Of the patients, there were 18346 males with an mean age of 59.2±8.9, and 12168 females with an mean age of 59.7±8.7. All the patients had been performed radical esophagectomy without radiotherapy and chemotherapy before surgery, and the invasive depth records were retrieved from the medical records in hospitals after surgical resection. Based on the 6th version of UICC criteria, the invasive depth (T) was classified as Tis, and T1-4. Of the 30,514 ESCC patients, 20,288 cases were successfully followed until the end of 2015. The Logistic regression method were used to determine the correlation between T stage and LNM status. The Kaplan-Meier method was applied to analyze the survival in different groups. The results showed that, of the 30,514 ESCC patients, there were 3324 (10.9%) patients with Tis+T1, 9616 (31.5%) with T2, 17249 (56.5%) with T3 and 325 (1.1%) with T4. Accordingly, from Tis&T1 to T4, the number of the patients with positive LNM were 554 (16.7%), 3392 (35.3%), 7737 (44.9%) and 205 (63.1%), respectively. Logistic regression analysis indicated the risk of LNM was dramatically increased from 2- to 8-folds with the T stages from Tis&T1 to T4, with OR values of 2.725 (T2: 95%CI: 2.465-3.013), 4.067 (T3: 95%CI: 3.695-4.477) and 8.542 (T4: 95%CI: 6.699-10.892), respectively. Interestingly, seventeen percent of the patients with Tis&T1 stages had occurred positive LNM, indicating that LNM may occur in very early stage of ESCC. Kaplan-Meier analysis showed that T staging was obviously associated with the survival in ESCC patients with negative LNM (P value < 0.05). Overall, the present results indicated a strong correlation between invasive depth and LNM status, suggesting that the invasion depth may be one of crucial markers to reflect