430. MAPPING OF LYMPH NODE METASTASIS FROM ESCC AFTER NEOADJUVANT TREATMENT: A PROSPECTIVE ANALYSIS FROM A HIGH-VOLUME INSTITUTION IN CHINA

Abstract

Abstract Objective The aim of the study was to describe the prevalence of lymph node metastases per lymph node station for esophageal squamous cell carcinoma (ESCC) after neoadjuvant treatment. Methods Clinicopathological variables of ESCC patients were retrieved from the prospective database of the Surgical Esophageal Cancer Patient Registry in West China Hospital, Sichuan University. Two-field lymphadenectomy was routinely performed and an extensive three-field lymphadenectomy was performed if cervical lymph nodes metastasis were suspected. Lymph node stations according to AJCC 8 were separately investigated. Percentage of patients with lymph node metastases was defined as number of patients with metastatic lymph nodes/number of patients with lymph node dissection of this station. Data is also separately analyzed according to pathological response of the primary tumor, pretreatment tumor length and tumor location. Results Between January 2019 and March 2023, 623 patients who underwent neoadjuvant therapy followed by transthoracic esophagectomy were enrolled (Table 1–1). Lymph node metastases were found in 215 patients (34.5%) and most frequently seen in lymph nodes along the right recurrent nerve (10.1%, 58/575), paracardial station (11.4%, 67/587) and lymph nodes along the left gastric artery (10.9%, 65/597). For patients with pretreatment tumor length > 4 cm and non-PCR of primary tumor, the metastatic rate of right lower cervical paratracheal lymph nodes is 10.9% (10/92) and 10.6% (11/104), respectively (Table 1–2). For patients with an upper thoracic tumor, metastatic lymph nodes were most frequently seen along the right recurrent nerve (14.2%, 8/56). For patients with a middle thoracic tumor, metastatic lymph nodes were most frequently seen in the right lower cervical paratracheal lymph nodes (10.3%, 8/78), paracardial lymph nodes (10.2%, 29/285) and lymph nodes along the left gastric artery (10.4%, 30/289). For patients with a lower thoracic tumor, metastatic lymph nodes were most frequently seen in paracardial station (14.2%, 35/247) and lymph nodes along the left gastric artery (13.1%, 33/252) (Table 1–3). Conclusion The study accurately identified the distribution of lymph node metastases from ESCC after neoadjuvant treatment, which may contribute to guide the optimal extent of lymphadenectomy in the surgical treatment of ESCC patients after neoadjuvant treatment.