380. UTILITY OF PET/CT FOR LYMPH NODE METASTASIS DETECTION IN PT1 EARLY ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Nodal staging for early esophageal squamous cell carcinoma (ESCC) was mandatory to decide therapy strategy. Utility of preoperative Positron Emission Tomography/Computed Tomography (PET/CT) for lymph node metastasis (LNM) detection in early ESCC was evaluated in the study. 186 consecutive patients with pathologically confirmed T1 tumors undergoing preoperative PET/CT at Zhongshan Hospital between 2015 August to 2020 December were retrospectively enrolled. Clinical characteristics and PET/CT results were collected and compared between patients with or without LNM. A PET integrated risk score model for prediction of LNM was established and validated. Survivals were compared between high risk group and low risk group by Log Rank test. 40 out of 186 patients were diagnosed with LNM on PET-CT. PET/CT alone for LNM detection was with a 53.3% sensitivity, 84.65% specificity, and 90.4% negative predictive value. Tumor size >2.5 cm (P = 0.015), tumor depth (P = 0.012), LVI (P < 0.001), differentiation (P = 0.066) and PET LN (+) (P < 0.001) were included in the prediction model for LNM. The AUC of ROC in derivation cohort and validation cohort was 0.860 and 0.846 respectively. High risk group scoring >3 points showed poorer 5-year recurrence free survival (62.6% VS. 74.7%, P = 0.046) and similar overall survival (87.6% VS. 86.9%, P = 0.942) as compared to low risk group. PET/CT for LNM detection in early ESCC was of 53.3% sensitivity and 84.65% specificity. PET integrated risk score model for LNM was of fair property with 0.860 AUC and was predictive of recurrence.