Clinical Significance of FDG-PET to Predict Pathologic Tumor Invasion and Lymph Node Metastasis of Superficial Esophageal Squamous Cell Carcinoma.

Abstract

To determine the preoperative ability of [¹⁸F]-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) to predict pathologic tumor invasion and lymph node status in cT1N0M0 esophageal squamous cell carcinoma (ESCC). We retrospectively analyzed 40 consecutive patients diagnosed with cT1N0M0 ESCC between February 2006 and April 2011. All patients were treated by esophagectomy with two- or three-field lymphadenectomy without neoadjuvant therapy. We evaluated the relevance between clinical variables including maximum standardized uptake values (SUV_max) of the primary tumor on FDG-PET and pathologic tumor invasion and lymph node status using a logistic regression model. Tumors invaded the middle submucosal layer (SM2) and beyond in 21 (52.5 %) patients, and 6 (15 %) had lymph node metastases. The areas under receiver operating characteristic (ROC) curves for SUV_max of the primary tumor used to predict factors involved in tumor infiltration to SM2 or deeper and lymph node metastasis were 0.75 (p = 0.006) and 0.79 (p = 0.025), respectively. The optimal SUV_max cutoff was 2.7. The findings of univariate and multivariate analyses identified SUV_max as the only significant preoperative predictor associated with tumor infiltration into SM2 or beyond and lymph node metastasis. Furthermore, SUV_max ≥ 2.7 of the primary tumor on FDG-PET was associated with poor recurrence-free and disease-specific survival (p = 0.019 and p = 0.012, respectively). FDG-PET is helpful for diagnosing tumors that can infiltrate SM2 and beyond as well as occult lymph node metastasis of cT1N0M0 ESCC that are valuable indications in deciding therapeutic strategies for superficial ESCC.