FDG-PET in the prediction of pathologic response after neoadjuvant chemoradiotherapy in locally advanced, resectable esophageal cancer

Purpose: To assess the efficacy of 18Fluorodeoxyglucose-positron emission tomography (FDG-PET) for predicting a pathologic response in locally advanced esophageal cancer after neoadjuvant chemoradiotherapy. Methods and Materials: All enrolled patients were treated with neoadjuvant chemoradiotherapy followed by esophagectomy and underwent two FDG-PET scans, before and after neoadjuvant chemoradiotherapy. We compared the results of the preoperative FDG-PET scans with the pathologic results. Results: From July 2001 to July 2004, 32 patients (29 men and 3 women) were enrolled in this study. Pathologic complete response (pCR) in the esophagus was achieved in 21 of 32 patients (66%). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in the primary tumors of the preoperative FDG-PET were 27%, 95%, 75%, and 71%, respectively. In regional lymph nodes, these values were 16%, 98%, 36%, and 93%, respectively. The mean standardized uptake value (SUV) of primary tumors was initially 5.6 ± 3.6 and changed to 1.5 ± 1.3 after neoadjuvant chemoradiotherapy ( p < 0.05). If analysis of metabolic response (SUV decrease, ΔSUV) was limited to initially highly metabolic primary tumors (SUV ≥4.0), pathologic response was correlated with metabolic response ( p = 0.006). Conclusions: This study suggested that the pathologic response of an initially highly metabolic tumor after neoadjuvant chemoradiotherapy could be correlated with the metabolic response, and FDG-PET can provide additional information on tumor response to chemoradiotherapy.