Ability of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography to Predict Outcomes of Neoadjuvant Chemoradiotherapy Followed by Surgical Treatment for Esophageal Squamous Cell Carcinoma.

Abstract

Responses of esophageal cancer to neoadjuvant therapy and patient prognosis are difficult to predict preoperatively. This study aimed to determine the ability of fluorine-18 fluorodeoxyglucose ((18)FDG) positron emission tomography (FDG-PET) to predict outcomes of trimodal therapy on esophageal squamous cell carcinoma (ESCC). The responses of 111 patients with ESCC were monitored using FDG-PET before and after neoadjuvant chemoradiotherapy (nCRT) followed by surgical treatment. Associations between the maximum standardized uptake value (SUVmax) and pathologic responses (PRs) and prognosis were analyzed. Responses were significantly associated with SUVmax after nCRT (post-SUVmax) and with the rate of decreases in the SUVmax (%ΔSUVmax) of the primary tumor. The optimal cutoffs for post-SUVmax and %ΔSUVmax determined from receiver operating characteristic (ROC) curves were 2.7 (area under the curve [AUC], 0.68; 95% confidence interval [CI], 0.58-0.78; p = 0.001) and 75 (AUC, 0.64; 95% CI, 0.54-0.75; p = 0.01) for predicting a pathologic complete response (pCR) and 3.7 (AUC, 0.76; 95% CI, 0.63-0.89; p < 0.001) and 70 (AUC, 0.65; 95% CI, 0.52-0.78; p = 0.02) for predicting a good response according to Japan Esophageal Society response criteria. These values reliably separated patients into groups with and without pCR and with and without a good response. Multivariate analysis showed that %ΔSUVmax (≤70 and >70) was an independent prognostic factor for disease-specific survival (hazard ratio [HR], 0.45; 95% CI, 0.21-0.98; p = 0.04). SUVmax is a valuable preoperative predictor of tumor response and survival among patients who undergo trimodal therapy for ESCC.