Locally advanced esophageal adenocarcinoma: Response to neoadjuvant chemotherapy and survival predicted by [18F]FDG-PET/CT

Background. ([18F])fluorodeoxyglycose-Positron Emission Tomography/Computer Tomography (([18F])FDG-PET/CT) is commonly used in staging of locally advanced esophageal cancer. Its predictive value for response to neoadjuvant therapy and survival after multimodality therapy is controversial. Methods. Sixty-six consecutive patients with locally advanced adenocarcinoma of the esophagus or esophagogastric junction underwent surgery after neoadjuvant chemotherapy. Staging was done prospectively with ([18F])FDG-PET/CT, before and after completion of neoadjuvant therapy. Pre- and post-therapy maximal standardized uptake values for the primary tumor (SUV1 and SUV2) were determined, and their relative change (SUV Delta%) calculated. Percentage change in SUV1 was compared with histopathologic response (HPR, complete or subtotal histologic remission), disease-free- (DFS) and overall survival (OS). Results. Resection with negative margins was achieved in 60 patients. HPR rate was 14 of 66 (21.2%). Median follow-up was 16 months (range 4-72). For all patients, OS probability at three years was 59% and DFS 50%. In receiver operating characteristics (ROC) analysis, HPR was optimally predicted by a > 67% change in baseline maximal SUV (sensitivity 79% and specificity 75%). In univariate survival analysis (Cox regression proportional hazards), HPR associated with improved DFS (HR 0.208, p = 0.033) but not OS (HR 0.030, p = 0.101), SUV Delta% > 67% associated with improved OS (HR 0.249, p = 0.027) and DFS (HR 0.383, p = 0.040). In a multivariate model (adjusted by age, sex, and ASA score), neither HPR nor SUV Delta% > 67% was predictive of improved OS and DFS. However, SUV Delta% as a continuous variable was an independent predictor of OS (HR 0.966, p < 0.0001) or DFS (HR 0.973, p < 0.0001). Conclusion. Our results support previous results showing that ([18F])FDG-PET/CT can distinguish a group of patients with worse prognosis after neoadjuvant chemotherapy in adenocarcinoma of the esophagus or esophagogastric junction. This information could offer a new independent preoperative marker of prognosis.