Abstract
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∆%) 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 % > 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∆% > 67% was predictive of improved OS and DFS. However, SUV∆% 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.
Acknowledgments
The authors thank Mrs. Yvonne Sundström for her skillful technical and secretarial assistance. This study was supported by Helsinki University Central Hospital Research Funds (EVO). We have no conflict of interest to declare.