Limitations of positron emission tomography in predicting histopathologic response or prognosis following neoadjuvant chemoradiation for esophageal cancer

Abstract

4529 Background: Neoadjuvant chemoradiation is frequently applied to improve the prognosis of patients with advanced esophageal cancer. However, only a major histopathological response will provide a survival benefit. Recent studies suggest that [18F]-fluorodeoxyglucose-positron emission tomography during neoadjuvant chemotherapy significantly correlates with histopathological response and survival in patients with resected esophageal adenocarcinoma. Aim of this study was to evaluate the predictive and prognostic potential of FDG-PET in the multimodality treatment of patients with esophageal cancer. Methods: Study patients were recruited from a prospective clinical observation trial on neoadjuvant chemoradiation for esophageal cancer between 1997 and 2006. 133 patients with advanced esophageal cancer (uT2–4, Nx, M0) were included. All patients received neoadjuvant chemoradiation (cisplatin, 5-FU, 36 Gy) and underwent transthoracic en bloc esophagectomy. Histomorphologic regression was defined as major histopathological response when resected specimens contained less than 10 % vital residual tumor cells (major response: 52 patients; minor response: 81 patients). FDG-PET was performed before and 3–4 weeks after the end of chemoradiation with assessment of the intratumoral FDG-uptake [pre-treatment standardized uptake value (SUV1); post-treatment SUV(SUV2); percentage change (SUVΔ%)]. These variables were correlated with histopathological response and survival. Results: Neoadjuvant chemoradiation led to a significant reduction of intratumoral FDG-uptake (p<0.0001). No significant correlations between SUV1 or SUV2 and histopathological response or prognosis were found. Also, the SUVΔ% did not show any impact: SUVΔ% major response: SUVΔ% minor response=69%/57%. A SUV threshold with predictive or prognostic value was not identified. Histomorphological tumor regression was confirmed as an important prognostic factor (p<0.05). Conclusions: Our study does not support recent reports that the metabolic response by FDG-PET is associated with histomorphological response or survival in patients with esophageal cancer following neoadjuvant therapy and esophagectomy. No significant financial relationships to disclose.