Response Evaluation after Neoadjuvant Chemoradiation by Positron Emission Tomography-Computed Tomography for Esophageal Squamous Cell Carcinoma

Purpose Parameters of positron emission tomography-computed tomography (PET-CT) were compared with the results of histopathologic examination in order to determine which can provide an objective indication of response after neoadjuvant chemoradiation for treatment of thoracic esophageal squamous cell carcinoma (SCC). Materials and Methods Between August 2003 and January 2010, data on 25 patients who underwent neoadjuvant chemoradiation and subsequent resection for treatment of esophageal SCC were retrospectively reviewed. Changes in maximum standardized uptake value (Delta SUVmax), metabolic tumor volume (Delta MTV), and total lesion glycolysis (Delta TLG) were analyzed by comparison with the histopathologic findings. Results Pathologic complete remission (CR) for the main tumor was achieved in 11 patients. Postradiation esophagitis was observed in 10 patients. Delta SUVmax of the main tumor was significantly greater in the CR group than in the partial response (PR) group (p=0.039), while Delta MTV and Delta TLG of the main tumor were not (p=0.141 and p=0.349, respectively). The cut-off Delta SUVmax value for CR was estimated as 72.1%, indicating significantly better accuracy than visual interpretation (p=0.045). Of the 48 involved lymph nodes, Delta SUVmax and Delta MTV of lymph nodes were significantly greater in the CR group than in the PR group (p=0.045 and p=0.014, respectively), while Delta TLG was not (p=0.063). The cut-off value of Delta SUVmax for prediction of CR in lymph nodes was calculated as 50.67%. Conclusion PET-CT could be used for prediction of response to neoadjuvant treatment in thoracic esophageal SCC. Delta SUVmax may be a more significant predictor for CR after neoadjuvant chemoradiation than Delta TLG and Delta MTV.