Prediction of response to definitive chemoradiotherapy in esophageal cancer using positron emission tomography.

BACKGROUND: Positron emission tomography (PET) with 18-F-fluorodeoxyglucose (FDG) has already proven useful in assessing the extension of esophageal carcinomas, detecting tumor recurrence and monitoring responses to therapy. The current study aims to assess the potential role of FDG-PET in predicting the response of esophageal squamous cell carcinoma (SCC) to definitive chemoradiotherapy (CRT).

PATIENTS AND METHODS: Twenty-seven patients with thoracic esophageal SCC who received definitive CRT between January 2001 and December 2005 underwent PET before and after CRT. The clinical evaluation of the primary tumor response to treatment was classified as either complete response (CR) or non-CR.

RESULTS: All patients had intensive FDG uptake in the primary tumor prior to CRT. The standardized uptake value (SUV) averaged 8.2+/-4.7 before CRT and decreased significantly to 2.8+/-1.8 after CRT (p<0.0001). The SUV before CRT averaged 10.2 in the non-CR group (n=17) and 4.9 in the CR group (n= 10). The SUV after CRT averaged 3.7 in the non-CR group and 1.4 in the CR group. The change in SUV for the CR group was higher than that in the non-CR group (p<0.05). The relationship between clinical features and clinical CR was analyzed using logistic regression analysis which revealed significant correlations between clinical CR and the longitudinal dimension of the tumor (p <0.05), SUV before CRT (p<0.05), SUV after CRT (p<0.01) and tumor classification (p <0.05). If the clinical features before CRT were limited, multivariate analysis revealed that the SUV before CRT was an independent predictor for clinical CR (p<0.05).

CONCLUSION: In predicting clinical evaluation of therapy prior to CRT, we suggest that SUV prior to definitive CRT is one of the most reliable predictors of response, along with tumor dimensions and classification.