The utility of PET-CT after preoperative chemoradiation in predicting treatment outcomes in locally advanced esophageal cancer.

Abstract

182 Background: In the treatment of gastroesophageal junction (GEJ) cancer, trimodality treatment with preoperative chemoradiation followed by surgery is the standard of care. However, predicting patient survival outcomes remains difficult. One possible means of predicting outcomes is comparing pre-treatment PET-CT with post-treatment PET-CT to see if a favorable response on imaging correlates with survival outcomes. Methods: We conducted a retrospective chart review of locally advanced GEJ cancer patients who underwent preoperative chemoradiotherapy followed by esophagectomy with negative margins. All patients underwent two PET-CT scans (before and after preoperative chemoradiation). We compared PET-CT imaging results and pathology results with survival outcomes. Values such as pre-treatment max SUV, post-treatment max SUV, change in max SUV, percent residual max SUV, complete response on PET-CT, and pathologic complete response were analyzed for potential impacts on recurrence rates and survival outcomes. Results: Forty patients had sufficient data to be included in our study. The median follow-up was 22.5 months. The majority of patients were male (82.5%), Caucasian (84.2%) and had adenocarcinoma histology (97.5%). Altogether, 75% of patients had stage III disease and 67.5% had locoregional nodal involvement. The majority (90%) of patients received some form of taxane and platinum based chemotherapy. Pre-treatment max SUV, post-treatment max SUV, change in max SUV, percent residual max SUV, and complete response on PET-CT were not associated with local recurrence, regional recurrence, disease-free survival, or overall survival. Pathologic complete response was associated with a decrease in the rate of distant metastasis ( P= 0.021) but not disease-free survival ( P= 0.411) or overall survival ( P= 0.878). Conclusions: Response on PET-CT after preoperative chemoradiation is not a predictive factor for recurrence, disease-free survival, or overall survival. Pathologic complete response predicted for a decrease in the rate of distant metastasis but not disease-free survival or overall survival.