Currently, routine testing for esophageal cancer at MD Anderson includes a PET/CT scan at the time of diagnosis and 5 or 6 weeks after chemoradiation is completed. Researchers hope that analyzing changes seen in an "early" PET/CT scan (performed between 10-14 days after starting chemoradiation) compared to the PET/CT scan taken at the time of diagnosis may predict how well the chemoradiation will work against the patient's cancer.