Biomarkers in Phototherapy of Barrett's Esophagus

Inclusion Criteria: * All patients will have biopsy proven Barrett's esophagus with evidence of specialized intestinal epithelium and dysplasia (either high grade dysplasia or low grade dysplasia) on histology. * Patients must have endoscopically visible segments of Barrett's esophagus of greater than 1 centimeter in length. * All patients must be eligible for longterm follow-up as well as tolerate endoscopy, biopsy, and cytology. * Patients must be willing to travel to Rochester, Minnesota for follow-up * Patients must have a friend or relative accompany them on visits since sedatives will render them unable to operate a motor vehicle * If patients are on anticoagulation, they must be able to tolerate reversal of anticoagulation for study biopsies and therapy * All patients must be able to tolerate proton pump inhibitor therapy. Esomeprazole will be provided but can be changed to another proton pump inhibitor if the patient is intolerant. * All patients who have histological or cytological evidence of high grade dysplasia will be seen by an experienced thoracic surgeon for consideration of esophagectomy. Exclusion Criteria: * Patients who are unable to follow light avoidance instructions * Patients with a history of prior esophageal surgery or successful fundoplication * Patients who had prior photodynamic therapy * Patients with pre-existing strictures in their esophagus * Patients who have known allergies to porphyrin compounds * Patients with a prior biopsies of Barrett's esophagus that contain carcinoma * Patients who require continuous anti-coagulation * Patients who are pregnant or are capable of pregnancy will be excluded from this study unless they have been on effective birth control measures * Lactating mothers are excluded from this study as it is unclear whether the photosensitizer sodium porfimer can cross to the feeding infant * Patients with underlying liver disease are excluded since their metabolism of porphyrin based photosensitizers is uncertain. Evidence of liver disease will be an transaminase elevation of three times normal, a bilirubin increase of twice normal, or an alkaline phosphatase (liver fraction) elevation of twice normal. * Patients who have underlying medical conditions that are felt to limit their survival to less than one year.