Proton Beam Therapy to Treat Esophageal Cancer

Inclusion Criteria: * Histologically documented adenocarcinoma or squamous cell carcinoma of the cervical or thoracic esophagus or gastroesophageal junction or cardia of stomach. * Staged by PET/CT and esophagogastroduodenoscopy (EGD) OR CT w/contrast and EGD to have stage II or III disease. Endoscopic ultrasound (EUS) is encouraged but not required. * Prior endoscopic mucosal resection (EMR) with a diagnosis of stage II or III esophageal cancer is eligible, irrespective of margin status. * Induction chemotherapy prior to concurrent chemoradiation is allowed. * Prior thoracic radiation is allowable if degree of overlap with the esophageal radiotherapy treatment is deemed to be safe by the treating radiation oncologist. * At least 18 years of age. * ECOG performance status ≤ 2 (Karnofsky \> 60%) * Normal bone marrow and organ function as defined below: * WBC \> 2,500/mcL * Platelets ≥ 75,000/mcl * Total bilirubin ≤ 1.5 x IULN * AST(SGOT)/ALT(SGPT) ≤ 3.0 x IULN * Creatinine ≤1.5 x IULN OR creatinine clearance ≥ 50 mL/min/1.73 m2 for patients with creatinine levels above institutional normal * Women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control, abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she must inform her treating physician immediately. * Ability to understand and willingness to sign an IRB approved written informed consent document. * English speaker. * Financial coverage for proton therapy. Exclusion Criteria: * Planned treatment with radiation therapy alone without concurrent chemotherapy or chemotherapy alone. * Previous or concomitant cancers within the past 3 years other than curatively treated carcinoma in situ of the cervix, basal cell carcinoma of the skin, curative treatment for transitional cell carcinoma of the bladder, and low risk prostate cancer. Except for prostate cancer (which can be observed if low risk), other cancers listed must have been treated in the past 3 years without evidence of recurrence at the time of registration. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia not controlled by pacer device, myocardial infarction within 3 months of registration, or psychiatric illness/social situations that would limit compliance with study requirements * Pregnant and/or breastfeeding. Patient must have a negative pregnancy test within 7 days of study entry.