Radiation Therapy in Preventing Liver Metastases in Patients With Uveal Melanoma Who HaveMonosomy 3 or DecisionDx Class 2 Disease and Are More Likely to Develop Liver Metastases

Inclusion Criteria: * Histologically confirmed uveal melanoma * Monosomy 3 status (by fluorescent in situ hybridization \[FISH\] or multiplex ligation-dependent probe amplification \[MLPA\]) or DecisionDx class 2 * Tumor thickness \> 3.0 mm * Has received definitive treatment of uveal melanoma with brachytherapy, proton therapy, stereotactic radiosurgery, or enucleation * Karnofsky performance status (KPS) \>= 70 or Eastern Cooperative Oncology Group (ECOG) * Total bilirubin \< 1.5 mg/dl * Aspartate transaminase (AST) up to two times normal limit * Alanine transaminase (ALT) up to two times normal limit * Creatinine \< 2.0 mg/dl * Functional left kidney based on computed tomography (CT) imaging * Positron emission tomography (PET)/CT demonstrating no evidence of metastatic disease * If a woman is of childbearing potential, a negative serum pregnancy test must be documented; women of childbearing potential must agree to use contraception for the duration of radiation therapy (approximately 3 weeks) * Understands the trial and procedures and is willing and able to sign the Informed Consent Form Exclusion Criteria: * Previous malignancy, other than localized cutaneous squamous cell carcinoma or basal cell carcinoma * History of prior irradiation to the thorax or abdomen * Inadequate hepatic or kidney function (as specified above) * Active peptic ulcer disease * Upper gastrointestinal bleeding * Pregnant women or women that refuse to use contraception throughout the entire stu…