Sodium Selenite and Radiation Therapy in Treating Patients With Metastatic Cancer

Primary Objectives: * To determine the maximum tolerated dose (MTD) of sodium selenite when given in combination with palliative radiation therapy * To assess the safety and tolerability of the combination of sodium selenite and palliative radiation therapy in metastatic cancer Secondary Objectives: * To assess the pharmacokinetics of sodium selenite * To evaluate the anti tumor activity of sodium selenite and palliative radiation therapy when given in combination OUTLINE: Patients receive sodium selenite orally (PO) 2 hours before daily radiation therapy treatments. Treatment continues for the duration of the course of radiation therapy in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 2 months.