Ropidoxuridine in Treating Patients With Advanced Gastrointestinal Cancer Undergoing Radiation Therapy

Prior treatment

• Patients who have had chemotherapy or radiotherapy within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier
• Patients who are receiving any other investigational agents
• Pregnant women are excluded from this study; breastfeeding should be discontinued if the mother is treated with IPdR

Other illness

• History of allergic reactions attributed to compounds of similar chemical or biologic composition to IPdR
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements

Other

• Patients with known brain metastases should be excluded from this clinical trial

• Patients must have histologically or cytologically confirmed advanced, incurable cancers of the esophagus, liver, stomach, small bowel, pancreas, bile duct, colon or rectum and be eligible to receive chest, abdominal and/or pelvic radiation therapy (RT) for palliation; documentation of this is required in physician note; concomitant systemic therapy is not allowed during administration of palliative RT; palliative RT can be considered for advanced primary tumors or metastatic disease as above
• Patients must not have received systemic chemotherapy for at least 4 weeks, and must not have received prior radiation therapy to the tumor site being irradiated on this study
• Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 (Karnofsky \>= 60%)
• Life expectancy of greater than 12 weeks
• Leukocytes \>= 3,000/mcL
• Absolute neutrophil count \>= 1,500/mcL
• Platelets \>= 100,000/mcL
• Total bilirubin within normal institutional limits
• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 2.5 x institutional upper limit of normal
• Creatinine within normal institutional limits OR creatinine clearance \>= 60 mL/min/1.73 m\^2 for patients with creatinine levels above institutional normal
• Women of child-bearing 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 she or her partner is participating in this study, she should inform her treating physician immediately; men and women treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 4 months after completion of IPdR administration
• Ability to understand and the willingness to sign a written informed consent document
• Human immunodeficiency virus (HIV) positive (+) patients with cluster of differentiation 4 (CD4) counts \>= 250 cells/mm\^3 on anti-viral therapy
• Women of child-bearing potential must have a negative pregnancy test