This phase I trial studies the side effects and best dose of 3-dimensional conformal radiation therapy (CRT) or intensity-modulated radiation therapy (IMRT) in treating patients with recurrent tumors. Radiation therapy (RT) uses high energy x rays to kill tumor cells. Palliative radiation therapy may help patients with recurrent tumors live more comfortably.

PRIMARY OBJECTIVES:

I. To determine the maximum tolerated dose (MTD) of reirradiation with the pulsed low dose rate technique.

SECONDARY OBJECTIVES:

I. To investigate the dosimetric tolerance of normal structures to reirradiation with the pulsed low dose rate technique.

II. To determine the palliative efficacy and quality of life in patients treated on this protocol.

III. To determine duration of response and time to progression.

OUTLINE: This is a dose-escalation study.

Patients undergo 3-dimensional CRT or IMRT once daily (QD), 5 days a week for 10-30 days. Treatment continues in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up every month for 6 months and then every 12 weeks thereafter.

Inclusion Criteria:

• Patients must have histologically-confirmed malignancy
• Patients must have recurrent or metastatic tumor located within a previously irradiated field
• Tumor within the irradiated field is negatively impacting patient's quality of life or threatening catastrophic complication if left untreated as determined by the treating physician
• Patient is not a candidate for, or has not demonstrated a significant local response to chemotherapy, biologic, hormonal ,or other therapies
• Patient is not a surgical candidate or tumor is not surgically resectable, as documented by surgical oncologist
• Information on previous radiation treatment, including total dose and fractionation must be available; additional information including radiation fields and dose-volume-histogram or isodose lines is preferable
• Tumor sites eligible for inclusion on this protocol include thorax, abdomen, and pelvis
• Patients must have measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 in the previously irradiated field
• Women of childbearing potential must be non-pregnant (negative pregnancy test within 72 hours prior to radiation simulation, postmenopausal woman must have been amenorrheic for at least 12 months to be considered of non-childbearing potential) and nonlactating, and men and women must be willing to exercise an effective form of birth control (abstinence/contraception) while on study and for 3 months after therapy completed
• Eastern Cooperative Oncology Group (ECOG) performance status determined to be between 0 and 3
• Absolute neutrophil count (ANC) >= 1,500/ul
• Platelets (PLT) >= 75,000/ul
• Subjects must sign a written informed consent and Health Insurance Portability and Accountability Act (HIPAA) consent prior to performance of study-specific procedures or assessments and must be willing to comply with treatment and follow-up

Exclusion Criteria:

• Patients who have had chemotherapy or radiotherapy to the reirradiation target within 4 weeks prior to entering the study
• Concurrent chemotherapy or biologic therapy
• A history of ataxia telangiectasia or other documented history of radiation hypersensitivity
• Scleroderma or active connective tissue disease
• For abdominal or pelvic irradiation: active inflammatory bowel disease
• Serious, active infections requiring treatment with intravenous (IV) antibiotics
• Uncontrolled intercurrent illness including, but not limited to, or psychiatric illness/social situations that would limit compliance with study requirements
• Reirradiation targets located within the head, neck, or brain are excluded from this study