Conformal Radiation Therapy in Treating Patients With Metastatic Cancer Outside the Brain

DISEASE CHARACTERISTICS: * Pathologically confirmed cancer * No active disease at the primary site as assessed by physical examination, clinical evaluation, or site-specific imaging * Measurable metastatic disease meeting the following criteria: * Four or fewer sites of extracranial lesions \< 5 cm in size * If metastatic site(s) is within the lung, the following criteria must be met: * No more than two metastases in the proximal bronchial tree area (defined as 2 cm from the trachea or mainstem bronchi) * Carbon monoxide diffusing capacity (DLCO) \> 30% predicted and forced expiratory volume 1 (FEV1) \> 1.2 L (in patients with more than one metastatic site in the lungs) * If metastatic site(s) is within 2 cm of either kidney, creatinine level must be \< 1.5 times upper limit of normal (ULN) * If metastatic site(s) is within 2 cm of the liver, bilirubin level must be \< 1.5 times ULN * Patients with metastatic disease that meets any of the following criteria are excluded: * Proposed site(s) of treatment has been previously treated with radiotherapy * Metastatic site(s) requires emergent treatment (e.g., spinal cord compression, cauda equina, airway compromise, or life-threatening end-organ dysfunction) * Disease that is untreated or previously treated and progressive in the brain * Pathologic fracture or impending pathologic fracture at the metastatic site * Metastatic site(s) of a disease histology that is known to be sensitive to low doses of radiotherapy (e.g., pure seminoma, lymphoma, or small cell carcinoma) * Patients in whom surgery is deemed an appropriate option as standard of care (e.g., isolated lung metastasis from sarcoma or isolated liver metastasis from colon cancer) but who refuse surgical therapy are eligible PATIENT CHARACTERISTICS: * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * Life expectancy \> 12 weeks as assessed by the consulting radiation oncologist * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No history of lupus erythematosus or scleroderma * No known hypersensitivity to therapeutic radiotherapy * No other malignancy within the past 2 years except nonmelanoma skin cancer or in situ malignancies of the cervix, bladder, or head and neck * No unrelated systemic illness that, in the judgment of the investigator, would compromise the patient's ability to tolerate study therapy or would likely interfere with study procedures or results * Able or likely to adhere to study treatment PRIOR CONCURRENT THERAPY: * See Disease Characteristics * More than 2 weeks since prior and no concurrent chemotherapy * Prior or concurrent hormonal agents, including antiandrogens, gonadotropin-releasing hormone agonists, aromatase inhibitors, tamoxifen, or similar agents allowed * No change in systemic therapy for 6 weeks before or within 4 weeks after initiating study radiotherapy