Stereotactic Radiotherapy (SRT) Liver (COLD 1)

Inclusion Criteria: * Primary hepatobiliary confirmed pathologically or via imaging * Liver metastases from colorectal cancer or other solid malignancy, confirmed pathologically * New radiographic liver lesions most consistent with metastases, in a patient with previously pathologically proven solid malignancy and a previously negative liver contrast CT or MRI * The tumor must be unresectable or the patient must be medically inoperable or extra-hepatic metastases must be present * Karnofsky performance status (KPS) \> 60 * Age \> 18 years * Patients must have recovered from the effects of previous surgery, radiotherapy or chemotherapy * Chemotherapy must be completed at least 2 weeks prior to radiation therapy or not planned to be administered for at least 2 weeks * Adequate organ function as assessed as follows:Hemoglobin \> 90 g/L, Absolute neutrophil count \> 1.5 bil/L, Platelets \> 80,000 bil/L, Bilirubin \< 3.0 times upper range of normal, INR \< 1.3 or correctable with vitamin K, AST or ALT \< 6.0 times upper range of normal, Creatinine \< 200 umol/L (other than patients who are having dialysis or already have dialysis lines in place for future dialysis for renal failure. These patients may be treated on study with no upper limit on their creatinine.) * Child A liver score * Previous liver resection or ablative therapy is permitted. * Life expectancy \> 3 months * Multiple metastases are permitted (volume of uninvolved must be at least 800 cc, and the maximal effective liver volume that may be treated is 80%. * Informed consent form Exclusion Criteria: * Patients with active hepatitis or clinically significant liver failure * Prior radiation therapy to the right upper abdomen, precluding re-irradiation of the liver. (Prior pelvic radiation is permitted, as long as no overlap between pelvic and liver radiation fields occurs.) * Prior uncontrolled, life threatening malignancy within the past year. * Gross (clinically apparent) ascites. * Pregnancy is not permitted, and in women of child bearing age, a pregnancy test and birth control are warranted.