The proposed study will evaluate if "curative intent" SBRT can provide high response rates and clinically meaningful cancer control with acceptable toxicity specifically in patient with metastatic colorectal cancer (mCRC) who do not have surgical options and are no longer responding to systemic therapy

SBRT for Oligo-metastatic Colorectal cancer

Inclusion Criteria:

• Pathologically confirmed Colo-rectal Cancer
• 1-3 Liver metastasis measurable on Computed Tomography (CT) or Magnetic Resonance Imaging (MRI)
• Surgically resected primary disease
• Technically/medically inoperable or patient declined surgery
• Progression or Stability after at least 1 Line of chemotherapy
• Adequate marrow function: Hb > 80g/L, Platelets > 100 x 109/L, White blood cell > 2 x 109/L
• Eastern Cooperative Oncology Group (ECOG) status 0-2
• Age > 18 years
• Patient must sign study specific informed consent prior to study entry

Exclusion Criteria:

• Prior liver radiation, or radiation in close proximity to planned treatment sites
• Prior invasive malignancy
• Severe, active co-morbidity
• Active hepatitis or Child Pugh Score B (9) or worse
• Pregnant or nursing women
• Extra hepatic disease: Any Bone/Any Brain, 2 or more Lung metastasis
• Life expectancy < 6 mo from any cause
• Concurrent chemotherapy
• Response to prior chemotherapy with minimal measurable disease in liver