Colon cancers without lymphatic spread (Duke stage A and B) are often treated with surgery along. Chemotherapy is shown to improve survival for colon ca with positive lymph nodes but no distance metastasis (Duke stage C). Management for distance metastases (Duke stage D) is palliative, which may still include surgery for local control, and radiation/chemo. Radiation therapy is often used for Duke’s B and C rectal cancer. It is also used in palliative care for colon cases with distance metastases. I don't think it is widely used for treating primary colon cancer that's further proximal.