Chemotherapy uses drugs to kill cancer cells or inhibit their growth. It can be used at different stages of colon cancer treatment. Adjuvant chemotherapy may be given after surgery to eliminate any remaining cancer cells and reduce the risk of recurrence. Neoadjuvant chemotherapy may be used before surgery to shrink tumors and make them more manageable. In advanced or metastatic cases, chemotherapy is used to control the disease and improve quality of life.