Surgery to remove the cancer is the most common treatment for colorectal cancer. The type of surgery that a doctor performs depends mainly on where the cancer is found. Chemotherapy is the use of anticancer drugs to kill cancer cells. The anticancer drugs circulate in the bloodstream and affect cancer cells throughout the body. Radiation therapy , also called radiotherapy, involves the use of high-energy x rays to kill cancer cells.
Radiation therapy affects the cancer cells only in the treated area.
Biological therapy , also called immunotherapy , uses the body's immune system , either directly or indirectly, to fight cancer. The immune system recognizes cancer cells in the body and works to eliminate them. Biological therapies are designed to repair, stimulate, or enhance the immune system's natural anticancer function. Clinical trials to evaluate new ways to treat cancer are an appropriate treatment option for many patients with this disease. Through research, doctors learn new ways to treat cancer that may be more effective than the standard therapy .