Cancer Therapy comprises treatment of cancers by surgery, chemotherapy, radiation therapy, hormonal therapy, targeted therapy including immunotherapy such as monoclonal antibody therapy and synthetic lethality. The choice of therapy depends upon the location and grade of the tumor and the stage of the disease, as well as the general state of the patient. A number of experimental cancer treatments are also under development. Complete removal of the cancer without damage to the rest of the body that is, achieving cure with near-zero adverse effects is the ideal goal of treatment and is often the goal in practice. Sometimes this can be accomplished by surgery, but the propensity of cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effectiveness and chemotherapy and radiotherapy can have a negative effect on normal cells.