Chemotherapy drugs destroy cancer cells by focusing on halting the rapid cell division that characterizes these cells. However, scientists have also developed other drug treatments that attempt to destroy cancer cells or control the spread of cancer in other ways. Because these alternative medications do not damage normal cells along with cancer cells, as traditional chemotherapy agents do, patients using them typically notice fewer side effects than with a standard chemotherapy regimen.
Differentiating Agents
Differentiating agents work by causing cancer cells to change, or differentiate, into normal cell types. Subtypes of differentiating agents include retinoids, tretinoin, bexarotene and arsenic trioxide. According to Merck Manuals, they are most useful for preventing the recurrence of cancer and for use in conjunction with traditional chemotherapy drugs, since when used alone their effects are not long-lasting.
Hormone Therapy
Hormone therapy drugs include natural or synthetic hormones, compounds similar to hormones and compounds that increase or decrease the activity of natural hormones in the body. They are most useful for hormone-dependent cancers such as breast cancer, ovarian cancer, cervical cancer, prostate cancer and endometrial cancer. Tamoxifen, prednisone, letrozole and flutamide are examples.
Targeted Therapies
Targeted therapy drugs are small molecules that direct their attack at a particular aspect of tumor cell biology, and are often highly effective against a few very specific types of cancer. For example, the drug trastuzumab targets human epidermal growth factor receptor 2 in some types of breast cancer. Other targeted therapies stimulate some cancers to spontaneously die, modify the proteins of cancer cells or block specific enzymes or growth factors that the cancer cells use, explains the National Cancer Institute.
Antiangiogenesis Drugs
Antiangiogenesis drugs are actually a subclass of targeted therapy that operates by attacking the blood vessels that supply tumors. Because tumors need a reliable blood supply to survive, antiangiogenesis agents can halt growth and strangle the tumor, leading to its death. An example of an antiangiogenesis drug is bevacizumab, which prevents the growth of new blood vessels in lung cancer, breast cancer, renal cancer and colorectal cancer.
Immunotherapy Agents
Immunotherapy is sometimes considered a form of targeted therapy, but immunotherapy agents specifically involve an immune response to cancer. Some immunotherapy drugs work by inducing the body to mount a strong immune response and attack the cancer itself. Others provide antibodies generated externally that assist the immune system in fighting cancer cells. Examples include rituximab, thalidomide and interferon-alpha. Immunotherapy agents may target a specific type or subtype of cancer or they may be broad-spectrum against many cancer types. According to the American Cancer Society, researchers are currently working on vaccines for use as immunotherapy agents, although as of 2009, none had yet been approved by the FDA.
