Cancer drugs are most effective when given in combination. The rationale for combination therapy is to use drugs that work by different mechanisms, thereby decreasing the likelihood that resistant cancer cells will develop. When drugs with different effects are combined, each drug can be used at its optimal dose, without intolerable side effects. (See also Cancer Treatment Principles Cancer Treatment Principles Treating cancer is one of the most complex aspects of medical care. It involves a team that encompasses many types of doctors working together (for example, primary care doctors, gynecologists... read more .)
For some cancers, the best approach is a combination of cancer surgery Surgery for Cancer Surgery is a traditional form of cancer treatment. It is the most effective in eliminating most types of cancer before it has spread to lymph nodes or distant sites (metastasized). Surgery may... read more , radiation therapy Radiation Therapy for Cancer Radiation is a form of intense energy generated by a radioactive substance, such as cobalt, or by specialized equipment, such as an atomic particle (linear) accelerator. Radiation preferentially... read more , and chemotherapy Chemotherapy and Other Systemic Cancer Treatments Systemic treatments are those that have effects throughout the body rather than being applied directly to the cancer. Chemotherapy is a form of systemic treatment that uses drugs to kill cancer... read more or other cancer drugs. Surgery or radiation therapy treats cancer that is confined locally, while cancer drugs also kill the cancer cells that have spread to distant sites. Sometimes radiation therapy or drug therapy is given before surgery to shrink a tumor, thereby improving the opportunity for complete surgical removal (this technique is called neoadjuvant therapy). Radiation therapy and/or drug therapy given after surgery (called adjuvant therapy) help to destroy any remaining cancer cells.
The stage and type of the cancer often determines whether single therapy or combination therapy is needed. For example, early-stage breast cancer may be treated with surgery alone or surgery combined with radiation therapy, drug therapy, or with all three treatments, depending on the size of the tumor and the risk of recurrence. Locally advanced breast cancer is usually treated with chemotherapy Chemotherapy and Other Systemic Cancer Treatments Systemic treatments are those that have effects throughout the body rather than being applied directly to the cancer. Chemotherapy is a form of systemic treatment that uses drugs to kill cancer... read more , radiation therapy Radiation Therapy for Cancer Radiation is a form of intense energy generated by a radioactive substance, such as cobalt, or by specialized equipment, such as an atomic particle (linear) accelerator. Radiation preferentially... read more , and surgery Surgery for Cancer Surgery is a traditional form of cancer treatment. It is the most effective in eliminating most types of cancer before it has spread to lymph nodes or distant sites (metastasized). Surgery may... read more .
Sometimes combination drug therapy is used not to cure but to reduce symptoms and prolong life. Combination drug therapy can be useful for people with advanced cancers that are not suitable for radiation therapy or surgical treatment (for example, people with non–small cell lung cancer, esophageal cancer, or bladder cancer that cannot be completely removed by surgery).
