What is chemotherapy?
Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy is a systemic treatment, meaning it circulates throughout the entire body, killing cancer cells that are circulating in the body, those at the primary site and those that may have spread to other locations (metastasis).
Goals of chemotherapy
Adjuvant treatment: Chemotherapy is used to destroy cancer cells that may have been left behind after surgery or radiation therapy.
Curative Treatment: Chemotherapy is used to successfully treat the cancer and keep it from recurring (returning).
Neoadjuvant treatment: Chemotherapy is used to shrink a larger tumor before surgery or radiation therapy.
Palliative Treatment: Chemotherapy is used to control the disease and prevent it from spreading, to decrease the size of the tumor and reduce the symptoms caused by the cancer.
Radiosensitization: Chemotherapy is used in combination with radiotherapy to enhance the effects of radiotherapy.
How a patient receives chemotherapy?
Chemotherapy is given in different ways. The drugs may be swallowed, injected into a vein or infused into a certain area of the body. This depends on the patient’s cancer type, the physical location of the cancer, and the properties of the drug.
A patient may receive chemotherapy as an inpatient or outpatient of a hospital, in a doctor’s office, or at home/work depending upon how the drugs are administered (given).
Newer Systemic /Targeted Therapies
There are four main types of systemic therapy other than conventional chemotherapy:
- Hormonal therapy: Hormones or hormone-like drugs block the effect of the body’s natural hormones. This therapy can control or reverse growth of breast, prostate, and uterine cancers. Examples include the anti-estrogen tamoxifen (Nolvadex); aromatase inhibitors letrozole (Femara), anastrozole (Arimidex), exemestane (Aromasin); progestin megestrol acetate (Megace); and the anti-androgen flutamide.
- Targeted therapy: Cancer researchers have developed new drugs that specifically recognize unique characteristics of cancer cells, such as proteins that allow cancer cells to grow and spread. Examples include imatinib (Gleevec), trastuzumab (Herceptin), rituximab (Rituxan), erlotinib (Tarceva), bevacizumab (Avastin), cetuximab (Erbitux), and sorafenib (Nexavar).
- Immunotherapy: Immunotherapy (also called biologic therapy) stimulates or mimics the immune system to fight cancer. Currently available immunotherapies include interferon, a protein that helps strengthen the immune system; interleukin-2 (IL-2) and cancer vaccines, which aim to stimulate the body’s own defenses to destroy cancer cells.
- Anti-angiogenesis agents: Rather than targeting the cancer cells directly, anti-angiogenic agents prevent new blood vessels from providing nutrients to cancer cells, essentially starving the tumor. Bevacizumab (Avastin) is an example of this type of treatment and is currently used to treat advanced colorectal, lung and breast cancer