Each drug works by different mechanisms, so that some are able to ‘poison’ directly to malignant cells by damaging their DNA, while others trigger an immune system response so that it is capable of recognizing them as ‘foreign elements’ and order his implementation. In other cases, the activity or rest of the unhealthy cells depends on their reaction to the hormones produced by the human body naturally. In this case, the drug is intended to offset the effects of hormones of the patient.
The agents used in cancer therapies can be divided into several categories according to how they work and how they affect the malignant cells. Knowing what time of the cell cycle they act and what particular activity block to stop the propagation of the disease, scientists can decide which drugs work best on each type of tumor, whether to combine several of them to achieve greater efficiency, if you can used in conjunction with another type of medication and even when to use to achieve the desired effect.
* Alkylating agents (cisplatin, carboplatin, chlorambucil, busulfan …): they act directly on DNA to prevent diseased cells continue playing. They are effective in the treatment of chronic leukemias, non-Hodgkin lymphomas as well as those with Hodgkin’s disease, multiple myeloma and certain tumors of lung, breast and ovary.
* Nitrosureas (carmustine or lomustine, for example): this second group of drugs acts similarly to alkylating agents, hindering the activity of enzymes responsible for DNA repair. Are generally used in treating brain tumors or malignant melanomas.
* Antimetabolites: These are agents that combine with cellular DNA to alter the stuctured of cells die so that these can no longer be reproducing normally. This type of drugs, among which include, for example, 5-fluorouracil or metroxato is administered to patients suffering from breast, ovary or gastrointestinal tract and also to patients with chronic leukemia.
* Antitumor Antibiotics (doxorubicin, mitoxantrone, etc.) do not function as antibiotics used in the case of infections, but its mechanism of action by altering the membrane around the cells and block the process by which cells multiply.
* Mitotic Inhibitors: from paclitaxel to docetaxel, the substances derived from natural products and are able to stop the process of cell reproduction and the action of the enzymes responsible for cell reproduction.
* Immunotherapy: this group includes all those drugs capable of stimulating the patient’s own immune system so that it is able to recognize and fight the diseased cells. Some experts consider them a different form of treatment outside of chemotherapy. The first evidence of ‘Immunotherapy’ dates from the early century, when William Cloey, a New York surgeon assessed spontaneous regression of sarcoma among those patients who had previously suffered a bacterial infection.