ABSTRACT
Cancer chemotherapy is the treatment of malignant disease with drugs rather than radiation or surgical removal. Systemic therapy can be used alone or, more commonly, in combination with surgery or radiotherapy as an adjuvant to enhance local control and to attack potential sites of metastases. Cancer chemotherapy agents act upon cell division, interfering with normal cell replication. They can be broadly classified as follows: drugs acting on the structure of DNA; drugs acting on mitosis; signal transduction inhibitors, drugs inducing apoptosis; and drugs targeting tumour vasculature. Because of their mode of action, certain drugs require cells to be in specific phases of the cell cycle to have any effect. For example, those acting on the synthesis of DNA will act only on cells actively synthesizing at the time they are exposed to the drug. Cytotoxic drugs can be given as single agents but are more usually given as multiple drug combinations.
