Cancer cells are our own body cells, which due to some reasons, gets out of control and start dividing at very fast rate, conventional chemotherapy drugs acts on these fast dividing cells. Various chemotherapy drugs are used in different combinations to fight cancer.
Apart from these routine chemotherapy drugs, there are lot of newer modalities of treatment, which works differently from chemotherapy drugs. These are Targeted Drugs and Monoclonal Antibodies, and these drugs works specifically against particular targets and mutations in cancers.