Since cancer cells divide more rapidly than normal cells, traditional chemotherapy involves treating patients with cytotoxic compounds designed to kill growing cells. The general approach of all chemotherapy is to decrease the growth rate (cell division) of the cancer cell. These medications target various phases of the cell cycle (Fig. 1), resulting in one of the following effects: damaging cellular DNA, inhibiting DNA synthesis, or stopping mitosis (splitting of the original cell into two new cells).

A classification of cancer chemotherapeutic agents is presented in Table 2. Overall, there are more than 50 different chemotherapic drugs. While these medications may be administered alone, often a combination of two, three, or more drugs is used in cancer therapy.

Classification Chemotherapeutic Drugs
Figure 1 Schematic representation of the cell cycle showing phases targeted by various classes of chemotherapeutic agents.
Table 2 Classification of Anti-Cancer Agents





Stop tumor growth by cross-linking guanine

Nitrogen mustards: Cyclophosphamide, chlorambucil


nucleobases in DNA double-helix strands, directly

Nitrosureas: carmustine

attacking DNA

Platinum: cisplatin, carboplatin, oxalplatin

Others: bsulfan, temozolomide


Interfere with the production of nucleic acids

Folic acid: methotrexate

by preventing synthesis of normal nucleoside

Purine: clofarabine, fludarabine, cladribine,

triphosphates, resulting in decreased DNA or

pentostatin, mercaptopurine

RNA synthesis

Pyrimidine: cytarabine, fluorouracil, gemcitabine


Inhibit DNA and RNA synthesis by intercalating

Anthracyclines: doxorubicin, daunorubicin,


between base pairs of the DNA/RNA strand


Others: bleomycin, hydroxyurea

Plant alkaloids

Bind to tubulin, inhibiting microtubule and

Taxanes: docetaxel, paclitaxel

mitotic spindle formation. Cell division is stopped

Yinca: vinblastine, vincristine,


Inhibit enzymes blocks topoisomerase enzymes

Topotecan, irinotecan, etoposide, teniposide


(I, II), which are involved in DNA structure

and cell growth

The majority of drugs currently on the market are not specific, which leads to the many common side effects associated with cancer chemotherapy. Because the common approach of all chemotherapy is to decrease the growth rate (cell division) of the cancer cells, adverse reactions typically involve organs and tissues that have a rapid turnover of cells such as blood cells forming in the bone marrow and cells in the digestive tract, reproductive system, and hair follicles.

Continue reading here: Hormonal Therapy

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