Antineoplastic agents

Cancer refers to a malignant neoplasm or new growth. Cancer cells manifest uncontrolled
proliferation, loss of function due to loss of capacity to differentiate, invasiveness, and the ability
to metastasize.
Cancer arises as a result of genetic changes in the cell, the main genetic changes being;
inactivation of tumor suppressor genes and activation of oncogenes.
There are three approaches for the management of cancer:

1. Radiotherapy
2. Surgery
3. Chemotherapy
   Most anticancer drugs are antiproliferative, and hence affect rapidly growing dividing normal
   cells. Anticancer drugs are broadly classified into two: cytotoxic drugs and hormones.
   Cytotoxic drugs are further classified into:

• Alkylating agents and related compounds (e.g. cyclophosphamide, lomustine, thiotepa,
  cisplatin): These groups of drugs act by forming covalent bonds with DNA and thus
  impending DNA replication.
• Antimetabolites (e.g. methotrexate, fluorouracil, mercaptopurine): These drugs blocks or
  destabilize pathways in DNA synthesis.
• Cytotoxic antibiotics (e.g. Doxorubucin, bleomycin, dactinomycin): These drugs inhibit
  DNA or RNA synthesis or cause fragmentation to DNA chains or interfere with RNA
  polymerase and thus inhibit transcription.
• Plant derivatives (e.g. vincristine): Inhibits mitosis
  Hormones and their antagonists are used in hormone sensitive tumors (eg. glucocorticoids for
  lymphomas, oestrogens for prostatic cancer, tamoxifen for breast tumors).
  General toxic effects of anticancer drugs:
• Bone marrow toxicity.
• Impaired wound healing.
• Sterility.
• Loss of hair.
• Damage to gastrointestinal epithelium.