Chemotherapy, principle

Biology Complicates the Delivery of Radiation Biology Also Complicates the Delivery of Chemotherapy Principles Guiding the Integration of Chemoradiation Ideal Radiosensitizer ... 

Grem JL. Fluorinated pyrimidines. In Chabner BA, Collins JM, editors. Cancer Chemotherapy Principles and Practice. Philadelphia Lippincoft, 1990 180-225. 

Swain. S.M. a/. (1990) Endocrine therapies of carKer. in Cancer Chemotherapy Principles and Practice. Chabner. BA. et a/.. Lippincott, Philadelphia. 

Cancer treatment is a multimodality treatment, i.e., surgery is combined with radiotherapy and antineoplastic chemotherapy. The latter treatment mode is used mainly for cancers which have disseminated. Different forms of cancer differ in their sensitivity to chemotherapy with antineoplastic agents. The most responsive include lymphomas, leukemias, choriocarcinoma and testicular carcinoma, while solid tumors such as colorectal, pancreatic and squamous cell bronchial carcinomas generally show a poor response. The clinical use of antineoplastic agents is characterized by the following principles. 

Dronabinol (tetrahydrocannabinol), the active principle from cannabis and synthetic cannabinoids, nabilone and levonantradol are effective in treating nausea and vomiting in cancer chemotherapy. The mode of action is unclear but appears to involve cannabinoid CBi receptors. Cannabinoids have been shown to reduce acetylcholine release in the cortex and hippocampus, and have been suggested to inhibit medullary activity by a cortical action. Inhibition of prostaglandin synthesis and release of endorphins may also be involved in the antiemetic effect. A review of trials of dronabinol, nabilone or levonantradol concluded that while the cannabinoids were superior to placebo or dopamine receptor antagonists in controlling emesis... 

The antiviral strategies discussed earlier as well as all antiviral drugs available to date are based on the principles of conventional chemotherapy. However, recent discoveries and developments in molecular biology have opened perspectives for alternative approaches of intervention. 

Edwards PN (1994) Uses of fluorine in chemotherapy. In Organofluorine Chemistry Principles and Commercial Applications (Eds RE Banks, BE Smart, JC Tatlow), pp. 501-541. Plenum Press, New York. 

Another approach to increasing the effectiveness of antiviral therapy is to use combinations of compounds. This principle has been widely exploited in chemotherapy of cancer. 

Doroshaw JH, Cancer Chemotherapy and Biotherapy Principles and Practice, (eds Chabner BA and Longo DL) pp. 409-433. Lippincott-Raven, Philadelphia, PA. 1996. 

Although the delivery of radiation and chemotherapy as sole modalities is definitely more complex than outlined above, there needs to be guiding principles that will allow for their successful integration in combined modality therapy. Peckham and Steele introduced several key concepts that govern the interactions of both radiation and chemotherapy when they are administered together in an attempt to improve the therapeutic effect of their separate administrations (27). 

Cyclicity of administration is vital in the use of 5-FU as a radiosensitizer. The concept of cyclical treatment has been well established in cancer chemotherapy and alien to classical radiation therapy (where it is termed split-course therapy). 5-FU radio-sensitizes tumor tissue as well as normal cells. However, this normal tissue radio-sensitizationis limited to the irradiated field. Suitable fractionation (i.e., cyclical therapy) can permit rapid normal tissue recovery (23). The results of infused 5-FU and radiation in head and neck cancer supports the principle that cyclical treatment with 5-FU does not suffer from the limitations apparent in split-course radiation treatments. 

Three types of potential targets for antiparasitic chemotherapy can be discerned. Firstly, enzymes unique for the parasite could be present. Secondly, enzymes for which alternative pathways exist in the host may be targeted. And thirdly, in principle similar biochemical functions for parasite and host can differ enough to provide, if pharmacologically influenced, some selectivity. Apart from these three types of mechanisms there are antiparasitic agents for which the mechanism has not been identified. 

Baldessarini RJ. Chemotherapy in psychiatry principles and practice. 2nd ed. Cambridge (MA) Harvard University Press 1996. 

The value of combination chemotherapy has been proved in humans. The combined use of two or more drugs often is superior to single-agent treatment in many cancers, and certain principles have been used in designing such treatments ... 

Combination chemotherapy is frequently used and is often superior to single-agent treatment. All of the following principles have been used in designing combinations EXCEPT which of the following ... 

Baldessarini, R.J. Chemotherapy in Psychiatry Principles anil Practice. Harvard University Press, Cambridge, MA, 1985. 

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