Radiotherapy, mechanisms

Modem cancer therapy has been primarily dependent upon surgery, radiotherapy, chemotherapy, and hormonal therapy (72) (see Chemotherapeutics,anticancer Hormones Radiopharmaceuticals). Chemotherapeutic agents maybe able to retard the rate of growth, but are unable to eradicate the entire population of neoplastic cells without significant destmction of normal host tissue. This serious side effect limits general use. More recentiy, the immunotherapeutic approach to cancer has involved modification and exploitation of the cellular and molecular mechanisms in host defense, regulation of tissue proliferation, tissue differentiation, and tissue survival. The results have been more than encouraging. 

Liu S (2005) 6-Hydrazinonicotinamide Derivatives as Bifunctional Coupling Agents for "mTc-Labeling of Small Biomolecules. 252 117-153 Liu S, Robinson SP, Edwards DS (2005) Radiolabeled Integrin avp Antagonists as Radio-pharmaceuticals for Tumor Radiotherapy. 252 193-216 Liu XY (2005) Gelation with Small Molecules from Formation Mechanism to Nanostructure Architecture. 256 1-37... 

In this chapter we have summarised the mechanisms through which ionizing radiation kills cancer and normal cells and the strategies useful to increase the curative potential of photon energy. If we consider clinical efficacy and the incidence of side effects visible at the inception of radiotherapy, we are aware of the improvements acquired through the... 

Ward, J.F., 1986, Mechanisms of DNA repair and their potential modification for radiotherapy, Int.J.Radiat.Oncol.Biol.Phys. 12 1027-1032. 

These reactions belong to the most thoroughly studied ones in the field of radical- molecule reactions in aqueous solution. The interest in this area is to a large part due to its relevance to the understanding of the mechanism of action of nitroaromatics as sensitizers in the radiotherapy of cancer [12]. 

Fowler JF. Rapid repopulation in radiotherapy a debate on mechanism. The phantom of tumor treatment—continually rapid proliferation unmasked. Radiother Oncol 1991 22(3) 156-158. 

Steel GG, Peckham MJ. Exploitable mechanisms in combined radiotherapy-chemotherapy the concept of additivity. Int JRadiat Oncol Biol Phys 1979 Jan 5(1) 85—91. 

Additionally, MMPIs are not expected to replace currently used, proven-effective modalities of cancer treatment such as radiotherapy, hormonal/chemotherapy, or surgery. It is predicted that they will be clinically developed for use in combination with these agents. As expected, given nonoverlapping toxicities and differing mechanisms of action, MMPIs have been combined preclinically with radiation therapy (4), cytotoxic (5-9), resultant additive or supraadditive efficacy. With these data in mind, the ability to combine an MMPI with radiation therapy, chemotherapy, and hormonal therapy may become an important feature in the ultimate clinical success of these agents. 

It is newer compound. Mechanism of action is similar to ondansetron but can cause elevation of liver enzyme level e.g. SCOT, SGPT etc. It is mainly used in the management of nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy. 

The oxidation of DNA radicals by hypoxic sensitizers, normally nitro compounds, has found considerable interest in the context of attempts to improve irradiation regimes in the radiotherapy of solid tumors (Chap. 12.11). Concomitantly, model studies have been undertaken in order to shed some light on potential mechanism of their reactions. p-Nitroacetophenone (PNAP) has often been used as a convenient model sensitizer. 

Habib MJ, Asker AF. Photostabilization of doxorubicin hydrochloride with radioprotective and photoprotective agents potential mechanism for enhancing chemotherapy during radiotherapy. J Parenter Sci Technol 1989 43 259-261. 

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