tailieunhanh - Chapter 081. Principles of Cancer Treatment (Part 16)

The taxanes include paclitaxel and docetaxel. These agents differ from the vinca alkaloids in that the taxanes stabilize microtubules against depolymerization. The "stabilized" microtubules function abnormally and are not able to undergo the normal dynamic changes of microtubule structure and function necessary for cell cycle completion. Taxanes are among the most broadly active antineoplastic agents for use in solid tumors, with evidence of activity in ovarian cancer, breast cancer, Kaposi's sarcoma, and lung tumors. They are administered intravenously, and paclitaxel requires use of a Cremophor-containing vehicle that can cause hypersensitivity reactions. Premedication with dexamethasone (20 mg orally or intravenously. | Chapter 081. Principles of Cancer Treatment Part 16 The taxanes include paclitaxel and docetaxel. These agents differ from the vinca alkaloids in that the taxanes stabilize microtubules against depolymerization. The stabilized microtubules function abnormally and are not able to undergo the normal dynamic changes of microtubule structure and function necessary for cell cycle completion. Taxanes are among the most broadly active antineoplastic agents for use in solid tumors with evidence of activity in ovarian cancer breast cancer Kaposi s sarcoma and lung tumors. They are administered intravenously and paclitaxel requires use of a Cremophor-containing vehicle that can cause hypersensitivity reactions. Premedication with dexamethasone 20 mg orally or intravenously 12 and 6 h before treatment and diphenhydramine 50 mg and cimetidine 300 mg both 30 min before treatment decreases but does not eliminate the risk of hypersensitivity reactions to the paclitaxel vehicle. Docetaxel uses a polysorbate 80 formulation which can cause fluid retention in addition to hypersensitivity reactions and dexamethasone premedication with or without antihistamines is frequently used. A protein-bound formulation of paclitaxel called nab-paclitaxel has at least equivalent antineoplastic activity and decreased risk of hypersensitivity reactions. Paclitaxel may also cause hypersensitivity reactions myelosuppression neurotoxicity in the form of glove-and-stocking numbness and paresthesia. Cardiac rhythm disturbances were observed in phase I and II trials most commonly asymptomatic bradycardia but also much more rarely varying degrees of heart block. These have not emerged as clinically significant in the majority of patients. Docetaxel causes comparable degrees of myelosuppression and neuropathy. Hypersensitivity reactions including bronchospasm dyspnea and hypotension are less frequent but occur to some degree in up to 25 of patients. Fluid retention appears to result from a vascular leak .