[Radioprotective effects on head and neck tumors of amifostine--a broad-spectrum cytoprotection].

Differentiated thyroid cancer can be effectively treated with high-dose 131I and the other head and neck cancer can also be effectively treated with extra-radiotherapy, but these treatments often result in a reduction in salivary gland function, causing xerostomia. Collectively, these effects can lead to severe secondary complications, including difficulty in speaking and swallowing, decreasing appetite even affecting nutrition and sleep. Amifostine, an analog of cysteamine, is a phosphorlyated aminothiol prodrug and its active metabolite, WR-1065 etc, can selectively protect normal tissues from the cytotoxic effects of drugs and/or radiation while preserve antitumor effects. Many studies have demonstrated that amifostine protects normal tissues from both acute and late extra-radiation damage without protecting the tumor. It has been approved by FDA to be used for protecting the salivary gland from xerostomia caused by radiotherapy. It has also show protecting effects on intra-radiotherapy, but there are many problems waiting for study.