ABSTRACT
This chapter outlines the available knowledge on radiosensitization by arabinosylpurine and arabinosylpyrimidine nucleoside analogs. A variety of experimental studies have demonstrated that arabinosylpurine and arabinosylpyrimidine nucleoside analogs may have radioenhancement potential in the treatment of malignancy. Early in vitro data obtained with cytosine arabinoside (ara-C) and adenine arabino-side (ara-A) demonstrated their effect on the repair of potentially lethal damage, and these radiosensitizing properties have more recently been extended to more newly developed analogs such as fludarabine and gemcitabine. In head and neck squamous cell carcinoma cell lines, the degree of radiosensitization by ara-A appears to be inversely correlated with intrinsic cellular radioresistance. The radiosensitizing effect of ara-C is postulated to result from inhibition of DNA and chromosome damage induced by radiation. Fludarabine has been reported to increase radiation-induced clonogenic cell death in several cell lines.
