PART II
Modern Technologies in Radiotherapy (Cont'd)
3. Improvement of radiotherapy by using radioprotectors
Radioprotection is another important approach in radiotherapy. Basically, a therapeutic agent, radioprotector, is administered to a patient before the patient is treated by radiotherapy. In other words, radioprotectors protect normal tissues against radiation-induced side effects. Ideally, radioprotectors produce or stimulate certain biological reactions/products which then counteract the adverse effects caused by radiation.
Unfortunately, there has not been any
significantly improved radioprotector since the discovery and approval of a
popular broad-spectrum radioprotective drug, amifostine (Fig. 2.3), by the FDA.
Interestingly, amifostine was originally approved to reduce the cumulative renal toxicity associated
with repeated administration of cisplatin in patients with advanced ovarian
cancer and non-small cell lung cancer. However, while nephroprotection was
observed, amifostine also formed chelation with cisplatin and reduced its
anticancer activity. Therefore, its indication for chemoprotection in
cisplatin treatment in non-small cell lung cancer was withdrawn in 2005.
Fig. 2.3. Structure of amifostine (WR2721) and its metabolite
More details about amifostine and other radioprotectors are described in Part III.
© Jiajiu Shaw, 2021
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