Cytoprotective Efficacy of Amifostine Against Radiation- Induced Rectal Toxicity: Objective and Subjective Grading Scales for Radiomucositis

Abstract: Curative radiation therapy of pelvic malignancies, frequently results in doselimitingtoxicities such as serous, mucoid, or more rarely, bloody diarrhea. Several studieshave evaluated the cytoprotective effects of amifostine in preventing rectal mucositisassociated with radiation treatment. We searched Medline for published comparativestudies that evaluated the use of amifostine to reduce radiation-induced toxicity associatedwith pelvic irradiation. In ten studies there was an evidence-based cytoprotection (P less than 0.05)by amifostine. Although results are variable, current evidence suggests that amifostine mayhave a radioprotective effect in the rectal mucosa, particularly when administeredintrarectally. Significant improvements were seen in both symptomatic and objective(rectosigmoidoscopy) end points. There is a need to conduct well-designed clinical trialswith sufficient numbers of participants to confirm these findings together with a costbenefitstudy. Objective measurements using rectosigmoidoscopy are superior tosubjective measures such as WHO or RTOG/EORTC toxicity grading scales.