Purpose: To evaluate whether pretreatment with amifostine can reduce treatment-induced toxicity in patients with pelvic malignancies undergoing radiotherapy (RT). Methods and Materials: A total of 205 patients with pelvic malignancies (rectal, 32; bladder, 47; prostate, 40; gynecologic, 86) were randomized to receive RT (Group 1, n = 95) or RT plus amifostine (Group 2, n = 110). The patient characteristics for both treatment groups were well balanced. Amifostine was administered at 340 mg/m(2) i.v., 15 min before RT, with standard antiemetics 30 min before. All patients received conventional RT, radical (65-70 Gy) or postoperative (50 Gy), with 45 Gy given to the whole pelvis at daily fractions of 1.8-2.0 Gy, 5 d/wk. Skin, bowel, bladder, and hematologic toxicities were evaluated according to the Radiation Therapy Oncology Group/European Organization Research and Treatment of Cancer scoring system. Results: A significant reduction occurred in acute Grade 2-3 bladder and lower GI tract toxicities in the amifostine group (p <0.05, Weeks 3-7). With a median follow-up of 12 months, few late Grade 2-3 effects were observed in either group. No statistically significant difference between the two groups was observed in terms of response 6 weeks after RT completion (complete response plus partial response, 96.8% in the control and 98.3% in the amifostine arm). Amifostine was well tolerated, with only moderate hypotension occurring in 2 patients and moderate nausea in 1 patient. Conclusion: The results of this randomized trial support the role of amifostine in reducing acute radiation-related toxicity of the bladder and lower GI tract in patients with pelvic malignancies, without evidence of tumor protection. (C) 2003 Elsevier Inc.