Amifostine to Protect the Rectum During External Beam Radiotherapy for Prostate Cancer

Study Summary

This study will evaluate the safety and effectiveness of a drug called amifostine in reducing the bowel side effects of radiation treatment for prostate cancer. Amifostine is a 'radioprotector' medicine that to protects normal tissue from radiation damage. This study will determine whether placing amifostine in the rectum during radiation treatment for prostate cancer can decrease common side effects of treatment, including diarrhea, painful bowel movements, bleeding, and gas. Patients 18 years of age or older with prostate cancer may be eligible for this study. Candidates will be screened with a medical history and physical examination, blood tests, bone scan if a recent one is not available, and possibly computed tomography (CT) and magnetic resonance imaging (MRI) scans of the pelvis. They will also have a liquid retention test, in which they are given an enema of 4 tablespoons of salt water that they must retain for 20 minutes. Participants will receive standard radiation therapy for prostate cancer-5 consecutive days for 8 weeks-in the National Institutes of Health (NIH) Radiation Oncology Clinic. Amifostine will be placed in the rectum by a mini-enema before each radiation treatment so that it covers the lining of the rectum. To determine the side effects of the treatment, patients will undergo a proctoscopic examination before beginning radiation therapy, two times during therapy, and at each follow-up visit for 5 years after treatment ends. This examination involves inserting a proctoscope (a thin flexible tube with a light at the end) into the rectum and taking pictures. Patients will be followed in the clinic at visits scheduled 1, 3, 6, 12, 18, 24, 36, 48, and 60 months after treatment for a physical examination and routine blood tests, proctoscopic examination, and review of bowel symptoms.

Primary Outcome

A good toxicity outcome is defined as having less than grade 2 on both weeks 5 and 7 of treatment. The Radiation Therapy Oncology Group (RTOG) Acute radiation morbidity scoring scheme and the Rectal Mucosal Toxicity response criteria will be used to assess rectal toxicity. The RTOG measures the rectal toxicities. The physician assigns a grade based on symptoms reported by the patient. For details about the RTOG (method and scoring of radiation morbidity, etc.) see http://www.rtog.org/ResearchAss

Interventions

• RADIATION Radiation therapy
• DRUG Amifostine trihydrate