Intensity Modulated Radiation Therapy for Prostate Cancer

BACKGROUND: -This study represents a progression from findings in four previous National Cancer Institute (NCI) Radiation Oncology Branch (ROB) protocols (02-C-0167A, 02-C-0207E, 03-C-0190B, 04-C-0171). In these previous works we have begun to develop techniques to obtain Magnetic Resonance (MR) biological images and co-register tissue in prostate cancer patients. OBJECTIVES: -The primary objective of the first portion of this study is to assess the feasibility of using Intensity-modulated radiation therapy (IMRT) to treat the at-risk lymph nodes in prostate cancer. Also, if feasible, we hope optimize this technique with experience. ELIGIBILITY: -This is a study of image guided, targeted radiation therapy in patients with high risk of nodal metastases from prostate cancer. Patients with prostate cancer who have more than 15% risk of lymph node (as defined by the Partin tables) metastasis will be eligible for this study. DESIGN: * On the first 10 patients, we will perform approximately 5 computed tomography (CT) simulations throughout the course of their therapy. On each simulation, the initial treatment plan will be re-run. The dose-volume data from target and normal tissues will then be re-analyzed. From this analysis we will be better able to determine the size of margins needed to account for organ motion and changes such as varying amounts of gas in the bowel and fluid in the bladder. To the best of our knowledge, no such analyses have been published. * If the initial part of this trial is feasible, we will proceed to a phase I dose escalation trial of radiation to the at-risk lymph nodes. The primary statistical objective of the phase I portion of this study is to estimate the Maximum Tolerated Dose (MTD) of external beam radiation based on evaluating acute toxicity. The study will be conducted with a dose-escalation design with 3 patients in each dose cohort. If fewer than 2 of 3 patients experience an acute dose limiting toxicity (DLT) than patients wi