Stereotactic Body Radiation Therapy for Localized Prostate Cancer

This clinical trial studies the side effects of image-guidance and online adaptation with stereotactic body radiation therapy (SBRT) for the treatment of patients with prostate adenocarcinoma that has not spread to other parts of the body (localized). Image-guided SBRT is a standard treatment for localized prostate cancer. This treatment uses imaging of the cancer within the body to define and localize the area to be treated with the radiation. Imaging can be obtained using either computed tomography (CT), magnetic resonance imaging (MRI), or a combination of the two. Typically, with SBRT, a radiation plan is developed based on the CT or MRI images obtained before treatment begins and adjustments are not made to the plan during treatment. However, anatomy can be different from day-to-day which may cause radiation to be delivered to the normal surrounding structures and possibly more side effects. During image-guided SBRT with online adaptation, the initial radiation plan is designed similarly; however, when the patient presents for radiation, the attending radiation oncologist, a dosimetrist, and a medical physicist "re-optimize" the radiation plan using the current anatomy of the day, meaning the changes in bladder and prostate size/shape are taken into account. The initial plan and the re-optimized plan are then compared, and the plan that has the optimal balance between delivering a tumor killing dose of radiation and minimizing radiation dose to normal surrounding structures is delivered. Image-guidance and online adaptation with SBRT may lower side effects and be a safer way to treat localized prostate adenocarcinoma.