Guided Stereotactic Body Radiation Therapy

This phase II trial evaluates apalutamide in combination with image-guided stereotactic body radiation therapy (SBRT) for the treatment of patients with prostate cancer. Prostate cancer usually needs the hormone testosterone to grow. Apalutamide is a hormone therapy that blocks the effect of testosterone on prostate tumor cells. This may help stop the growth of tumor cells that need testosterone to grow. Image-guided SBRT is a standard treatment for some types of prostate cancer. This treatment combines imaging of cancer within the body, with the delivery of therapeutic radiation doses produced on a linear accelerator machine. SBRT uses special equipment to position a patient and deliver radiation to tumors with high precision. This method may kill tumor cells with fewer doses over a shorter period and cause less damage to normal tissue. Combining apalutamide with image-guided SBRT may increase a prostate cancer patient's chances of achieving an extremely low prostate specific antigen response, which is an early predictor of disease cure.