This randomized phase II trial studies how well olaparib with or without cediranib works in
treating patients with castration-resistant prostate cancer that has spread to other places
in the body (metastatic). PARPs are proteins that help repair DNA mutations. PARP inhibitors,
such as olaparib, can keep PARP from working, so tumor cells can't repair themselves, and
they may stop growing. Cediranib may stop the growth of tumor cells by blocking some of the
enzymes needed for cell growth. Giving olaparib and cediranib may help treat patients with
castration-resistant prostate cancer.