Methods and compositions for treating cancer are described herein. More particularly, the methods for treating cancer comprise administering a 17±-hydroxylase/C 17,20 -lyase inhibitor, such as abiraterone acetate (i.e., 3²-acetoxy-17-(3-pyridyl) androsta-5, 16-diene), in combination with at least one additional therapeutic agent such as an anti-cancer agent or a steroid. Furthermore, disclosed are compositions comprising a 17±-hydroxylase/C 17,20 -lyase inhibitor, and at least one additional therapeutic agent, such as an anti-cancer agent or a steroid.