A breast self-exam is a way for you to examine your breasts for lumps or anything else that doesn't seem normal. It is recommended that a breast self-exam be performed monthly, and it is important that you tell your doctor about any unusual breast symptoms as soon as you notice them.
http://www.empowher.com/news/herarticle/2009/04/24/your-best-chance-surviving-cancer-early-detection