When you have a cyst in your breast you should notice an oval or round lump that is easily movable and has distinct edges to it.
You can feel around your breasts for these lumps and if you do notice a lump or lumps in your breasts you should go get a mammogram taken to be sure the lumps are not cancerous.
If the breast lumps are cancerous and they're removed soon enough your chances of survival from breast cancer are much higher.
Always get checked out for breast cancer. That goes for men as well. Yes men can get breast cancer and do need checked out as well.