>One of the major reasons breast cancer prognosis is so good is because it's often caught early.

I don't believe the statistics bear this out. In fact, there isn't a lot of evidence early detection of breast tumors does much to prolong life. If your metric is the number of years you live after the cancer is detected, then certainly early detection seems like a huge win. But that would be true even if you didn't do anything at all upon having detected the tumor.