Not to beat a dead horse, but the stats (albeit a bit dated) on stage 4 at diagnosis are the ones that the NY Times article that I quoted for Elizabeth Edwards. These are for women originally diagnosed at stage 4. The ACS later had to issue an apology to the Edwards campaign, noting that it does not have statistics on women who later go on to have metastases. If I did it right, below should be a link to a PDF from the ACS with these stats. (Look at figure 8 for women with distant disease at diagnosis.)
http://www.cancer.org/downloads/STT/BCFF-Final.pdf
I would love to be proven wrong on this, since I have been searching for more favorable statistics on long term survival for stage four disease, but I have not found anything particularly encouraging. (If you have an article or study with better figures for someone orginally diagnosed at stage 4, please post it.) That said, I am currently NED, and I know that some women with stage 4 disease do quite well on Herceptin for a long term. Everyone is different, and responds differently to chemotherapy and Herceptin. So, I am merely posting this to back up my original position, not to discourage anyone. I personally, intend to be someone who beats the odds.