Natural course of metastatic breast cancer

Can someone refer me to an article published in the medical literature that discusses how long a woman with metastatic breast cancer (visceral or bone metastases) will live on average  if she has NO treatment?  I found an interesting article by Bloom and Richardson from 1962, but they don't talk about Stage IV cancer.  Any suggestions are appreciated!  Thanks!

[Cleveland Clinic]

Dear dreds:  I am not aware of any such article.  There have been no trials because it is unethical to randomize women to no treatment and VERY few would choose "no treatment" so it is impossible to get any reliable statistics.  Further, Stage 4 disease could range from one small spot on a bone to a liver full of disease to brain metastasis to any combination.  Prognosis will vary both based on extent and behavior (which often cannot be predicted) of the disease.  Good question but no easy answer.  Sorry.