Hi Steve,
I'm not sure if the picture is as grim as painted (on those websites) or not

I would encourage you to search the breast cancer archives with the word Brain
and draw your own conclusions.
http://groups-beta.google.com/advanced_search?q=&

I just did. It took me about 20 minutes to go back to June 2004.
(I ignored Kaye - she's been convinced for years that she has mets everywhere
and none have been found)
I ignored the "chemo brain" posts. I ignored "troll posts" and/or replies to
"crossposted news items" from various other non-regulars of the breast cancer
newsgroup.

http://groups-beta.google.com/group/alt.support.cancer.breast/msg/cd56fd70283364b5

Alan - Herceptin does not cross brain barrier

http://groups-beta.google.com/group/alt.support.cancer.breast/msg/44bca3673e3c255b

Mark - 6 brain lesions in 2001 - still hanging in there...      replying to
jayu - whose mother has brain mets.

There's one by Tim replying to someone who had whole brain radiation and new
brain mets appeared. You would have to read both the original post and Tim's
reply.
<http://groups-beta.google.com/group/alt.support.cancer.breast/browse_frm/thread/
953ecc57ac576c35/0bd762fd238ef0f1?q=%22brain%22+group:alt.support.cancer.breast#
0bd762fd238ef0f1>

http://groups-beta.google.com/group/alt.support.cancer.breast/msg/918a71acd93564c4

There's one by Natalie (who is a young/inexperienced UK radiologist) explaining
that some brain mets respond to radiation, some don't and why. She also
mentions surgery, which I think may be unthinkable with 17

There's an RN who claims some live for years with brain mets. Although I
believe she also mentioned "older=slower growing".
(you did not mention your relative's age)

Another says "a few months to a few years".

http://groups-beta.google.com/group/alt.support.cancer.breast/msg/a287a1a44f30aecf

David - in Stage IV for five years and IIRC describes brain mets/treatments.
She did have brain surgery though.

There's a few possibles that I hadn't thought of...
1) the/your relative had breast cancer before and it's a recurrence and they
therefore know how to treat it.
2) imaging problem sometimes occurs with breast implants and/or primary will be
found another way.

Having said all that;
there's a poster on s.m.d.c. whose father has undetermined lung cancer who had
brain and other radiation; is flat on his back with fatigue- doctors give him 8
- 12 months. Online doctors are disagreeing; one says a few months, the other
says "don't give up hope yet, he might rally from the radiation therapy
fatique.
Then there's Bob with SCLC (small cell lung cancer - mets to several places,
had brain and other radiation therapy and has recovered quite well)..NED = no
evidence of disease at the mo, doing well. As I recall, he said it took a year
to recover from the fatique from the radiation.

So situations vary, depending on what they find. the location of the brain
mets, how they respond to treatment, her health/age, how well she recovers from
the treatment (or not), where the actual primary is...

I just don't want to paint a negative view if there's hope.
Nor do I want to encourage false hope.
Hope you understand.

If you find out more about the type of cancer, please feel free to post to
sci.med.diseases.cancer (which is troll infested but still watched by doctors)
and/or one of the two cancer newsgroups, depending on the primary.

J