How Long until Herceptin Kicks in??

[sabpri]

I have the most unusual situation. At diagnosis, I had 2 Tumors, totally pathologically different, one ER/PR+ Her2-, and the other this weird Triple Negative with a small subpopulation within it that was very Her2+ amplified. No one knew what to really do with me, and the Oncs disagreed as to whether I was really Her2+ or not, but decided in the end since that weird sub pop was Her2+, they would give me Herceptin. At diagnosis, I had 2 small bone mets.

I stayed on herceptin for one year, then my Onc took me off since it was standard protocal and we never knew if I was truly her2+. That one year mark was 10/06, and by January 2007, my tumor markers started rising. After additional TM rise in April, scans showed major bone mets and a spot on the lining of my lung. I started cabro/abraxane and after 3 months, TM dropped some and although lung spot is gone, bones are worse. Bone biopsy showed path to be ER/PR/HER2-. I just thought it was very coincidental that I went off Herceptin in October and for the first time in over a year my TM went up and then my cancer came back. I know it was peak recurrance time, so maybe it was just the timing. Now we are going to be switching chemo to see if we can stop the bone mets, but I have successfully won my plea to at least "try" the Herceptin. Maybe my path was weird and it didn't get the small subset that showed Her2+ like before, or maybe herceptin just works for me.

Anyway, I told Onc I wanted to try one or two cycles of the Herceptin before switching chemo treatments, because if I switch and the bone mets go away, I won't know if it was the Herceptin or the new chemo (I am still on the Abraxane). I just had my first 3 week dose one week ago. Does anyone know how long it would take to work if it was going too? I don't want to wait too long to see if it is going to do something, but I want to give it enough time as well. My TM are pretty reliable, and have been hanging around upper 30's (normal is 12) since the lung spot disappeared (was 70's). I would hope that if it dropped to 20 or less, than I could assume it was working, but I don't know how long that might take. I don't know if anyone would even know, but I am trying to decide how long I should try it before adding a new chemo to it.

Thoght I would pose this question here and see if anyone would have any insights. I feel half of this medical practice of cancer is a total crap shoot!!

Thanks,
Natalie