New to board - ? herceptin 3 yrs after tx

[Brea]

I am new to this board and have a question about herceptin. I was stage II, ER/PR -, HER2 + in 2003. I wasn't given herceptin after 6 rounds CEF because my Oncologist said it was only for patients with mets. I now have a few friends that are 2 and 3 years out of treatment and they have started herceptin. Does anyone have any info if it would still be effective that long after tx?

Thank you for your help.