I am fortunate enough to have spoken with several top docs in the country due to the nature of my job, I am also ER/PR neg and HER2 positive. My oncologist, my breast surgeon and the opinion of several other doctors is 12 months of Herceptin. I had a lumpectomy last month and I start chemo with Taxotere, Carboplatin and Herceptin 6 rounds and I'll continue with the Herceptin for a full 12 months.

I did Taxotere, carboplatin and Herceptin for 8 rounds then a year of herceptin and perjeta after mastectomy. On my last treatment June 30th.

As far as i know tamoxifen is only useful for er + cancer ie hormonal cancers. Since yours is negative it is pointless as it works by blocking the hormone receptors that cause the cancer.

I had a lumpectomy, onco type low.one lymph node poss. now on Letrozole.

Had grade 1 dcis in situ er+ Her2+ no node involvement. I had 11 rounds of taxol, then 6 months of Herceptin (check out Persephone Project. That research is what made me break "protocol" and shorten it to 6 months) , then 16 rounds tumor bed radiation. Finished it all in May 2020. So far, so good.