Neo-adjuvant chemotherapy

I had 4 cycles of AC before my double mastectomy.  They found a 1.5 cm tumor on the left side with negative nodes and also found an .8cm tumor on the right side(not seen at all on mammography) with negative nodes.  If you do the chemo first, can they still tell if you have negative nodes? Will there still be traces of cancer in the nodes?  They told me that all my nodes were negative.  They did a sentinel node biopsy on the left side and took 4 axillary nodes on the right.  Thank you.

[CCF-RN,MSN-JS]

Dear Redbean, This is one of the controversies about neo-adjuvant therapy.  We don