Axilllary Node Breast Cancer

I have been diagnosed with Axillary Breast Cancer. No cancer in the breast can be found, only 3 lymph nodes postive for adenocarcinoma by axilllary node disection last week.
They want to do chemo only, no radiation or mastectomy.
They say it is systemic and not in the breast anymore, or maybe never was. Has anyone faced this type of cancer before? I am told because it is so rare, no good studies exist.
I am scheduled for more opinions, but want to know if anyone here has had this experinence. Would appreciate any help.
Thank you and Blessing to you all, Bonnie