Breast cancer and chemotherapy

I was diagnosed wiht stage one breast cancer in March.  It was invasive ductal carcinoma. The tumor size was .45 mm but poorly differentiated, grade 3.  I chose to have a bi-lateral mastectomy due to family history and the fact that I'm BRAC2 positive.  My oncologist sent for a Onca test to be performed in order to determine if I needed chemo or not.  The onca test came back but with no results because they said there wasn't enough cancer tissue to perform the test.  When I first met with oncologist I was told I probably wouldn't need chemo but now with no test results she is telling me I should have chemo.  What do you think?

[Cleveland Clinic]

Dear scouch01, Adjuvant therapy is treatment given after surgery to try to prevent or minimize the growth of microscopic deposits of tumor cells that might grow into a recurrent tumor. Adjuvant therapy may be hormone therapy, chemotherapy, or radiation therapy to the site

[scouch01]

I forgot to include that I am ER+ (Percent Positive 100) and I thought I was PR neg but on my path report it says 36 percent positive (whatever that means) and also HER2 neg (Fish test).   My tumor was 4.5 mm not .45mm.  I was also node negative.  I had good margins.  My surgeon told my family after surgery that it was so small she had trouble finding the tumor with the naked eye.

[hooperjan]

A related discussion, Chemo reduce reoccurrance Stage 1 ER+/PR-/HER2- 1.4cm was started.