Chemo and Medullary Carcinoma

I have breast cancer which is Medullary Carcinoma. My tumor size is 0.09. My question to you:Is it okay to have Chemo treatments with a tumor less then 1cmm? Will it cause more harm to my body then if I just did radiation treatments. I am very nervous about this because my mother-inlaw had breast cancer and just did raditation treatments and two years later it came back more aggressive. She said she had wished she did the Chemo. Because of this I have chosen Chemo treatments and want to make sure I am making the right decision. My doctor left the decision up to me.

[BJSaws]

     I also had medullary carcinoma of the breast.  My tumor was 1.1 cm.  Medullary carcinoma is less aggressive than adenocarcinoma (the most common breast cancer), but it is also triple negative (er -, pr -, and Her2 -).  Since it is triple negative, you are not eligible for the anti-hormone treatments such as tamoxifen or the anti-Her2 drug herceptin.  In my case, I had a mastectomy (my choice) and, therefore, did not have to have radiation.  I did have chemotherapy.  My oncologist said that if the tumor was less than 1 cm, chemo would have been optional, but since it was 1.1 cm she felt chemo would be best for me.  My sentinel node biopsy was also negative for any trace of cancer. I celebrated the fifth anniversary of my surgery on November 20th.
     I think your decision should be discussed with your oncologist.  I assume from your posting that your tumor was .9 cm or did you really mean .09 cm?  I also assume you had a lumpectomy.  If you had a lumpectomy and not a mastectomy, then radiation would be a necessity.  If your nodes were negative and your tumor was .09 cm, then your oncologist would probably not recommend chemo.  If it was .9 cm, or if you had any positive lymph nodes, then chemo will probably be offered as an option.  It depends on how aggressive you want to be with your treatment.
     Although everyone reacts differently to chemo, for me it was not near as bad as I had anticipated.  I made it through, my hair grew back, and I have been blessed with good health since.
     Good luck with whatever your treatment plan may bring.