Radiation therapy for breast cancer

I am 49 y/o with invasive ductal ca,tumor was 1.1 cm, E+, P+, HER/neu negative, 2 sentinel nodes positive, 21 axillary nodes negative. I was told it was Stage IIAHad bilateral mastectomies (my choice), dose dense chem A/C x 4 and Taxol x 4.
Do I need radiation therapy?
My onc and the radiation onc feels so because of two things in my biopsy: No clean margins (it reads invasion of deep soft tissue amrgin up to 0.6 cm) and focal lymphatic involvement. Their feeling is that I have a 20% chance of local recurrence.
If XRT is needed what woulod be the toal dose and duration?
I also want to know if Arimidex can be given with XRT or it has to come afterwards.
Thanks you very much
IreneM

[CCF-RN,MSN-rf]

Dear Irene M:  Radiation therapy is given primarily for local control of disease.  Radiation is frequently recommended following mastectomy in patients who have larger tumors, involvement of the surgical margin or involvement of 4 or more lymph nodes.  The role of radiation following mastectomy in patients with fewer involved lymph nodes (1 to 3) is less certain.  Radiation is also usually given following breast conserving surgery.  If radiation treatment is recommended for you, the dose and duration would be determined by the radiation oncologist.  Technically, hormone therapy can be given during radiation therapy or after radiation therapy. It is generally physician preference.    

[Remy]

Sorry to hear what your going thru. I'm certainly not qualified, but as just recently have gone thru radiation, I can let you know that I did take the Arimidex when I started radiation. My Dr's. both discussed it and said it was fine for me to start right away.  I have been on Arimidex now for 4 months and have had no side effects from it. I take it a night to avoid possible stomach upset.  Good luck.

[hemi384]

A related discussion, Radiation treatment was started.