Is surgery necessary for complete clinical remission of breast cancer?

6 years ago I was diagnosed with stage 3 breast cancer through a mass of cancerous axillary lymph nodes and what was thought to be an occult primary breast cancer.  I went through dose dense AC and Taxol, whole breast and axillary and supraclavicular radiation, 5 years of tamoxifen and soon to start an aromatase inhibitor.  In retrospect the cancer was identified as the so called "benign" fibroadenoma.  This fibroadenoma disappeared with chemo and upon review by experts at a cancer center was determined to be the so called occult primary, but was completely gone by mammogram, ultrasound and breast MRI.  The surgeon said that I could essentially have a mastectomy or elect to be monitored by breast MRIs.  I chose the MRIs. I would like your opinion on this.  Would i be better off with a mastectomy or should I continue my now annual bilateral breast MRIs.  It haunts me that I never had surgery to remove the tumor, but as the surgeon said, "There is nothing to remove now and we will never know if we got the right area of tissue unless a complete mastectomy is done".

[Cleveland Clinic]

In general, in women who present with locally advanced breast cancer who elect to do neoadjuvant chemotherapy, the follow-up treatment would generally be mastectomy and then radiation therapy if indicated.  Whether or not a mastectomy would be recommended 6 years after diagnosis would depend on the surgeon, oncologist and you.  A second opinion might be a good option to help you determine what would be best for you.