Timing of surgery in menstrual cycle

I am in my early 40s and was diagnosed with ductal carcinoma invasive in late March. I had been on HRT for the prior year, which was stopped as of the diagnosis. Because of the HRT, I had been having regular periods each month; prior to the HRT they were very irregular, and my hormone levels confirmed I was in early menopause. Question: I have read some research indicating that survival rate from breast cancer surgery (both lumpectomy & mastectomy) is impacted by the point in the patient's menstrual cycle that surgery occurs. Some of the studies on this subject were inconclusive, but at least one was very positive that a better result is obtained having surgery after day 13 of the cycle. What would be your thoughts on this research, and if it's important, how does someone whose cycles were artificially maintained fit into this scheme? (I have a call in to my surgeon as well). Thank you.

[CCF-RN,MSN-JS]

Dear Mary, As you had mentioned in your question, the studies regarding timing of surgery and menstrual periods are inconclusive.  I have checked with our Breast Center and was told that current practice is, if the timing works out that