Hi Diane -
I agree with Laurie & PJ. Recurrence is ALWAYS a possibility with a mastectomy, though it doesn't always mean you'll have one. I know from experience that if one tiny little cell of brest tissue is left behind and maybe the meds you are on fail to work properly, that the cell can indeed grow larger and become cancerous. I know because I had a modified radical mastectomy 3 yrs ago and my cancer came back in the same spot of my chest wall. I originally had Invasive Ductal Carcinoma, stage 11a at 31. Now exactly 3 yrs later I have what they call Recurrent Brest Cancer - no staging given, and it is beleived to not have spread. I've had more chunks of my chest wall removed and am going through radiation at the moment, then on to chemo. But I understand that with remaining chest wall left, I could STILL develop cancer if this radiation does not put a stop to it (hopefully) once and for all.
I just wanted to chime in and tell you that from personal experience, recurrence CAN happen with a mastectomy - it seems it's something the drs forget to tell us. They focus instead on how the longer you are in remission the better your chances are, and blah, blah, blah. So I suggest that you and your doctor get to the bottom, and rule out even the most impossible of diagnosises, so that you can find out what it is that is truly causing this.
Good Luck!
Angi