lumpectomy for IDC but DCIS left over

abcd

 I had lumpectomy twice.  On 19th May the first one and no clear margin.  Second lumpectomy was on 9th June and again one margin showed just 0.  We are told DCIS left. The surgeon saying he took away the breast tissue as much as possible and mastectomy will not help.  According to him mastectomy does not remove the muscle ( pectoralis) so mastectomy will not help.  He reassured that DCIS can not spread from there but I am not convinced.  They are now going to have  MDT ( multi disciplinary team ) meeting where surgeon, oncologist and histologist will discuss.  My family and I are confused and worried.  Anyone had this experience?  Invasive cancer has been removed according to the histology but this DCIS is still left.

Please enlighten me if you can.  Thank you.