Multifocal DCIS

Are there studies which support use of mastectomy for multifocal DCIS?  In other words. if there are clear margins and treatment is followed by radiation, does the fact the DCIS is multifocal matter?  Is there research to show any affect on recurrence?  (Already have it bilaterally, so that is not an issue).

[Cleveland Clinic]

Dear Jordymom,  Ductal Carcinoma In Situ (DCIS) refers to an early ductal cancer in which the abnormal cells are confined to the duct.  This diagnosis (DCIS) is based on findings from looking at the cells under the microscope.   If DCIS is present in only one area and no cancer is found at the edges of the first surgical incision – either total mastectomy or lumpectomy followed by whole breast radiation is suggested.  Mastectomy is recommended if the DCIS cannot be completely removed by breast-conserving surgery.  The prognosis of DCIS is excellent whether or not it is multicentric. The extent of disease in the breast, however, may alter what surgical options are best.  A surgeon who specializes in breast disease would be most appropriate to advise.  These specialists are often associated with large medical centers.