○ All grade III DCIS ○ Male DCIS ○ Concurrent diagnosis of invasive or micro-invasive breast cancer in either breast prior to randomization ○ Documented mass on examination or imaging at the site of DCIS prior to biopsy yielding diagnosis of DCIS ○ Bloody nipple discharge or skin changes associated with DCIS ○ Mammographic finding of BI-RADS 4 or greater within 6 months of registration at site other than that of known DCIS, without pathological assessment ○ Use of investigational cancer agents within 6 weeks prior to diagnosis ○ Any serious and/or unstable pre-existing medical, psychiatric or other existing condition that would prevent compliance with the trial or consent process ○ Pregnancy ○ Documented history of prior tamoxifen, aromatase inhibitor, or raloxifene in last 6 months |