Ductal carcinoma in situ and breast cancer-specific mortality in postmenopausal women

Analysis of postmenopausal women in the prospective Women’s Health Initiative investigated the association between ductal carcinoma in situ (DCIS) and breast cancer-specific mortality. Of 68,132 participants, the analysis included 781 women with incident DCIS and 781 matched controls. After 20.3 year total and 13.2 year mediane post-diagnosis follow-up, DCIS was associated with a higher breast cancer-specific mortality (HR 3.29; p=0.01). The absolute 20-year breast cancer mortality was 1.2% without DCIS and 3.4% after DCIS (p=0.026). Findings were similar by age (<70 versus ≥70 years) with no interaction (p=0,80). Incident DCIS was not associated with cardiovascular disease-specific mortality (p=0.14) or all-cause mortality (p=0.68). The authors conclude that in postmenopausal women, incident DCIS was associated with over three-fold higher breast cancer-specific mortality, with similar findings in younger and older postmenopausal women.