The management of ductal carcinoma in situ of the breast : a screened population-based analysis

A recent SEER study identified significant variations in the care of women with DCIS, yet several potential confounding variables were not included. We report a patterns of care study of women with DCIS to better understand the gap between evidence-based knowledge and the management of DCIS. We studied all cases of DCIS diagnosed through the Ontario Breast Screening Program from 1991 to 2000. Data was obtained by database linkage and chart abstraction. A logistic regression model using generalized estimating equations to adjust for clustering was used. About 320,236 women were screened and 727 individuals were diagnosed with DCIS. The rate of mastectomy was 30% and was associated with multifocality (OR: 3.5 [1.7, 7.1], P = 0.0005), tumor size (OR: >2 cm vs.