Correlation of histopathologic features of ductal carcinoma in situ of the breast with the oncotype DX DCIS score

The Oncotype DX Breast Cancer Assay for ductal carcinoma in situ is used to determine local recurrence risk in patients with ductal carcinoma in situ. The results help select patients with low-risk ductal carcinoma in situ who could forgo radiation therapy after conservative surgery. The genes assessed include five proliferation genes, progesterone receptor (PR), and GSTM-1. Our objective was to determine if PR, mitotic counting, or any other pathologic feature of ductal carcinoma in situ could predict the Oncotype DX DCIS Score. We identified 46 cases of ductal carcinoma in situ with a Oncotype DX DCIS Score. In addition to information obtained from routine pathology, we counted mitotic figures in the ductal carcinoma in situ and noted presence of dense chronic inflammatory infiltrate surrounding ductal carcinoma in situ. We found that PR ≥90% (P=0.004), mitotic count ≤1 (P=0.045), estrogen receptor ≥90% (P=0.046), and low nuclear grade (P<0.0001) were associated with a low score. Dense chronic inflammation surrounding ductal carcinoma in situ was associated with a high score (P=0.034).All 13 cases with PR ≥90%, ≤1 mitotic figure and absence of dense chronic inflammation around ductal carcinoma in situ had a low score (100% specificity). A low score was not observed in any case with at least two of the following - negative PR, >1 mitotic figure, and/or presence of dense chronic inflammation around ductal carcinoma in situ (100% specificity). Our study suggests using a combination of PR (≥90% vs negative) with mitotic count in ductal carcinoma in situ (≤1 vs >1) and dense chronic inflammation around ductal carcinoma in situ one could predict the Oncotype DX DCIS score. Mitotic counting and evaluation of immune response might provide prognostic information in ductal carcinoma in situ.