Impact of the presence and quantity of ductal carcinoma in situ component on the outcome of invasive breast cancer

INTRODUCTION: The role of ductal carcinoma in situ (DCIS) component on the outcome of invasive breast cancer is not yet completely clear. Our study aims to assess the impact of the presence and quantity of DCIS component on the outcome of patients operated for invasive breast cancer. MATERIALS AND METHODS: We collected retrospective data about patients operated at their breast for invasive cancer between 2007 and 2012, focusing on the presence of DCIS component. Then, we divided patients into four groups based on the quantity of DCIS component as follows: not found (group A), minimal (group B, <25%), extensive (group C, 25-75%), and prevalent (group D, >75%). We further defined "extensive intraductal component" (EIC) groups C and D together. RESULTS: DCIS component was associated with young age, familial history of breast cancer and worse biological characteristics, including high grading, higher prevalence of Her2/Neu overexpression, hormone receptors negativity, comedo-like necrosis and multifocality/multicentricity. Despite the unfavorable prognostic factors, invasive cancers associated with EIC were frequently treated with radical surgery and resulted to have long disease-free survival and low local recurrence rate. In patients with DCIS component (groups B, C, and D) the extension of this component resulted indirectly correlated with local recurrence rate, tumor lymphovascular invasion, and lymphnode extracapsular invasion. The highest prevalence of local recurrences was found in group B, which tended to be less frequently treated with radical surgery than group D (P<0.05) and C (P=n.s.). CONCLUSIONS: Different clinical and tumor features among invasive breast cancer with and without DCIS component indicate that they are distinct entities probably originating by different pathways that deserve to be studied. Furthermore, the controversial results about the management of cancer with minimal intraductal component require further studies in order to reduce local recurrence.