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PS1-16: Patterns of Surgical Care for Ductal Carcinoma In-situ

Background/Aims Overall prognosis for ductal carcinoma in-situ (DCIS), a non-invasive breast malignancy, is generally quite positive with a mortality rate of < 2%. DCIS may progress to invasive breast cancer if left undetected or inadequately treated. Age, family history and individual preference are factors influencing quality and extent of surgical treatment of DCIS. Breast conserving surgery with or without radiation is commonly used to treat limited DCIS, with consideration for adjuvant endocrine therapy. Re-excision is not uncommon for DCIS, as it may be difficult to initially obtain a negative margin and also there may be suspicion of co-existing invasive breast cancer. Sentinel lymph node biopsy and prophylactic mastectomy have been considered over-treatment for DCIS, except in cases where DCIS is high grade, diffuse, large size, or has components of microinvasion. Our study aim was to evaluate patient characteristics and impact of features of DCIS on surgical patterns of care for DCIS. Methods Data relating to initial surgical treatment of stage 0–III breast cancer was collected both electronically and by manual chart abstraction to develop the multicenter Breast Cancer and Surgical Outcomes database. Study sites included the University of Vermont, Marshfield Clinic (Wisconsin), Kaiser Permanente (Colorado) and Group Health (Seattle). Women with a pre-operative diagnosis of DCIS (n=943) between 2003–2008 were included in this analysis. Results Of 943 women with a pre-operative diagnosis of DCIS, 932 (99.0%) had post-operative final diagnosis of DCIS. Planned analyses include determination of variability in surgical treatment of DCIS, including initial mastectomy and sentinel node biopsy, and incidence of positive margins following initial surgical excisions. Variability will also be examined based on factors unique to this dataset such as surgeon-specific and regional variation patterns of surgical care. Patient characteristics, DCIS features, MRI use and prophylactic contralateral mastectomy rate will also be reported. Discussion Understanding the variability of surgical treatment for DCIS may lead to improved quality of care and better outcome for patients with DCIS.