Abstract P5-14-18: Extended Pure Ductal Carcinoma In Situ of the Breast on Preoperative Biopsies. Prognostic Factors for Infiltrating Carcinoma and Lymph Node Involvement

Abstract

Abstract Introduction: The aim of our study was to identify predictive factors of infiltrating carcinoma and lymph node involvement in patients with an initial diagnosis of extended pure ductal carcinoma in situ (DCIS) of the breast. Material and Methods: 241 patients diagnosed with extended pure ductal carcinoma in situ (DCIS) underwent treatment at the Institut Curie (2000-2009) consisting of mastectomy with or without immediate breast reconstruction (IMR). Axillary staging (sentinel node and/or standard procedure) was performed in 92% of patients. Patients with micro-invasive lesions at diagnosis, recurrence or contralateral breast cancer were excluded. Differences between groups were analysed by Chi-square or Fisher Exact tests for categorical variables and Student's t-test for continuous variables. Survival analyses were performed using KaplanMeier, with comparisons using the logrank test and hazard ratios estimated using the Cox proportional hazard model. P-values were considered significant when below 0.05. Results: Respectively 15% and 20%of patients had a final diagnosis of micro-invasive (MIC) and invasive ductal carcinoma (IDC). The median sizes of the DCIS and IDC were respectively 40mm [0-95] and 6mm [2-50] according to final histological assessment. Univariate analysis showed that the following variables at diagnosis were significantly correlated to the presence of either MIC or IDC in the mastectomy specimen; palpable tumor (p=0.02), high grade DCIS (p=0.02), detection of an opacity on mammography (p=0.01). Axillary lymph node involvement was reported in 9% of patients. In univariate analysis a BMI>25 (p=0.007), a palpable tumor (p=0.01), the detection of an opacity (p=0.04) were associated with an increase rate of lymph node involvement. A IMR was performed in 69% of patients. These patients were younger (P<0.00001), thinner (p=0.005), with fewer palpable tumors (p=0.01), and DCIS of lower grades (p=0.03) than patients denied of breast MRI. With a median follow-up of 30 months, 7 patients (3%) experience locoregional recurrence. In univariate analysis a BMI>25 (p=0.06), a palpable tumor (p=0.0004), an opacity (p=0.01) and extended microcalcifications (p=0.02) were associated with a higher rate of loco-regional recurrence. Immediate breast reconstruction was not a significant risk factor for loco-regional recurrence (p=0.31). Conclusion: Extended pure ductal carcinoma of the breast on preoperative biopsies is associated with a substantial risk of finding not only micro-invasive or invasive carcinoma on the mastectomy specimen but also axillary lymph node involvement. Some risk factors have been identified and should be used to exclude patients from immediate reconstruction surgery due to an increased risk of getting adjuvant systemic treatment and radiotherapy. Immediate breast reconstructive surgery was not associated with an increased risk of loco regional recurrence in our series. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-14-18.