Abstract PO5-03-02: Ductal carcinoma in situ: An excess regard of the axilla?

Abstract Abstract: Ductal Carcinoma in Situ (DCIS) is a malignant proliferation of the epithelial inside the breast duct, which does not invade the myoepithelial layer and, therefore, does not have the capacity to generate metastases. 1. However, an upstaging after surgery is possible, since there may be a concomitant invasive lesion that was not diagnosed in the pathological examination from biopsy, being discovered only after the surgical procedure 1. In the pre-screening mammography era, DCIS was diagnosed. more commonly in symptomatic women presenting with a palpable nodule, papillary flow, or through an incidental finding on a breast biopsy 2, accounting for 1-2% of cancer cases. 3. After the advent of mammographic screening, the incidence has considerably increased among asymptomatic women with mammographic changes such as calcifications. 4. Nowadays the diagnosis of DCIS corresponds to 20-25% of biopsies secondary to screening mammographic changes. 1. As we do know that the chance of axillary metastasis is potentially null, old series where axillary dissection (AD) was performed ipsilareral to the index tumor, axillary involvement was observed in less than 1% of cases 9. Objectives: Our objective in this study was to describe in a single breast cancer reference center the surgical treatment of patients diagnosed with DCIS (mastectomy or breast conservative surgery – BCS). Methods: A retrospective analysis was made using the Pérola Byington Hospital’s database, from January 2011 to December 2019. During this period, 11,373 cases of breast cancer were treated int the institution and 812 (7.4%) were DCIS. Data was available and we could analyze 494 patients who underwent vacuum-guided biopsy guided by mammography or ultrasound and were diagnosed with DCIS and underwent surgical treatment at the Hospital. We grouped the patients into 3 age groups: under 40, 40-49, and 50 and over. In all groups, we had patients who underwent SNB using the patent blue technique or AD and were evaluated using the H 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-03-02.