Abstract P6-10-13: Associated ductal carcinoma in situ in primary operated TNBC is associated with a longer time to distant event

Abstract

Abstract Purpose We studied presence of accompanying ductal adenoma in situ (accom-DCIS) in a consecutive series of primary operated TNBC for distant time-to-event outcome. Methods A retrospective cohort study (diagnosis 1/1/2000 - 31/12/2017) of prospectively registered primary operated TNBC patients in UZ Leuven. Only TNBC of no special type were included. We compared patient (age, BMI, symptomatic/screening-detected) and tumor related factors (Nottingham Prognostic Index (NPI), Lymphovascular Involvement (LVI)) for accom-DCIS and analyzed the effect of accom-DCIS on distant time to event outcome using the Cox proportional hazards model. Multivariate models were used to correct for possible confounders. Results We included 524 patients. Median follow-up was 102 months. Mean age of patient was 57.3 [26-90] years and 361 had accom-DCIS (68,9 %); demographics, clinical-pathological characteristics and postoperative chemo- and radiotherapy were similar in patients with and without accom-DCIS; only LVI was significantly more likely to be present in accom-DCIS cases (p=<0.001). There were no differences in distant relapse rate (16.6% in accom-DCIS group vs 12.9% in no DCIS group [HR = 1.350, 95% CI (0.817;2.248) p=0.239]. Time to distant event was later if accom-DCIS was present: Mean time to distant event was 2.72yrs in the accom-DCIS group and 1.61yrs in the group with absent DCIS. In accom-DCIS 20/63 (31.8%) distant relapses occurred after 3 years while only 1/21 distant relapse (4.8%) occurred after 3 years in the non-DCIS group [HR =6.667, 95% CI (0.952-46.705) p=0,029]. Conclusion In our series of TNBCs, patients with and without accom-DCIS had similar distant relapse rates. Significantly more distant relapse occurred after 3 years in patients with accom-DCIS compared to patients without accom-DCIS. Citation Format: Jan Ardui, Hans Wildiers, Giuseppe Floris, Hava Izci, Kevin Punie, Tatjana Geukens, Els Van Nieuwenhuysen, Sileny Han, Patrick Berteloot, Annouschka Laenen, Hilde Janssens, Ann Smeets, Caroline Weltens, Ignace Vergote, Patrick Neven. Associated ductal carcinoma in situ in primary operated TNBC is associated with a longer time to distant event [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-10-13.