Abstract P2-12-11: Does conservative surgery treatment for locally advanced breast cancer safe after neoadjuvant treatment?

BACKGROUND: The aim of this study was to assess the oncological efficacy of breast conserving surgery (BCS) after neoadjuvant chemotherapy in patients with local advanced breast cancer. PATIENTS AND METHODS: A retrospective cohort study was conducted with locally advanced breast cancer invasive (Stage IIb to III) treated at ICESP, an oncologic referral center between 2008 and 2016. Endpoints were disease free survival (DFS), local disease free survival (LDFS) and overall survival (OS). Multivariable analyses were performed using Cox proportional hazards models. RESULTS: 530 patients were included, 26% (138) were stage IIB, 41.9% (222) IIIA, 29.6% (157) IIIB and 2.5% (13) IIIA. 88.8% (470) were invasive ductal carcinoma. The mean age was 51.5(23-95). 95.5% and 4.5% were submitted Neoadjuvant Chemotherapy and Hormone therapy, respectively. The BCS were performed in 24.5% (130) patients versus 75.5% (400) of mastectomies. The mean follow up was 36.4(0.16-80.2) months. There were no differences in local disease free-survival 59 (95%CI 58-61) versus 60 (95%CI 57-60); p=0.4 and overall survival 56.2 (95%CI 52-60) versus 59.3(95%CI 53-65); p= 0.24 for mastectomy and BCS. The disease free survival was lower at mastectomy group 51.4 (95%CI 49-53) versus 56,8 (95%CI 53-59); p=0.01. Logistic regression models were significant only for cancer stage both patterns, although the results were better for masses, particularly when kinetic assessments were included (LR 12.8; p = 0.005) CONCLUSION: In our population, the BCS does not affect the overall and local disease-free survival rates, which seems to be safe to perform in patients who desire to conserve the breast after neoadjuvant treatment. Citation Format: Boufelli G, Mota BS, Franca FC, Doria MT, Maesaka JY, Ricci MD, Piato JRM, Rocha FBC, Giribela AHG, Gonçalves R, Masili-Oku S, Mano MS, Chala LF, Thompson BM, Baracat EC, Filassi JR. Does conservative surgery treatment for locally advanced breast cancer safe after neoadjuvant treatment? [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-12-11.