Abstract P6-09-04: Predictive factors for considering to avoid axillar lymphadenectomy in selected node positive breast cancer patients after neoadjuvant chemotherapy
Authors: Fernandez-Gonzalez S , Falo Zamora C , Nuñez D , Vethencourt A , Pla MJ , Soler T , Guma A , Perez X , Gil M , Ponce J , Garcia A 
Published: May 2019

Abstract
Background:
To perform a systematic axillar lymphadenectomy (ALND) in clinical node positive (N+) patients after neoadjuvant chemotherapy (NACT) is currently under discussion. We aimed to study which factors are related to a pathological complete axillar response (ypN0) after NACT in order to select which patients could benefit from a sentinel lymph node biopsy without interfering with survival.
Material and methods
N+ patients who underwent ALND after NACT between June 2008 and December 2016 were retrospectively analyzed. Clinical features, molecular and histological factors, recurrence and specific mortality rates were compared between patients achieving a complete pathological axillary response vs not (ypN0 vs ypN+).
Results
345 N+ patients were reviewed. After NACT, 137 (39.6%) become ypN0[CF1] , 9 (2.6%) ypN1 mic, 113 (32.7%) ypN1, 60 (17.3%) ypN2 and 22 (6.4%) N3. Univariate analysis results regarding the predictive factors for ypN0 are detailed in [table 1]. Multivariate analyses showed molecular subtype (TN and Her2+) and clinical response as independent predictors of ypN0 [table 2]. After a mean follow-up of 58 months, overall survival was statistically superior in ypN0 vs ypN1 (p= 0.001).
Table 1.Predictive factors for ypN0 YpN0 (n = 137)YpN+ (n = 208)pAge (mean, years)58.3 ± 13.2758.59 ± 12.340.799BMI (mean)27.8±5.4927.8±5.360.973Dosis of QT (median)(%) 0.575IIA6 (31.6)13 (68.4) IIB71 (39.3)110 (60.8) IIIA28 (36.8)48 (63.2) IIIB24 (43.6)31 (56.4) IIIC7 (58.3)5 (41.7) Radiological image(%) 0.930Nodule77 (38.1)125 (61.9) Non-mass distortion10 (43.5)13 (56.5) Radiological size (median)32 (0-115)29 (0-130)0.246Suspicious a-LN by US(%) 0.486130 (30.9)37 (24.3) 25 (5.2)14 (9.2) &gt;257 (58.8)91 (59.9) Histological subtype(%) 0.093Invasive Ductal Carcinoma133 (40.9)192 (59.1) Invasive Lobular Carcinoma2 (20)8 (80) Others2 (22.2)7 (78.8) Nottingham grade(%) &lt;0.001G11 (6.2)15 (93.8) G244 (28.6)110 (71.4) G386 (53.4)75 (46.6) Molecular-like subtype(%) &lt;0.001Luminal A-like2 (5.3)36 (94.7) Luminal B-like (Her2 -)21(18.1)95 (81.9) Luminal B-like (Her2 +)40 (63.5)23 (36.5) HER-2 enriched (non luminal)43 (74.1)15 (25.9) Triple Negative31 (44.9)38 (55.1) Vascular invasion19 (42.2)26 (57.8)0.889Clinical Response(%) &lt;0.001Complete61 (75.3)20 (24.7) Partial69 (31.8)148 (68.2) No response6 (20.7)23 (79.3) Progression1 (10)9 (90) Percentage are given per row.
Table 2.Multivariate analysis logistic regression of clinical predictive factors of ypN0. OR95% Confidence Intervalp valueMolecular subtype No-luminal vs Luminal7,7483,913-15,343&lt;0,001Clinical response Response vs not response6,8491,834-25,5710,04OR: Odd ratio. No-luminal includes: luminal B (HER2 +), HER2 Henriched and triple negative. Luminal includes: Luminal A and Luminal B (HER2 -).
Conclusions
A remarkable percentage of N+ became ypN0 after NATC. Molecular subtype and complete clinical response were independent predictive factors of ypN0. We propose to offer the benefit of a targeted axillary procedure in those patients.
Citation Format: Fernandez-Gonzalez S, Falo Zamora C, Nuñez D, Vethencourt A, Pla MJ, Soler T, Guma A, Perez X, Gil M, Ponce J, Garcia A. Predictive factors for considering to avoid axillar lymphadenectomy in selected node positive breast cancer patients after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-04.