Abstract P3-03-22: Prognostic impact of axillary lymph node status after neoadjuvant chemotherapy for patients with breast cancer

Abstract

Abstract BACKGROUND: Patients were stratified by final pathological axillary status: ypN0, ypN1, pN0 or pN1. The prognostic impact of lymph node involvement after neoadjuvant chemotherapy (NAC) for breast cancer is not straightforward. The aim of this study was to compare overall survival (OS) between pathologically node-positive T1,T2 T3 breast cancer patients treated with NAC, with ypN0 or ypN1 and those treated without NAC with pN0 or pN1. METHODS: A total of 3903 consecutive patients with operable breast cancer were prospectively identified at our institution between April 2006 and December 2017. Patients with suspicious axillary LN of breast cancer were assessed using preoperative imaging, underwent fine-needle aspiration cytology or core needle biopsy. The patients in this study were divided into four groups as follows: the ER(+), the ER(+)/HER2(+) , the HER2(+) and the Triple negative (TN) group. We evaluate the prognostic impact of the ypN0, ypN1 (with one to three positive lymph nodes after NAC), pN0 and pN1 with no NAC. The main outcome measures DFS and OS were analyzed using Kaplan–Meier survival analysis. Result A number of 270 and 3633 patients were included for NAC and non NAC, respectively. Pathologic nodal status was ypN0 in 58%, ypN1 in 42% for NAC and pN0 in 76%, pN1 in 24% of patients for non NAC. Overall, 10-year DFS and OS was 81%, 93% in ypN0, 67%, 80% in ypN1, in 90%, 97%, in pN0 and 83%, 94% in pN1 (p <0.001). In subgroup analysis, 10-year DFS of ypN0, ypN1, pN0 and pN1 was 86%,77%,95% and 80% in the ER group, 91%,56%,93%,and 76% in the ER/HER2 group,89%,55%,91% and 80% in the HER2 group, 85%,59%,92% and 80% in the TN group. 10 years DFS for the ER group were significantly different between ypN0 and pN0 (HR, 2.42 (1.03–4.86, p = 0.04) but were not significantly different between ypN0 and pN0 for the ER/HER2 group (HR 3.58 (0.2–6.88, p = 0.66), for the HER2 group (HR 2.6 (0.78–7.65, p = 0.10) and for the TN group (HR 1.22(0.56–2.38, p = 0.58), respectively). In all group, DFS for ypN1 was inferior to ypN0. Conclusions In the ER group treated with NAC, DFS for ypN0 be inferior to pN0 with adjuvant treatment. In the HER2, the ERHER2 and the TN group treated with NAC, ypN0 is similar to pN0 with adjuvant chemotherapy. Axillary nodal status ypN1 in each subgroup is associated with a less favorable prognosis compared to ypN0. In conclusion, the HER2 or TN group is highest for predicting ypN0, shown to be most prognostic of long-term survival similar to the patients with pN0. They could be omitted the axillary dissection. Citation Format: Nakamura R, Yamamoto N, Miyaki T, Itami M. Prognostic impact of axillary lymph node status after neoadjuvant chemotherapy for patients with breast cancer [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 P3-03-22.