The prognostic value of lymph node response to neoadjuvant therapy among breast cancer subtypes

Abstract

Objectives. The aim of this study was to assess the prognostic value of persistent node involvement after neoadjuvant chemotherapy among breast cancer subtypes. Materials and methods. A total of 258 patients with T1-T4 and N0-N3 breast cancer treated by neoadjuvant chemotherapy followed by tumor excision and axillary lymph-node dissection between January 2015 and December 2019 were selected from the Coltea Clinical Hospital database and retrospectively evaluated. Association between nodal involvement (ypN) binned into four classes (0, 1-3, 4-9 and >10), relapse free-survival and overall survival among the whole population and according to breast cancer subtypes was analyzed using Statistical Package for Social Science Version 29.0.2.0. Outcomes. After a median follow-up of 20.7 months (range 1-97 months) post neoadjuvant chemotherapy nodal involvement was significantly associated with disease free survival in the whole population (X2(3)= 23.161, p <.001) and between breast cancer subgroups (X2(3) = 27.871, p= <.001). After univariate cox regression analyses by breast cancer subtypes nodal involvement was statistically significant only in the Luminal B(HER-) (X2(3)=14.867, p=.002) and triple-negative breast cancer (X2(3)= 9.867, p=.020). In Luminal B(HER2-) breast cancers all nodal involvement subgroups were associated with impaired relapse free survival compared to ypN0 tumors (1-3 nodes, HR= 4.871, 95%CI [1.32-17.94], p=.017; 4-9 nodes, HR=5.126, 95%CI [1.341-19.59], p=.017; >10 nodes, HR=8.744, 95%CI [2.379-32.13], p=.001). In triple negative breast cancers, relapse-free survival was associated with an adverse prognosis in patients with more than 10 nodes involved when compared with ypN0 (HR=16.57, 95%CI [3.25-84.30], p=<.001). There was no statistically significant association in the univariate cox regression analyze between post neoadjuvant chemotherapy nodal involvement and overall survival neither in the whole population (X2(3)=.992, p=.803) nor among breast subtypes (X2(3)=1.191, p= .779). Kaplan Meier analyze of RFS adjusted for BC subtype showed a statistically significant relapse rate in all groups (1-3 (p=.035), 4-9(p=<.001), >10 (p=<.001)) compared with ypN0 group. Kaplan Meier overall survival analyze showed no statistical difference in survival among node groups. Conclusions. Post neoadjuvant chemotherapy lymph node status in breast cancer subtypes represents an important prognostic factor of relapse-free survival and the prognostic value of residual axillary disease should be interpreted according to breast cancer subtype.