A new molecular-based lymph node staging classification determines the prognosis of breast cancer patients

Abstract

Background:The one-step nucleic acid amplification (OSNA) assay is a novel molecular method that can detect metastasis in a whole lymph node based on cytokeratin 19 mRNA copy number. This cohort study aimed to establish an OSNA-based nodal staging (pN(mol)) classification for breast cancer.Methods:The cohort consisted of 1039 breast cancer patients who underwent sentinel node (SN) biopsy using the OSNA assay. Cutoff value of the SN tumour burden stratifying distant disease-free survival (DDFS) was determined, and predictive factors for DDFS and breast cancer-specific survival (BCSS) were investigated. pN(mol) classification of the SN status was defined as: pN0(mol)(sn), SN negative; pN1mi(mol)(sn), SN positive and tumour burden