The Clinical Significance of Breast-only and Node-only Pathologic Complete Response (pCR) after Neoadjuvant Chemotherapy (NACT): A Review of 20,000 Breast Cancer Patients in the National Cancer Database (NCDB)
Oluwadamilola M. Fayanju*1, Yi Ren*1, Samantha M. Thomas*1, Rachel A. Greenup*1, Jennifer K. Plichta*1, Laura H. Rosenberger*1, Nina Tamirisa*1, Jeremy Force*1, Judy C. Boughey*2, Terry Hyslop*1, E. Shelley Hwang1
1Duke University, Durham, NC;2Mayo Clinic, Rochester, MN
OBJECTIVE(S) Pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) is a validated surrogate for overall survival (OS) in breast cancer. We determined whether achieving pCR in the breast, lymph nodes, or both was independently associated with OS. METHODS Women≥18 with cT1-3,cN0-1 breast cancer diagnosed 2010-2014 who underwent surgery following NACT were identified in the NCDB and divided into 4 phenotypes by hormone receptor (HR) and HER2 status. Kaplan-Meier curves were used to visualize unadjusted OS with significance declared for log-rank p<0.05. Multivariate logistic regression and Cox proportional hazards models were used to estimate associations with response to NACT, defined as upstage; no change (clinical stage=yp stage); complete (i.e., breast+axilla, ypT0N0), breast-only (ypT0N1/N1mic), or node-only (ypT1-3N0) pCR. RESULTS 20,265 patients were included. 31.4% of patients achieved breast+axilla pCR; among cN1 patients (n=8624), 5.7% had breast-only and 13.1% had node-only pCR. In multivariate modeling, breast+axilla pCR was associated with improved OS vs no stage change across all cN1 patients, but breast-only pCR was associated with improved OS only in triple-negative disease (HR=0.58,95%CI=0.37-0.89). Node-only pCR was associated with OS in both triple-negative (HR=0.55,95%CI=0.39-0.76) and HR+/HER2- disease (HR=0.54,95%CI=0.33-0.89, all p<0.05). For patients achieving breast+axilla pCR, unadjusted 5y OS among all phenotypes was 0.94 (95%CI=0.93-0.96) and did not differ between those who presented with cN0 (0.95,95%CI=0.93-0.96) vs cN1 disease (0.94,95%CI=0.92-0.96). CONCLUSIONS Response to NACT and its association with survival differ significantly by cN stage and receptor phenotype. In patients achieving pCR, OS is driven more by response to NACT than by cN stage at presentation.
Back to 2018 Program