Receptor Status Change From Primary to Residual Breast Cancer After Neoadjuvant Chemotherapy and Analysis of Survival Outcomes

Abstract Background To evaluate the frequency of receptor change from pretreatment to residual breast cancer after NCT and their correlation with outcomes. Patients and Methods Three hundred ninety-eight women were identified retrospectively. Estrogen receptor, progesterone receptor, and HER2 were reviewed. Patients were classified as not having receptor change versus any receptor change. Kaplan–Meier was used to estimate survival outcomes according to changes. Cox proportional hazards models were used to determine the association of receptor status changes with outcomes after adjustment for patient and tumor characteristics. Results One hundred sixty-two (40.7%) patients had a change in at least 1 of the receptors from pretreatment to residual disease. Patients who had no change in receptor status had a significantly greater triple-negative breast cancer (TNBC) rate at baseline ( P  = .0001). Of the 193 hormone receptor (HR)-positive tumors, 9 (4.7%) and 29 (15.1%) became HER2-positive and TNBC, respectively. Of the 72 HER2-positive tumors, 20 (27.8%) and 9 (12.5%) became HR-positive and TNBC, respectively. Of the 128 TNBC tumors, only 2 (1.6%) and 33 (25.8%) became HER2-positive and HR-positive, respectively. At a median follow up of 40 months, 5-year overall survival (OS) was 73% and 63%; and 5-year relapse-free survival (RFS) was 63% and 48% for patients with or without any receptor change ( P  = .07 and P  = .003), respectively. Any receptor change was associated with better RFS (hazard ratio, 0.63; 95% confidence interval [CI], 0.44-0.9) but not OS. (hazard ratio, 0.79; 95% CI, 0.53-1.18). Conclusion Changes in receptor status between the pretreatment and residual disease after NCT are frequent and appear to be associated with improved RFS because of the receptor stability of TNBC.