Neoadjuvant chemotherapy for luminal a breast cancer: Factors predictive of histopathologic response and oncologic outcome

Background The benefit of chemotherapy (NAC) for patients with ER/PR positive, HER2 negative breast cancer is unclear. Our aim was to determine factors associated with histopathologic response and oncologic outcome following NAC in this group. Methods Consecutive female patients undergoing neoadjuvant therapy and surgery for locally advanced Luminal A breast cancer between 2010 and 2015 were studied. Multivariable linear, logistic, and Cox regression analysis was undertaken. Results 114 patients were studied. Pathological complete response (pCR) was achieved in 7.9% of patients, ypN0 in 25.5%, and downstaging in 33.6%. However, 43.9% exhibited a Sataloff C-D response. Tumor grade independently predicted pCR (P = 0.039), while PR score predicted ypN0 (P = 0.017) and downstaging (P=0.029). 5-year invasive disease-free (iDFS) and overall survival (OS) were 68.5 ± 4.7% and 77.7 ± 4.3%, respectively. Conclusion After NAC for Luminal A breast cancer, pCR rates are low. Patients with high grade tumors with weak PR expression exhibit the most promising response rates.