Primary Systemic Therapy for HER2/Neu-Positive Operable Breast Cancer Increases the Number of Breast-Conserving Surgery and Disease-Free Survival: Retrospective Cohort Analysis at Single Institution

Abstract

Objective The aim of this study was to evaluate the efficacy and cardiotoxicity profile, and to reduce the extend of breast cancer surgery in primary systemic therapy (PST) HER2/neu–positive operable breast cancer patients. Materials and Methods A total of 152 patients diagnosed from 2010 to 2015 were included in the study. The PST consisted of a sequential regimen of taxanes and anthracyclines plus trastuzumab. The clinical and pathological responses and the type of breast cancer surgery were evaluated and correlated with clinical and biological factors. The cardiotoxicity profile and long-term benefits were analyzed. Results The median patient age was 47 (37–67) years, with T2 and T3 67 (44.1%) and 85 (55.9%), respectively. Axillary lymph node breast cancer at diagnosis N0 was 104 (68.4%) and N1 and N2 were 28.9% and 2.6%, respectively. A total of 95.7% of patients had nonspecific type of breast cancer, 67% of tumors were hormonal receptor–negative, 75.5% were grade III, 100% Ki67 > 20%, and 90% of tumors were confirmed to be HER2/neu–positive through immunohistochemistry. Following PST, pathological complete response (pCR) rate was achieved in 44.7% evaluable patients. The pCR rate was higher in HR-negative (93.1% vs. 6.9%) cancer and in grade III (86.2%) than in grade I and II (13.8%) cancer; only 75.5% of complete response (CR) on ultrasound and magnetic resonance imaging were also CR on pathology results. Breast conserving surgery was performed in 41.4%. Regarding type of chemotherapy, there were no significant differences between chemotherapy with anthracycline backbone or taxanes to achieved pathological complete response. Despite that, we were unable to demonstrate an association between pCR and better DFS with p = 0.096; HR 5.7 95.0% CI (0.73–45.52). Patients who are hormonal receptor positive tend to have lower disease-free survival (DFS) than those who are hormonal receptor negative; HR = 6.34, 95.0% CI (1.54–26.00) and p = 0.010. Five years DFS was higher for those who achieved pCR compare with those who did not. Even in this research we failed to show it is statistically significant. Conclusion A sequential regimen of taxanes and anthracyclines plus trastuzumab was effective with high pCR rates and increases the possibility to do breast conservation surgery and had tolerable cardiotoxicity profile.