Neoadjuvant versus adjuvant chemotherapy with taxanes and anthracycline-based regimen: Which leads to better outcome in patients with different subtype breast cancer?

Abstract

1084 Background: Neoadjuvant chemotherapy was reported to lead to equal outcome with adjuvant therapy in operable breast cancer. However, different molecular subtypes show variant response to chemotherapy, which is associated with different long-term prognosis. This study was to clarify whether molecular subtypes lead to different outcome between neoadjuvant and adjuvant chemotherapy. Methods: We identified 406 patients with stage II-III breast cancer who were treated with neoadjuvant or adjuvant chemotherapy between 2000 and 2008. To minimize the confounding bias, only patients received taxanes and anthracycline based regimen (TA) were included. Cases were divided according to receipt of neoadjuvant and adjuvant therapy. Data were compared using χ2test and analysis of variance. Kaplan-Meier Curves were generated. Results: Of the 406 patients, 201(49.5%) received neoadjuvant chemotherapy and 205(50.5%) received adjuvant TA regimen. The pCR rate was 12.9%(26/201) in total, and 7%, 14%, 33.3%, 19.4% for Luminal A, Luminal B, HER2+ and Triple negative breast cancer(TNBC), respectively. The HER2+ and TNBC have significantly higher rates of pCR than Luminal type (p<0.05). In general the two groups showed little survival variance (p=0.073 for DFS and p=0. 601 for OS). In Luminal B, neoadjuvant settings led to worse disease free survival (DFS) and overall survival (OS) than adjuvant settings after controlling for the covariates associated with survival in unadjusted tests (HR=0.41, p=0.028 for DFS; HR=0.32, p=0.020 for OS). In HER2+ subtype, neoadjuvant group corresponded to better DFS and OS (HR=5.65, p=0.024 for DFS; HR=10.52, p=0.010 for OS). On the contrary, patients with TNBC and Luminal A undergoing neoadjuvant chemotherapy had equal DFS and OS compared with patients receiving adjuvant therapy (p>0.05). Conclusions: The results demonstrate survival difference between patients receiving neoadjuvant and adjuvant cytotoxic therapy in variant subtypes. Prospective studies are necessary to determine if the finding is durable and optimize the timing of chemotherapy for breast cancer with different molecular background.