Discrepancy of pathologic complete response and outcome between breast tumor and axillary node in HER2 positive breast cancer after neoadjuvant chemotherapy.

Abstract

e12503 Background: The pathologic complete response (pCR) rate in primary tumor and axillary node after different chemotherapy regimens of neoadjuvant chemotherapy (NAC) in HER2 positive breast cancer (BC) is unknown, the impact of pCR on disease free survival (DFS) and overall survival (OS) is still controversial. Methods: A cohort of 350 HER2 positive BC (296 cytologically proved axillary node metastasis) received NAC with different regimens, antracyclin with taxotere (AT), docetaxel with transtuzumab (DT) and docetaxel with transtuzumab and pertuzumab( DTP) between 2005 and 2016 in a large medical center were analyzed retrospectively. The impact of pCR rates of breast and axillary node on DFS and OS were analyzed. Results: Of 350 women with HER2 positive BC received NAC, median age was 50 years(18~93), median tumor size was 4.3 cm, the pCR rates of breast and axillary node were 16.2% and 28.7% ( P= 0.018) in patients received AT( n= 130) , 47.6% and 66.9% ( P= 0.00028 ) in patients received DT( n= 191) ,65.5% and 77.8% ( P= 0.372 ) in patients received DTP( n= 29), respectively. The 5-year DFS were 79.3% and 66.0% ( p= 0.0023), 5-year OS were 89.5% and 76.6% ( P= 0.0201) in patients with breast pCR and non-pCR, respectively. The 5-year DFS were 75.7% and 58.4% ( P= 0.00037), 5-year OS were 85.7% and 72.6% ( P= 0.0024) in axillary pCR and non-pCR patients, respectively. The 5-year DFS were 79.3% and 75.7% ( P= 0.430), and 5-year OS were 89.5% and 85.7% ( P= 0.695) in breast and axillary pCR, respectively . The 5-year DFS in breast pCR whom received targeted therapy (DT and DTP groups) was significantly better than whom not received targeted therapy (AT groups), 85.3% and 65.0% ( P= 0.039), respectively Conclusions: Higher pCR rate in axillary node than breast was found in this cohort. Either pCR in axillary node or breast was associated with improved DFS and OS, but no difference of DFS and OS between breast and axillary pCR . The 5-year DFS in breast pCR received targeted therapy were significantly better than breast pCR patients received chemotherapy alone.