Association of pathologic non-complete response of axillary node with outcome after neoadjuvant chemotherapy in node positive breast cancer.

Abstract

e12101 Background: The pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) correlates with better outcome in specific subtype of breast cancer and the axillary nodal pCR (N-pCR) rate are more common than breast pCR (B-pCR). While only a few studies to compare the survival in terms of B-pCR and N-pCR, and no study compare between the outcome for those non pCR either in breast or axillary node. Methods: A cohort of 968 cytologically proved nodal metastatic breast cancer (cT1~4N1~2) received NAC in a single medical center between 2005~2017 were analyzed retrospectively. NAC regimen included anthracycline and taxanes in all patients, Trastuzumab was used in 308(70.3%) HER2(+) patients. The percentage of both breast and axillary pCR (T-pCR) 、B-pCR and N-pCR were compared in different subtypes. The impact of T-pCR、B-pCR and N-pCR to DFS and OS were analyzed using univariate and multivariate Cox proportional hazard model. Results: The median follow-up time was 45 months. The median age was 49 years old, average tumor size was 4.2cm, and 543 (56.1%) patients were N1 disease. 382(39.5%) patients were HR(+) HER2(-), 222(22.9%)were HR(+)HER2(+),216(22.3%) were HR(-)HER2(+) and 148(15.3%) were HR(-)HER2(-). After NAC, T-pCR was found in 213 (22.0%) patients, B-pCR and N non-pCR in 31 patients, N-pCR and B non-pCR in 245 patients and T non-pCR in 479 patients. N-pCR rate(47.3%) were significantly higher than B-pCR(25.2%) and this trend found in all subtypes ( P<0.0001).The predicting factors of N-pCR were N1,HER2(+) and HR(-). In survival analysis the pCR (either T,B or N) patients had significantly better 5-year DFS and OS than non- pCR(T-pCR v.s T non-pCR, DFS,85.1% v.s 58.4%;OS,91.2% v.s 73.6%,p<0.0001). B-non pCR had a significant better DFS than T non Pcr(65.1% v.s 58.4%,p=0.041) and non- significant. Cox better 5-year OS(78.9% v.s73.6%,p=0.059). Cox regression model demonstrated that T4,N2,grade 3, HR(-) and T non-pCR were poor prognostic factors in DFS and OS. Conclusions: The study demonstrated higher N-pCR rates than B-pCR in all subtypes after NAC, either T-pCR;B-pCR or N-pCR were associated with better outcome than non pCR. The worst outcome found in those T non-pCR or N non-pCR.