Abstract P1-13-13: The treatment patterns and clinical outcomes of trastuzumab in early human epidermal growth factor receptor 2 (HER2) positive breast cancer in the real-world setting in China

Abstract

Abstract Background:Several prospective interventional studies have proved the efficacy and safety of trastuzumab in adjuvant treatment in HER2positive breast cancer,while limited data existed to address the treatment patterns and real-world performance of trastuzumab in early HER2 positive breast cancer in China. Methods:We retrospectively analyzed all the pts who were diagnosed with HER2-positive breast cancer,underwent surgery and received adjuvant treatment in National Cancer Center from 2000 to 2012.The treatment patterns and disease free survival (DFS),overall survival (OS) were analyzed respectively. Results:A total of 1398 HER2 positive breast cancer pts were identified.The median follow-up time was 79.1 months.68.5% pts received chemotherapy alone,3.4% pts only received mono trastuzumab,28.2% pts received trastuzumab plus chemotherapy.Among 433 trastuzumab treated pts,64.7% received concurrent trastuzumab with chemotherpy,and 35.3% pts received sequential trastuzumab with chemotherapy Baseline characteristics by Chemotherapy alone and Chemotherapy + Trastuzumab.No(%) of patients characteristicTrastuzumab- (N=957)Trastuzumab+ (N=441)Total (N=1398)Age (years) <=3596 ( 10.0)44 ( 10.0)140 ( 10.0)36 - 50434 ( 45.4)244 ( 55.3)678 ( 48.5)>50427 ( 44.6)153 ( 34.7)580 ( 41.5)Histologic grade I15 ( 1.6)7 ( 1.6)22 ( 1.6)I-II,II480 ( 50.2)224 ( 50.8)704 ( 50.4)II-III,III285 ( 29.8)166 ( 37.6)451 ( 32.3)IDC148 ( 15.5)29 ( 6.6)177 ( 12.7)Other29 ( 3.0)15 ( 3.4)44 ( 3.1)Clinical stage 026 ( 2.7)16 ( 3.6)42 ( 3.0)I259 ( 27.1)108 ( 24.5)367 ( 26.3)II434 ( 45.4)196 ( 44.4)630 ( 45.1)III238 ( 24.9)121 ( 27.4)359 ( 25.7)Hormone receptor status Positive635 ( 66.4)256 ( 58.0)891 ( 63.7)Negative322 ( 33.6)185 ( 42.0)507 ( 36.3) .Trastuzumab plus chemo had significantly longer DFS compared with chemo alone.(85.03%vs72.15%,hazard ratios,HR=0.531,95% confidence interval,95%CI:0.406-0.696, p<0.001).In addition,the concurrent trasuzumab showed the trend with longer DFS compared to the sequential regimen(86.07%vs82.35%,HR=0.843,95%CI:0.515-1.378, p=0.495).Age,tumor size, lymph node status,clinical stage were associated with DFS Results of Cox regression hazard model with treatment groups and patient characteristics on DFSGroupHR95% CIP valueTreatment group Concurrent Trastuzumab0.8430.515-1.3780.495Sequential Trastuzumab Chemotherapy+Trastuzumab0.5310.406-0.696<0.001Chemotherapy alone Age group (years) 0.001<=351.6501.198-2.2730.00236 - 500.8880.702-1.1220.319>50 Histologic grade <0.001I0.5200.210-1.2880.158I-II,II0.5040.379-0.671<0.001II-III,III0.5320.390-0.725<0.001Other0.5140.264-0.9970.049IDC Clinical stage <0.00100.2610.107-0.6370.003I0.2860.207-0.395<0.001II0.4800.379-0.607<0.001III Hormone receptor status 0.022Positive0.7730.621-0.9620.021Negative .OS was also prolonged in trastuzumab plus chemotherapy compared with chemotherapy alone.(93.20%vs85.45%,HR=0.561,95%CI:0.377-0.835, p=0.004). Conclusions:Our study revealed that,there were still more than half of HER2-positive breast cancer pts couldn't reach anti-HER2 therapy in China,the early stage HER2-positive breast cancer pts could significantly benefit from trastuzumab adjuvant therapy in real-world setting. Citation Format: Guo J, Xu B, Li Q, Zhang P, Yuan P, Wang J, Ma F, Fan Y, Cai R, Luo Y, Li Q. The treatment patterns and clinical outcomes of trastuzumab in early human epidermal growth factor receptor 2 (HER2) positive breast cancer in the real-world setting in China [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-13.