Trastuzumab Treatment After Progression In HER2-positive Metastatic Breast Cancer Following Relapse Of Trastuzumab-based Regimens

Objective To evaluate the clinical efficacy of continuous treatment with trastuzumab in HER2-positive advanced breast cancer patients who progressed on previous trastuzumab-based regimens and assess the effect of trastuzumab resistance on survival outcomes of inclusive patients after cross-line trastuzumab treatment.Methods We retrospectively analyzed the clinical characteristics and survival outcomes of HER2-positive advanced breast cancer patients which were adopted in the trastuzumab aid project from Chinese Cancer Foundation from 2012 to 2016.Based on whether to retreatment with trastuzumab after failure on initial trastuzumab,we divided them into two cohorts and confirmed the clinical efficacy by statistical significance.Data was analyzed by SPSS 24.0.Results Among 195 patients with HER2-positive advanced breast cancer who met the inclusion criteria,70,89 and 73 patients were adopted in first/second/third-line treatment respectively.The first-line continuous trastuzumab treatment after failure on adjuvant trastuzumab could prolong progression-free survival(PFS)(9 months and 6 months respectively,P=0.027)and overall survival(OS)(20 months and 16 months respectively,P=0.031).After disease progression on previous trastuzumab-based regimens,retreatment with trastuzumab in second-line therapy could improve PFS(9 months and 5 months respectively,P=0.026)and present no significant effect on OS.No statistical improvement in PFS and OS was found in third-line therapy with the continuation of trastuzumab.Without existence of trastuzumab resistance in adjuvant therapy,retreatment with trastuzumab in first-line therapy could prolong PFS(9 months and 7 months respectively,P=0.027),but provided no significant effect on OS.For patients with trastuzumab resistance in first-line treatment,no significant improvement of PFS and OS was found in patients with the continuation of trastuzumab in second-line therapy.Conclusion Continuation of trastuzumab in first/second-line chemotherapy after failure on trastuzumab-based regimens could significantly prolong PFS and retreatment with trastuzumab in first-line therapy would improve survival.Trastuzumab resistance could not influence the clinical outcomes of retreatment with trastuzumab in HER2-positive advanced breast cancer.