Adjuvant application of trastuzumab in HER2 positive breast cancer and impact on time to relapse

Abstract

Background: Of all breast cancers 20-25% are HER2 positive. Overexpression of HER2 protein on the surface of the malignant cell leads to excessive cell proliferation through different signaling pathways. Trastuzumab is a human monoclonal antibody that binds to domain IV of HER2 receptor and blocks signaling pathway for proliferation. The result is an improved prognosis for HER 2 positive breast cancer patients, even when compared to patients with other types of breast cancers. Methods: The study presents 74 women patients with early HER2 positive breast cancer who were previously operated (either radicaly or using breast conserving surgery), and received adjuvant chemoand radiotherapy. Fourty four patients received adjuvant trastuzumab for one year, and 30 patients did not (control group). Observed time to relapse of the disease was 60 months. Results: There was a significant difference in survival in favor of the group that received trastuzumab (p<0.001). Application of trastuzumab also delayed relapse of the disease by 51.7%. No significant difference was observed between estrogen receptor positive and estrogen receptor negative cancers., In the control group there was a significant difference in relapse free survival in favor of estrogen and progesteron receptor positive tumors (p<0.001). Conclusion: Survival of patients with a HER2 positive breast cancer whose prognosis was initially worse compared to HER2 negative patients, significantly improved after administration of trastuzumab.

Keywords

• cancer
• breast
• tyrosine kinase receptor
• her2
• trastuzumab
• prognosis
• antibodies