Effect of Delay in Initiation of Adjuvant Trastuzumab and Dose Interruptions on Overall Treatment Outcome in Breast Cancer Patients, a Retrospective Study

Abstract Background HER2 amplification or protein over-expression is found in 20% of invasive breast cancers. It’s clearly associated with accelerated cell growth and proliferation and poor clinical outcome. The amplification of HER2 was historically an adverse prognostic factor associated with a higher risk of recurrence, lack of or lower levels of ER expression, and relative resistance to endocrine therapy and CMF based chemotherapy. Objectives We aimed in this study to assess the impact of delaying the initiation of adjuvant Trastuzumab for more than three months after the diagnosis of breast cancer and the effect of irregular and interrupted doses of adjuvant Trastuzumab, on progression free Survival, relapse, and overall survival (OS) among patients with breast cancer. Patients and Methods A Retrospective cohort study was conducted in Ain Shams University Hospitals. The study included one hundred patients with HER2 positive breast cancer. from January 2011 till December 2016 at the" Department of Clinical Oncology and Nuclear Medicine, Ain Shams University Hospitals". Results The median time to progression in group I was 19 months compared to 30 months in group II. There was statistically significant decrease median of group I compared to group II according to PFS. Conclusion We concluded that delays in the initiation of adjuvant treatment may be particularly harmful in patients with more aggressive tumor types.