66P - Prognostic and clinical values for prediction of breast cancer recurrence in HER2 positive early breast cancer after surgery in King Chulalongkorn Memorial Hospital 2005-2016

Abstract

Background: Human epidermal growth factor receptor 2 (HER-2) overexpressed breast cancer occurs in 15-20% and associated with diminished disease-free and overall survival. After surgery, the standard treatment in HER-2 positive early breast cancer is systemic chemotherapy combined with trastuzumab. However, one fifth of these patients had disease recurrence in five years after treatment. So, the study was aimed to identify prognostic and clinical values that associated with survival outcomes especially in term of recurrence free survival. Methods: One hundred and sixty-nine patients with early stage HER-2 positive breast cancer who were diagnosed and treated at King Chulalongkorn Memorial Hospital from January 2005 to December 2016 were reviewed retrospectively. Clinico-pathologic features and survival outcomes were analyzed. Results: In initial analysis, median age was 50 years (26-83), 49.1% had premenopausal status, 93.4% had invasive ductal carcinoma, 52.6% had T2 tumor, 58.6% had node negative, 46.1% had lymphovascular invasion, 79.2% had free margin and 46.7% had positive estrogen and progesterone receptor. For the treatment, 69.8% underwent modified radical mastectomy, 96.4% received neoadjuvant/adjuvant chemotherapy, 55.6% received adjuvant trastuzumab, 48.5% received adjuvant hormonal therapy and 68% received post-operative radiotherapy. 35 out of 169 (20.7%) patients had recurrence disease. Distant metastasis was identified in 62.8%. From univariate and multivariate analysis, trastuzumab used (HR 0.44 [95%CI 0.21-0.9]; p = 0.007 from multivariate) and surgical margin (HR 1.02 [95%CI 1.0-1.03]; p = 0.012 from multivariate) were associated with increase risk of recurrences. After median follow up 4.9 years, the 5-years recurrence free survival was 81.2%, 89.2% and 70.7% in overall populations, trastuzumab used subgroup and non-trastuzumab used subgroup, respectively. Overall survival will be further analyzed. Conclusions: Trastuzumab used and surgical margin status were statistically significant prognostic values for predicting disease recurrence in HER-2 positive early breast cancer. Legal entity responsible for the study: Division of Medical Oncology, Department of Medicine, Faculty of Medicine, Chulalongkorn University and the King Chulalongkorn Memorial Hospital. Funding: None Disclosure: All authors have declared no conflicts of interest.