Abstract PS10-52: Adjuvant treatment with paclitaxel plus trastuzumab for node negative human epidermal growth factor receptor 2-positive breast cancer: Real life experience

BackgroundInvasive breast cancers are characterized by overexpression or amplification of the human epidermal growth factor receptor 2 (HER2) approximately 15 to 25%. Survival outcomes was improved after introduction of Trastuzumab treatment. Trastuzumab treatment was applied mostly with combination chemotherapy regimens at pivotal trials. There were some efforts to avoid the toxicity of combination chemotherapies and reduce the amount of treatment given especially in stage I HER 2 overexpressed breast cancer patients. Adjuvant paclitaxel plus trastuzumab was shown excellent disease free survival (DFS) and overall survival (OS) in node negative, 3 cm and smaller HER 2 overexpressed breast cancer patients. MethodsAll breast cancer patients that treated in Medical Oncology departments of Hacettepe University (Ankara, Turkey), Dr. Abdurrahman Yurtaslan Oncology Training and Research Hospital (Ankara, Turkey), Nicosia Dr. Burhan Nalbantoglu State Hospital (Nicosia, Cyprus) and Near East University (Nicosia, Cyprus) were retrospectively reviewed from patient files, center’s databases and chemotherapy files.ResultsWe retrospectively analyzed 173 patients who treated with adjuvant paclitaxel plus trastuzmab between April 1, 2012 and April 10, 2020. Median age was 52 years (range, 25 to 84 years) and 62.4% had estrogen receptor positive disease. 68.8% of the tumors were high-grade. 14.4% of patients had tumors 1 cm or smaller. 45.0% of patients had tumors larger than 2 cm and 32.3% of patients had tumors larger than 2 cm and up to 3 cm. 12.6% of patients had tumors larger than 3 cm. Mean tumor size was 2.2 cm. 88.4% of patients had N0 disease and 2.9% of patients had microscopic nodal metastasis. 164 of 173 patients completed all 52 weeks of adjuvant treatment. Median follow up of 43 months there were 8 DFS events observed: four distant recurrences (2.3%), three locoregional recurrences (1.7%) and one died without documented recurrence. 3-year DFS rate was 96.6%. There was no recurrences in patients who had tumors 1 cm or smaller. There were 5 DFS events in patients had tumors larger than 2 cm and up to 3 cm subgrup. ConclusionThis real life experience with paclitaxel plus trastuzumab demonstrated few distant recurrences and further supports the APT trial findings. Citation Format: Omer Diker, Burak Yasin Aktas, Recep Ak, Bahadir Koylu, Onur Bas, Polat Olgun, Hakan Taban, Deniz Can Guven, Neyran Kertmen, Berna Oksuzoglu, Sercan Aksoy. Adjuvant treatment with paclitaxel plus trastuzumab for node negative human epidermal growth factor receptor 2-positive breast cancer: Real life experience [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-52.