Abstract PS13-48: Impact of oncologists’ beliefs and habits on treatment decisions in hormone receptor positive (HR+)/ HER2 negative advanced breast cancer (ABC)
Authors: Peron Julien , Giacchetti Sylvie , Cassuto Ophélie , Deverge Tullia , Bouyssou Charlotte , Ferrero Jean-Marc , Luporsi Elisabeth , Lerebours Florence 
Published: February 2021

Background Current international expert guidelines in the 1st line setting for HR+/HER2- ABC recommend endocrine therapy plus a CDK4/6 inhibitor unless there is a visceral crisis. However, due to a lack of sequencing data, recommendations for further treatment lines are not clear-cut. In this context, treatment decisions are often based on response to first line treatment, aggressiveness of the disease and clinical expertise. Evidence-based medicine should inform decisions. This study aims to estimate the weight of beliefs and habits in therapeutic strategy choices. Methods This observational survey « Chemotherapy : beliefs and habits » was conducted among a representative sample of French oncologists with a breast cancer activity in private and public hospitals. The survey was conducted between November 2019 and January 2020. Oncologists were asked about their knowledge, perception and practice regarding the treatment of HR+/HER2- ABC patients. A focus was made on their perception of best available external clinical evidence leading to guidelines. Results 119 physicians answered the survey. They agreed that in absence of visceral crisis the first line treatment of HR+/HER2- metastatic breast cancer should be endocrine therapy plus a CDK4/6 inhibitor (98,3%). First line endocrine therapy was believed to be associated with a higher progression-free survival benefit (79%) and overall survival benefit (75%) compared to chemotherapy. Even in case of primary or secondary endocrine resistance, oncologists remained in favor of using an endocrine-based therapy at first line in 82% and 66% of cases respectively. The visceral crisis concept was presented through clinical cases. In a life-threatening situation, 10% of physicians maintained their choice of 1rst line endocrine therapy plus a CDK4/6 inhibitor. The oncologists were asked to choose the determinants of treatment choices (patient’s preferences, efficacy, safety, quality of life). Oncologists valued patients’ preference and quality of life with increasing treatment lines while clinical efficacy as measured by survival data were less and less guiding in their choice of treatment. Conclusion Evidence-based medicine is the integration of best research evidence with clinical expertise and patient values. It is a useful framework held as a standard in therapeutic strategy. However, beliefs and habits play an important role in the choice of treatment for HR+/HER2- ABC beyond the first treatment line. Clinical trials are needed in this setting to determine the best sequence of treatments. A comprehensive analysis of the survey results will be presented at the meeting.

Citation Format: Julien Peron, Sylvie Giacchetti, Ophélie Cassuto, Tullia Deverge, Charlotte Bouyssou, Jean-Marc Ferrero, Elisabeth Luporsi, Florence Lerebours. Impact of oncologists’ beliefs and habits on treatment decisions in hormone receptor positive (HR+)/ HER2 negative advanced breast cancer (ABC) [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 PS13-48.