Abstract PO2-05-11: Patient Perspectives on the Value of Stereotactic Body Radiotherapy (SBRT) in the Management of Breast Cancer: The PERSPECTIVE Study

Abstract

Abstract Background: Oligometastatic disease describes limited metastases amenable to local therapy such as stereotactic body radiotherapy (SBRT). Within the UK National Health Service (NHS), SBRT is a standard of care for up to 3 metachronous sites of oligometastatic breast cancer (OMBC), offering high local control rates with low toxicity. The SABR-COMET study demonstrated improved progression-free survival (PFS) and overall survival (OS) with SBRT compared to standard of care in a number of oligometastatic cancers, including breast cancer [1]. Conversely, the NRG-002 trial results suggest no PFS or OS improvement with the addition of SBRT to standard systemic therapy in OMBC [2]. The OS data for this study are yet to mature and in the meantime the results of other prospective studies are awaited. As patients’ attitudes and perspectives govern their preferences around treatment decisions, it is vital to understand whether PFS and OS are the most important considerations for patients. This study aims to explore patients’ perspective on the role of SBRT in breast cancer management. Their views will help inform future trial endpoints and support clinicians to support patients with their decision making and expectations. Methods: We conducted an exploratory qualitative study with focus groups and individual interviews, to understand participants knowledge, views and opinions on SBRT in treating breast cancer. All patients were asked to watch an educational video about SBRT in advance of participating in the interviews. An interview guide with open-ended questions was developed. Breast cancer patients were recruited using a purposive sampling matrix based on the patients age, presence of metastatic disease and previous experience with radiotherapy. Each focus group had at least two moderators and all interviews were digitally recorded and then transcribed. The data were managed and coded using NVivo version 12 and analysed using a thematic analysis approach. Results: A total of 18 breast cancer patients participated in this study, with 7 (39%) having primary disease and 11 (61%) with metastatic disease. The study included two focus groups (group one = 5 patients; group two = 9 patients) and four individual interviews conducted between May and June 2023. The participants had a median age of 54 years (range 38-74). The majority of participants (83%) had previous experience with radiotherapy, with 4 (27%) having received SBRT previously for their OMBC. Only 2 (2%) patients who had not previously received SBRT were aware of it before participating in this study. Most of the patients (78%) were Caucasian and 72% had attained at least an undergraduate degree level of education. Throughout the study, three main themes emerged: theme 1 - participants experience with radiotherapy; theme 2 - interests and considerations regarding SBRT (including desired treatment outcomes) and theme 3 - willingness to consider SBRT in absence of a survival benefit. Extending their life was unanimously described as the most important desired outcome of SBRT, followed by quality of life. Other desired treatment outcomes expressed included reduction of tumour size, minimal collateral damage/side effects, relief of symptoms, avoidance of recurrence and increase in time to change of systemic therapy. Conclusion: In our study, while extension of life was a desired treatment outcome of SBRT for OMBC, all participants expressed willingness to consider SBRT for its potential benefits in local control and durable pain control, even in absence of a survival benefit.