Background: Patients with glioblastoma have a poor prognosis and treatment is palliative in nature from diagnosis. It is therefore critical that the benefits and burdens of treatments are clearly discussed with patients and caregivers. Aim: To explore experiences and preferences around glioblastoma treatment communication in patients, family caregivers and healthcare professionals. Design: Qualitative design. A thematic analysis of semi-structured interviews. Setting/participants: A total of 15 adult patients with glioblastoma, 13 caregivers and 5 healthcare professionals were recruited from Leeds Teaching Hospitals NHS Trust. Results: Four themes were identified: (1) Communication practice and preferences. Risks and side-effects of anti-tumour treatments were explained clearly, with information layered and repeated. Treatment was often understood to be ‘the only option’. Understanding the impact of side-effects could be enhanced, alongside information about support services. (2) What matters most. Patients/caregivers valued being well-supported by a trusted treatment team, feeling involved, having control and quality of life. Healthcare professionals similarly highlighted trust, maintaining independence and emotional support as key. (3) Decision-making. With limited treatment options, trust and control are crucial in decision-making. Patients ultimately prefer to follow healthcare professional advice but want to be involved, consider alternatives and voice what matters to them. (4) Impact of COVID-19. During the pandemic, greater efforts to maintain good communication were necessary. Negative impacts of COVID-19 were limited, caregivers appeared most disadvantaged by pandemic-related restrictions. Conclusions: In glioblastoma treatment communication, where prognosis is poor and treatmentwill not result in cure, building trusting relationships, maintaining a sense of control and being well-informed are identified as critical.

BACKGROUND Given the poor prognosis of glioblastoma, it is critical that the benefits and burdens of treatments are clearly discussed with patients and family caregivers. We investigated experiences and preferences around glioblastoma treatment communication in patients, caregivers, and healthcare professionals (HCPs). METHODS Semi-structured qualitative interviews were conducted with adult glioblastoma patients, their caregivers, and HCPs. Purposive sampling was used to capture views across the entire disease trajectory and different specialties. Interviews were recorded, transcribed verbatim, and analysed thematically. RESULTS In total, 15 patients, 13 caregivers (in N=12 individual and N=8 dyadic interviews), and five HCPs participated (N=5 individual interviews). Four main themes were identified. 1) Communication practice and preferences. Risks and side-effects of anti-tumour treatments were explained clearly, with information layered and revisited frequently to aid understanding. Treatment was often understood to be ‘the only option’, particularly at recurrence. Understanding the impact of side-effects on daily life could be enhanced, including those from supportive medication (e.g., corticosteroids); alongside more proactive communication about support services. 2) What matters most. Patients/caregivers valued being well-supported by a trusted treatment team, feeling involved, having a sense of control, and quality of life. HCPs similarly highlighted trust, maintaining independence and quality of life, and emotional support as key. 3) Decision-making. With limited treatment options, trust and control are crucial in decision-making among patients, caregivers, and HCPs. While patients ultimately prefer to follow HCP advice they want to be involved, consider all alternatives, and voice what matters to them. 4) Impact of Covid-19. During the pandemic, greater efforts to maintain good communication were necessary. While negative impacts of Covid-19 were limited, caregivers appeared most disadvantaged by pandemic-related restrictions (e.g., limited visiting). DISCUSSION In glioblastoma treatment communication, building trusting relationships, maintaining a sense of control, and good support are identified by patients, caregivers, and HCPs as critical.