Treatment for blood cancers has improved significantly, and more patients are now living longer. However, these treatments are often intensive and long-lasting, and many patients experience serious side effects and symptoms. As more patients require ongoing treatment and long-term care, the demand for haematology services is increasing.

Home-based treatment is expected to play an increasingly important role in the future. It can support more patient-centred care, help patients maintain their everyday lives, improve quality of life, and reduce pressure on hospitals. Despite these benefits, some patients are either not eligible for home-based treatment or choose to decline it. The reasons for this are not yet well understood.

This study combines quantitative data-such as medical information, sociodemographic characteristics, and questionnaire responses about quality of life and health literacy-with qualitative interviews involving patients, relatives, and healthcare professionals. The aim is to identify barriers and differences between patients, and to better understand why some patients opt out of or are unable to participate in home-based treatment.

The findings will help support the development of more inclusive and patient-centred care models, ensure more equal access to home-based treatment, and improve support for socially vulnerable patients. The results will be shared with patients and families through patient organisations, with hospitals through the Treat@Home programme, and at national and international conferences.

Background Advances in treatment have improved survival for patients with hematologic malignancies, yet these patients remain at risk of severe complications and a high symptom burden.

As more patients require treatment and long-term care, the demand for hematologic services continues to grow. Home-based treatment is therefore expected to play an increasingly important role, with the potential to enhance patient-centered care, support daily life, improve quality of life, and reduce hospital burden. However, a proportion of patients do not meet the eligibility requirements for home-based treatment, and others choose to decline this option despite being offered the opportunity. Understanding the characteristics, experiences, and perspectives of these patients is essential for developing equitable, patient-centered approaches to treatment delivery and ensuring that home-based care models do not inadvertently exacerbate health disparities. Understanding this knowledge gap is crucial. These patients often undergo long, intensive treatment, and socially vulnerable patients may face additional practical, emotional, or social challenges. Home-based treatment could provide flexibility and support to reduce such inequalities. Without insight into why some patients decline or are ineligible for home-based treatment, there is a risk that these models will primarily serve more resourceful patients, potentially reinforcing health disparities.

The overall aim of this mixed methods study is to investigate reasons for declining or being deemed ineligible for home-based treatment among patients with hematologic malignancies, their caregivers and healthcare professionals.

This will be addressed with the following questions:

1. Are there differences in medical, sociodemographic, and patient-reported outcomes between patients who decline or are ineligible for home-based treatment and those who accept it?
2. What barriers exist to receive home-based treatment for a hematologic malignant disease?
3. How do combined insights from the qualitative and quantitative data enhance understanding on barriers to home-based treatment? Methods Context This study is part of the Treat@Home research program, which aims to generate evidence on home-based interventions for patients with hematologic malignancies in Denmark. The program is anchored at the Department of Hematology, Zealand University Hospital (ZUH) and is led by the head of program and main applicant. It is supported by a management team and a national research group with interdisciplinary representatives from hematology departments across all Danish regions. In addition to several individual studies, the program includes two PhD projects investigating the implementation of home-based treatment with Daratumumab for multiple myeloma and Cytarabine for acute leukemia.

Design A mixed methods design will be applied, using quantitative and qualitative data. The qualitative study will apply interpretive description as a methodological framework. The qualitative and quantitative data will be merged, and through the mixed methods design, our aim is to converge two data sets and draw meta-inferences to gain deeper insights into the complexity of barriers to home-based treatment.

Participants In the quantitative sub-study, all patients from the Department of Hematology at Odense University Hospital (OUH) and ZUH who are enrolled in the two Treat@Home studies will be invited to participate, including those who accept, decline, or are deemed ineligible for home-based treatment. Inclusion will occur prospectively following enrollment. The aim is to include 50 participants, with 25 recruited from each site. While a formal sample size calculation is not appropriate at this stage, this number is justified on practical and methodological grounds.

In the qualitative sub-study, patients are eligible if they are invited to the quantitative sub-study but either declined or are deemed ineligible for home-based treatment. The aim is to include 20-25 participants, a range expected to achieve thematic saturation while allowing in-depth exploration of individual narratives. The final sample size will be determined based on Malterud's concept of information power, considering interview quality and participant variation.

Data collection In the quantitative sub-study, general medical data, comorbidities (Charlson Comorbidity Index), cancer-specific data, sociodemographic data, and patient reported outcomes will be collected at time of recruitment. Patient reported outcomes include health literacy (Health Literacy Questionnaire), quality of life (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30), and caregiver burden (Caregiver Roles and Responsibilities Scale). In the qualitative sub-study, separate semi-structured interview guides for patients, caregivers and health professionals will be developed based on the literature to define key research topics. Participants can choose to be interviewed at home, the research facility, or during a hospital visit.

Analysis In the quantitative sub-study, data will be analyzed using descriptive statistics. Numerical variables will be reported as means and medians (with ranges) and compared using Student's t-test. Categorical variables will be presented as counts and percentages. Differences between patients who accept or decline/are deemed ineligible will be assessed using appropriate tests, such as the Wilcoxon rank-sum test and Fisher's exact test. A p-value <0.05 will be considered statistically significant.

In the qualitative sub-study, all interviews will be transcribed verbatim and analyzed using Braun and Clarke's thematic analysis framework. The six-step process includes: 1) familiarization with the data through repeated reading and listening, 2) generating meaningful units, 3) identifying initial themes, 4) reviewing themes, 5) defining and naming themes, and 6) reporting the findings. Steps 1-3 will be conducted by a trained research nurse and steps 4-5. Analyses will be performed using NVivo version 14. Ethical considerations The study will be registered with the Danish Protection Agency and Clinical Trials. Participants will receive written and verbal information, including assurances of confidentiality in line with the Helsinki Declaration, and written consent will be obtained at recruitment. Given participants' potential vulnerability, extra care will be taken to ensure voluntary participation, and they will have time to debrief and discuss their experiences.

Project feasibility This study is highly feasible due to its integration within the national Treat@Home research program, which provides established infrastructure, clinical networks, and experience. OUH and ZUH have both conducted home-based treatment studies with Daratumumab and Cytarabine, ensuring access to the target patient population and familiarity with study protocols. The research team includes experienced clinicians and researchers in hematology, patient-reported outcomes, and mixed-methods research. Recruitment is facilitated through ongoing Treat@Home studies, and the qualitative sample size is achievable using thematic saturation and information power principles. Data collection and analysis procedures are well-established, using validated instruments and software to ensure robust integration of quantitative and qualitative findings.

Limitations The mixed-methods design strengthens this study by combining quantitative and qualitative data to understand why some patients decline or are deemed ineligible for home-based treatment. Limitations include potential constraints from sample size, missing data, and recruitment challenges, particularly among socially vulnerable groups, which may introduce selection bias. The qualitative findings, while rich, may have limited transferability and depend on participants' willingness to share experiences. Despite these challenges, integrating both data types allows triangulation and nuanced insights, providing critical knowledge to guide future studies and develop interventions that promote equitable access to home-based hematology treatment.

Inclusion Criteria:

• >=18 years old
• diagnosed Multiple Myeloma or acute leukemia, and recieving treatment with either Daratumumab or Cytarabine.

Exclusion Criteria:

- Dementia, psychotic disorders, or other cognitive impairments limiting participation.

All patients from the Department of Hematology at Odense University Hospital and Zealand University Hospital who are enrolled in the two Treat@Home studies will be invited to participate, including those who accept, decline, or are deemed ineligible for home-based treatment. We aim to include 50 participants, with 25 recruited from each site.

Considering sharing data upon request.