Introduction

There is great interest currently on the issue of financial toxicity (FT) in cancer care with research papers, commentaries, and press articles on the topic substantially growing. The term ‘FT’ is used to describe the financial distress or hardship as an outcome of cancer treatment [1]. Alleviating the impact of FT requires knowledge of how health services are organised and funded within the respective health system and the efforts of numerous groups including policy makers, clinicians, advocacy groups, and industry. The supportive care community has taken the mission of lessening the negative impact of FT very seriously. Regardless of how it is measured, relatively high levels of FT are experienced by oncology patients and their caregivers [1]. Our recent systematic review of the FT literature found that the frequency of FT ranged from 28 to 48% using monetary measures like percentage of household income, and 16 to 73% using self-report measures such as impacts on everyday living expenses [1].

While high financial burden reduces health-related quality of life, especially the emotional well-being domain [2,2,3,4,6], little is known about the relationship between FT and symptom burden, especially physical symptoms. We propose that increased knowledge of the experiences of having both FT and physical symptoms and, how they relate to each other, will inform the development and testing of interventions to decrease FT and/or symptom burden. This commentary discusses the importance of investigating the relationships between FT and symptom burden.

Why would increased knowledge of the relationships between FT and symptoms be helpful?

In an Irish study of 654 cancer survivors, participants who reported FT were three times more likely to develop depression and anxiety [7]. Similarly, in a US study of patients with advanced disease (n = 149), significant relationships were found between patient-reported FT and psychological distress, including anxiety and depression [8]. However, while the relationships between financial burden and psychological distress are becoming clearer, very few studies have evaluated the relationships between FT and physical symptoms or symptom clusters.

Research findings [9, 10] and clinical experience suggest that symptoms do not occur in isolation. In recent years, our understanding of the underlying biologic mechanisms for symptom clusters has increased [11]. With the increased knowledge of the impact of FT on cancer patients and their caregivers, researchers in the supportive care community must investigate the relationships between FT and symptom/symptom clusters. For example, one plausible research question could be ‘How does FT impact sleep disturbance, as well as a symptom cluster that include sleep disturbance?’. Given the previous findings on the relationships between FT and psychological distress [7, 8], one would ask ‘How does FT influence a symptom cluster that includes anxiety and/or depression?’. For those patients who are experiencing FT and are struggling to meet the costs of cancer treatment, one could ask ‘How is FT associated with the costs of treatment for symptom management?’. We already know that caregivers experience significant symptom burden [12, 13]. Another question would be ‘What are the relationships between FT (that influence the entire household) and symptom burden in caregivers?’. When answered, these important clinical questions may assist with developing interventions to reduce the impact of FT as well as symptom burden.

Fatigue, pain, cognitive dysfunction, depression, and peripheral neuropathy may decrease patients’ function status and impede cancer survivors’ ability to return to work [14]. However, no studies have evaluated if effective management of these symptoms increases survivors’ ability to return to work. A 2015 Cochrane review of 15 RCTs (n = 1835) investigated the effects of interventions designed to enhance return to work in cancer patients. Of these 15 included studies, only one aimed to decrease fatigue and in turn enhance return to work [15]. While acknowledging that unemployment or restricted employment after cancer can be multifactorial, it would be important that future research determines whether and how symptom burden is responsible for unemployment or restricted employment which in turn worsens FT.

In addition to costs of anti-neoplastic drugs, it is essential that clinicians discuss with patients and caregivers the costs associated with supportive care treatments. Communication between physicians and patients about the costs of cancer treatment is sub-optimal [16, 17]. Therefore, robust discussions are taking place and expectations about the pivotal role that oncologists play in preparing patients for the costs associated with cancer treatments is increasing [18, 19]. However, research studies that examine the quality of health professional/patient communication around the costs of supportive care and the financial impact for patients are limited. While oncology nurses often assume an important role in symptom management, our recent survey of 423 oncology nurses found that discussions with cancer survivors about employment and financial issues were one of the least frequently discussed topics [20, 21]. Furthermore, nearly half of the participants did not agree that these discussions were part of their role. Compared to other types of survivorship care interventions, cancer nurses expressed that they were the least confident in their ability to discuss these issues.

Conclusions

In conclusion, this paper highlights the importance of increasing the new knowledge of the relationships between FT and symptom burden. We recommend that future research tests the relationships between FT and symptom burden in different groups of oncology patients and caregivers at various stages of their survivorship journey. Based on the discussion above, we propose a theoretical framework that can serve as a guide for future testing (see Fig. 1). A variety of research methods such as big data study and mixed-methods designs may be useful to tease out the relationships among a variety of phenotypic characteristics and outcome measures.

Fig. 1
figure 1

Proposed theoretical framework for evaluating the relationships between financial toxicity and symptom burden

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