Cancer is a disease with a significant economic impact for patients and relatives. This statement might probably be unquestionable in countries with health systems with liberal models or voluntary private insurance, where healthcare depends on individual purchasing power. In settings with public health systems, this is at least a matter to be considered; although a complete coverage for health costs would be expected, many families face an unexpected financial burden along the prolonged process of oncological treatment (1).

Around 2,000 million people in the world are dealing with the devastating cost of healthcare (2). Scientific evidence highlights that all current health systems generate a certain level of financial difficulties, including public models, where one third of oncological patients will experience stress and anxiety as a consequence of the economic difficulties faced (3). In Spain, a recent report by the Spanish Association against Cancer (4) showed that 16.5% of the survey participants reported economic expenses over 10,000 euros as a consequence of the disease.

The economic burden faced by patients with cancer has been identified as a negative collateral effect for new therapies, which are promising and effective but have a high cost, and for the assignation of cancer as a chronic condition, perpetuating the loss of income and additional expenses derived of the pathological process (5). This scenario also generates impact on the economic and general wellbeing of the family unit, which should not be overlooked in the clinical evaluation and follow-up of the patient.

In this sense, it has become evident in the last decades that the disease needs to be addressed in terms of its economic aspect, and the concept of Financial Toxicity (FT) has appeared, which includes the subjective financial anxiety resulting of direct costs (e.g., medication-related costs), and indirect costs (e.g., the loss of income as a consequence of time off work) of the disease process (6). This has already been identified as an adverse effect of cancer, with the same relevance as clinical complications (1).

The response by a person faced with the economic burden of the disease can appear through multiple mechanisms, such as the termination or reduction of their leisure patterns, the reduction in treatment adherence, or even delaying or renouncing to healthcare (6). Financial toxicity, at the same time, leads to unfavourable health results, and a worse quality of life is reported (7,8) and higher early mortality in those persons suffering it (9).

The conceptualization of financial toxicity has become effective in countries with a prevalence of private health care and in the oncology setting; there is limited scientific evidence in public health systems, particularly in systems with universal coverage. However, we cannot ignore the burden that might be due to the type of health system, as well as the rest of social determinants of health, on the development of this phenomenon.

To this respect, bibliography shows that financial toxicity is mostly determined by sociodemographic, economic and occupational factors that characterize subjects before and during their cancer diagnosis and treatment; the health system is a key factor determining the degree of toxicity that patients might suffer (10). The interdependence of these social factors with financial toxicity leads to identifying it as a social health inequality, unfair and avoidable through multidisciplinary and cross-sectional strategies.

Scientific evidence suggests the need to introduce the model of social determinants of health as the theoretical framework to reveal the complexity of the phenomenon (11). That is why, in the context of the final research paper for the Master’s Degree in Research and Nursing Care for Vulnerable Populations by the Universidad Autónoma of Madrid, our aim was to begin exploring the financial toxicity in Spain, in order to start filling the existing gaps given the lack of studies in our setting. In order to begin this exploration, we focused on describing FT among patients receiving an allogeneic hematopoietic stem cell transplant (allo-HSTC) in the Health Service of Madrid from the approach of social determinants of health.

People undergoing an allo-HSTC have been identified as a particularly vulnerable population regarding this phenomenon, due to the prolonged treatments received, their intensive post-transplant follow-up, and the agglutination of transplant centres in urban areas of reference. Only 14 autonomous communities are conducting this complex procedure in Spain, and this means that many patients and their relatives must travel to another autonomous community in order to receive treatment, with an increase in additional derived costs, among others, for maintenance, travelling and lodging.

During the study, it was observed that the majority of participants experienced some level of FT in the post-transplant stage, and these levels were higher than those reported in previous research conducted both in combined and private health systems. Besides, some social determinants of health, such as being woman, having a monthly household income lower or equal to 1,000 euros, or perceiving a reduction in income after the transplant and receiving economic subsidies, were linked to experiencing a higher financial toxicity.

Regardless of the universal coverage offered by our health system, financial toxicity is also present in its users. To conceptualize this phenomenon in our setting could help to establish a solid basis about the causes and consequences that financial toxicity presents for patients in the public health systems as well as for their relatives. All this could favour the creation of more accurate multidimensional tools and the implementation of interdisciplinary strategies for screening and intervention which will allow to prevent, detect and treat this phenomenon. That is why it should be imperative to continue along this line of research, and to reach a commitment to extend it to other medical conditions.