Cancer has been identified as a fatal disease, a growing health concern and economic burden worldwide (1–3). During the past decade, with the help of medical advancements in early detection, the survival rate of cancer patients has risen with a concomitant increase in treatment costs (4, 5). As a result of this situation, some insurance systems have changed their policies to limit their coverage and not defray extra costs (5). In developing countries, disproportionate rising price of cancer therapies (6) and diversity of health insurance coverage have given rise to disparities in access to care and treatment among different populations and communities (7).
Due to insufficient insurance coverage, more out-of-pocket expenses required for treatment has escalated financial burden of cancer patients and their family. The negative effect of this is the devastating emotions in the personal and social life of those affected by cancer (Altice, Banegas et al. 2017; Chan, Gordon et al. 2019, Salsman, Bingen et al. 2019) to the extent that some end up in debts (8, 9). Some patients may have perilous reactions such as to discontinue or non-adherence to treatment in order to avoid financial hardships (10). The direct and indirect costs of cancer-related treatment can give rise to what is known as financial toxicity defined as a potential consequence of subjective financial distress experienced by patients (Witte, Mehlis et al., 2019). Past research has supported the impact of financial toxicity on physical burden and mental symptoms such as pain, fatigue, depression, cognitive dysfunction and neuropathy (11). In addition, financial toxicity has been found to be associated with lower probability to survive or an earlier death (12). Such threats brought about by financial toxicity substantially affect the welfare of patients as well as people around them. It is therefore important for care providers to understand the negative impact of financial toxicity. Appropriate intervention is necessary in order to curb such occurrences or to reduce the risk of financial toxicity.
The prevalence of financial toxicity has attracted researchers’ attention with a significant rise in research. However, the review of literature shows that despite the importance and prevalence of financial toxicity, there is no conclusive definition in either a broader context or a disease-specific for financial toxicity or financial distress (2, 4). Witte, Mehlis (4) in their systematic review define financial toxicity as a potential consequence of subjective financial distress experienced by patients due to cancer-related (or anticipated) direct and indirect treatment costs. In this definition, financial toxicity is a cognitive or subjective state (internal feeling) that has been induced through perceived distress as a result of objective loads (external and real). Therefore, such patients should cope with both monetary and psychosocial costs of their illness (4).
If there is no conclusive definition for financial toxicity, there is equally an absence of an agreed scale that could adequately capture the dimensions of financial toxicity. Chan, Gordon (8) categorized the instruments to measure financial toxicity into three main groups: monetary, objective and subjective measures. Monetary instruments investigate the currency values of out-of-pocket costs or percentage paid relative to income for direct medical and nonmedical costs as well as indirect costs (2, 8). Objective measures examine real methods or strategies used to manage financial burden such as borrowing money from others or using invested savings and funds, while subjective instruments evaluate perceived financial burden arisen from cancer and its care (2, 4, 8). The results of the review conducted by (4) revealed that more than 88 percent of the studies conducted in developed countries used various designs to assess financial toxicity (4, 8). Researchers have also raised concerns regarding the validity of some of the scales (12, 13). Among the three main approaches to measurement, subjective measures receive widespread interest among researchers.
Past reviews have identified three subjective scales specifically used to measure perceived financial toxicity among cancer patients: The Comprehensive Score for financial Toxicity (COST), Breast Cancer Finances Survey Inventory (BCFS), and Socioeconomic Wellbeing scale (SWBS) (4). The COST is the latest instrument developed by de Souza et al. (2014) based on cancer patients’ reports and it has been validated using US patients (14). The COST is an 11-item instrument measuring financial toxicity with one item on financial spending, two items on financial resources, and eight items on the psychosocial responses of cancer patients.
Research conducted in the US and Canada to explore causes and effects of financial toxicity using the COST instrument, have recommended it as an effective and feasible measure (4, 15). Review of studies on different instruments for assessing financial toxicity have reported that COST is a valid and most widely used measure (2, 4, 6). Moreover, the Japanese version (12) and Chinese version (16) of the COST have shown good reliability and validity. However, in less developed societies that are expected to face more difficulties (mortality and costs) among cancer patients and their family, research is relatively scarce (1–3, 17). Besides income, patients from different social, and cultural backgrounds may experience different financial toxicity. The objective of this study is to assess the psychometric properties of the Persian version of the COST in Iran that has specific financial challenges and a healthcare system that differs from other countries (18).
Iran as a middle-income country has the greatest cancer incidence and death attributable to that in the Middle East (19). Meanwhile, various sanctions imposed by the US and the United Nations over the past four decades although not directly targeting pharmaceuticals and medical equipment, they have caused many disturbances in trading and producing essential drugs and medical equipment for more than thirty serious and life-threatening diseases such as cancer (19). Moreover, Gross Domestic Product (GDP) per capita in Iran has declined owing to sanctions which in turn has substantially reduced the purchasing power of Iranians (19). In addition, due to the high inflation in health expenditures (both for the government and consumers), it is estimated that Iranians have to spend almost 60% out of pocket payment to get imported drugs and services which are necessary to treat special diseases such as cancer (19). In this regard, cancer patients and their caregivers (i.e. family and nurses) are under extreme strain and distress with high risk of financial toxicity.
Despite the aggravated circumstances that could cause people to succumb to financial toxicity, little is known about financial toxicity among Iranian patients. Although some studies have been conducted to investigate financial distress of cancer patients using, for example, financial well-being scale (20), no prior research, to the authors’ knowledge, has measured financial toxicity or financial burden among cancer patients. Utilizing a standardized and multidimensional instrument such as COST could improve our understanding of this phenomenon and allow us to achieve more robust, consistent and comparable results (4). The results of such studies like the present study will be useful for policy makers to develop intervention strategies to mitigate financial toxicity and improve quality of life of cancer survivors. At the same time, this study will fill a significant gap in the empirical literature of financial toxicity as this study aims to assess psychometric properties of the Persian version of the comprehensive scores for financial toxicity (COST) scale among cancer patients in Iran.