Cancer is an important cause of mortality worldwide, with a trend that seems to only increase. Along with the growth in morbidity and mortality, the economic burden of direct and indirect costs is also increasing. This study aimed to characterize the out-of-pocket costs of cancer treatment incurred by patients during treatment, either through the SUS or research protocols.
Our study population was mostly female (61%), with a mean age older than 50 years, findings that are consistent with those in other studies involving patients with cancer [6, 12–19]. There was greater participation by individuals who reported being white (60%), although the majority of the Brazilian population self-reports as black [20]. Based on the literature, the main comorbidities of patients with cancer are hypertension, diabetes and dyslipidemia, consistent with the results of our study [6].
Regarding cancer characteristics, breast cancer is the most prevalent among patients both in our study and in the literature, but the time since diagnosis differs, and in our study, most patients had been diagnosed more than 12 months prior (42.6%) [12, 13, 20].
In the analysis of the total out-of-pocket costs incurred by patients, the mean final value, i.e., R$ 453.80 (US$ 78.92) per month, was lower than that found in a similar study conducted in the United States, in which the monthly mean was approximately R$ 1071.00 (based on the dollar exchange rate at the time) [21]. In addition, the total monthly expenditure found in this study was also substantially lower than that found in another study conducted in northern India in which the mean out-of-pocket expenditure by patients with head and neck cancer was R$ 2123.86 (US$ 369.37) based on the rupee/real exchange rate in 2019 [14]. This difference may be explained by the type of cancer investigated, indicating that there is a difference in spending not only between different regions but also between different types of cancer.
When comparing our results with the Brazilian reality, 43.4% (R$ 1045.00/US$ 181.74) of 1 minimum wage in 2020 was spent by patients on out-of-pocket expenses; however, in another Brazilian study, the total out-of-pocket spending represented 78.4% of the minimum wage at the time (2018) [6], indicating that even though the value is high, the percentage found in this study was not higher than that in 2018.
Stratifying the out-of-pocket costs surveyed, the transportation expenditure was the highest, approximately R$ 100.00 (US$ 17.39) per month, a finding similar to that in another Brazilian study and to that in a Canadian review that also found transportation among the top 4 highest expenses for patients with cancer [21]. This finding indicates that transportation to treatment-related commitments (consultations, chemotherapy, radiotherapy, and laboratory tests, among others) is a critical part of out-of-pocket costs and, thus, where patients would benefit the most from receiving aid.
No significant difference was found between the SUS and RP groups regarding the means of transportation, and the proportion of patients who used cars or public transportation was similar in each group; however, compared to previous studies conducted in Brazil, in this study, there was an increase in the proportion of patients who used their own car [12]. Despite the similarity in the use of means of transportation and the finding that SUS patients make more trips, the RP patients had a 46.25% higher mean transportation expenditure. Interestingly, the 2 groups spent more on transportation than did patients in a previous study [17] but less on transportation than did patients in studies from other regions and countries, indicating perhaps greater difficulty in accessing health services in these locations [6, 20]. However, we cannot exclude the roles of inflation and our setting as causes of the differences in transportation costs between studies conducted at different times.
The results of the multivariate analysis show that there was no significant difference between the SUS and RP groups. This may be due to the balance between some expenses among the evaluated costs. For example, while the RP group spent more on telephones, the SUS group had higher expenses related to the number of trips. Differently from another study conducted on the costs incurred by cancer patients that found that employed patients incurred higher costs, in this study, patient occupation was not significant in determining the difference between costs. In contrast, education level, type of cancer, sex, age and ethnicity were not significant either in our study or in another study conducted in Brazil [6].
Because of the observational nature of our study, the limitations include the impossibility of establishing cause and effect relationships and include the possible presence of biases and confounding factors. Our questionnaires, especially those related to cost-time, required that patients remember various expenses and situations, potentially introducing recall bias. Additionally, the different proportion of patients from the SUS and RP may have influenced the results, but unfortunately, in the context of the COVID-19 pandemic, several patients were lost to follow-up, especially in the RP group. Last, our patient sample represents only a portion of patients undergoing cancer treatment, which includes patients from several other health centers that may have their own patient protocols and services.