Approximately one-third of CGs of patients starting radiation treatment had limited to marginal health literacy, indicating they may struggle to read patient education materials and might require assistance. Before radiation treatment, patients and CGs receive extensive information, including details about the cancer diagnosis, diagnostic tests, complex treatment options, and potential side effects [30]. Despite the National Institutes of Health (NIH) recommending that healthcare materials be written at an eighth-grade readability level, most patient education materials are written at an 11.2 to 13.8-grade level [31]. Furthermore, most radiation treatment education materials used in cancer centers do not meet health literacy best practices, contributing to health disparities [32]. Consequently, CGs feel overwhelmed, experience information overload, and face uncertainty and unpreparedness [30]. During this stressful time period, low health literacy in CGs may result in poor understanding of the information provided, ultimately leading to poor outcomes for both patients and CGs [33].

The findings of this study highlight the elevated levels of anxiety experienced by CGs prior to the initiation of patient treatment (M = 53.48), which was higher than the mean score of 50 for the general US population. Our results align with a previous study that identified anxiety as a prevalent problem among cancer CGs prior to the start of cancer treatment, affecting more than 40% of them [34]. The impacts of education can be limited when CGs are anxious, as anxiety can impede their concentration and understanding of the new information provided [35]. Therefore, healthcare providers need to be aware of and manage CG’s anxiety before initiating education.

Our study identified a significant relationship between CGs’ health literacy, socioeconomic status, health, anxiety, and fatigue. These findings align with the Health Literacy Skills Conceptual Framework, which guided this study. According to the framework, background factors, including individual resources such as socioeconomic status, influence health literacy skills, which in turn impact health-related outcomes, measured here as mental and physical health, anxiety, and fatigue. These findings are also consistent with existing research that links lower health literacy and socioeconomic status to poorer health outcomes, increased anxiety, and fatigue in general populations and patients with cancer [36, 37]. This suggests that the challenges faced by CGs may be exacerbated by their health literacy and socioeconomic status, similar to patterns observed in the general population. Our findings suggest that CGs with lower health literacy and socioeconomic status may be particularly vulnerable during this period, as they may struggle more with the complex information and logistical challenges associated with preparing a patient for radiation treatment. This highlights the critical need for resources and interventions that can empower these CGs, ensuring they are equipped to fulfill their essential roles effectively. For example, interventions could include implementing health literacy screening tools during initial consultations to identify CGs who may need additional support. Tailored education programs, such as workshops or online modules, can provide practical guidance on caregiving tasks, treatment processes, and symptom management. Additionally, CG could benefit from simplified and visually engaging materials to enhance their understanding of complex healthcare information. Furthermore, integrating CG navigators or peer support groups can provide ongoing assistance, particularly for those with lower health literacy and socioeconomic challenges.

Our correlation analysis indicated significant positive relationships between both education and health literacy, and socioeconomic status and health literacy. However, in our structural equation model, the direct path from education to health literacy was not significant, while the path from socioeconomic status to health literacy remained significant. One possible explanation for this discrepancy is that the effect of education on health literacy is mediated by socioeconomic status. Higher education levels are likely to lead to higher socioeconomic status, which in turn improves literacy [38]. In addition, measurement error in the education variable might also contribute to the non-significant direct path. In our study, education was measured using broad categories: “less than high school,” “high school diploma/GED,” “college,” and “post-graduate.” While these categories provide a general sense of educational attainment, they also introduce some limitations, such as loss of precision, as they do not capture the finer differences within each educational level. The structural equation model accounts for measurement error, potentially leading to more accurate but non-significant estimates. However, our model specification and fit indices indicate a well-fitting model, suggesting that the lack of significance is not due to poor model fit but rather than the underlying relationships between the variables. Future research should consider using more granular categories or treating education as a continuous variable (e.g., years of education) to capture more detailed variations in educational attainment and provide more accurate estimates of its relationship with health literacy.

Surprisingly, previous caregiving experience and professional caregiver experience were not significantly associated with CG health literacy, despite the conceptual framework suggesting that prior knowledge influences health literacy. This finding suggests that familiarity with caregiving tasks, whether through personal or professional experience, does not necessarily translate into higher health literacy levels. It suggests that health literacy is not automatically enhanced by caregiving experience alone but may require targeted education and support to improve CGs'ability to manage health-related tasks effectively. It may be that oncology, or radiation oncology in particular, comes with its own unique language and challenges for health literacy. Healthcare providers should provide tailored support and education to all CGs, recognizing that experience does not automatically equate to proficiency in health literacy in this unique context.

The study findings emphasize that it is crucial to acknowledge CG health literacy during patient healthcare visits. According to a study that utilized a national survey, the majority of cancer caregivers (87.6%) were actively involved in cancer treatment decision-making [39]. The high level of involvement underscores the necessity of assessing and addressing CG health literacy to ensure that they can fully comprehend the complexities of cancer treatment options, potential outcomes, and care instructions. In addition, healthcare providers should adhere to the AHRQ Health Literacy Universal Precautions Toolkit [40] for all CGs. Employing plain language and the teach-back method, providing written materials at appropriate readability levels, and offering additional support and resources are crucial for improving comprehension among CGs with low health literacy. Furthermore, healthcare providers should be mindful of information overload during patient and CG education at the start of treatment, as a heavy volume of information is often delivered within a short period [10, 13, 41]. This information overload can further increase stress and misunderstanding of information [41]. To minimize information overload, strategies such as providing tailored education, offering written handouts with pictographic materials, and limiting the amount of information given at one time can be used [41].

This study has several limitations. First, the study findings may have limited generalizability to the broader cancer CG population due to the use of a convenience sampling method. The demographic characteristics of the study sample overrepresent females, white individuals, and non-Hispanic/Latino CGs, which may limit the generalizability of the findings to more diverse CG populations. Additionally, more than half of the participants had a college degree or higher and an annual household income exceeding $50,000. Second, the study did not assess CGs’ primary language, although language proficiency is a key factor affecting health literacy and the ability to navigate complex healthcare information. Third, the study used self-report measures which may be subject to response bias. Lastly, the study design was cross-sectional, so future research could benefit from a longitudinal approach to better understand the comprehensive impact of health literacy on cancer CGs and patients over time. While the study has certain limitations, the study employed validated tools to ensure the reliability and validity of the measurements. Also, we utilized structural equation modeling, a robust analytical method that allows for the examination of complex relationships between variables. These strengths enhance the study’s rigor and provide valuable insights into the relationships between CG’s health literacy, demographic variables, and health-related outcomes.