Cancer is a leading cause of death and accounted for nearly 10 million deaths by 2020, globally [1]. It is the leading cause of death in South Korea and a major public health concern. However, with advances in treatment technologies, the cancer patient survival rate has increased [2]. Chemotherapy is one of the primary treatment modalities for cancer and has contributed significantly to improved cancer survival rates [3]. However, chemotherapy can cause acute side effects, such as nausea, vomiting, mucositis, alopecia, and fatigue, resulting in poor Quality of Life (QoL) in cancer patients [3]. Chemotherapy treatment is a vulnerable time for patients physically and psychologically. It follows that patients undergoing chemotherapy have substantial care needs [4].

During this challenging time, family caregivers may be valuable sources of support in oncology by participating in patient care [5]. Family caregivers can assist patients with daily activities, help manage cancer or treatment-related symptoms, provide emotional support and transportation, prepare meals (if chemotherapy is outpatient clinic-based), and even manage finances [5]. However, caregiving for chemotherapy patients can be demanding and exhausting, leading to symptom-based problems, care burden, distress, and poor QoL [4, 6, 7, 8]. Furthermore, caregiver problems have been found to directly affect cancer patients’ QoL, treatment, and prognosis [6]. Given these severe repercussions on patients and caregivers, special attention should be paid to family caregivers.

The QoL of family caregivers of patients with cancer is critically compromised [9, 10, 11, 12], and factors associated with this have been identified. Sociodemographic factors associated with poor QoL include being older, a woman, low household income, and spousal relationships with the patient [9, 10, 11, 12]. A longer duration of care was associated with lower QoL as a care-related factor [10]. Psychosocial factors such as care burden, distress (including anxiety and depression), strain, unmet needs, and limited social support have been associated with caregivers’ poor QoL [9, 10, 11, 12, 13].

Among these factors, the caregiver burden has been widely explored as an important concern for family caregivers [13, 14, 15]. Researchers have recently reported the detrimental impact of distress on family caregivers’ QoL [9, 12, 13, 14]. The most common symptoms of distress were anxiety and depression [16]. Empirical research has reported that the rates of anxiety and depression among family caregivers are 30~50% and 12~59%, respectively [15, 17], and managing distress among family caregivers should be prioritized to improve QoL.

While previous studies have focused on the negative aspects of chemotherapy for family caregivers, such as care burden, anxiety, depression, and diminished QoL [9, 10, 12, 13, 14, 15, 17], there is a need to determine which factors promote QoL and act as protective buffers. Walsh’s framework [18] defines family resilience as the ability to recover from adversity and acquire new strengths and social resources during challenging times. They posit that family caregivers can cope with overwhelming distress through resilience [18]. In previous studies, family resilience positively affected caregivers’ QoL [19, 20, 21] and was negatively associated with distress and care burden [22, 23, 24]. Previous studies not involving cancer [25, 26] have supported the moderating role of family resilience in the relationship between negative antecedent factors and QoL. For instance, Ertl et al. [25] found that family resilience could moderate between perceived stress and QoL in Parkinson’s disease patients. Luo et al. [26] showed that family resilience could moderate the relationship between care burden and QoL among parents of children with type 1 diabetes.

To our knowledge, no published studies have examined the moderating role of family resilience in the relationship between distress and QoL among family caregivers of cancer patients. Therefore, we aimed to evaluate distress, family resilience, and QoL in family caregivers of cancer patients undergoing chemotherapy and explore whether family resilience has a moderating effect on the relationship between distress and QoL.

The present study examined distress, family resilience, and QoL of family caregivers of cancer patients undergoing chemotherapy. To our knowledge, this study is the first to explore the moderating effect of family resilience on the association between distress and QoL among caregivers of cancer patients. As caregivers’ provision of supportive care services is limited [12], the current study has important implications for oncology nursing practice.

The mean score of CQoLC in our sample was 71.19±18.90, similar to the results of other Korean studies, including the work of Choi (68.6±17.2), Kim (74.6±20.5), and Son (74.0±18.7) [9, 10, 11]. However, it was much lower than the scores reported in Western countries such as the UK (88.9±24.4), the US (95.3±16.3), and Canada (98.8±15.8) [8, 32, 33]. Our results indicated that Korean family caregivers of patients with cancer undergoing chemotherapy exhibited deteriorated QoL. It is difficult to compare the QoL of family caregivers across countries because of the different clinical features of the patients they care for. Hence, deteriorated QoL may be related to South Korea’s healthcare system. In recent years, outpatient cancer care services have been bolstered with improved anticancer drugs, increasing caregivers’ participation in cancer care [10]. However, Korean family caregivers might not receive enough support from hospitals or the government [9, 10], which may be one reason for the deterioration in QoL. This lack of support may include current oncology nursing practices. Therefore, there is a need to facilitate support programs such as education, skills training, and respite services to improve family caregivers’ QoL [9].

Our participants’ mean total HADS score was 15.31±6.91, higher than reported in Langenberg et al.’s study (8.96±6.91) using the same instrument [7]. Langenberg et al. [7] evaluated distress among Dutch caregivers of colon cancer patients who received adjuvant chemotherapy. The main reason for this remarkable discrepancy between the two studies may be the difference in patients’ treatment-related characteristics. They included only the caregivers of patients who received adjuvant chemotherapy, whereas our study did not. This means that caregivers of patients undergoing palliative chemotherapy might have been included in our study. Caring for terminally ill patients with cancer may cause substantial distress. However, we did not collect information on the patients’ cancer stage or the purpose of chemotherapy (i.e., curative, adjuvant, or palliative). Therefore, we should exercise caution in our interpretation of our findings. Another possible reason for the HADS discrepancy may be the Coronavirus Disease 2019 (COVID-19) pandemic. Data collection in this study was performed between December 2020 and February 2021, during the COVID-19 pandemic. This may have influenced the caregivers’ mental health. Wimberly et al. [34] reported that caregivers are more likely to experience changes in medical care, financial disruptions, and emotional distress due to COVID-19, supporting our supposition.

The mean score on the FRS-C (3.26±0.27 for the item average) was slightly lower than reported by Cho (3.60±0.56, n=115) using the same instrument [28]. Cho’s was the only study with which to compare our results. One possible explanation is the difference in the modality of patient treatment between the two studies. We only included caregivers involved in the patient’s chemotherapy, whereas Cho [28] placed no limitations on the patient’s treatment modality. However, the variation in cancer types and treatment trajectories and the small sample sizes in both studies limit possible explanations for this difference. Further studies are needed to establish the general FRS-C levels among Korean family caregivers.

Among the demographic variables, only age was significantly associated with QoL (β=-.22, p=.047), which explains 6.2% of the variance, consistent with previous findings [8, 10]. This outcome indicates that older family caregivers may be at greater risk of decreased QoL and should be a focus for support from health care providers. After controlling for covariates, our results showed that distress and family resilience were crucial factors affecting caregivers’ QoL, explaining 62.8% of the total variance. Specifically, distress was significantly and negatively associated with QoL, consistent with prior research [7, 12, 13]. Distress was the strongest factor related to caregivers’ QoL [7, 12], and a potential target for intervention strategies. Examining the results of recent randomized controlled trials, nurse-guided psychosocial programs [34, 35] have effectively relieved distress and enhanced QoL among family caregivers. We found that family resilience was positively associated with QoL, consistent with previous studies [19, 20, 22, 23]. Highly resilient family caregivers can safeguard themselves from stressors, be more optimistic, and experience lower burden of care when providing cancer care [24]. This might contribute to a better QoL.

Contrary to our expectations, we found no moderating effect of family resilience on the relationship between distress and QoL in this study. Previously, no study has investigated the moderating role of family resilience among family caregivers of cancer patients, thus limiting our research. Although the study population differed, Li et al. [36] found a significant moderating role of resilience in the relationship between distress and QoL in infertile women. They reported that the higher their resilience, the weaker the effect of infertility-related distress on QoL. This indicates that resilience is a protective factor for infertile women. When extrapolating these results to our study, family resilience might not protect against QoL deterioration. One possible explanation for our null finding could be the high levels of distress in our sample. If family caregivers are exposed to severely distressing situations, they can become overwhelmed or deplete their coping resources [37]. This may cause a decrease in the level of family resilience or inhibit its effect [38], leading to a non-significant effect. Another reason may be measurement-related issues. The FRS-C used in the current study may be appropriate for determining family resilience in Korean culture involving caregivers of patients with cancer. However, psychometric validation of the FRS-C has not been performed; thus, caution should be exercised regarding its validity and reliability. The Cronbach’s α in this study was .70, indicating only borderline reliability.

This study has several limitations. First, the cross-sectional design does not allow for an explanation of causality, and a longitudinal study is required to verify our findings. Second, this study lacked information regarding patients’ clinical characteristics (e.g., cancer stage and number of chemotherapy cycles) because we only gathered data from family caregivers. Regarding the ECOG status, most patients (81.2%) had a performance status of 0 or 1, which may have influenced the interpretation of our findings. Third, we did not include other variables previously proposed to be associated with caregivers’ QoL (e.g., caregiver burden, caregivers’ health, and social support). Future studies should also consider these variables. Fourth, the FRS-C used in this study was not a validated tool. It is necessary to validate the tool before conducting psychometric evaluations in future studies. The study was conducted in a metropolitan city in South Korea. Therefore, caution should be exercised when extrapolating these results to family caregivers in rural areas.

In this study, family caregivers of cancer patients undergoing chemotherapy demonstrated a low QoL. High distress and low family resilience significantly predicted a poor QoL. Our findings indicate that oncology nurses need to relieve distress and enhance family resilience to improve family caregivers’ QoL. Family resilience did not moderate the relationship between distress and QoL. More studies are required to confirm the moderating role of family resilience and better understand the mechanism by which family resilience affects distress and QoL.