Investigation of Factors Influencing the Fear of Cancer Recurrence in Breast Cancer Patients Using Structural Equation Modeling: A Cross-Sectional Study

Objective This study aimed to investigate the fear of cancer recurrence (FCR) in breast cancer patients and develop a structural equation model of influencing factors to help formulate clinical intervention strategies. Methods A convenience sample of 325 patients was surveyed using a general and disease-related data questionnaire, which combined the Fear of Progression Questionnaire-Short Form, Mishel Uncertainty in Illness Scale, Perceived Social Support Scale, and Medical Coping Modes Questionnaire. Results The total score of FCR in breast cancer patients was 35.06 ± 10.83, and 53.8% of patients reached the clinical level. The structural equation model demonstrated that illness uncertainty had a direct positive impact on FCR (β = 0.275, p < 0.05), and it could have an indirect impact through social support and resignation coping methods (β = 0.254, p < 0.05). Conclusion The fear of cancer recurrence in breast cancer patients needs further understanding. Medical staff can reduce or buffer FCR in breast cancer patients by strengthening positive influences, such as social support, or weakening negative influences, such as illness uncertainty and resignation coping.


Introduction
According to a 2020 report by the American Cancer Society [1], breast cancer is one of the most common malignancies among women, representing a serious threat to their future health. With the advance of medical technology, the treatment of breast cancer is improving although recurrence and metastasis are common problems that breast cancer patients face after diagnosis and treatment [2,3]. A related study [4] revealed that more than half of breast cancer patients sufer from fear of cancer recurrence (FCR) after their rehabilitation. Tis refers to a psychological state of fear, worry, or anxiety that cancer may reappear or progress [5]. Te occurrence of FCR can seriously afect patient health, reduce the quality of life for patients and their families, cause excessive use of medical resources, and increase the potential costs to the medical system [6]. Disease uncertainty, social support, and coping strategies have been reported as some of the essential infuencing factors for FCR in breast cancer patients [7]. Chinese scholars Ye et al. [8] found that disease uncertainty in breast cancer patients was positively correlated with FCR, and good social support was an essential external resource to promote mental health. Other studies [8,9] have reported that FCR tends to be lower in breast cancer patients with better social support. Another factor infuencing FCR is the patient's coping style, which describes how the individual behaves and responds to their health problems; various coping styles may have diferent efects on patients. A study [10] revealed that breast cancer patients who take more efective coping strategies had lower FCR levels, while those with negative coping styles, such as avoidance, had higher FCR levels. Most of these studies adopted correlation or regression analyses to confrm the efects of these factors on FCR in breast cancer patients. However, the internal mechanisms of infuencing factors and FCR remain unclear. As a statistical method, a structural equation model can deal with the relationship between multiple independent and dependent variables and clarify the relationship structure among factors. Terefore, in this study, based on the stress coping theory and literature review, structural equation modeling was applied. Tis helped to analyze the impact path and efects of disease uncertainty, social support, and coping styles on FCR, which may allow clinical staf to better understand FCR in breast cancer patients and implement appropriate psychological interventions.

Design and Procedure.
Tis study adopted a convenience sampling method, enrolling hospitalized breast cancer patients in surgery, chemotherapy, and radiotherapy departments from June to December 2019. Inclusion criteria are as follows: (1) patients aged ≥18 years old; (2) clinical diagnosis of stage I-IV breast cancer; (3) patients who were aware of their condition; and (4) patients who were informed of the study's purpose and provided informed consent to participate voluntarily. Exclusion criteria are as follows: (1) breast cancer had metastasized from other malignancies rather than being the primary cancer; (2) patients with a previous history of mental illness or severe psychological or cognitive impairment; (3) patients with dyslexia relating to reading, writing, and verbal communication; and (4) patients who were critically ill and could not cooperate.
After the review and approval of the Hospital Ethics Committee and the consent of relevant departments, the investigators went to the appropriate departments to carry out their study. Before commencing, the researchers explained the purpose, signifcance, and methods to the patients who met the research criteria. After obtaining each patient's consent, the consent form was signed, and the investigation was carried out in a quiet and undisturbed environment. Te patient flled out the questionnaire anonymously. While flling out the questionnaire, the researchers took time to clarify any topics prone to misunderstanding and answered patients' questions; this helped to ensure the accuracy and authenticity of the data. After completing the questionnaire, the forms were collected on the spot, and the accuracy of the questionnaire was checked at the same time. Questionnaires with regular answers or missing answers greater than 20% were eliminated. If the form was incomplete, it was flled in again, returned after checking, and then numbered. In this study, 340 questionnaire forms were distributed, and 325 valid questionnaires were fnally recovered. Te validity rate of the questionnaires was 95.6%.  [13]. Tere are 25 items on the scale, including two dimensions uncertainty and complexity factors. Scores are measured using a 5-point Likert scale: 1 means strongly disagree and 5 means strongly agree; the scale's total score is 25-125 points. Te higher the patient's score, the higher the uncertainty surrounding the disease. In the present study, Cronbach's α coefcient was 0.919, the uncertainty factor dimension was 0.923, and the complexity dimension was 0.78. (4) Te Perceived Social Support Scale (PSSS): Tis scale was compiled by Zimet et al. [14]. It measures the level of support perceived by the individual from various aspects of society. Its total score refects the total degree of social support felt by an individual. Te total Cronbach's α coefcient of this scale was 0.992. Te adjusted PSSS developed by Chinese scholars Huang et al. [15] was adopted in this study. Te scale includes two dimensions such as in-family support (4 items) and extra-family social support (8 items). Te score is calculated using a 7-point Likert scale, where a score of 1 means strongly disagree and 7 means strongly agree. Te total score of the scale ranges from 0 to 84; the higher the score, the higher the level of social support. In the present study, the total Cronbach's α coefcient of the scale was 0.93, and the in-family support dimension was 0.69, and the extra-family social support dimension was 0.964. (5) Medical Coping Modes Questionnaire: Tis questionnaire was developed by the American scholar Feifel et al. [16] and is mainly used to evaluate the coping style of patients in the face of disease. In 2000, Shen and Jiang [17] translated the scale into Chinese. Te questionnaire includes three dimensions such as acceptance, avoidance, and resignation, covering a total of 20 items. Te score is measured using a 4point Likert scale: the higher the score for a coping method, the more frequently it is adopted. Te Cronbach's α coefcients of dimensions were 0.69, 0.60, and 0.76, respectively. In the present study, Cronbach's α coefcient of the acceptance dimension was 0.724, the avoidance dimension was 0.557, and the resignation dimension was 0.614.

Construction of the Hypothetical Model.
In this study, based on the literature and theoretical analysis, the hypothetical model was formed using the stress coping theory by Lazarus and Folkman; this included two important psychological processes such as cognitive assessment and response. Coping methods include taking positive action, avoiding, letting things go, seeking information and help, and applying psychological defense mechanisms. Coping resources include an individual's functional status, social support system, and individual capabilities. In this model, it is pointed out that the disease uncertainty of breast cancer patients afects their psychosocial adaptation, with social support and coping mode acting as mediating factors; furthermore, social support plays a regulatory role in the patients' coping. Te FCR in breast cancer patients was regarded as an endogenous latent variable, and the two dimensions of FCR (physical health and social family) were taken as the observation variables. Te uncertainty in illness in breast cancer patients was regarded as an exogenous latent variable; its two dimensions (uncertainty and complexity factors) were regarded as observation variables. Social support and coping style were regarded as external variables, whereas the two dimensions of social support (family and outside-of-family support) were regarded as the observation variables. Using all these variables, the study constructed the assumption diagram of the structural equation model of infuencing factors for FCR in breast cancer patients ( Figure 1).

Statistical Analysis.
Data were inputted by two persons. SPSS 22.0 statistical software and Amos 21.0 structural equation model software were used to analyze the data. Normally distributed measurement data were expressed as mean ± standard deviation (x ± SD). Count data were expressed as frequency and percentage. Pearson's correlation analysis was employed to explore the correlation between breast cancer patients' FCR and uncertainty in illness, social support, and coping styles. Finally, Amos 21.0 software was used to ft, analyze, and modify the hypothetical structural equation model. Te inspection level was set at α � 0.05, with p < 0.05 considered as being statistically signifcant.

Te Score of Fear of Cancer Recurrence in Breast Cancer
Patients. In breast cancer patients, the total score of FoP-Q-SF was 35.06 ± 10.83 points, the score of the physical health dimension was 18.22 ± 5.65, and the society/family dimension score was 16.84 ± 5.87. Te score of the physical health dimension was slightly higher than society/family. Tere were 175 patients with a total score of ≥34, accounting for 53.8%. See Table 2 for details.

Correlation Analysis between Fear of Cancer Recurrence and Uncertainty in Illness, Social Support, and Coping Style in
Breast Cancer Patients. Pearson correlation analysis showed that the total score of FCR was positively correlated with the total score of disease uncertainty (p < 0.01, r � 0.624). Te total score of FCR was negatively correlated with the total score of social support (p < 0.01, r � −0.29). Te total score of International Journal of Clinical Practice 3 fear of recurrence was negatively correlated with acceptance coping (p < 0.01, r � −0.245) and was statistically signifcant for resignation coping (p < 0.01, r � 0.51). See Table 3 for details.

Fitting and Modifcation of the Structural Equation Model of Fear of Cancer Recurrence Infuencing Factors.
Correlation analysis results revealed that the avoidancebased coping style did not infuence FCR, so this path in the hypothetical model was removed. Amos 21.0 software was used to ft the hypothetical model with the maximum likelihood method. Te paths without statistical signifcance were removed, and the model was adjusted by modifying the index. Terefore, the structural equation model of infuencing factors for FCR in breast cancer patients was obtained ( Figure 2). Te ftting index of the modifed structural equation model is presented in Table 4. Te efect of uncertainty in illness, social support, and resignation coping on FCR is shown in Table 5.         [19] found that FCR in breast cancer patients was positively correlated with disease uncertainty; this result was the same for the present study. In addition to corroborating these fndings, this study also revealed the specifc pathways through which disease uncertainty can infuence FCR by constructing a structural equation model. Tus, the results can provide theoretical support for clinical staf who wish to reduce FCR and improve the psychological wellbeing of breast cancer patients. Te results of the structural equation model showed that social support was an indirect infuence on FCR, with social support mediated by submission coping having an indirect negative efect on the level of FCR. In a survey of 192 inpatients, Xing et al. [20] found that FCR was negatively associated with social support. Also, in a study of 180 breast cancer patients, Ye et al. [19] found that FCR in breast cancer patients was negatively correlated with social support. Tis suggests that when patients face the heavy blow of a cancer diagnosis and uncomfortable treatments, good social support is an important mental health resource. Te care and assistance of friends and relatives help to relieve patients of adverse emotions during treatment, reduce psychological pressure, improve patients' compliance with treatment, and enhance their confdence in overcoming the disease. Terefore, while providing knowledge about the disease, healthcare professionals should encourage patients to strengthen communication with friends, colleagues, and other patients through diferent social activities. Tis may enhance their confdence in the treatment and optimize the role of social support in disease treatment.

Model
Additionally, the results of structural equation modeling showed a direct efect of the submission coping style on FCR, where breast cancer patients who adopted this coping had increased levels of FCR. In their survey study of 228 breast cancer patients, Cai et al. [21] found that submission, or yield, coping was positively correlated with FCR in breast cancer patients, which is refected in the present study. Adding to this research, the present study sets out a more detailed pathway analysis,

Limitations.
Tis study only investigated breast cancer inpatients in surgery, radiotherapy, and chemotherapy departments at a tertiary care hospital in Hebei province, which faced problems fnding a sufcient representative sample. Additionally, this study used a cross-sectional survey method, which could only determine the factors infuencing FCR among breast cancer patients. In the future, multiple methods can be used to develop and validate specifc intervention strategies for FCR among breast cancer patients, which may provide more targeted strategies and suggestions for reducing FCR.

Conclusion
Te current situation of FCR in breast cancer patients in China is not optimistic. For more than half of the patients surveyed, FCR reached the clinical level, which suggests the need for clinical intervention. In addition, the structural equation model analysis demonstrated that uncertainty in illness, social support, and resignation were the infuencing factors for FCR in breast cancer patients. Uncertainty in illness not only had a direct positive impact on FCR but also had an indirect positive impact through social support and resignation coping; social support had an indirect negative impact on FCR, meaning that patients with higher levels of social support tended to have lower FCR levels; and resignation coping had a direct positive impact on FCR. Tis suggests that clinical medical staf should pay attention to FCR as it may afect the psychological well-being of breast cancer patients.

FCR:
Fear of cancer recurrence FoP-Q-SF: Fear of progression questionnaire-short form MUIS: Mishel' s uncertainty in illness scale PSSS: Perceived social support scale.

Data Availability
Te datasets used and/or analysed during the current study available from the corresponding author on reasonable request.

Ethical Approval
Tis study was conducted with approval from the Ethics Committee of Afliated Hospital of Hebei University. Tis study was conducted in accordance with the declaration of Helsinki. Written informed consent was obtained from all participants.

Conflicts of Interest
Te authors declare that they have no conficts of interest.