Exploring determinants of fear of cancer recurrence in postoperative colorectal cancer patients: a random forest model approach.

Introduction
Colorectal cancer (CRC) is one of the most common malignancies of the digestive system. Globally, it ranks third in incidence and second in cancer-related mortality (Liu and Zhang 2024). In China, recent national statistics reported approximately 555,000 new cases and 286,000 deaths in 2023, placing CRC second in incidence and fifth in mortality nationwide (National Health Commission et al. 2023). These figures highlight the substantial and growing public health burden of CRC, underscoring the need to address not only survival outcomes but also the broader physical and psychological challenges faced by patients.

With continuous advancements in medical technology and the widespread implementation of early screening programs, the overall prognosis for CRC patients has markedly improved, as evidenced by substantial increases in five-year survival rates (Adam et al. 2024). However, extended survival has brought new psychosocial challenges. An increasing number of patients report persistent psychological distress during postoperative recovery, with fear of cancer recurrence (FCR) emerging as one of the most prevalent and distressing concerns among CRC survivors (Lebel et al. 2016). FCR is a common psychological stress response characterized by heightened vigilance and excessive attention to bodily sensations. While a moderate level of FCR can be adaptive—enhancing patients’ awareness of potential recurrence or metastasis and promoting healthier behaviors—excessive FCR may exacerbate negative illness perceptions and uncertainty about the future, increase symptom burden, and even trigger severe psychological disorders such as somatic symptom disorder (SSD) or post-traumatic stress disorder (PTSD) (Cai et al. 2023). Moreover, elevated FCR has been associated with impaired social functioning, disruption of life and career planning, diminished subjective well-being, and reduced overall quality of life (Gao et al. 2024; Yang et al. 2024).

Although FCR is relatively common among postoperative CRC patients, systematic assessments and targeted interventions in China remain limited. A few pilot programs have been reported, but these are generally small in scale, methodologically heterogeneous, and lack standardized evidence-based approaches (Zhou et al. 2023). Moreover, China’s unique cultural context may shape the manifestation of FCR. In particular, collectivist family values, cancer-related stigma, and patients’ tendency to suppress negative emotions can intensify illness perceptions, hinder emotional disclosure, and reduce the utilization of social support, thereby contributing to the development and persistence of FCR (Liu et al. 2018; Mahendran et al. 2021; Yu et al. 2022).

To address these gaps, this study applied a random forest (RF) algorithm to identify and prioritize psychosocial predictors of FCR in postoperative CRC patients. RF was selected because it mitigates multicollinearity, accommodates high-dimensional data, and captures non-linear relationships and interactions that traditional regression models often overlook (Wang et al. 2023). Compared with other machine learning approaches, RF offers both strong predictive performance and interpretable rankings of variable importance, making it particularly well-suited for oncology risk factor identification (Cessna Palas et al. 2021; Hall et al. 2019). The key psychosocial predictors—illness perception, social support, and emotion regulation—were subsequently validated using binary logistic regression, thereby integrating qualitative insights with quantitative rigor (Liu et al. 2018; Yu et al. 2022). Building on these validated predictors, this study provides a robust risk assessment framework to inform clinical decision-making, guide personalized psychological interventions, and ultimately reduce FCR while improving postoperative quality of life.

Patients and methods

Patient

A convenience sampling method was employed to select 314 colorectal cancer (CRC) patients who underwent surgical treatment at Fudan University Shanghai Cancer Center between November 2023 and May 2024 as the study population. The inclusion criteria were as follows: (I) age 18–80 years (with a cutoff at 80 years to exclude individuals with severe cognitive impairment); (II) a diagnosis of primary CRC based on the World Health Organization (WHO) diagnostic criteria and pathological examination and completion of surgical resection of cancerous tissue with a postoperative time not exceeding 5 years; (III) ability to read and understand Chinese questionnaires and communicate verbally; and (IV) voluntarily participation and expressed willingness to provide informed consent. The exclusion criteria were the following: (I) patients unaware of a CRC diagnosis; (II) presence of clinical, laboratory, or radiological signs suggestive of recurrence or metastasis or a previous history of recurrence or metastasis; (III) physical weakness prohibiting participation in the survey; (IV) cognitive impairment, mental illness, or a history of psychological treatment; (V) and concurrent enrollment in other interventional studies.

The required minimum sample size for multiple linear regression was estimated based on established principles of multivariate statistical analysis. Specifically, the formula N = (number of variables × 10–20) × (1 + anticipated dropout rate) was applied. Given the inclusion of 23 independent variables and an anticipated 10% dropout rate, a total of 330 questionnaires were distributed to ensure sufficient statistical power.

Methods

Survey tools
The tools used in this study comprised the Chinese versions of the Fear of Cancer Recurrence Inventory (FCRI), Cognitive Emotion Regulation Questionnaire (CERQ), Brief Illness Perception Questionnaire (BIPQ), Social Support Rating Scale (SSRS), the Social Constraints Scale-15 (SCS-15), and a demographic questionnaire, all of which were administered in Chinese.

Demographic questionnaire
The personal information questionnaire, developed by the researcher based on existing literature, includes 18 questions addressing socio-demographic factors (e.g., sex, age, ethnicity, religious belief, marital status, educational level, employment status, type of medical insurance, monthly disposable income, place of residence, and experience of negative life events) and disease and clinical-related variables ((e.g., colorectal cancer stage, type of surgery, history of chemotherapy, history of radiotherapy, time since diagnosis, presence of chronic comorbidities, and family history of colorectal cancer).

Fear of cancer recurrence inventory (FCRI)
The FCRI, developed by Simard et al. (Simard and Savard 2009) in 2009, evaluates the multidimensional fear of cancer recurrence (FCR) experienced by patients with cancer. This scale is grounded in the cognitive behavioral model of FCR. Totaling 42 items, it comprises seven dimensions: triggers, severity, coping strategies, psychological distress, functional impairment, insight, and reassurance-seeking. The FCRI uses a 5-point Likert scale (0–4), with total scores ranging from 0 to 168, with higher scores indicating a greater FCR. The severity dimension independently assesses FCR, with a maximum score of 36. A score of 13 or higher indicates a high level of fear, while a score of 13 or lower indicates a moderate to low level of fear. The scale demonstrates excellent reliability, with a Cronbach’s α coefficient of 0.95, and the coefficients for each dimension range from 0.71 to 0.94, which indicates strong validity and reliability.

Cognitive emotion regulation questionnaire (CERQ)
The CERQ, originally developed by Garnefski et al. (Garnefski et al. 2001). And subsequently translated into Chinese by Zhu Xiongzhao et al. (Zhu et al. 2007). Consists of 36 items covering nine dimensions and assesses two types of cognitive emotion regulation strategies: CERQ-adaptive (CERQ-A) and CERQ-maladaptive (CERQ-M). The adaptive strategies include five dimensions such as acceptance and positive refocusing, reflecting positive coping mechanisms; the maladaptive strategies include four dimensions such as self-blame and rumination, indicating negative coping styles. Each item is rated on a 5-point Likert scale ranging from 1 to 5. Dimension scores range from 4 to 20, with a total score ranging from 36 to 180. Where higher scores indicate a greater tendency to use the corresponding strategy. The Chinese version of the CERQ has demonstrated satisfactory reliability and validity, with a Cronbach’s α of 0.81 for the total scale, subscale coefficients ranging from 0.62 to 0.89, and a two-week test–retest reliability of 0.70 (Dong et al. 2008; Liu et al. 2025).

Brief illness perception questionnaire (BIPQ)
The BIPQ was developed by Broadbent et al. (Broadbent et al. 2006). in 2006 and includes items on various aspects of illness perception, such as illness consequences, timeline, personal control, treatment control, symptom identity, concern, emotional response, illness understanding, and perceived causes. It consists of one dimension and nine items. Items 1–8 are scored on a 0–10 numerical scale, with items 3, 4, and 7 being reverse-scored. The total score ranges from 0 to 80, with higher scores indicating more negative perceptions of illness. The final item is an open-ended question asking respondents to list the three most important causes of their disease. The Chinese version of the BIPQ demonstrates good reliability and validity, with an internal consistency coefficient of 0.831, test–retest reliability of 0.931, and criterion-related validity of 0.640 (Sun et al. 2015).

Social support rating scale (SSRS)
The Chinese version of the SSRS was developed by Xiao Shui Yuan in 1986 and has since been widely used in various studies within Chinese communities, demonstrating strong validity and reliability (Xiao 1994). The scale consists of 10 items that evaluate 3 dimensions of social support: objective support, subjective support, and support utilization. Objective support refers to tangible or actual assistance received in the past, while subjective support encompasses the emotional experience of feeling respected, supported, and understood within the community. Support utilization assesses the behaviors associated with seeking social support. Items are rated on a 4-point Likert scale, with total scores ranging from 12 to 66. Higher scores indicate a greater level of social support.

Social constraints scale-15 (SCS-15)
Lepore et al. developed the SCS-15 to assess the frequency with which patients encounter social constraints from spouses, family members, or friends in response to specific stressors over the previous month (Lepore et al. 1996). The scale comprises 15 items, each rated on a 4-point Likert scale, with 1 indicating “not at all” and four indicating “most of the time”. The total score ranges from 15 to 60, with higher scores representing more significant levels of social constraints. The Chinese version of the scale has shown strong reliability, with a Cronbach’s α coefficient of 0.92.

Survey methods
In October 2023, a pilot study was conducted at the Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, involving 18 postoperative colorectal cancer patients. Two senior clinical nurses collaborated with CRC specialists to screen and recruit eligible participants, who provided informed consent. Guided by the researchers, participants completed questionnaires with clear instructions and an explanation of the study’s purpose. The pilot study aimed to evaluate the clarity, comprehensibility, and feasibility of the instruments. Results indicated satisfactory face validity, with no major difficulties reported; only minor wording adjustments were made, confirming the tools’ suitability for the target population.
After the participants completed the questionnaires, they were reviewed, and participants were requested provide any necessary missing information. Questionnaires with multiple unanswered items, instances in which participants refused to supply additional details, or cases in which most answers were identical were deemed invalid.
The study protocol was approved by the ethics committee of the Fudan University Shanghai Cancer Center (approval no. 2404294-Exp4). All participants provided written informed consent and were made aware of their right to withdraw from the study at any time.

Statistical analysis
Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 26.0. Normally distributed data were presented as mean ± standard deviation (x̄ ± s) and compared using independent sample t-tests. Non-normally distributed data were expressed as median and interquartile range (IQR) and compared using the Mann–Whitney U test. Categorical variables were described as frequencies and proportions, and comparisons were made using the chi-square test or rank-sum test, as appropriate. A random forest model was constructed using the Random Forest Classifier algorithm in R version 4.2.2. The key parameters were set as follows: number of decision trees = 100, minimum samples per split = 5, maximum tree depth = unlimited, and random seed = 42 to ensure reproducibility. A total of 23 variables were ranked by importance, and those with a contribution rate > 5% were subjected to univariate analysis. Variables with P < 0.05 were subsequently included in a binary logistic regression model. Prior to logistic regression, the linearity between continuous independent variables and the logit(p) was assessed using the Box–Tidwell test, with all interaction terms yielding P > 0.05, indicating linearity. Multicollinearity was evaluated using the variance inflation factor (VIF), and all variables had VIF values < 3, suggesting no significant multicollinearity. A two-sided significance level of α = 0.05 was used for all statistical tests.

Results

Demographic characteristics
Of the 330 distributed questionnaires, 314 were deemed valid, resulting in a response rate of 95.2%. Participants included 193 males (61.5%) and 121 females (38.5%), with an average age of 59.72 ± 12.32 years (8.6% aged 18–39 years, 33.4% aged 40–59 years, and 58.0% aged ≥ 60 years). Over half (53.8%) had a junior high school education or lower, and 97.8% of the participants were diagnosed within the previous year. The majority (86.3%) underwent sphincter-preserving surgery, 42.7% had chronic diseases, and 10.8% reported a family history of Colorectal Cancer (CRC). (Table 1).

Fear of cancer recurrence inventory (FCRI)
The mean FCRI score was 69.64 ± 27.10, with a severity subscale score of 13.91 ± 5.996. A total of 58.9% of participants scored above the clinical cutoff, indicating a high prevalence of Fear of Cancer Recurrence (FCR), while 129 participants (41.1%) reported moderate-to-low levels of FCR.
The mean score for coping strategies was 17.36 ± 8.25, suggesting a moderate level of use. Among the subscales, the highest scores were observed for triggers (12.46 ± 6.40), followed by functional impairment (9.99 ± 5.11) and psychological distress (6.16 ± 4.16). In contrast, scores for reassurance-seeking (5.44 ± 2.85) and insight (4.33 ± 2.98) were relatively low, indicating limited engagement in external support-seeking and self-awareness strategies. (Table S1, Table S2).

Forest plot of the random forest model for FCR and the ranked importance of predictive variables
Gradient Boosting Regression Trees (GBRT) were used to optimize the hyperparameters of the random forest (RF) model. The relationship between the number of decision trees and model error indicated that the error rate decreased rapidly at first and then plateaued when the number of trees reached approximately 100, suggesting enhanced generalisation performance and stable model fitting (Fig. 1).

Ranked importance of predictive variables based on the RF model
Based on the RF algorithm, the initial set of 23 variables was ranked according to their importance, with higher importance scores indicating a greater impact on classification (Table 2). The top seven variables with an importance score greater than 5% were as follows: Brief Illness Perception Questionnaire (BIPQ) (23.05%), Cognitive Emotion Regulation Questionnaire – maladaptive strategies (CERQ-M) (12.31%), Social Support Rating Scale (SSRS) (8.65%), Social Constraints Scale-15 (SCS-15) (8.39%), age (7.91%), Cognitive Emotion Regulation Questionnaire – adaptive strategies (CERQ-A) (7.20%), and monthly income (5.16%) (Figure S1).

Univariate analysis
The top seven variables identified by importance ranking (BIPQ, CERQ-M, SSRS, SCS-15, CERQ-A, and monthly income) were included in the univariate analysis to compare differences between the high FCR group and the low FCR group. The analysis revealed that monthly income, CERQ-A (positive coping), and SSRS reached statistical significance (P < 0.05), whereas illness perception, CERQ-M (negative coping), and social constraints exhibited stronger associations with high statistical significance (P < 0.001). (Table 3).

Multivariate analysis
A binary logistic regression analysis was performed with the occurrence of FCR as the dependent variable and six variables with P < 0.05 in the univariate analysis as independent variables to further identify significant predictors. Independent variables were coded as follows: BIPQ, CERQ-A (adaptive coping), CERQ-M (maladaptive coping), SSRS, and SCS-15 were entered as continuous variables; monthly income was categorized as [1 =  < 2500 CNY; 2 = 2500–5000 CNY; 3 = 5001–7500 CNY; 4 =  > 7500 CNY], with the low-income group (< 2500 CNY) serving as the reference category. The results indicated that monthly income level, illness perception (BIPQ), maladaptive coping strategies (CERQ-M), and social constraints (SCS-15) were significant predictors of FCR among colorectal cancer patients (P < 0.05). In contrast, social support (SSRS) and adaptive coping strategies (CERQ-A) were not significantly associated with FCR (P > 0.05). Although age contributed more than 5% in the RF model, it did not reach statistical significance in the logistic regression analysis. This may reflect nonlinear or confounding effects of age that were captured by the random forest but not by regression (Table 4, Figure S2).

Discussion

Prevalence of fear of cancer recurrence (FCR) in postoperative colorectal cancer (CRC) patients
This study confirmed that FCR is highly prevalent among postoperative CRC patients, consistent with previous reports (Custers et al. 2016). FCR imposes a substantial psychological burden, closely associated with anxiety, depression, distorted self-perception, and reduced quality of life (Podina et al. 2023). Collectively, these findings highlight not only the pervasiveness of recurrence-related concerns but also the complex interplay of physical and psychological challenges faced by patients after surgery.
Compared with other solid tumors, such as breast cancer, CRC presents unique challenges due to its anatomical location and treatment-related consequences. Visible physical changes, including abdominal scars and stomas, can significantly impair body image and psychosocial adjustment (Vonk-Klaassen et al. 2016). When combined with emotional distress, maladaptive illness perceptions, and insufficient social support, these factors further compromise self-image and psychological resilience, thereby intensifying FCR (Yu et al. 2022).

Despite successful tumor resection, many patients continue to experience fears of recurrence, uncertainty during follow-up, and functional impairments, which exacerbate anxiety and depression and diminish quality of life (Li 2023). These observations underscore the importance of extending clinical care beyond tumor biology to address patients’ emotional and psychological needs. Early identification of high-risk individuals through standardized assessments, coupled with tailored interventions—such as psychological support, patient education, and emotion regulation strategies—is essential for optimizing recovery outcomes.

Random forest (RF)–based analysis of factors influencing FCR in CRC patients

Socioeconomic status: monthly household income
Monthly income, a key indicator of socioeconomic status, appears to influence FCR. Although the protective effect of higher income did not reach statistical significance, the observed trend suggests that greater financial resources may mitigate FCR, and this marginal association could reflect a true effect undetectable due to limited sample size or variability, warranting further investigation in larger, more balanced cohorts. Higher-income patients may benefit from greater financial stability, proactive access to medical information, and better healthcare resources, which can enhance coping ability and psychological resilience, thereby reducing anxiety and uncertainty (Liu et al. 2022; Yao 2023). Conversely, lower-income patients are more likely to experience financial strain, delays in seeking medical care, and concerns about imposing economic burdens on their families, all of which increase psychological distress and, in turn, intensify FCR (Kang et al. 2022).
From a clinical perspective, socioeconomic status should be systematically incorporated into psychological assessments. Low-income patients may be prioritized for targeted interventions, such as personalized financial counseling, guidance on insurance or subsidy programs, access to affordable healthcare, and structured psychological support for stress and anxiety management. Delivering these interventions through a multidisciplinary team—including clinicians, psychologists, and social workers—could help mitigate FCR and improve overall recovery outcomes (Tauber et al. 2019).

Illness perception
Illness perception, assessed using the Brief Illness Perception Questionnaire (BIPQ), is a key determinant of FCR. Consistent with previous studies (Han et al. 2024; O'Rourke et al. 2021), patients who hold negative or threatening views of their illness may misinterpret common postoperative symptoms—such as abdominal pain, bleeding, or changes in bowel habits—as signs of cancer recurrence. These misinterpretations increase vigilance and anxiety, thereby exacerbating emotional distress and FCR (Yang et al. 2018). Such findings indicate that interventions targeting maladaptive illness perceptions—including cognitive restructuring, patient education, and symptom management guidance—may help reduce FCR and enhance psychological well-being in postoperative cancer patients (Yuyan et al. 2025).
Facing the combined burden of physical discomfort and psychological stress, patients often find it difficult to maintain an objective and rational appraisal of their condition. This can lead to cognitive biases that overestimate the likelihood of recurrence and amplify feelings of uncertainty and worry, ultimately impairing quality of life (Yan et al. 2023). Therefore, clinical care must emphasize patients’ illness perceptions and address maladaptive beliefs through targeted health education. This approach helps patients develop more accurate and constructive understandings of their condition, enhancing their emotional regulation and self-management skills (Liu et al. 2023). Moreover, educating patients to differentiate between normal postoperative symptoms and true warning signs can reduce catastrophic thinking. Tailored symptom monitoring and coping plans should also be implemented to effectively alleviate FCR and improve psychological well-being.

Cognitive emotion regulation
This study identified maladaptive cognitive emotion regulation strategies, assessed using the Cognitive Emotion Regulation Questionnaire–Maladaptive Subscale (CERQ-M), as key contributors to FCR, highlighting the substantial psychological impact of emotion regulation on cancer coping and recovery (Garnefski and Kraaij 2007). Such strategies—including self-blame, rumination, catastrophizing, and blaming others—exacerbate emotional distress rather than alleviate it. They often originate from maladaptive beliefs, defined as irrational or exaggerated thoughts regarding illness, symptoms, or personal vulnerability, which lead to distorted interpretations of bodily sensations and health risks (Liu et al. 2022; Liu and Zhang 2024; Yao 2023). For example, heightened sensitivity to bodily sensations may prompt patients to catastrophize minor symptoms, amplifying fears of recurrence, while persistent rumination can evoke painful memories and negative emotions, further intensifying anxiety. Consistent with previous research, these maladaptive strategies were strongly associated with elevated FCR (Hall et al. 2019; Yu et al. 2022).
Although adaptive coping strategies may provide some psychological protection, many patients lack adequate cognitive regulation skills, external support, and effective coping resources to sufficiently manage emotional distress. Therefore, clinical practice should emphasize the systematic assessment of patients’ cognitive coping styles and implement targeted interventions aimed at fostering more positive and adaptive emotion regulation. Such efforts are essential to enhancing patients’ overall rehabilitation experiences and psychological well-being.

Social factors
In the Chinese cultural context, social support is strongly shaped by family-centered and collectivist values. While strong family involvement can buffer stress and promote adherence to treatment, overprotective behaviors may inadvertently create social constraints, limiting emotional expression and heightening perceptions of uncertainty, thereby amplifying FCR (Cui et al. 2021; Yu et al. 2022). Although not statistically significant in logistic regression, social support ranked third in the RF model, underscoring its importance. This observation is broadly consistent with international evidence demonstrating that insufficient support and greater social constraints are associated with elevated FCR and poorer quality of life (Ajmera et al. 2025; Koch-Gallenkamp et al. 2016; Mikrut et al. 2020). Nevertheless, the ways in which social support operates are likely to be shaped by broader sociocultural contexts.
Emerging cross-cultural research further illustrates that the impact of social support is not universal but context-contingent. For example, in East Asian countries such as Japan and South Korea, family members frequently adopt protective silence regarding prognosis, which may inadvertently constrain emotional disclosure and increase psychological distress (Mori et al. 2023). By contrast, Western contexts privilege autonomy and open communication, which can facilitate disclosure of fears but may also limit the scope of instrumental support provided by families (Choi et al. 2016). Collectively, these contrasts highlight that cultural norms shape not only the availability of support but also its psychological ramifications, thereby influencing patients’ adjustment to survivorship (Syse and Geller 2011).
Taken together, these findings underscore the imperative for culturally attuned interventions. In collectivist societies, strategies might include educating families about balanced caregiving and fostering open dialogue within family units, which have been shown to enhance psychological outcomes (Ashing et al. 2017; Yu et al. 2022). Likewise, encouraging participation in peer networks or support groups can reduce isolation and improve quality of life. Conversely, in more individualistic contexts, strengthening structured psychosocial services and leveraging digital platforms may prove particularly valuable. Moving forward, cross-cultural investigations are warranted to delineate how cultural norms modulate the pathways between social support and FCR, and to evaluate the transferability of intervention models across settings (Anderson et al. 2021).

Age as an indirect predictor of FCR
In addition to the factors discussed above, age contributed over 5% in the RF model but was not retained as an independent predictor in regression analysis. This suggests that age may exert its influence on FCR indirectly through interactions with psychological and social factors. Younger patients often report heightened concerns about role functioning, fertility, and family responsibilities, whereas older patients may experience greater physical vulnerability and comorbidities, both of which can indirectly increase psychological distress. These patterns may explain why age demonstrates moderate predictive value in machine learning models yet loses significance after adjusting for psychosocial variables (Lim and Humphris 2020; Lyhne et al. 2023). Future longitudinal and mediation studies are warranted to clarify the mechanisms underlying age-related influences on recurrence-related fears.

Conclusions
This study demonstrates that fear of cancer recurrence (FCR) is highly prevalent among postoperative colorectal cancer (CRC) patients, affecting over half of the cohort. Illness perception, social constraints, and maladaptive cognitive emotion regulation strategies emerged as the primary determinants of FCR, underscoring its multifactorial nature. These findings emphasize the necessity of comprehensive, multidimensional assessments in postoperative care. Interventions that target patients’ disease cognition, social environment, and emotional coping are crucial for effectively mitigating FCR and improving both postoperative quality of life and social adaptation.

Strengths and limitations
This study has several notable strengths. It addresses the understudied psychosocial issue of fear of cancer recurrence (FCR) among postoperative colorectal cancer (CRC) patients in China, a population with distinct cultural and healthcare characteristics. By Using a random forest (RF) algorithm effectively mitigates multicollinearity issues often encountered in multifactorial analyses, thereby improving the reliability of predictor selection. Integrating machine learning with traditional logistic regression provides a comprehensive assessment by combining variable importance ranking with quantitative effect estimation. The relatively large sample size (n = 314) and inclusion of a broad range of psychological and social variables, such as illness perception, emotion regulation, social support, and social constraints, allow for a multidimensional understanding of FCR, enhancing the clinical relevance of the findings. Furthermore, these results offer valuable implications for the development of personalized psychological interventions and tailored postoperative care strategies for Chinese CRC survivors.
Despite its contributions, this study has several limitations. First, the cross-sectional design prevents causal inference between identified factors and FCR; longitudinal studies are needed to clarify temporal relationships. Second, convenience sampling from a single oncology hospital in Shanghai may limit the generalizability of results to broader populations. Third, important variables such as personality traits, mental health history, and clinical factors (e.g., tumor location, treatment side effects) were not included, potentially missing additional influences on FCR. Finally, reliance on self-reported data may introduce response and recall biases, affecting data accuracy.
Future research should adopt longitudinal, multicenter designs with larger, more diverse samples and incorporate objective clinical data to improve validity. Intervention studies are also needed to assess strategies for reducing FCR in this population.

Supplementary Information
Below is the link to the electronic supplementary material.