Breast cancer survivors face significant financial stress (also called financial toxicity) due to the high costs of cancer treatment. This financial stress can worsen quality of life. Previous studies have demonstrated that breast cancer survivors may draw on inner psychological strengths to cope effectively. This study aims to examine whether psychological resources, specifically resilience and posttraumatic growth (PTG), buffer the longitudinal association between financial toxicity and quality of life (QoL) among breast cancer survivors.

Hypotheses: H1: Financial toxicity is negatively associated with QoL over time. H2: Resilience moderates the association between financial toxicity and QoL, such that higher resilience attenuates the negative impact of financial toxicity.

H3: Posttraumatic growth (PTG) moderates the association between financial toxicity and QoL, such that moderate to high levels of PTG attenuate the negative impact of financial toxicity.

Participants will complete questionnaires at three time points: before their first chemotherapy cycle, at two months (mid-treatment), and at four months (end of chemotherapy). The questionnaires measure financial stress, quality of life, resilience, and posttraumatic growth.

The study plans to enroll at least 160 participants. Data will be analyzed using statistical methods that track changes across time and test whether resilience and posttraumatic growth buffer the impact of financial stress on quality of life. All data will be de-identified and stored securely.

Background:

Breast cancer is the most prevalent malignancy among women worldwide. In China, five-year survival rates have reached approximately 83%, making breast cancer survivors the largest cancer survivor group. Quality of life (QoL) has emerged as a key patient-centered outcome in oncology. Survivors undergoing chemotherapy commonly experience impaired physical function, psychosocial difficulties, and treatment-related symptoms that adversely affect QoL.

Financial toxicity encompasses both the objective financial burden and subjective financial distress arising from cancer-related costs. National survey data indicate that 82.6% of breast cancer survivors in China experience financial toxicity, with 40.9% reporting severe levels. Financial toxicity has been associated with treatment non-adherence, delayed care, and poorer QoL. A meta-analysis of 31 studies found a moderate negative association between financial toxicity and QoL. Survivors undergoing active treatment report higher financial toxicity than those who have completed therapy.

Psychological Resources:

Resilience is conceptualised as the capacity to adapt in the face of adversity, trauma, or significant stressors, which is linked to better QoL in cancer populations. A meta-analysis of 66 studies found that higher resilience was significantly associated with better QoL. Emerging cross-sectional evidence suggests that resilience partially mediates the association between financial toxicity and QoL; however, its longitudinal buffering role remains unclear.

Posttraumatic growth (PTG) refers to positive psychological change that emerges through the process of struggling with highly challenging life circumstances. A systematic review of 37 studies found a positive association between PTG and QoL. Higher financial distress has been associated with greater PTG. Although PTG appears to moderate the relationship between cancer-related stressors and health outcomes, its longitudinal role in buffering financial toxicity on QoL has not been established.

Theoretical Framework:

This study is guided by Conservation of Resources (COR) theory, which conceptualizes financial toxicity as a resource-loss stressor. Within this framework, resilience and PTG are positioned as psychological resources that offset resource loss and may buffer the adverse impact of financial toxicity on QoL.

Study Design:

This is a non-intervention longitudinal observational cohort study. Data will be collected at three time points corresponding to key chemotherapy phases: prior to the first chemotherapy cycle (baseline, T1), at mid-treatment (2 months, T2), and at the completion of chemotherapy (4 months, T3). The study is conducted at Henan Cancer Hospital, China.

Participants:

Sample size: G*Power calculation assuming medium effect size (f² = 0.10), α = 0.05, power = 0.95, and 3 predictors yielded a minimum of 132 participants. Adjusting for 20% attrition, the target sample size is at least 160 participants.

Measures:

Financial toxicity: Comprehensive Score for Financial Toxicity (COST); Quality of life: Functional Assessment of Cancer Therapy - General (FACT-G); Resilience: Resilience-14; Posttraumatic growth: Posttraumatic Growth Inventory (PTGI) Sociodemographic and clinical characteristics collected at baseline (age, menopausal status, histological grade, occupational status, medical insurance type, monthly household income, treatment type.

Statistical Analysis:

Primary analysis: Linear mixed-effects models (LMM) will examine longitudinal changes in QoL and the moderating effects of resilience and PTG on the financial toxicity-QoL relationship. Interaction terms (financial toxicity × resilience, financial toxicity × PTG, and time interactions) will be included to evaluate whether buffering effects vary across treatment phases.

Supplementary analysis: Cross-lagged panel models within a structural equation modeling (SEM) framework will examine temporal and directional relationships among financial toxicity, psychological resources, and QoL (e.g., financial toxicity at T1 predicting resilience or PTG at T2, and subsequently QoL at T3).

Inclusion Criteria:

• Histopathologically confirmed diagnosis of breast cancer
• Aware of their diagnosis
• Able to read and complete the questionnaire
• Scheduled to undergo a standard chemotherapy regimen

Exclusion Criteria:

• History of severe psychiatric disorders (e.g., schizophrenia or bipolar disorder)
• Another prior cancer diagnosis
• Evidence of distant metastasis (stage IV disease)
• Severe comorbid conditions that could interfere with study participation or outcomes (e.g., severe cardiovascular disease or cognitive impairment)

Adult female breast cancer patients receiving chemotherapy at Henan Cancer Hospital, China