Financial Toxicity, Quality of Life, and Psychological Resources in Breast Cancer Survivors : A Longitudinal Study

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).

• Change in Financial Toxicity [Time frame: Baseline (T1, prior to first chemotherapy cycle), 2 months (T2, mid-treatment), and 4 months (T3, completion of chemotherapy)]
• Change in Resilience [Time frame: Baseline (T1, prior to first chemotherapy cycle), 2 months (T2, mid-treatment), and at 4 months (T3, completion of chemotherapy)]
• Change in Posttraumatic Growth [Time frame: Baseline (T1, prior to first chemotherapy cycle), 2 months (T2, mid-treatment), and 4 months (T3, completion of chemotherapy)]