Abstract
PURPOSE: Financial toxicity (FT) associated with cancer and its treatment has become increasingly important. This study investigated factors associated with the development of FT during radiation therapy (RT). SOCOFIN was the first longitudinal prospective study to systematically evaluate FT in the context of RT. METHODS: Financial toxicity was measured with the Comprehensive Score for Financial Toxicity (COST-12) at RT initiation, completion, and at 3 months afterwards. Secondary endpoints included socioeconomic factors, health-related quality of life (EORTC QLQ-C30), depression (PHQ-9), coping mechanisms, and sense of coherence. The data were collected digitally; missing data were estimated using multiple imputation with chained equations. RESULTS: Between July 2023 and June 2024, 230 patients were recruited. Analyses were performed on 170 records. During RT, FT did not increase; a slight overall decrease was descriptively observed. Of seven tumor groups, the highest difference in FT at baseline was measured between prostate (median 33) and pelvic cancer patients (median 19), reaching statistical significance (Kruskal-Wallis test, p = 0.01). Nonetheless, tumor entity was not found to be a significant predictor of FT following RT in multivariate linear regression models. While factors associated with FT differed between timepoints, financial difficulties at baseline predicted the occurrence of FT most strongly (p < 10(-13)) and persistently. CONCLUSION: Predictors of FT were predominantly socioeconomic, such as baseline financial difficulties, net income, employment stability, and sense of coherence, which superseded tumor- or treatment-specific variables. The findings of this study underscore the necessity of multifactorial, early screening before RT to mitigate FT among radiation oncology patients.