Perceived financial toxicity after active treatment and its association with clinical outcomes among breast cancer survivors: A prospective cohort study

Background: Perceived financial toxicity (FT) is an increasingly recognized concern among cancer survivors. However, its association with long-term oncologic outcomes, particularly after completion of active treatment, remains underexplored. Methods: We conducted a prospective cohort study of 4163 breast cancer survivors from a tertiary cancer center in South Korea. Eligible participants were within 18 months of diagnosis, had completed surgery and any adjuvant chemotherapy or radiotherapy, and had no evidence of recurrence at enrollment. Perceived FT was assessed using the Comprehensive Score for Financial Toxicity (COST) questionnaire. FT was defined by a COST score <26. Primary outcome was recurrence-free survival (RFS), and secondary outcomes included all-cause mortality and quality-of-life (QoL) domains. Multivariable Cox proportional hazard models adjusted for age, stage, treatment, and socioeconomic factors. Results: Among the cohort, 2109 (50.7 %) patients reported perceived FT after active treatment. FT was independently associated with increased risk of recurrence or death (HR 1.42, 95 % CI 1.08–1.87), and higher all-cause mortality (HR 1.74, 95 % CI 1.02–2.97). FT was also associated with significantly worse emotional functioning, social functioning, and future outlook. Conclusions: Perceived financial toxicity following active breast cancer treatment was associated with worse oncologic and quality-of-life outcomes, regardless of objective socioeconomic status. These findings underscore the need for routine assessment of perceived financial burden during survivorship care and targeted financial interventions, even in patients without traditionally defined financial vulnerability.