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