The interaction of financial toxicity and social support on social functioning in post-chemotherapy breast cancer patients: a cross-sectional study.

PURPOSE: To explore the correlation between financial toxicity, social support, and social functioning in post-chemotherapy breast cancer patients, as well as any possible interaction of financial toxicity and social support on social functioning.

METHODS: Post-chemotherapy breast cancer patients admitted to the thyroid and breast surgery departments of three first-class general hospitals in East China from December 2020 to January 2022 were recruited by convenience sampling for a cross-sectional survey. The survey instruments included the general information form, the comprehensive scores for financial toxicity based on the patient-reported outcome measures (COST-PROM), the social roles and activity participation subscale from the patient-reported outcomes measurement system-breast-chemotherapy (PROMS-B-C) (score range: 8-40), and the social support subscale from PROMS-B-C (score range: 16-80).

RESULTS: The results showed that low social functioning (low score) in post-chemotherapy breast cancer patients was positively correlated with high financial toxicity (low score) as well as poor economic resources (low score) and poor psychosocial responses (low score) (P<0.01) and negatively correlated with low economic expenditures (low score) (P<0.01); high social functioning (high score) was positively correlated with high social support (high score) (P<0.01). The interaction analysis results showed an additive interaction between financial toxicity and social support in social functioning.

CONCLUSION: There was an additive interaction of financial toxicity and social support in the social functioning of post-chemotherapy breast cancer patients. Those patients with high financial toxicity and low social support are the most likely to benefit from relevant intervention measures compared to other breast cancer populations.