Total treatment interval and quality of life of women living with breast cancer in Ethiopia: the mediating role of financial toxicity

Delays in breast cancer care are common in low-resource settings and may adversely affect patients’ quality of life (QoL). Prolonged total treatment interval (TTI) can also impose substantial financial hardship. This study aimed to get insights into the potential mechanisms of how prolonged treatment interval impacts QoL through a mediation model and explore the mediating role of financial toxicity (FT) among Ethiopian women with breast cancer. A cross-sectional study was conducted among 458 women with histologically confirmed breast cancer receiving treatment at three oncology centers in Ethiopia (Black Lion, Jimma, and Hiwot Fana Hospitals) between July and September 2024. QoL was assessed using the EORTC QLQ-C30, where higher functioning and global health scores indicate better QoL, while higher symptom scores reflect greater symptom burden. Financial toxicity was measured using the COST–FACIT tool, with lower scores indicating greater financial hardship. TTI was calculated as days from symptom recognition to treatment initiation. Mediation and moderated mediation analyses were performed using PROCESS v4.3 for R, controlling for sociodemographic and clinical factors. Of 456 (99.6%) women with complete data, 71% experienced delayed treatment initiation (> 90 days). The mean (SD) global health status and EORTC QLQ-C30 summary scores were 81.2 (19.9) and 85.8 (15.2), respectively. Longer TTI was significantly associated with poorer QoL, with declines observed in both global health status (r = − 0.22, p < 0.001) and the QLQ-C30 summary score (r = − 0.17, p < 0.001). In multivariable models, longer TTI (> 90 days) was associated with lower FT scores, indicating greater financial hardship (β = −2.72, p = 0.001). Financial toxicity was positively associated with GHS scores (β = 0.63, p < 0.001). The indirect effect of TTI on GHS through financial toxicity was significant (β = −1.70, 95% CI [− 2.94, − 0.66]), while direct and total effects were not. Similar patterns were observed for the EORTC QLQ-C30 summary and functional/symptom domains. Cancer stage did not significantly moderate the indirect pathway. Prolonged TTI impair quality of life among women with breast cancer in Ethiopia primarily through increased financial hardship rather than direct clinical effects. Interventions aimed at reducing delays and mitigating financial burden may enhance patient well-being and treatment outcomes in low-resource settings.