Socioeconomic disparities impacting breast cancer care and survival in Iran

Abstract

Breast cancer is the most common cancer among women. However, individuals with a lower socioeconomic status (SES) tend to experience poorer prognosis. We aimed to study disparities in diagnosis, treatment, quality of care, and survival by SES in Iran. Data from breast cancer patients at the Cancer Institute of Iran between 2014 and 2016, registered in the clinical breast cancer registry of Iran (CBCR-IR), were used. Clinical data were obtained from CBCR-IR, while follow-up data and information on SES, including 10 household assets and education level, were gathered through telephone interviews. The primary outcome was survival, determined through active follow-up. Additionally, we studied delays in treatment and the quality of care based on European Society of Breast Cancer Specialists (EUSOMA) standards. A Cox proportional hazard model was used to investigate the association between SES and survival in women with breast cancer. The inequality in breast cancer survival was analyzed using the Blinder-Oaxaca decomposition model. The 5-year overall survival rates were 87.7 (95 CI: 83.9-90.7) for low SES patients, 90.2 (95 CI: 86.7-92.8) for mid SES, and 92.1 (95 CI: 89.0-94.3) for high SES patients (log-rank test P-value = 0.077). A 3.3 gap in breast cancer mortality was observed between high and low SES patients (95 CI: 1.3-5.5), with the model explaining 2.2 of this difference. Differences in delay in treatment and stage at diagnosis accounted for 0.5 (95 CI: 0.2-0.7) and 1.8 (95 CI: 1.2-2.3) of the disparity. Breast cancer mortality is higher in low SES patients, primarily due to late diagnosis and delays in treatment initiation.