Racial and regional disparities impact the incidence of, mortality from, and survival from breast cancer, but the role of other socioeconomic factors is unclear. Researchers from Fudan University in Shanghai, China, conducted a large study and found that marital status, insurance status, median household income, and residence also contribute to survival from nonmetastatic breast cancer. They presented the findings at the San Antonio Breast Cancer Symposium on December 7, 2018.

Using the Surveillance, Epidemiology, and End Results database, researchers identified 274,108 female patients diagnosed with malignant breast cancer between 2007 and 2014. They assessed marital status, insurance status, residence, median household income, poverty rate, unemployment rate, and education level.

Patients with a better prognosis were married (p < 0.001) and insured (p < 0.001). Insured patients had better survival than uninsured patients and those with Medicaid (p < 0.001), regardless of age, but uninsured patients aged 18–35 years had poorer survival than Medicaid beneficiaries (p < 0.05).

Non-Hispanic black patients had the worst survival compared to other races (p < 0.001).

Residence in a nonmetropolitan area increased the risk of death (hazard ratio [HR] = 1.084; p < 0.05), whereas residence in counties with higher median household income (defined as more than $72,800 U.S. dollars) resulted in more favorable overall survival (OS; HR = 0.843; p < 0.001).

Researchers used socioeconomic factors to construct nomograms for three-, five-, and seven-year OS and breast cancer-specific survival and found that C-indexes of these nomograms were higher than those of the TNM Classification of Malignant Tumors staging system for predicting OS (0.776 versus 0.678; p < 0.001) and breast cancer-specific survival (0.842 versus 0.776; p < 0.001). The ability of the nomograms to predict OS was significantly lower when excluding socioeconomic factors (p < 0.001).

“The findings may highlight the importance of developing health-related policies and the necessity of targeted social support-based interventions for high-risk patients,” the researchers concluded.