People with lung cancer who live in low-income, less-educated areas tend to be diagnosed at a later cancer stage than those in areas where adult residents earn more and attended school longer, according to new findings published in the journal Cancer. Duke University researchers investigated the impact of income and education, along with other factors related to socioeconomic status, on lung cancer diagnoses in different racial and ethnic groups.
Lung cancer is the second most common type of cancer in the United States and the leading cause of cancer-related deaths, accounting for almost 25 percent of cancer deaths. Most lung cancer cases are not diagnosed until the later stages, making it difficult to treat, especially among Black adults. Previous studies found that Black adults are more often diagnosed with advanced-stage lung cancer compared with white adults.
Although lung cancer survival rates continue to rise, research has shown that racial disparities remain. In recent studies, researchers have investigated factors that drive late-stage diagnoses in Black adults, such as socioeconomic status, access to health care, and location of residence. The Duke team took a deeper look into how these factors contribute to advanced-stage diagnoses in certain groups.
The Duke researchers used data from the National Cancer Database from 2004 to 2016, pulling information on people ages 18 to 89 who were diagnosed with non-small cell lung cancer (NSCLC). More than 1.3 million people were included in the study.
Overall, more people living in lower-income, less-educated zip codes had advanced-stage NSCLC than residents of higher-income, more educated areas. Specifically, people living in areas with the lowest education level (more than 17.6 percent of residents without a high school diploma) were 12 percent more likely to have advanced-stage NSCLC compared with those in areas with the highest education level. Broken down by race/ethnicity, white adults were 4 percent more likely to be diagnosed with advanced-stage cancer, whereas Black, Hispanic, and Asian adults were, respectively, 15 percent, 14 percent, and 9 percent more likely.
Income levels also correlated — people from lower-income areas (median income less than $40,227) were 13 percent more likely to have advanced-stage NSCLC than those from higher-income areas. Again, broken down by race/ethnicity, white adults were 2 percent more likely to be diagnosed at a later stage compared with Black, Hispanic, and Asian adults at 13 percent, 14 percent, and 11 percent, respectively.
The authors also noted that Black adults residing in areas with the highest income and education levels had more advanced-stage diagnoses compared with white adults from areas with the lowest income and education levels.
The study authors also examined the type of insurance and cancer treatment facility used by participants. Whether they had government-issued or private insurance, those living in areas with the lowest education and income remained at the same higher risk of receiving an advanced-stage lung cancer diagnosis.
The associated impact of income and education status on a diagnosis of advanced-stage lung cancer also persisted at all types of health care facilities, including community, academic/research, and integrated network. The researchers found that in the lowest-educated areas, the odds of an advanced-stage diagnosis remained higher no matter where people received treatment. In low-income areas, similar trends were seen.
Study co-author Tomi Akinyemiju, Ph.D., said in an interview, “Our findings support that poverty is a fundamental cause of poor lung cancer outcomes. Strikingly, for Blacks, higher income did not necessarily translate to better outcomes compared with whites. This highlights the urgent need for targeted efforts to ensure equitable access to smoking cessation and lung cancer screening and additional research into other factors that drive lung cancer aggressiveness in Blacks.”