Social Determinants of Health Disparities Emerge for Lung Cancer

January 18, 2021 - Members of racial minorities have better survival rates than White patients for limited-stage small cell lung cancer (L-SCLC) after adjustment for other social determinants of health, according to a new study that serves as an outlier in the body of health disparity research.

The study, published in JAMA Network Open, analyzed demographic information from the National Cancer Database, one of the largest clinical cancer registries in the world. The data covered 72,409 patients diagnosed with L-SCLC from 2004 to 2014. Of the patient information analyzed, 14.7 percent had stage I disease, 10.6 percent had stage II disease, and 74.7 percent were diagnosed with stage III disease.

This was the first widespread study to examine how social determinants of health may affect L-SCLC patient outcomes in particular. 

Other characteristics associated with better survival were female sex, high income, high education, private insurance, and earlier stage at diagnosis.

Researchers found that compared to White patients, the hazard of death from L-SCLC decreased to 0.92 for African American patients and 0.83 for Asian patients. The difference in median survival among different racial groups was significant only among those diagnosed with stage III disease.

These findings stand in stark contrast with most of the current data about racial health disparities. Across different disease types, Black patients tend to have poorer health outcomes than White patients.

While some health disparity studies point to better outcomes for African American patients, they are few and far in between. For instance, a study found that African American patients have worse SCLC survival rates compared to White patients, primarily due to access to care disparities that lead to less preventative care and consequently, later diagnoses. 

In contrast, another study that analyzed data from Veterans Affairs hospitals found that African American patients with multiple myelomas had better overall survival than White patients.

However, by and large, the African American community is worse off in terms of health outcomes due to institutional racism. COVID-19 has helped bring these disparities to light. In November, the Centers for Disease Control & Prevention reported that Black patients are 1.4 times more likely to contract COVID-19 and 2.8 times more likely to die from it compared to White people.

The new L-SCLC study revealed that patients with a median annual income of over $63,000 had a significant reduction in the hazard of death, which mirrors findings from previous social determinant of health studies. In addition to a higher median income, the researchers found that patients with higher education and private insurance had better survival rates as well.

Part of the reason higher education and higher average income are likely to lead to better outcomes is because patients with more resources have better access to care. These patients can travel further to larger referral centers that are often academic institutions for treatment.

Past studies have indicated that patients with NSCLC, oral cancer, or pancreatic adenocarcinoma who receive treatment at academic centers are more likely to have prolonged survival.

Researchers found that treatment characteristics such as diagnostic confirmation by positive cytological analysis and an increased number of sampled regional lymph nodes resulted in higher survival rates through more proper treatment. Additionally, survival rates were generally higher for patients who were diagnosed with L-SCLC at an earlier stage.

Consistent with previous SCLC data, men in the study had worse L-SCLC survival outcomes than women.

Unlike extensive-stage SCLC, which is incurable and primarily treated with systemic chemotherapy with or without immunotherapy, L-SCLC is potentially curable and treated primarily with concurrent chemoradiotherapy or surgery and adjuvant chemotherapy, said the authors.