The reason why African Americans are more likely than Caucasians to be not only diagnosed with head and neck cancer, but also die from the disease has been revealed in a new study.
Researchers at Henry Ford Hospital say the answers may lie in the differences in lifestyle, access to care and tumour genetics.
Their study also found that African Americans are more likely to be past or current smokers, one of the primary risk factors for head and neck cancer.
"We're really trying to understand why African Americans with head and neck squamous cell carcinoma do so poorly," said study lead author Maria J. Worsham, Ph.D., director of research in the Department of Otolaryngology-Head and Neck Surgery at Henry Ford.
"Using a comprehensive set of risk factors that are known to have some bearing on the disease, we're able to gain a better understanding of what contributes to racial differences and work to help improve patient care," she stated.
Henry Ford researchers found that while 88 percent of African Americans in the study had medical insurance, the majority had Medicare or Medicaid instead of private health insurance.
African Americans also were more likely to be unmarried or living alone, both of which previous studies suggest have a negative impact on quality of life and survival.
The study showed fewer African Americans opted for surgery than Caucasians.
The tumour tissue samples also held important clues. African American tumours were six to seven times more likely to present with lymphocytic response, which essentially is an entourage of immune system cells.
These cells behave not only as first responders against tumours, but can also produce growth factors (chemicals) that feed tumour growth, such as forming blood vessels.
Compared to Caucasian tumours, African American tumours were almost two times more likely to have loss of the CDKN2A (cyclin-dependent kinase inhibitor 2A) gene and gain of the SCYA3 (small inducible cytokine A3) gene.
CDKN2A is important to cell cycle regulation, and the SCYA3 gene product has dual roles of tumour lymph node metastasis and local host defence against tumours in HNSCC.
"Understanding and accounting for factors contributing to differences in head and neck cancer racial groups will ultimately aid in eliminating disparities and saving more lives from this devastating disease," concluded Dr. Worsham.
The findings were presented in San Francisco at the American Academy of Otolaryngology-Head and Neck Surgery Foundation Annual Meeting on September 14.