Why are African Americans more likely than Caucasians to be diagnosed with head and neck cancer and to die from the disease? While the answer isn't a simple one, differences in lifestyle, access to care, and tumor genetics may be partially to blame, according to a new study. Researchers presented their findings recently at the American Academy of Otolaryngology-Head & Neck Surgery Foundation Annual Meeting in San Francisco.
The researchers, led by Maria Worsham, PhD, of Henry Ford Hospital, in Detroit, 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 [(HNSCC)] do so poorly," said Dr. Worsham, director of research in the Department of Otolaryngology-Head & Neck Surgery. "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."
An estimated 52,140 new cases of head and neck cancer were diagnosed this year, and roughly 11,460 died from oral cavity, pharyngeal and laryngeal cancers.
African Americans are more likely to be diagnosed with late-stage HNSCC and have a worse five-year survival rate than Caucasians. It's unknown whether significant biological rather than socioeconomic differences account for some of the disparities in outcomes.
Dr. Worsham and her team studied a large multi-ethnic group of 673 patients with HNSCC. African Americans comprised 42 percent of the study group.
The researchers took a very broad approach to the study, examining many of the intertwined variables that influence health and disease to look for differences between the two races.
The study focused on 136 risk factors, including demographics, smoking and alcohol use, access to care, and type of cancer treatment (radiation and/or surgery). Tumor characteristics - such as stage, biology and genetics - also were examined.
Much of the disparities seen among African Americans with head and neck cancer can be traced to access-to-care barriers, including insurance, that prevent them from getting timely and high-quality medical care, often resulting in late-stage diagnosis.
The researchers found that 88 percent of African Americans in the study had medical insurance, but 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.
In terms of cancer treatment, African Americans were more than two times more likely than Caucasians to receive radiation therapy. If the tumor is extensive or it is not feasible to completely remove it, radiotherapy initially is given to try to shrink it. The study showed fewer African Americans (43 percent) opted for surgery than Caucasians (49 percent).
Samples of tumor tissue also held important clues. Tumors in African Americans were six to seven times more likely to present with lymphocytic response, which involves immune system cells. These cells behave not only as first responders against tumors but also can produce growth factors that feed tumor growth, such as forming blood vessels.
The tumors in African Americans were almost two times more likely than tumors in Caucasians 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 tumor lymph node metastasis and local host defense against tumors 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," said Dr. Worsham.
Study co-authors included Josena Stephen, MD, Mei Lu, PhD, Kang Mei Chen, MD, Shaleta Havard, Veena Shah, MD, and Vanessa Schweitzer, MD.
The study was funded by a grant from the National Institutes of Health.
nfl week 12 picks jason witten ucla vs usc rich rodriguez rich rodriguez the muppet movie the muppet movie
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.