African American Women Are Less Likely to Benefit From HPV Vaccines for Cervical Cancer Prevention
Vaccines currently available to prevent the two most common strains of human papillomavirus (HPV), HPV 16 and 18, responsible for about 70% of cervical cancers, may not be protective in African American women, according to a study by Cathrine Hoyo, PhD, MPH, Associate Professor in the Obstetrics and Gynecology Department at Duke University School of Medicine in Durham, North Carolina, and colleagues. According to their findings, African American women with abnormal Pap test results are about 50% less likely to be infected with HPV subtypes 16 and 18 than non-Hispanic white women. The results were presented today at the 12th Annual AACR International Conference on Frontiers in Cancer Prevention Research, in National Harbor, Maryland.
“African American women are about 20% more likely to develop cervical cancer and almost twice as likely to die from the disease compared with non-Hispanic white women,” Dr. Hoyo said in a statement. “If screening rates are comparable in African American and white women, why are the rates of cervical cancer and mortality higher among African American women when we have a program that works so well?”
To better understand these disparities, Dr. Hoyo and her colleagues conducted the Cervical Intraepithelial Neoplasia Cohort Study (CINCS) to identify markers that distinguish early cervical intraepithelial neoplasia (CIN1) from advanced cervical intraepithelial neoplasia (CIN2 and 3). The researchers enrolled 572 participants—280 African American women and 292 non-Hispanic white women—and found that 245 (43%) had no precancerous cervical abnormalities, 239 (42%) had early precancerous cervical abnormalities, and 88 (15%) had advanced precancerous cervical abnormalities.
Study Results
When the researchers examined the specific subtypes of HPV, they found that white women and African American women often had different subtypes. The most frequently detected HPV subtypes among the non-Hispanic white women with CIN1 were HPV 16, 18, 31, 56, 39, and 66, whereas among the African American women with CIN1, the most common HPV subtypes were 33, 35, 58, and 68.
In those women with advanced precancerous cervical abnormalities, HPV 16, 18, 33, 39, and 59 were the most common genotypes detected in white women, and HPV 31, 35, 45, 56, 58, 66, and 68 were the most prevalent HPV subtypes among the African American women.
New Vaccine in the Works
According to Dr. Hoyo, a new vaccine targeting nine HPV subtypes— 6, 11, 16, 18, 31, 33, 45, 52, and 58—is currently being tested in phase III clinical trials and may be more beneficial to African American women then the current FDA-approved HPV vaccines. However, “the most disconcerting part of this new vaccine is it doesn’t include HPV 35, 66, and 68, three of the strains of HPV of which African American women are getting the most,” said Dr. Hoyo in a statement. “We may want to rethink how we develop these vaccines given that African Americans tend to be underrepresented in clinical trials.”
Dr. Hoyo and her colleagues are continuing their research to define epigenetic markers that can be used to predict which precancerous cervical abnormalities will progress.
The research was funded by the National Institutes of Health and the National Cancer Institute.
The study authors reported no conflicts on interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
