researchers say that reducing rates of high-grade cervical lesions among young women Americans in 2008-12 can be down to a combination vaccine HPV and cervical changes screening guidelines.
high-grade cervical lesions or precancerous cervical lesions, abnormal changes in cervical tissue that can become cancerous. These lesions do not cause any symptoms but can be detected by screening cervical cancer .
More than 50% of high-grade cervical lesions are caused by persistent infection with HPV (human papilloma virus), most commonly HPV types 16 and 18. As such, they can be prevented with vaccination against HPV.
The HPV vaccine Gardasil, which protects against HPV types 16 and 18, as well as types 6 and 11 – known to cause genital warts – was approved by the Administration Food and Drug US (FDA) in 2006. in 2009, another HPV vaccine – Cervarix – was approved to protect against HPV types 16 and 18.
According to the Centers for Disease Control and Prevention (CDC), girls of 11 and 12 years of age are recommended to receive HPV vaccination in three doses, such as girls and women aged 13-26 are They not already have been vaccinated.
significant reductions in high-grade cervical lesions for women 18-20 years of age
For their study – published in the journal Cancer – lead author, Dr. Susan Hariri, Division of STD Prevention at the CDC, and his team set out to estimate rates of high-grade cervical lesions among American women aged 18-39 between 2008 and 2012.
All women included in the study were from catchments in California, New York, Connecticut and Oregon, and were part of HPV-IMPACT Project, which monitors the impact population vaccination against HPV.
The incidence of high grade cervical lesions among women was identified through manual review board electronic health records, and the team applied the Cochran-Armitage test to assess trends in the incidence of these injuries.
In addition, the researchers used administrative data and surveys to estimate the annual cervical screening in California, New York and Oregon.
The team found that during the period of 5 years was a significant reduction in the incidence of high grade cervical lesions among women 18-20 in the four states aged included in the study. In California, for example, as a lower incidence of 94 per 100,000 women 5 per 100,000 women, while in Oregon, rates fell from 202 per 100,000 to 37 per 100,000.
High incidence of cervical injury also fell for women 21-29 years of age, although to a lesser extent. In Connecticut, for example, as a lower incidence of 762 per 100,000 women to 589 per 100,000 inhabitants, while the fall of 770 per 100,000 to 465 per 100,000 women in New York.
There was no change in the incidence of high-grade cervical disease among women 30 to 39 years old.
reductions probably a combination of HPV vaccination and changes in screening guidelines
Researchers have noted that the recommendations of detecting cervical cancer were changed during the study period. Introduced in 2012, the new guidelines for cervical screening recommended that women under 21 should no longer be tested, while women 21 and older should be screened every 3 years instead of annually.
Dr. Hariri and colleagues identified significant reductions in rates of screening among women aged 18-20 years old, while a smaller reduction was found among women 21-24 years old.
Since the high-grade cervical lesions can only be identified by screening, researchers believe that the reduced as a result of screening orientation changes may have contributed to a fall in rates of these lesions.
However, they believe that the introduction of HPV vaccination may also have played a role. The team adds:
“Declines in CIN21 [cervical intraepithelial neoplasia grade 2, 3 and adenocarcinoma in situ – cervical high grade lesions] screening in young women were probably due to reduced detection, but could also reflect the impact of vaccination.
These data illustrate the challenges in interpreting CIN21 ecological trends in the new era of prevention of cervical cancer and stress the importance of information, such as HPV types detected in
injury to assess the impact of HPV vaccine in precancerous lesions of the cervix. “
Dr. Hariri said that many years will be needed to establish the impact of HPV vaccination on rates of cervical cancer and other cancers associated with HPV because of a long latency between HPV infection and the development of cancer.
Earlier this month, Medical News Today reported on a study published in The Lancet Oncology suggesting that a single dose of the HPV vaccine could be enough to prevent cervical cancer .