Benefit of HPV
Vaccination, Frequent Screening for Women
Over 41 Is Likely to Be Low, Study Suggests
ScienceDaily - The overall potential
benefits of human papillomavirus (HPV)
vaccinations or frequent HPV screenings for
women over the age of 41 are low, concludes
a new study published online February 15 in
the Journal of the National Cancer
Institute.
The study found that the rate of new
infections preventable by vaccination
declines with age. Furthermore, new
infections among women at any age typically
do not progress to cervical intraepithelial
neoplasia grade 2 (CIN 2) or CIN 3, the
precursors for cervical cancer.
This study was undertaken because
researchers wanted to examine whether
women's age and the duration of carcinogenic
HPV infections influenced subsequent
persistence of infection and risk of CIN 2
or worse disease.
Ana Cecilia Rodríguez, M.D., of the Proyecto
Epidemiológico Guanacaste, Fundación
INCIENSA, in San José, Costa Rica, and
colleagues screened over 9,000 women in
Costa Rica aged 18 to 97 years.
Those with CIN 2 or worse disease at
enrollment were treated and not followed
further. Among the remaining participants,
those at low risk of CIN 2 or worse were
rescreened at 5-7 years (passively
followed), whereas higher-risk participants
and subsets of low-risk women and initially
sexually non-active women were rescreened
annually or semiannually (actively followed)
for up to 7 years.
Most of the CIN 2 or worse disease diagnosed
during the study period was associated with
persistent carcinogenic HPV infections that
were prevalent, or already present at the
time of initial testing.
The vast majority of newly detected
carcinogenic HPV infections did not persist
and did not lead to CIN 2 or worse disease
during the study period, regardless of age.
The rate of newly detected carcinogenic HPV
infections declined with increasing age and
ranged from 35 percent in women aged 18-25
years to 13.5 percent in women aged 42 years
and older.
"Understanding the relevance of the concept
of duration of infection can improve
cervical cancer prevention strategies that
integrate prophylactic vaccination with HPV
screening," the authors write. "For example,
evidence that newly detected infections in
older women do not harbor a higher risk of
persistence or CIN 2 [or worse disease] than
in younger women and that older women
acquire fewer new infections indicates that
the possible benefit of vaccinating older
women is much reduced..."
Study limitations: The most important
conclusion that newly-detected HPV
infections typically do not progress to CIN2
or worse at any age might not hold beyond
the 7 years of follow-up in this study. |
|
|
|
|
| |
|
|
|
|
|
