DESCRIPTION: (Adapted from Investigator's Abstract) In 1993 the authors
began an epidemiologic cohort study of the natural history of human
Papillomavirus (HPV) infection and cervical neoplasia in a population of low
income women in Sao Paulo, Brazil, one of the highest risk areas worldwide
for cervical cancer. This study was designed to answer questions that have
not yet been addressed in epidemiologic investigations of this neoplastic
disease. Although few would dispute that HPV infection is an important
cause of cervical cancer, most of the epidemiologic data have come from
retrospective studies, which do not provide information on the dynamics of
cervical HPV infection in the same individual. The Brazilian cohort study
is testing the hypothesis that persistent infections with oncogenic HPV
types are more likely to be the true precursor events leading to cervical
carcinogenesis. Persistence of infections is being documented on the basis
of molecular variants of HPV, which provides a much finer level of detail
than simple HPV typing and may unveil in addition to persistence per se
other prognostic markers of progression across the spectrum of cervical
lesions.
The study will accrue 2000 female subjects through February 1996. Subjects
are being followed up over a 5 year period in scheduled returns every 4
months, in the first year, and once yearly thereafter, for a total of 8
visits as follows: initial, 4, 8, 12, 24, 36, 48, and 60 months. In each
of these visits, subjects are submitted to a questionnaire-based interview,
have a cervical specimen taken for Pap cytology and HPV testing, and a blood
sample drawn for serologic testing for HPV antibodies. A cervicography is
performed once in the first year and at 24 and 48 months.
Considering the public health and economic importance of cervical cancer
screening and given the current impetus within the federal government to
examine the utility of HPV testing in augmenting existing screening
programs, the investigators argue that there is a clear need for
long-ranging multidisciplinary studies of the natural history of this
malignant disease. In brief, this ongoing investigation will further
understanding of the etiopathogenesis of cervical neoplasia by tackling the
following specific objectives: (1) to study the prevalence and incidence of
transient and persistent cervical HPV infection in asymptomatic women; (2)
to verify the hypothesis that persistent HPV infection increases risk of low
grade and high grade cervical lesions; (3) to search for epidemiologic
determinants of persistent cervical HPV infection; (4) to search for
specific molecular variants of oncogenic types of HPV that may be associated
with an increased risk of cervical neoplasia; (5) to verify the hypothesis
that measures of viral burden in the cervix may be correlated with
persistent infections and with low and high grade lesions; and (6) to study
the humoral immune response to capsid antigens of HPV as a possible marker
of persistence of cervical HPV infection and of likelihood of progression in
lesion severity.
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