NEW YORK, Jan 04 (Reuters Health) -- Testing vaginal swabs collected by
patients for the presence of a particular virus is an effective way of screening
for cervical cancer, according to a study published in Wednesday's issue of The
Journal of the American Medical Association.
Traditionally, Pap smears -- swabs taken from the cervix during
gynecological exams -- are used to screen for cervical cancer. But some women
neglect to have routine exams, and some areas lack basic medical facilities, so
investigators searched for another means of screening for cervical cancer.
Dr. Thomas C. Wright, Jr. of Columbia University in New York and
colleagues studied the use of vaginal swabs collected by patients themselves as
an alternative to the Pap smear. The swabs were tested for the presence of DNA
from human papillomavirus (HPV), a sexually transmitted virus associated with
the development of cervical cancer. The study compared HPV testing with Pap
smears in outpatient clinics in the area of Cape Town, South Africa, between
January 1998 and April 1999. A total of 1,415 previously unscreened black South
African women between the ages of 35 and 65 were included in the study.
The women submitted self-collected vaginal swabs for analysis by HPV DNA
testing and also underwent gynecologic exams for HPV DNA testing, Pap smears,
and direct visualization of the cervix by clinicians. All women with abnormal
results on any of the tests underwent a further exam called colposcopy so that a
diagnosis of cancer could be confirmed under the microscope.
"What this study shows is that the clinician-obtained HPV samples actually
detected more cases of... cervical cancer precursors and invasive cervical
cancer than did the conventional Pap smear. The HPV DNA test was positive in 84%
of the women with... cervical cancer precursors and invasive cervical cancers
whereas the regular Pap smear detected only 68% of these cases," Wright said at
a briefing held to announce the study results.
"What is even more important is that the patient-collected samples worked
as well as did the regular Pap smear but it did so without requiring the
gynecologic examination... In the United States we know that almost 60% of women
with invasive cervical cancer have not had a Pap smear within the past 3 years,"
Wright commented.
The HPV test used in the study was manufactured by Digene Corporation of
Gaithersburg, Maryland. In a statement issued by the company, Wright said that
since HPV testing could be done from swabs collected by the patient, this method
"should greatly increase access to screening and hopefully prevent cervical
cancer."
A similar study was conducted in Guanacaste Province, Costa Rica, by Dr.
Attila T. Lorinez of the National Cancer Institute in Bethesda, Maryland, and
colleagues. The researchers studied HPV DNA testing using two HPV DNA tests in
1,119 sexually active women who also underwent Pap smear testing.
Lorinez's team identified 138 high-grade lesions and 12 cancers. "The HPV
test was significantly more sensitive than the Pap smear and detected 70% more
women with cervical disease," Lorinez said at the briefing.
Accompanying the two reports is a note of caution from editorialist Dr.
Jack Cuzick of the Imperial Cancer Research Fund in London, UK. He writes,
"whether widespread HPV testing is feasible or affordable and whether it will
eventually lead to fewer cases of invasive cervical cancer or reduce... (illness
and death associated with) the disease will require further study to optimally
identify and treat the population of women at risk."
