HPV Test Helps Detect Cervical Cancer
Study Shows Lesions That Lead to Cancer Spotted Earlier Than With Pap Test Alone
Oct. 3, 2007 -- The Pap test has been used for more than six decades to
detect cervical cancer and precancerous cells, but a different screening method
may help in better identifying precancers early in women in their 30s and
beyond, findings from a large European study suggest.
Researchers reported that human papillomavirus (HPV) DNA testing combined
with the Pap test detected the high-risk lesions that lead to cervical cancer
earlier than Pap testing alone.
HPV testing could also lead to less frequent screening for women who are 30
and over, the researchers say.
HPV DNA testing is known to be more sensitive than the traditional Pap test,
meaning that it is able to detect more cervical abnormalities early. But it has
not been clear until now if these abnormalities were clinically relevant, says
the study's principal investigator.
"We showed that these lesions were indeed clinically meaningful, and
that HPV DNA testing leads to their earlier detection," Chris Meijer, MD,
of Amsterdam's VU University Medical Center, tells WebMD.
He adds that HPV testing may eventually replace Pap testing as the
first-line screening method for cervical cancer if longer follow-up confirms
HPV and Cervical Cancer
It is now clear that virtually all cervical cancers -- more than 99%,
according to the American Cancer Society -- are related to HPV infection, which
is a sexually transmitted virus. Just two strains of the virus, HPV 16 and HPV
18, account for 70% of cervical cancers. Most genital HPV infections don't
cause cancer though.
Current screening guidelines in the U.S. call for annual Pap screening
within three years of vaginal intercourse or no later than age 21. Beginning at
age 30, low-risk women who have had three normal consecutive Pap smears can
safely be screened less often.
In the U.S., HPV testing is approved in cases where Pap tests results are
unclear or in conjunction with Pap screening after age 30. HPV testing is
not a replacement for Pap testing.
In an effort to clarify the value of HPV testing in cervical cancer
screening, researchers in the Netherlands have enrolled roughly 45,000 women in
an ongoing comparison trial of HPV plus Pap testing vs. Pap testing alone.
Interim results involving just over 17,000 women between the ages of 29 and
56, enrolled in the study for an average of seven years, are reported in the
Oct. 4 online edition of the journal The Lancet.
For the first five years of annual screening, about half the women got Pap
tests and HPV tests to detect the presence of viral infection associated with
cervical cancer and half got Pap testing alone. After five years, both tests
were given to both groups.
In the follow-up analysis, women who had both tests early on also had
earlier detection of lesions with the potential to lead to cervical cancer.
However, the total number of these precancerous lesions was the same between
the two groups over the two screening sessions.