Replacing the Pap Smear?
Researchers believe HPV testing may detect cervical cancer earlier than Pap testing
CR | Page No. 12 | Summer 2009
For decades, Pap smears have
been the standard method of
screening for cervical cancer.
However, the regimen of repeat
testing over the years can be a
burden in poor countries, which
often lack sufficient health care
infrastructure. A new study
suggests that a better alternative
might already exist. A single
checkup for human papillomavirus
(HPV) infection is enough to catch
cancer early and save lives, the
study found.
For a Pap smear, a clinician
collects secretions from a woman’s
cervix and analyzes the sample for
the presence of abnormal cells.
An HPV test also involves the
analysis of cervical cells. But
instead of looking for signs of
cancer or precancer, it checks
for the primary cause of cervical
cancer: infection from one of the
more than a dozen carcinogenic
forms of HPV. Doctors can follow
up positive results from either
of the tests with a full exam to
remove lesions and prevent cancer
from developing.
The new study, published April 2
in the New England Journal
of Medicine, compared these
screening methods in more than
130,000 healthy women in India
between the ages of 30 and 59.
Researchers randomly assigned
women to a single round of one of
three tests—a Pap smear, HPV test,
or visual inspection of the cervix—
or to the current standard of
care in India, which involves little
screening. Researchers followed
the women for eight years.
The HPV test significantly beat
out a single Pap smear or visual
inspection, results showed. Not only
did HPV testing enable doctors to
catch lesions and cancer earlier, it
also was associated with a reduction
in the overall death rate from cervical
cancer, says radiation oncologist
Rengaswamy Sankaranarayanan
at the World Health Organization’s
International Agency for Research
on Cancer in Lyon, France, who is
the lead author of the study. “HPV
screening is probably more sensitive
than the other tests in finding
potentially malignant precancerous
lesions,” he says.
Pap smears require repeated
testing at least every few years to
catch new abnormal cell growth.
In comparison, a single HPV test
can provide substantial benefits,
Sankaranarayanan says. But HPV
screening programs should focus
on women 30 years and older to
minimize the number of necessary
medical visits, he says. That’s
because women typically become
infected with HPV through sexual
intercourse early in their lives and
fight it off—and so it is usually
linked to cervical cancer only if
the infection persists for a decade
or so. American Cancer Society
guidelines now say that women
over 30 with average risk may get
screened every three years with
both a Pap test and an HPV test, as
an alternative to getting a Pap test
every two or three years.
Cervical cancer is one of the
top three leading causes of cancer
deaths in women worldwide.
Out of the roughly half-million
new cases diagnosed every year,
80 percent are in developing
countries. And because the disease
affects women at a young age—the
median is 48—its impact on
families worldwide is particularly
devastating, says medical
epidemiologist Mark Schiffman of
the National Cancer Institute.
In the U.S., people in many
communities also lack easy
access to regular Pap tests,
says cancer epidemiologist
Electra D. Paskett at Ohio State
University in Columbus. Women
in Appalachia, rural Alaska
and migrant communities, for
example, have disproportionately
high rates of cervical cancer and
could benefit from HPV screening.
“This kind of gynecological care
has tremendous potential in the
United States, too,” Paskett says.
—Regina Nuzzo
Cancer cells on the cervix
JOHN BAVOSI / PHOTO RESEARCHERS INC.
