Results from a study of more than 330,000 women showed
that most can safely undergo screening for cervical cancer once every 3 years,
according to data presented at a press conference in advance of the 2011 ASCO
Additionally, the findings demonstrated that HPV testing
alone is more accurate than Pap smear for determining cervical cancer risk. HPV
testing was “clearly superior” to Pap smear for predicting who would
develop severe dysplasia or cancer within 5 years, although Pap smear detected
additional HPV-positive women with cancer or precancer.
Screening guidelines from the American College of
Obstetricians and Gynecologists and ACS endorse concurrent HPV testing with Pap
tests as an alternative to Pap testing alone for women aged at least 30 years
and recommend co-testing every 3 years for women who are HPV-negative and have
a normal Pap test.
Hormuzd A. Katki, PhD, principal investigator in
the division of cancer epidemiology and genetics at the NCI, called the results
“a formal confirmation” of the safety of 3-year follow-up for women
who have a negative HPV test and normal Pap result.
“A single negative HPV test provided 5 years of
extremely low cancer risk for women, and this risk was not appreciably lowered
by also having a normal Pap test,” he said. “These findings directly
demonstrate the safety of current guidelines, which recommend a 3-year
screening interval for women who test negative for HPV.
“Furthermore, these findings suggest that all
HPV-negative women could safely return no earlier than 3 years,” Katki
said at the press conference.
For 5 years, researchers followed 331,818 women aged at
least 30 years who enrolled in Kaiser Permanente Northern California’s
co-testing program between 2003 and 2005. Five-year cancer risk for
HPV-negative women with a normal Pap test was 3.2 per 100,000 women per year.
HPV-negative women had half the cancer risk of women
with a normal Pap test, 3.8 per 100,000 women per year vs. 7.5 per 100,000.
Cancer risk for HPV testing alone was similar to HPV and Pap testing together,
3.8 per 100,000 women per year vs. 3.2 per 100,000 women per year.
HPV testing also identified more women at high risk for
cervical cancer. Regardless of Pap or HPV test results, women who were
HPV-positive at enrollment had a higher 5-year risk for cervical cancer or
precancer than women with an abnormal Pap test at enrollment, 1.5% per year vs.
0.9% per year.
The 5-year risk for developing cancer or precancer was
7.6% in women who were HPV-positive compared with 4.7% for women who were
HPV-negative, for an excess risk of 7.4%. Katki said women who were
HPV-negative had a lower risk for developing cancer or precancer than women who
had negative Pap results.
“This shows that the HPV test is better for
separating women into categories of high risk for cancer and low risk for
cancer,” he said. “However, that does not mean that a Pap test was
useless. When we combine HPV testing and Pap testing, we can get something even
Katki said the Pap test did not tell HPV-negative women
much about their risk, but for women who were HPV-positive, the Pap test
discovered an additional 6% of women who had cancer or precancer.
“Most of that extra 6% were found at enrollment
into the co-testing program, which shows that the Pap test is able to identify
women who have immediate disease, whereas women who were negative for the Pap
test but HPV-positive may develop cancer or precancer, but likely at some point
off in the future,” he said. – by Jason Harris
Katki HA. #1508. Presented at: 2011 ASCO Annual Meeting;
June 3-7, 2011; Chicago.
The data presented certainly support the argument that
if you are a woman who is HPV-negative and Pap smear-negative, a test every 3
years would be reasonable. It is not surprising to say that HPV testing alone
would be potentially better than Pap smear alone because we know that almost
all cervical cancer is caused by HPV, but I would not agree nor do I think the
authors are saying that we should not perform a Pap smear. These data do not
suggest that a Pap smear is not a cost-effective test or that the HPV test
should be the standard. Before one would change any established practice, we
would need to see a peer-reviewed paper.
– Maurie Markman, MD
HemOnc Today Editorial Board member
Disclosure: Dr. Markman reports no relevant finan