By Kathleen Raven
NEW YORK (Reuters Health) - Certain tests can detect precancerous cervical cells from self-collected samples with nearly the same accuracy as a physician's swab taken in a clinic, according to a new review of past studies.
Compared with those gathered by a physician, self-collected samples were about 11 percent less sensitive in identifying precancerous growth.
However, the research team stops short of recommending at-home test kits as a cancer screening method for women infected with the sexually-transmitted human papillomavirus (HPV).
Some strains of HPV are directly linked to cervical cancer risk, while others appear to have no negative effect on a woman's health.
"We want the current screening programs to continue to run," said Marc Arbyn.
"We do not want to promote self-sampling procedures over doctor's visits just yet," he said.
Arbyn, from the Unit of Cancer Epidemiology at the Scientific Institute of Public Health in Brussels, is the review's lead author.
HPV tests, and not Pap smears, are "the new standard of cervical cancer detection," Arbyn said.
In 2010, nearly 4,000 women in the U.S. died from cervical cancer, according to the Centers for Disease Control and Prevention (CDC). Meanwhile, a 2011 study found that 43 percent of girls and women between ages 14 to 59 are infected with HPV.
Even though an HPV vaccine is available, the CDC reported that in 2012, only 33 percent of U.S. girls between 13 and 17 years old had received the full, three-dose vaccination.
"Most cervical cancer cases reside in women who do not make regular clinic visits," said Attila Lorincz of Queen Mary University in London. Lorincz was not involved in the current study.
"It's unacceptable to have a status quo where a preventable cancer continues to occur among women," Lorincz said.
In their analysis of 36 studies that included a total of 154,556 women, Arbyn and his team compared the accuracy of HPV tests taken by women themselves and those collected by physicians.
On average, HPV tests from self-samples detected 76 percent of moderate precancerous growth and 84 percent of severe cervical cancer growth.
"This study is a sort of challenge to health authorities," Lorincz said. "It is a way of asking them, 'Are you doing all you can to contact women by phoning or writing them?'"
"If not, then it may be time to consider self-sample tests," he said.
An editorial that accompanies the study published in Lancet Oncology states, "For the billions already infected or without access to HPV vaccination, improved screening for early detection and treatment remain the best option for reducing cancer burdens."
Physicians should be aware of this new meta-analysis, Abryn said, because "it is important to be able to know which are the best combinations of tests and analyses."
But, he added, "We do not promote the ability of women to buy such kits in a supermarket. We need an organized system behind HPV test kits."
A large, randomized-control clinical trial - the gold standard of evidence in medical studies - might provide additional reassurance that HPV self-testing has a place in public health campaigns, much like at-home sexually-transmitted disease kits for chlamydia do now, Lorincz said.
The most important aspect of a self-test is its sensitivity, Lorincz said.
For example, if 100 women in a room have precancerous growth, and an HPV test does not detect this growth in 10 women, then the sensitivity rate is 90 percent.
If a test doesn't catch pre-cancerous cell growth, "then you have lost your patient," Lorincz said.
"There are advances coming along in the consumer space that might encourage women to be more open to HPV self-tests," Lorincz said.
"If they see a nicely designed tool, then they might think, 'Oh, this looks nice, I would use this,'" he said.
Arbyn pointed to The Netherlands as a country that has already decided to use self-sampling tests as a back-up to the preferred method of a physician visit.
"Women receive invitations to contact their doctors for a cervical cancer screening," Abryn said. "And the non-responders later receive a self-sampling test."
"But it is difficult to translate messages from one country to another," he said.
SOURCE: http://bit.ly/19OQDLu Lancet Oncology, online January 14, 2014.