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As British Columbia rolls out new cervical cancer screening guidelines that say the procedure should begin later and take place less often, health experts in the province are already looking toward new options that may be more accurate and accessible than standard Pap tests.
B.C.'s new policy says women should be screened for cervical cancer with a Pap test every three years instead of two and starting at the age of 25 rather than 21. The new regulations are designed to avoid over-diagnosis and unnecessary treatment, the B.C. Cancer Agency says.
"I think it's a good thing," said Gina Ogilvie, a professor at the University of British Columbia who holds the Canada research chair in the global control of HPV-related disease. "I think B.C. is now coming in line with what the emerging evidence is around the frequency of screening."
The Canadian Task Force on Preventive Health Care published recommendations on screening for cervical cancer three years ago. They also say that women should be screened every three years and not before the age of 25. Those guidelines were endorsed by the College of Family Physicians of Canada.
Alberta suggests getting screened every three years starting at age 25, or three years after becoming sexually active, if that is later. Ontario also recommends getting Paps at three-year intervals, but starting at the age of 21. Manitoba suggests starting regular screenings at 21, and then every three years after that.
B.C., among other provinces, recommends that women who have received a vaccine for the human papillomavirus still get tested.
Dirk Van Niekerk, who leads the cervical screening program for the B.C. Cancer Agency, said recent data have shown that potentially unnecessary treatment may be causing more harm than good.
Women under the age of 25 often have cervical abnormalities that will go away on their own, he said, but since there is no way of predicting whether they will, doctors end up treating most of these cases. He said in some cases, such treatment can damage a woman's cervix enough to double the risk of premature labour.
"It's coupling the almost thousand women that we would have to treat for these cervical abnormalities that might go away versus the one or two cases of cancer a year," Dr. Van Niekerk said. "It isn't the best balance of benefit and harm."
The B.C. Cancer Agency says research shows screening every three years is as effective as doing it every two. It notes that cervical cancer goes through a pre-cancerous phase that lasts for years before evolving, which makes the disease very preventable if detected early on.
Meanwhile, Dr. Ogilvie is leading the province's HPV FOCAL study – a 25,000-person trial that compares standard Pap screenings with HPV testing, in an effort to determine which option should be used as a primary testing method.
The human papillomavirus is a very common sexually transmitted disease – about three-quarters of sexually active people will get it at some point – but some strains of HPV are known to cause cervical cancer.
Pap tests and HPV tests are similar, though they differ in how samples are processed. With a Pap, cells scraped from the cervix are examined under a microscope for abnormalities, while an HPV test looks for the virus's DNA within the cells.
"We want to wait for the clinical trial to really define the optimal way to roll this out first," Dr. Ogilvie said. "That is why I think the province is being quite methodical in having a step-wise approach, starting first with the new cervical cancer screening guidelines with Paps."
The results of the trial, the largest of its kind in Canada, are expected to be available within the next year.
Dr. Ogilvie said she thinks the province is keen to consider HPV testing – a method she says is more accurate than Pap testing – as a way to further optimize cervical screening.
"We will definitely be looking at the data and making a decision in the near future, on whether HPV DNA testing might be more appropriate in certain age groups," Dr. Van Niekerk said.
"Because we know most cancers are caused by infection by HPV, it really puts us earlier in that pathway to cancer," he said, adding that women who test negative for HPV are less likely to develop abnormalities over a longer period of time, so it might even be possible to screen less frequently for those women.
"The increased detection and the longer protection are the two things we are really very interested in," Dr. Van Niekerk said.
Dr. Ogilivie said this new method might come with an added benefit: the ability to bring testing to people who aren't already getting it, since HPV testing can also be done by a self-collection method.
"What would likely happen is that as part of rolling out HPV testing, [the province] would consider a self-collection arm, to really try to improve uptake in those women who haven't been able to come in for a pelvic exam, for whatever reason." she said.
"We are very interested in that option to allow women who are currently not participating in screening to screen," Dr. Van Niekerk said. "It appears from the data that a self-collected HPV sample is almost as accurate as a physician-collected HPV DNA sample."