After years of needlessly conducting countless Pap tests and subsequent follow-up exams on low-risk women, North American health organizations are finally moving to replace antiquated cervical cancer screening policies.
It's a long-overdue change that some cancer screening experts say will reduce waiting lists for secondary tests and the need for some painful, and even harmful, procedures. It will also relieve an unnecessary burden on the health-care system while helping doctors identify patients who may be at risk of developing cervical cancer.
On Friday, the American College of Obstetricians and Gynecologists unveiled new screening guidelines that advise women not to get a Pap test until age 21, after which they should be screened every two years until age 29. After that, women should be screened every three years.
It's a major departure from previous recommendations in Canada and the United States, which advised women to have their first screening at 18 and be tested every year after that.
It's a shift taking shape across North America as more experts recognize that, despite the traditional belief that more screening will result in lower disease rates, the evidence simply isn't there when it comes to Pap tests.
"We haven't really been very effective, and we've been causing harm to the women that have been coming in," said Jim Dickinson, professor of family medicine at the University of Calgary, who sat on the provincial committee reviewing cervical cancer screening guidelines.
Although screening guidelines vary province to province in Canada, most have changed their policies to reflect emerging evidence that the traditional programs had serious flaws.
Last month, Alberta officially updated its guidelines, advising women to start getting screened at age 21 or when they become sexually active. Instead of annually, women are now being told to get screened every three years.
It's similar to advice offered by the Society of Obstetricians and Gynaecologists of Canada. The group updated its guidelines in 2007 to say that Pap tests should be undergone within three years of becoming sexually active or by age 21. Other provinces, such as Ontario and British Columbia, advise women to be tested soon after becoming sexually active. Those provinces advise women to be tested every year until they have three normal tests in a row, after which they can be tested every two to three years.
One of the major factors driving the shift is the rare incidence of cervical cancer among women in their late teens and 20s, who in the past have been prime targets of Pap screening campaigns. The disease can also take years to develop, which is why many medical organizations are moving toward screening women at intervals longer than one year.
"It's been recognized that it's probably overkill to actually recommend annual Pap testing, especially in younger women," said Verna Mai, chairwoman of the Screening Action Group at the Canadian Partnership Against Cancer and provincial lead of public health at Cancer Care Ontario.
But the changes weren't made to help low-risk women save time or avoid the hassle of yearly tests. Rather, the updated rules are designed to prevent numerous unnecessary follow-up exams and potentially harmful procedures from being conducted on women who don't have cancer.
In a Pap test, also called a Pap smear, doctors swab the cervix and send the cells to a lab to look for changes or abnormalities that could signal the possibility of cancer. The problem is that human papillomaviruses, which are very common and are transmitted sexually, can cause abnormalities that are perfectly harmless.
But in order to determine whether abnormalities warrant serious concern, doctors must conduct one of several follow-up examinations, a process that may go on for months or years, until a woman's test results come back normal more than once. In some cases, women may have biopsies or other medical procedures done, even though the cells will probably return to normal on their own.
"It creates a lot of anxiety and concern," Dr. Dickinson said.
Experts say they hope the new guidelines become the practice in all provinces. In Saskatchewan, for instance, women are still told to begin getting screened at age 18.
Dr. Dickinson said it's also important for public health officials to better target those most at risk from cervical cancer, such as women in their late 30s to 50s, those with numerous sexual partners and those who simply never get screened.
But the guidelines could also change again, depending on the outcome of campaigns to vaccinate girls against HPV. The vaccine guards against two strains of the virus that most commonly cause cervical cancer. As the girls who are currently being vaccinated grow up, the incidence of cervical cancer may fall and there will be less need to conduct Pap tests every two or three years.
However, that's not to say girls who have been vaccinated don't need Pap tests. Women shouldn't be "falsely reassured," Dr. Mai said, because the HPV vaccine doesn't protect against all viruses that can lead to cancer.