Pap tests should start later, new guidelines recommend

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Canadian women will be spending a lot less time in gynecological stirrups if doctors heed new recommendations on cervical cancer screening.

Pap testing should begin at the age of 25 and be repeated at intervals of three years, regardless of a woman's sexual history and age, according to new guidelines from the Canadian Task Force on Preventive Health Care published Monday in the Canadian Medical Association Journal.

That is a significant change from the current practice of doing Pap tests after the initiation of sexual intercourse (or by 18) and continuing annually until the age of 69.

Dr. James Dickinson, a professor of family medicine and community health at the University of Calgary and member of the task force, said the new guidelines reflect the growing body of scientific evidence that more frequent screening does more harm than good.

"Screening every three years after age 25 is sufficient," he said. "Screening earlier and more often has the potential for a very, very small benefit but a significant likelihood of causing harm."

By harm Dickinson was referring to the trauma and additional medical interventions that come with abnormal tests – which occur in one in 10 Pap tests.

Pap testing consists of scraping cells from the cervix and testing those cells for abnormalities that could indicate cancer. (The cervix is located at the entrance of the uterus.) It is done during a pelvic exam, which can also serve to detect sexually transmitted infections.

"The pelvic exam is uncomfortable and doesn't provide very useful information much of the time," Dickinson said.

He noted, however, that the Pap test, while imperfect, remains the best screening method. The test was invented by Greek doctor Georgios Papanikolaou in the 1940s and B.C. began the first large-scale screening program in Canada in 1960.

Since screening guidelines were last published in 1994, the number of women diagnosed with cervical cancer has fallen by half and the number of women dying of the disease has decreased by about 80 per cent.

It is also now recognized that cervical cancer is caused almost exclusively by certain strains of human papilloma virus (HPV).

Under the new guidelines some older women could be still getting tested on a regular basis. The recommendation say a women should have three negative tests in the preceding decade for screening to stop at 69.

In an editorial also published in Monday's CMAJ, Dr. Janet Dollin of the department of family medicine at the University of Ottawa argues that there are other ways to tackle cervical cancer aside from screening with Pap tests.

She noted that HPV testing is more precise and is increasingly being used around the world, and pointed out that there is now a vaccine that prevents infection with the most dangerous strains of HPV.

"Pap testing is a single tool in an evolving tool kit to prevent cervical cancer," she wrote. "We envision a future where this cancer can either be prevented as a sexually transmitted viral infection or screened for less frequently with better tools."

Dollin said a larger problem is that testing and preventing practices vary widely between provinces and there is no reason there cannot be a pan-Canadian approach.

Dickinson said he agrees that much more can be done to prevent cervical cancer, notably ensuring that the women at highest risk – such as immigrants and refugees – be tested. (Immigrants and refugees often come to Canada as adults and have never been tested.) He said the task force felt that HPV testing, holds out a lot of promise, but the "evidence is not yet in for us to jump on that bandwagon."

Approximately 1,300 Canadian women were diagnosed with cervical cancer in 2011, and 350 died of the disease.