McMaster University

McMaster University

McMaster study informs new Canadian cervical cancer screening guidelines

By Amanda Boundris

Leslea Peirson
Leslea Peirson

A review by McMaster University researchers has resulted in new cervical cancer screening guidelines, published January 7 in the Canadian Medical Association Journal (CMAJ).

Key recommendations are that routine screening of women for cervical cancer should begin at age 25 and take place every three years, and that women over 69 only need screening if they have not been adequately screened in the past.

The guidelines were released by the Canadian Task Force on Preventive Health Care (CTFPHC), established by the Public Health Agency of Canada to develop clinical practice guidelines for primary care providers and policy makers. The Evidence Review and Synthesis Centre (ERSC), based at McMaster, conducts reviews on which the CTFPHC base their guidelines. This systematic review on cervical cancer screening was led by Leslea Peirson, a review coordinator with the School of Nursing.

The guidelines are an update to the last Task Force guidelines issued in 1994. They contain recommendations for the optimal use and frequency of the Pap test for cervical cancer in women with no symptoms who are or have been sexually active, regardless of sexual orientation.

The Task Force recommends:

  • No routine screening for women under age 25, including sexually active women. The 1994 guidelines recommended annual screening after becoming sexually active or at age 18.
  • Routine screening every three years for women aged 25 to 69.
  • Screening for women over age 69 if they have not undergone adequate screening (that is, three successive negative Pap tests over the previous 10 years).

Since the introduction of the Pap test in Canada 30 years ago, the proportion of women getting cervical cancer has declined from 1.5 per cent of all women to 0.66 per cent, and the proportion dying from the disease has declined from 0.94 per cent to 0.22 per cent, said Dr. James Dickinson, chair of the guideline working group and professor of Family Medicine and Community Health Sciences at the University of Calgary.

"While it is likely that most of this improvement is a result of screening, other countries have achieved similar outcomes despite initiating screening at an older age and implementing longer screening intervals. Reducing the number of Pap tests gives women the benefit from screening, while reducing the inconvenience, discomfort and potential harms caused by early and excessive testing," he added.

For clinicians and patients, the most important thing to take away from the evidence review is that it  "includes the most recent and best available evidence, which in turn has been used by the Canadian Task Force to develop evidence-based recommendations," said Peirson.

She added that her team was surprised to find that "there are so few trials that provide evidence for the outcomes of incidence of and mortality from invasive cervical cancer, and fewer studies still that report on these outcomes specifically for younger and older women."

Human papillomavirus (HPV) testing is not offered in all provinces and was not included in the guidelines. HPV is a sexually transmitted infection that can cause cervical cancer.

"The Task Force felt it premature to make a recommendation on the use of HPV testing in screening (either alone or in combination with Pap testing)," said Dr. Dickinson. "However, we will revisit this issue as new data become available."

The full guidelines and evidence review are available for physicians and patients on the Canadian Task Force on Preventive Health Care (CTFPHC) website.

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