See, Test & Treat

Pap smears that detect changes in cervical cells are one of three cancer screening methods suggested by the World Health Organization. (Craig Lassig/AP Images for College of American Pathologists)

Girls can be vaccinated with two doses of HPV vaccine to protect against cervical cancer instead of three, the World Health Organization now advises, based in part on Canadian research.

Cervical cancer is one of the world’s deadliest and easily preventable forms of cancer in women.  

On Wednesday, the UN public health agency released new guidelines on cervical cancer control at the World Cancer Leaders’ Summit in Melbourne, Australia.

The three main new recommendations are:

  • Reduce the dose of HPV vaccinations for girls from three doses to two to prevent infection with the human papillomavirus that causes most cases of cervical cancer.
  • Use HPV tests to screen women for cervical cancer prevention.
  • Promote communication with women of all ages instead of focusing on women aged over 29.

Some of the research to support a shift to two-dose vaccination was done by scientists in British Columbia, Quebec and Halifax and published last year. It suggested that two doses in pre-adolescent girls works as well as three doses in girls in their later teens and early 20s.

Since then, Quebec scaled back the number of shots it offers to girls.

The WHO suggested a range of options for cervical cancer screening depending on laboratory resources and ability to pay.

The screening options include:

  • Pap smears.
  • HPV DNA screening, which takes a sample of mucous from the cervix to check for the presence of HPV, including if it is a high-risk strain. Unlike the Pap smear, the HPV test can detect the virus before precancerous cells appear.
  • Visual inspection with acetic acid, also known as VIA.

In B.C, a clinical trial of about 25,000 women is expected to be completed late next year and could shed light on the potential advantages and disadvantages of switching to HPV DNA screening.

Cervical cancer kills more than 270,000 women globally each year, 85 per cent of them in developing countries, the WHO says. The Canadian Cancer Society estimates that this year 1,450 women in this country will receive a diagnosis of cervical cancer and  380 will die.

Research suggests that since the introduction of regular Pap smears in the 60s, Canada’s new cases of invasive cervical cancer and deaths have plummeted from to 2.2 per 100,000 women each year from a peak of 13.5 per 100,000, an 83 per cent drop.

With files from The Canadian Press