Women in Ontario age 21 and over should have a Pap test to screen for cervical cancer or other abnormalities every three years, even later if they aren't sexually active, according to new provincial guidelines.

Cancer Care Ontario's updated guidelines, released publicly Tuesday, differ from a Health Canada report that recommends annual screening beginning at age 18, and if a woman has two years of no cervical issues, then she can be retested every three years. A Canadian task force is currently working on new guidelines.

'I want to shout it from the rooftops that women need to schedule regular Pap tests with their doctor.'—Shannon Pethick, cervical cancer survivor

"In Ontario, cervical cancer screening is now recommended starting at age 21 and every three years until age 70 for all women who are or ever have been sexually active; screening is not recommended for women under the age of 21," says Cancer Care Ontario in a news release.

Dr. Linda Rabeneck of Cancer Care Ontario said a Pap test every three years starting at 21 can detect changes in the cervix that might lead to cancer. However, "new research shows that screening women under age 21, regardless of the age they first became sexually active, doesn't actually reduce their risk for cervical cancer," she said.

Any woman with a Pap test showing abnormal cell activity is likely to have more regular screening tests, under the direction of her physician.

Cervical cancer rates drop

This year, it’s estimated 1,350 Canadian women will be diagnosed with cervical cancer and 390 women are expected to die from the disease. In Ontario, the projection is that 500 women will be diagnosed and 140 will die.

Still, federal health agencies say the incidence of cervical cancer has dropped dramatically over the decades with the advent of Pap tests; each province has its own guidelines on when such screening should begin but they aren't radically different.

Changes to the cervix are linked to the sexually transmitted human papilloma virus (HPV), which remains a prime risk factor for cervical cancer. While HPV, which can also cause genital warts, is very common, most infections go away on their own and don't lead to cancer, Cancer Care Ontario says.

A special vaccine against HPV was approved for use in Canada in 2007. The National Advisory Committee on Immunization (NACI) says girls aged nine to 13 are the primary group recommended for vaccination, and that it should be administered before they become sexually active. NACI also recommends the vaccine for at-risk groups including females 14 to 26 years of age, and males aged nine to 26.

Cancer Care Ontario says the Canadian Cancer Society strongly supports the new provincial screening guidelines, which are similar to guidelines released by a U.S. task force in March that updated 2003 recommendations and say women should get Pap smears every three years rather than annually.

Women urged to get tested

The provincial agency, in the meantime, is still stressing the importance of getting Pap tests.

Shannon Pethick, 34, of Burlington, Ont., for instance, was diagnosed with cervical cancer in 2010 but underwent intensive treatment that put her into menopause and unable to have children.

In the Cancer Care Ontario release, Pethick, who does advocacy work for the Canadian Cancer Society, said having a Pap test could have prevented her cancer.

"Women need to talk about this," said Pethick. "I know Pap tests are not the most pleasant thing to experience, but going through radiation and chemotherapy is far worse. I want to shout it from the rooftops that women need to schedule regular Pap tests with their doctor."