Screening Programs

More than 70% of cervical cancers diagnosed in females aged 18–39 years were diagnosed at stage I (Canadian Cancer Statistics, 2018). The Canadian Cancer Society states that this is likely due to early detection through cervical cancer screening programs.

Screening tests for cervical cancer

A Pap test, or Papanicolaou test, is a procedure that removes a small sample of cells from the surface of the cervix. An instrument called a speculum is inserted into the vagina so the cervix can be seen. Cells are taken from the cervix and are sent to a laboratory to be examined under a microscope [16]. By observing the cells, a Pap test finds abnormal changes in cells early before cervical cancer develops [17].

A Pap test screens for cervical cancer but does not screen for other cancers in the reproductive organs, such as ovarian cancer, or for sexually transmitted infections (STIs), such as chlamydia, gonorrhea or human immunodeficiency virus (HIV) [18]. The Pap test is performed every one to three years, depending on the screening guidelines in your province or territory and your health history. According to the Ontario Cervical Screening Program guidelines [19], all women and people with cervixes who have ever had sexual skin-to-skin contact need to have to regular Pap tests starting at age 21.

The Pap test is a screening test, not a diagnostic test. An abnormal Pap test result means more testing, as cell changes found in Pap tests are very rarely cancerous, but do require follow-up [20]. Follow-up diagnostic tests are used to determine if a cancer or a pre-cancerous lesion are present [21].

Pap tests should be performed regularly performed on women, transgender men and other female-bodied non-gender conforming people who are over the age of 21 and have been sexually active. This includes women vaccinated with the HPV vaccine, women engaged in any sexual activity with genital-to-genital contact, women who have stopped having sex, women who have had a partial hysterectomy and still have a cervix and transgender men with a cervix that are sexually active.

There are people who should first discuss with their doctors whether or not they need a Pap test performed regularly:

  • If you have never been sexually active
  • If you have had a total hysterectomy
  • If you are older than 69
  • If you are a transgender woman with a neo-vagina and/or neo-cervix and are sexually active
  • If you are transgender man, based on your health and surgical history

Common results for Pap smear tests

  • Normal: There is no evidence of abnormal changes in the cells sampled.
  • ASCUS (Atypical Squamous Cells of Undetermined Significance): The cells are abnormal, but no definite diagnosis can be made. This test result can be caused by a yeast infection, using oral contraceptives, or problems with taking the sample. Usually doctors repeat the Pap smear in a few weeks or test for the presence of high risk types of HPV.
  • LSIL (Low-grade Squamous Intraepithelial Lesion): This result means an acute infection. If it persists for at least two to three visits, it can be assumed that it could lead to cancer.
  • HSIL (High-grade Squamous Intraepithelial Lesion): This result means more advanced lesions.
  • AGC (Atypical Glandular Cells): these abnormal cells are the precursors of about 20 per cent of cervical cancers. These cells are very difficult to detect.

[22] Information taken from CATIE

HPV primary screening and vaccinations

The HPV DNA test checks for the presence of high-risk types of HPV in the same way as a Pap test is performed. HPV DNA tests help identify women or people with cervixes that currently have cervical lesions, or are more likely to have precancerous lesions and a higher risk of developing cervical cancer. Studies have shown the HPV test to be significantly more effective in detecting precancerous changes in the cervix than the Pap test. The Canadian Cervical Screening Trial (CCCaST) was the first North American randomized controlled trial of Pap vs HPV testing, which targeted women between the ages 30-69 years, that confirmed the increased sensitivity of HPV testing to detect high grade lesions [23].

As a screening tool, HPV testing is more effective in screening people 30 and older. HPV testing is not an effective screening tool for those under 30, as HPV infections are more transient in this age demographic and usually go away on their own. There is a current gap in research as to what testing algorithm is most appropriate for this younger age group.

The HPV test is available in Canada, but is not currently funded as part of regular cervical cancer screening in any of the provinces or territories. Where it is available, the HPV test is used only for women 30 years of age and older as a follow-up to abnormal Pap test results [24].

Introduction of molecular HPV testing as the primary technology in cervical cancer screening: Executive summary

Report Introducing HPV primary screening


Cervical cancer screening and clinical guidelines across Canada
HPV vaccinations and cervical cancer
New special issue of Preventive Medicine analyzes the reasons for shifting from cytology to HPV testing
The Pap test
Transitioning to HPV primary screening in Canada






[17] “Diagnosis of Cervical Cancer.” Canadian Cancer Society. Canadian Cancer Society, 2015. Web. 11 Aug. 2015.
[18] “Pap Test for Cervical Cancer Screening.” Pap Test for Cervical Cancer Screening. CanceCare Ontario, 19 Feb. 2015. Web. 11 Sept. 2015.
[19] “Ontario Cervical Screening Program.” Canadian Cancer Society. Canadian Cancer Society, 2015. Web. 11 Aug. 2015.
[20] CancerCare Ontario. Cervical Cancer Screening: What Your Abnormal Pap Test Means. Ontario: CancerCare Ontario, 2012. CancerCare Ontario. CancerCare Ontario, May 2012. Web. 11 Sept. 2015.
[21] “How Is Cervical Cancer Diagnosed?” American Cancer Society. American Cancer Society, 26 Feb. 2015. Web. 10 Aug. 2015.
[22] Maclean, D., A. Ollner, and SR Hosein. “HPV, Cervical Dysplasia and Cancer.” HPV, Cervical Dysplasia and Cancer. CATIE. Web. 15 Dec. 2015.
[23] “CCCaST – Canadian Cervical Cancer Screening Trial.” Canadian Cervical Screening Trial (CCCaST). McGill, 2007. Web. 11 Aug. 2015.
[24] HPV DNA Testing. Powerpoint Presentation. Cervical Cancer Screening In Canada: Programs and Strategies. Canadian Partnership Against Cancer, Mar. 2013. Web. 11 Sept. 2015.