Cervical Cancer Screening: Why Swap from Pap to HPV?
Reviewed and verified by: Dr. Susana Huang, MD
Written by: Maureen Chang, HBSc
On March 3rd, 2025, the province of Ontario introduced a human papillomavirus (HPV) test to the Ontario Cervical Screening Program [1]. This means that the conventional Pap test, also known as the Pap smear or cervical cytology, will be replaced with a new HPV test for the screening of cervical cancer. But what are the key differences between these two tests? How does HPV relate to cervical cancer? This article will address both of these questions and explain how the HPV test benefits the health of all Ontarians.
What is Cervical Cancer?
Cervical cancer is a cancer of the cervix, the part of a woman’s body that connects the uterus to the vaginal opening [2]. Cervical cancer is the 4th most common cancer among women worldwide [3]. In Canada, it was estimated that 1,600 Canadians would be diagnosed and 400 would die from cervical cancer in 2024 [4]. Despite its prevalence, cervical cancer is a treatable disease. In fact, between 1980 and 2014, the rate of new cervical cancer cases in Canada declined dramatically as a result of widespread cervical screening measures [2]. When caught early, cervical cancer is highly treatable, with various different treatment options available. However, like any cancer, treatment becomes less effective at later stages. This is why your doctor and the province of Ontario stresses the importance of early detection.
What are Pap Tests?
So, how do we detect cervical cancer early on? Most women are familiar with the Pap test. This test was developed by George Papanicolaou in the 1920s and introduced to the public in the 1940s [5]. During a Pap test, a doctor swabs the cervix to obtain a sample of cells [6]. These cells are then sent to a laboratory to be observed under a microscope by a pathologist for any atypical changes [6]. However, although still effective, Pap tests may lead to false positive and false negative results due to human error [7].
How Does HPV Relate to Cervical Cancer?
This is where HPV tests come in. As it turns out, over 90% of cervical cancer cases are directly caused by HPV infection [8]. HPV is a family of viruses that is transmitted through sexual contact with another person and usually does not cause any harm or symptoms [2]. In fact, HPV is quite common; 8 out of 10 people will get HPV at least once in their lifetime [2]. As a result, many people can carry HPV for years without even knowing it. However, there are specific strains of HPV that are known to cause cancer [9]. The most common of which are HPV 16 and HPV 18 [9]. If the body’s immune system is unable to get rid of an infection with these high-risk strains, the virus may cause normal cervical cells to change into abnormal cells overtime [9]. The longer a high-risk HPV infection persists, the more at-risk an individual is for cervical cancer [8]. Thus, it is crucial for eligible individuals to get tested for HPV, and get tested early.
How Do HPV Tests Work?
For women coming into the doctor’s office, the HPV test procedure will be exactly like the Pap test. The main differences between the tests lie mostly within what laboratories do with the collected cervical cells. Instead of having a pathologist look for abnormal cells under the microscope, a machine will now test for the presence of HPV DNA [10]. This makes the HPV test more objective than the Pap test by avoiding inaccuracies associated with the subjective interpretation of results [10]. This also makes the HPV test more sensitive than the Pap test [10]. Since doctors will now be directly testing for the underlying cause of cervical cancer, fewer false results will be reported, ultimately leading to more accurate diagnoses and longer time intervals (5 years) between screens [10].
How to Get Tested
The Ontario cervical screening program recommends you to get screened if you:
- Are 25-69 years old
- Have a cervix
- Have ever had sexual contact with another person
- Do not have symptoms such as bleeding or discharge from the vagina
If you meet all of these criteria, please call your doctor to discuss cervical cancer screening and book an appointment today.
References
1. Ontario Health (Cancer Care Ontario). (2025, March 3). Bulletin 250203: Ontario Cervical Screening Program update – HPV. https://www.ontario.ca/document/ohip-infobulletins-2025/bulletin-250203-ontario-cervical-screening-program-update-hpv
2. Cancer Care Ontario. (n.d.). Cervical screening. Ontario Health. Retrieved May 16, 2025, from https://www.cancercareontario.ca/en/types-of-cancer/cervical/screening
3. Okunade KS. Human papillomavirus and cervical cancer. J Obstet Gynaecol. 2020 Jul;40(5):602-608. doi: 10.1080/01443615.2019.1634030. Epub 2019 Sep 10. Erratum in: J Obstet Gynaecol. 2020 May;40(4):590. doi: 10.1080/01443615.2020.1713592. PMID: 31500479; PMCID: PMC7062568.
4. Canadian Cancer Society. (2024, May). Cervical cancer statistics. https://cancer.ca/en/cancer-information/cancer-types/cervical/statistics
5. Tan SY, Tatsumura Y. George Papanicolaou (1883-1962): Discoverer of the Pap smear. Singapore Med J. 2015 Oct;56(10):586-7. doi: 10.11622/smedj.2015155. PMID: 26512152; PMCID: PMC4613936.
6. Canadian Cancer Society. (n.d.). Pap test. https://cancer.ca/en/treatments/tests-and-procedures/pap-test
7. Canadian Cancer Society. (n.d.). Benefits and limitations of screening for cervical cancer. https://cancer.ca/en/cancer-information/find-cancer-early/get-screened-for-cervical-cancer/benefits-and-limitations-of-screening-for-cervical-cancer
8. Centers for Disease Control and Prevention. (2024, September 17). Basic information about HPV and cancer. https://www.cdc.gov/cancer/hpv/basic-information.html
9. National Cancer Institute. (n.d.). HPV and cancer. U.S. Department of Health and Human Services. Retrieved May 16, 2025, from https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/hpv-and-cancer
10. Cancer Care Ontario. (2024, August 8). Abridged FAQs for providers offering cervical screening. https://www.cancercareontario.ca/sites/ccocancercare/files/assets/Abridged-FAQs-for-providers-offering-cervical-screening.pdf