Cervical Cancer Screening Follow-Up

Measure	Desired Direction	As of this Report
Percentage of Ontario screen-eligible women with a high-grade cervical dysplasia (abnormal) on a Pap test, aged 21 to 69, who underwent colposcopy or definitive treatment within 6 months of the high-grade abnormal screen date
See Methodology and Approach to find out how the ratings are calculated.

Key findings

In 2015, approximately 3,700 or 85% of Ontario women aged 21 to 69 who had a high-grade abnormal result on a Pap test were followed up with a diagnostic procedure or definitive treatment within 6 months; follow up for high-grade squamous intra-epithelial lesion (HSIL) was 89%, for atypical squamous cells, which cannot exclude HSIL (ASC-H), it was 84% and for atypical glandular cells (AGC) it was 73%. Despite notable regional variation, an overall increase was observed in follow up, from 80% in 2012 to 85% in 2015. Three diagnoses—HSIL, ASC-H and AGC—made up 98% of all high-grade abnormal Pap test results.

What is a cervical cancer screening (Pap test)?

• A screening test identifies people in a healthy asymptomatic population who may be at risk for disease. It is not a diagnostic test. The purpose of cervical screening is to prevent cervical cancer by identifying pre-cancerous changes to the cells of the cervix using the Pap test. Ontario operates screening programs for 3 types of cancer: breast, cervical and colorectal. 
• Changes in the cervix that lead to cancer—called precursor or precancerous lesions—usually develop slowly over many years, resulting in a long period of time when abnormal cell changes are present and can be found by a Pap test before cervical cancer appears. 
• Colposcopy is a diagnostic procedure performed after an abnormal Pap test result. This procedure allows a colposcopist to take tissue samples (biopsies) of cervical abnormalities so a pathologist can make a definitive diagnosis and a doctor can develop a treatment plan¹.
• After the diagnostic process is complete, a woman with a precursor lesion requiring treatment may undergo a loop electrical excision procedure, laser therapy or cold knife cone biopsy¹. Treating precursor lesions can prevent cervical cancer from developing.
• Cancer Care Ontario provides guidelines for the management of abnormal Pap test results and referral to colposcopy services. Referral to colposcopy following one abnormal Pap test is recommended for women with findings of ASC-H, HSIL and AGC. Endocervical and endometrial sampling is also recommended for women with AGC, when appropriate².

What do the results show?

More Ontario women with a high-grade abnormal Pap test are receiving timely follow up within 6 months (Figure 1).

• The proportion of Ontario women receiving follow-up within 6 months of a high-grade abnormal Pap test result improved, increasing from 80% in 2012 to 85% in 2015. For women with a high-grade abnormal Pap test, a higher rate follow up and diagnostic testing in colposcopy are needed. Colposcopy is an exam done by a specially trained doctor (i.e. a colposcopist) after a woman has an abnormal Pap test result. During colposcopy, a colposcopist takes tissue samples of abnormal cells in the cervix, makes a diagnosis and develops a plan of care.
• In 2015, the Local Health Integration Network (LHIN) with the highest follow up was Toronto Central (91%), while the North West LHIN had the lowest follow up (66%).
• A number of LHINs made substantial improvements in performance from 2012 to 2015. Waterloo Wellington, Erie St. Clair and North East all improved their follow up for abnormal cervical screening tests by 10 percentage points during this time.  The North West LHIN had the greatest decrease in follow up during this period, at 6 percentage points.  
• Among the most frequent abnormal cell types found on Pap tests, follow up was highest for women with HSIL (89% in 2015) and lowest for women with AGC (73% in 2015). A similar pattern can be seen in previous years (Figure 3). Of all abnormal cell types, including those with low incidence, adenocarcinoma in situ (32 people in 2015) had the highest follow-up rate (90%).

Follow up of high-grade abnormal Pap test results varies by age group (Figure 2). 

• Follow-up of abnormal cervical cancer screening results varied by age group. In 2015, follow up within 6 months of an abnormal Pap test result was highest in women aged 30 to 39 (88%) and women aged 40 to 49 (87%). Follow up within 6 months of an abnormal Pap test result was lowest in women aged 60 to 69 (78%).

Why is this important to Ontarians? 

Screening, and appropriate and timely follow up of abnormal results are essential. 

• Virtually all cervical cancers and their precursors are caused by persistent infection with high-risk oncogenic (i.e. cancer-causing) human papillomavirus (HPV) types, especially types 16 and 18^3–6. HPV is transmitted through intimate sexual contact and is common among sexually active men and women^7,8. Most sexually active men and women will get an HPV infection in their lifetime^8–10. Most high-risk HPV infections will go away, or clear, without causing harm. The reasons some HPV infections clear on their own and some persist are not well understood. 
• Persistent high-risk HPV infections are a necessary factor in the development of cervical cancer. HPV infections can cause abnormal cell changes in the cervix and abnormal Pap test results. Abnormal cervical cell changes, especially those that cause high-grade Pap test results, can slowly (over 10 years or more) lead to cervical cancer, unless they are found early through screening and treated appropriately. 
• An abnormal Pap test result does not mean that a woman has cervical cancer; however, it means that more follow up and diagnostic testing are needed. 
• The first cohort in Ontario’s school-based HPV vaccination program reached screen-eligible age this year. As the proportion of HPV-vaccinated women in the screening cohort increases, Cancer Care Ontario is exploring implications for screening practices related to this shift. HPV-vaccinated women should still be screened according to the current recommendations.
• Timely follow up of abnormalities found through cervical screening is necessary for the reduction of cervical cancer incidence (i.e. new cancer cases) and mortality (i.e. deaths).
• Cervical cancer incidence has decreased by as much as 80% where screening quality, access and follow up are high¹¹. 

Next steps

• Cancer Care Ontario is developing evidence-informed strategies to increase access, align processes, improve practices and enhance the quality of colposcopy services in the province. The OCSP recently released evidence-informed clinical guidelines for the delivery of colposcopy services in Ontario¹². Next steps include working with regional partners to encourage implementation of these guidelines. 
• An integrated Primary Care Screening Activity Report (PC SAR) for all 3 screening programs (cervical, breast and colorectal) was recently developed. This tool allows physicians in a patient enrolment model practice to see the complete screening status for each of their enrolled age-eligible patients, including those who are due for screening and follow up. Next steps include working with the Regional Primary Care Leads to identify barriers to adoption of the tool, and to promote and encourage use of the PC SAR. 
• The OCSP correspondence program began in the fall of 2013. Eligible women are mailed letters inviting them to get screened for cervical cancer, advising them of next steps based on their test results and reminding them when it is time to return for screening. Cancer Care Ontario is evaluating the impact of correspondence on participation. 

View Notes

1. Cancer Care Ontario [Internet]. Toronto: Cancer Care Ontario. Insight on cancer: news and information on cervical cancer; 2005 Oct [cited 2015 Dec 18]. Available from: https://cancercare.on.ca/common/pages/UserFile.aspx?fileId=13802.
2. Cancer Care Ontario [Internet]. Toronto: Cancer Care Ontario. Ontario cervical screening cytology guidelines summary; 2012 May [cited 2015 Dec 18]. Available from: https://cancercare.on.ca/common/pages/UserFile.aspx?fileId=13104.
3. Kwong J, Crowcoft N, Campitelli MA, Ratnasingham S, Daneman N, Deeks SL, et al. Ontario burden of infectious disease study (ONBOIDS). Toronto: Ontario Agency for Health Protection and Promotion, Institute for Clinical Evaluative Sciences; 2010.
4. Walboomers JM, Jacobs MV, Manos MM, Bosch FX, Kummer JA, Shah KV, et al. Human papillomavirus is a necessary cause of invasive cervical cancer worldwide. J Pathol. 1999 Sep; 189(1):12–9.
5. Franco EL, Schlecht NF, Saslow D. The epidemiology of cervical cancer. The Cancer Journal. 2003 Oct; 9(5):348–59.
6. Cancer Care Ontario. Ontario Cancer Screening Performance Report 2016.  Toronto: Cancer Care Ontario; 2016.
7. Yabroff KR, Mandelblatt JS, Kerner JF. Effectiveness of interventions to improve follow-up after abnormal cervical cancer screening. Prev Med. 2000 Oct; 31(4):429–39.
8. Brown DR, Shew ML, Qadadri B, Neptune N, Vargas M, Tu W, et al. A longitudinal study of genital human papillomavirus infection in a cohort of closely followed adolescent women. J Infect Dis. 2005 Jan 15; 191(2):182–92.
9. Koutsky L. Epidemiology of genital human papillomavirus infection. Am J Med. 1997 May 5; 102(5A):3–8.
10. Bosch FX, de Sanjosé S. Human papillomavirus and cervical cancer: burden and assessment of causality. J Natl Cancer Inst Monogr. 2003; 31:3–13.
11. World Health Organization and the International Agency for Research on Cancer (IARC). IARC handbooks of cancer prevention: cervix cancer screening. Vol. 10. Lyon: IARC Press; 2005.
12. Cancer Care Ontario [Internet]. Clinical guidance: recommended best practices for delivery of colposcopy services in Ontario; 2016 June [cited 27 Jan 2017]. Available from: https://cancercare.on.ca/common/pages/UserFile.aspx?fileId=361450