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Cervical Screening FAQs for Healthcare Providers

Find information about the cause of cervical cancer, the benefits and potential limitations of screening, cervical screening guidelines and follow-up recommendations. Educational materials for patients are also available on this page.

Topics Included in this FAQ

Cervical Cancer and Screening

Cervical Screening Guidelines

Cervical Screening Follow-Up

After Discharge from Colposcopy

The Ontario Cervical Screening Program, Guidelines and Your Practice

Cervical Cancer and Screening

What is the cause of cervical cancer?

The necessary cause of virtually all cervical cancers and their precursors is persistent infection with high-risk (oncogenic) types of human papillomavirus (HPV), especially types 16 and 18, which are implicated in the development of 70% of cervical cancer cases. HPV is a common infection among sexually active men and women. Most HPV infections resolve spontaneously (i.e., go away on their own without medical intervention).

Risk Factors for Acquiring HPV Infection

  • Number of intimate partners
  • Number of intimate partners that partner has had

Co-Factors Associated with Cervical Cancer that May or May Not Be Causal

  • Smoking tobacco and exposure to second-hand smoke

  • Immunosuppression (e.g., HIV, organ transplant, immunosuppressive drug therapy or chemotherapy)

  • Long-term (more than 5 years) use of hormonal contraceptives

  • More than 5 full-term pregnancies

  • Other sexually transmitted infections

  • Poor diet (especially low antioxidant intake)

What are the benefits and potential limitations of screening?

Benefits

  • The Pap test can generally detect early abnormalities in the cells of the cervix that could lead to cervical cancer. These changes usually precede cancer by many years, long before invasive cancer develops.
  • The Pap test can reduce cervical cancer incidence and mortality over the long term.

Potential Limitations

False-positives

  • Diagnostic interventions are needed to determine whether or not a woman with abnormal Pap test results has cervical dysplasia or cervical cancer.
  • A very small fraction of women with abnormal Pap test results will actually have cervical cancer.
  • Appropriate counselling to minimize fear and anxiety based on a single abnormal Pap test result is necessary.

False-negatives

  • No test is perfect. False-negative Pap test results occur.
  • Women with false-negative Pap test results may mistakenly believe that they have no risk for cancer, which may cause them to ignore symptoms and not have them investigated.
  • Pap testing is less effective in detecting pre-invasive glandular lesions of the cervix (adenocarcinoma in situ or AIS) than squamous lesions and has had limited impact in preventing adenocarcinoma.

Over-diagnosis

  • There is a risk of over-diagnosing changes in the cervix that do not lead to cervical cancer.
  • There is a risk of treating lesions that will never become cancer.

Over-treatment

  • Research demonstrates that very few low-grade cervical intraepithelial neoplasia in women in their early 20s would progress to cancer within 5 years if left untreated.
  • Treating young women with cervical dysplasia is linked to a small but significant risk of adverse future pregnancy outcomes (e.g., preterm delivery or low birth weight).
  • The risk to benefit ratio for treating low-grade lesions in women under age 25 strongly favours a conservative approach.

 

Cervical Screening Guidelines

What does the evidence say about triennial (every 3 years) screening vs. annual screening?

The 3-year screening interval is consistent with knowledge about the natural history of cervical cancer. There is no evidence that annual screening is superior to screening every 3 years. There is evidence that more frequent screening increases harms without significantly increasing benefits (see What are the benefits and potential limitations of screening?).

Screening Every 3 Years Is Safe and Effective

  • Pre-malignant changes in the cervix develop slowly, usually over many years, before cervical cancer develops.
  • Cervical changes that are clinically significant can be detected through regular screening every 3 years.
  • If these abnormalities do not resolve on their own, they can be treated so that cervical cancer is prevented.

The recommendation for a 3-year screening interval was based on solid evidence showing that screening every 3 years is safe and effective.

Why should sexually active women wait until age 21 to be screened?

Cancer Care Ontario, along with all Canadian jurisdictions and professional organizations, recommends that women initiate cervical screening at 21 years of age in its screening guidelines. The UK and most Western European countries do not start screening women for cervical cancer until an even older age.

Because the necessary cause of virtually all cervical cancers and their precursors is persistent infection with high-risk (oncogenic) human papillomavirus (HPV) transmitted through intimate sexual contact, women who have never been sexually active should delay cervical cancer screening until after initiating sexual activity.

Sexual activity includes intercourse, as well as digital or oral sexual activity involving the genital area with a partner of either gender.

What the Evidence Says

Screening women before there is a significant risk of cervical cancer leads to more harm than benefit

  • Cervical cancer is rare in women under age 21. In the 5-year period from 2005 to 2009, there were fewer than 6 cases in women ages 15 to 19 across Ontario.
  • Most younger women clear HPV infections without long-term consequences to their cervical health.
  • Although young women have high rates of low-grade cytological abnormalities, they are, in most cases, transient HPV infections.
  • Approximately 90% of young women will clear an HPV infection within 24 months.

Screening women under age 21 can lead to harms, regardless of when women become sexually active

  • Detecting low-grade abnormalities causes unnecessary interventions, anxiety and fear.
  • Treating young women with cervical dysplasia may have harmful effects on future pregnancies, such as preterm delivery or low birth weight.
  • Research demonstrates that very few low-grade cervical intraepithelial neoplasia in women in their early 20s would progress to cancer within 5 years if left untreated.

 

 

Under what circumstances should I screen women before age 21?

  • It is possible that, due to individual circumstances, some women younger than age 21 may benefit from cervical cancer screening. There is no good data to identify this rare cohort, which may include women who are immune compromised and those who have suffered sexual abuse at a very early age. Individual clinical judgement should be applied.
  • Human papillomavirus (HPV) immunization is also important especially for younger men and women. Appropriate vaccine coverage for girls, boys, young men and young women holds great potential for decreasing or eradicating cervical cancer and its precursors.

Under what circumstances should I screen women over the age of 70?

  • Screening should be continued in women over age 70 if they have not had 3 or more negative Pap tests in the previous 10 years.
  • There is no evidence to suggest that continuing to screen a woman over age 70 who acquires new partners is beneficial if she has an adequate negative screen history in the 10 years prior to age 70.

Note: The updated cervical screening guidelines do not override your clinical judgment in evaluating your patients’ circumstances. You may also choose to consult with a specialist to determine appropriate screening.

 

Under what circumstances should I screen women more frequently than what is recommended in the guidelines?

Certain populations of women benefit from more frequent screening than the average risk population. Annual cervical cytology screening for women age 21 or older is advised for:

How frequently should I screen my patients who have had previous treatment for high-grade cervical dysplasia (cervical intraepithelial neoplasia [CIN] II/CIN III) and/or cervical cancer?

  • There is insufficient data to make an evidence-based recommendation regarding ongoing screening/surveillance of women who have had high-grade cervical dysplasia (CIN II/CIN III) and/or cervical cancer.
  • There is evidence that these women are at greater risk of future lower genital tract neoplasia. Therefore, current practice is to screen more frequently than the average risk population. Annual screening is advised.

How often do I screen women who have been referred to colposcopy and discharged without treatment?

The colposcopist is the best source of guidance for specific recommendations regarding individual women. However, in general, the following recommendations apply:

Women referred for colposcopy and found not to have high-grade cervical dysplasia (high-grade squamous intraepithelial lesion or HSIL; cervical intraepithelial neoplasia [CIN] II/CIN III)

  • In the absence of the histologic diagnosis of HSIL or greater following a colposcopic investigation, returning to routine screening is likely safe and appropriate after discharge from colposcopy. Individual clinical judgement is advised.
  • In future, human papillomavirus (HPV) testing could play a role in ongoing screening for this group.

Women referred for colposcopy and treated for high-grade cervical dysplasia (CIN II/CIN III)

  • There is very little literature informing screening after the diagnosis and treatment of cervical dysplasia.  
  • Our current advice is annual screening over the long term for women treated for CIN II/CIN III.

 

Cervical Screening Follow-Up

What is the recommendation for follow-up when the results on the Pap test shows atrophy?

Atrophy is an observation that may or may not be of clinical importance. It requires action only if clinically indicated (e.g., for symptoms or for re-evaluation of a woman’s cytology).

 

What is the recommendation for follow-up when the result on the Pap test shows benign endometrial cells?

  • Pre-menopausal women who are asymptomatic require no action (continue to follow usual screening guidelines).
  • Post-menopausal women require investigations, including adequate endometrial tissue sampling.
  • Any woman with abnormal vaginal bleeding requires appropriate investigation, which should almost always include adequate endometrial tissue sampling.

What is the recommendation for follow-up when the cytology report states, “transformation zone components not present”?

  • Absence of transformation zone (T-zone) components alone does not require earlier re-screening.
  • Women whose cervical cytology is satisfactory for evaluation and negative for intraepithelial lesion or malignancy (NILM) but T-zone components are lacking, should be re-tested at their regular screening interval as per the recommendations for follow-up of abnormal cytology (see page 2 of the Ontario Cervical Screening Guidelines Summary).
  • Women with abnormal cervical cytology should follow the screening guidelines regardless of the presence or absence of T-zone components.

 

How do I follow up on abnormal screening tests for women who are under age 21?

Investigation of abnormal cytology should follow Cancer Care Ontario’s screening guidelines regardless of a woman’s age. However, in general, a very conservative approach to intervention is recommended in this age group.

 

After Discharge from Colposcopy

How should women be managed in primary care after being discharged from colposcopy?

After discharge from colposcopy:

  • Women who are found to be at low risk for cervical cancer by their colposcopist should return to routine screening every 3 years with the Pap test in primary care, whether or not they received treatment in colposcopy; and
  • Women who are found to be at elevated risk for cervical cancer by their colposcopist, but who do not need colposcopy, should have yearly surveillance with the Pap test in primary care, whether or not they received treatment in colposcopy.

If risk level or screening interval was not indicated by the colposcopist and cannot be clarified, then yearly screening is recommended.

If yearly screening is recommended after discharge from colposcopy, when can women resume screening every 3 years?

A woman can resume screening every 3 years when her risk of high-grade squamous intraepithelial lesion (HSIL) or greater is at or below the level of the population at large (i.e., she has a negative HPV test or, in the absence of HPV testing, has 3 consecutive normal yearly Pap tests).

When should women who have been discharged from colposcopy be re-referred to colposcopy?

Re-referral to colposcopy should be made according to cervical screening guidelines released by the Ontario Cervical Screening Program in May 2012 .

 

The Ontario Cervical Screening Program, Guidelines and Your Practice

Will healthcare provider incentives be changed to reflect the new guidelines?

The cervical screening guideline recommendations are based on solid evidence that balances the benefits of screening with the associated potential limitations.

The following changes were made to align with these evidence-based guidelines:

  • In January 2013, billing rules changed to limit Pap tests (G365) to 1 per patient every 33 months.
  • The billing code G394, which is used to follow up abnormal and inadequate Pap tests, was expanded to be used for women who would benefit from more frequent screening, including women who are immunocompromised (e.g., those who have HIV/AIDS) and for women in vulnerable groups who may have difficulty accessing the services within the specified time period. The Ontario Ministry of Health and Long-Term Care provides additional information on the changes to the Schedule of Benefits for Physician Services.

As of January 2014, the preventive care bonuses will also align with the guidelines. The Ontario Ministry of Health and Long-Term Care provides more information about the 2012–13 Cumulative Preventive Care Bonus Information.

 

What do I tell my patients who want to be screened annually?

What do I tell my patients who want to be screened for human papillomavirus (HPV)?

  • HPV testing should only be considered as a triage following an atypical squamous cells of undetermined significance (ASCUS) cytology result for women who are age 30 and older.
  • Cancer Care Ontario is working with the Ontario Ministry of Health and Long-Term Care (MOHLTC) to explore the role of funded HPV testing in the Ontario Cervical Screening Program (OCSP).
  • At this time, the HPV test is not funded by the MOHLTC. It is available from community labs on a user-pay basis for a cost of about $90 to $100 per test. Because this test is not publicly funded and patients have to pay for it, most women do not have access to this test. An appropriate alternative following an ASCUS cytology result is to repeat the Pap test in 6 months.

What educational materials are available for my patients?

View or download these resources from Cancer Care Ontario to share with your patients:

Visit The Society of Gynecologic Oncology of Canada website where you can access brochures and other resources.

Were the screening guidelines changed as a cost-cutting measure?

No, cost was not a consideration in the development of the screening guidelines. The recommendations were developed based on scientific evidence that balances the benefits of screening with the associated potential limitations.

  • Cancer Care Ontario’s guidelines were developed by an expert panel based on a rigorous systematic review and meta-analysis of high-quality evidence conducted by Cancer Care Ontario’s Program in Evidence-Based Care (PEBC).
  • There is no evidence that annual screening is superior to screening every 3 years. There is evidence that more frequent screening increases harms without increasing benefits. See What are the benefits and potential limitations of screening?.
  • The 3-year screening interval is consistent with knowledge about the natural history of cervical cancer.
  • Most Canadian jurisdictions do not screen women annually. Worldwide, several organized programs comparable to Ontario’s screen every 5 years. Moreover, some jurisdictions initiate screening women for cervical cancer at age 21 and many recommend initiation at an even older age (e.g., 25). No organized screening program recommends initiation of screening earlier than age 21.