Barbara A. Crothers, DO
Ritu Nayar, MD
Cervical cancer screening guidelines were updated recently in an effort to bring order to the complexity and multiplicity of screening practices, with special consideration to age and type of testing used.1 The recommendations also address followup, primary screening with HPV testing only, and the impact of HPV vaccination on screening. The American Cancer Society led the effort in collaboration with the American Society for Colposcopy and Cervical Pathology and American Society for Clinical Pathology. The U.S. Preventive Services Task Force has also updated its cervical cancer screening recommendations, which closely parallel those from the ACS/ASCCP/ASCP.2
The consensus meeting took place in November 2011 at the National Institutes of Health. Representatives from 25 organizations with an interest in women’s health attended. Guidelines were evidence-based and constructed using the Grading Recommendations Assessment, Development, and Evaluation (GRADE) system3 as a framework for the process. Benefits and harms were evaluated and strongly influenced decisionmaking. Several basic tenets were established to assess risk and risk-based interventions, including: 1) All cervical cancer cannot be prevented, 2) Reasonable risk was determined by using the benchmark of cytology screening alone, and 3) Women at similar risk of cancer should be managed in a similar fashion.1
The basic recommendations are as follows:
Age to initiate screening. Women under 21 should not be screened for cervical cancer because the biologic progression of HPV-related equivocal/low-grade squamous intraepithelial (ASC-US/LSIL) lesions is a slow event that occurs over decades and depends on persistence of high-risk HPV subtypes. This recommendation was initially endorsed by several organizations that participated in the June 2009 Practice Improvement in Cervical Screening and Management (PICSM) Symposium on Management of Cervical Abnormalities in Adolescents and Young Women.4 Nearly all women are exposed to the virus in adolescence or adulthood but will effectively eliminate the infection through an immune response. Cervical cancer is rare in women under age 21.5 The previous emphasis on early cervical cancer screening with aggressive ablative programs for low-grade squamous lesions caused net harm in the younger population owing to an increased risk of reproductive complications.
Screening intervals. Women ages 21–29 should be screened every three years with cytology alone. There is no preference for liquid-based or conventional Pap testing. Co-testing or standalone HPV testing is not recommended in this age group because of high HPV prevalence and the greater potential for harm than benefit. More frequent screening may not allow women sufficient time to clear the virus and could prompt sequential unnecessary ablative procedures for low-grade lesions. However, women ages 21–29 with prior negative Pap tests should not delay subsequent screening beyond three years because they remain at risk for precancer.6 Annual screening is specifically discouraged.
The preferred screening method for women 30 years and older is co-testing with HPV and Pap tests at an interval of five years. The HPV test should include only high-risk viral subtypes; there is no clinical role for screening for low-risk viral subtypes (such as HPV 6 and 11) since they are not oncogenic. HPV tests should be FDA-approved and laboratory-validated with reliable performance characteristics. Overly sensitive HPV tests may introduce harm through over-detection of clinically insignificant infections. Women 30 years and older may also be screened every three years by Pap test alone. A history of prior negative Pap tests is not a sufficient reason to extend this screening interval beyond every three years, but annual screening is specifically discouraged.
Cessation of screening. Women over 65 who have had an adequate negative screening history can be released from annual screening permanently. Women with a prior history of treated CIN2, 3+ should be screened every three years (as with the general population) once they have completed adequate post-treatment followup, but routine screening should continue for a minimum of 20 years after resolution of disease because of their increased risk of disease recurrence. Women who have had a hysterectomy with removal of the cervix for a disease other than CIN2, 3+ or cancer are permanently released from cervical cancer screening, regardless of age or lack of prior negative screening history. Finally, women who have permanently exited cervical cancer screening do not need to resume screening, even if they acquire a new sexual partner.
Screening following vaccination. Recommended screening guidelines should not change based on HPV vaccination status. At the present time, the HPV vaccination rates in the United States remain relatively low. Further, it is unclear how long vaccination will protect women against infection and whether it is cost-effective for the general population. Until there are further data in these areas, screening should not change based on vaccination status.1
These guidelines are discussed in detail in key publications (see the references) that further explain the evidence and rationale for the recommendations. The guidelines also include a discussion on areas for future research, such as increasing screening coverage, managing women with cytology-negative/HPV-positive results, and validating HPV testing methods. The ASCCP will hold a consensus conference this November to update management guidelines and algorithms for abnormal cytologic/molecular testing screening results that will complement the changes in cervical cancer screening guidelines. Despite these changes, the basic message remains the same: Women should be screened for cervical cancer precursors at appropriate intervals to prevent the development of cervical cancer.
1. Saslow D, Solomon D, Lawson HW, et al. American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer. Am J Clin Pathol. 2012;137:516–542. Also published online March 14, 2012 in CA: A Cancer Journal for Clinicians.
2. Screening for cervical cancer. The U.S. Preventive Services Task Force (USPSTF) recommendations on screening for cervical cancer. Current recommendation. Accessed April 27, 2012. www.uspreventiveservicestaskforce.org/uspstf/uspscerv.htm.
3. Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336:924–926.
4. Moscicki AB, Cox JT. Practice improvement in cervical screening and management (PICSM): symposium on management of cervical abnormalities in adolescents and young women. J Low Genit Tract Dis. 2010;14:73–80.
5. Castle PE, Carreon JD. Practice improvement in cervical screening and management: symposium on management of cervical abnormalities in adolescents and young women. J Low Genit Tract Dis. 2010;14:238–240; author reply 240.
6. Sawaya GF, McConnell KJ, Kulasingam SL, et al. Risk of cervical cancer associated with extending the interval between cervical-cancer screenings. N Engl J Med. 2003;349:1501–1509.
Dr. Crothers, vice chair of the CAP Cytopathology Committee, is in the Department of Pathology and Area Laboratory Service, Walter Reed National Military Medical Center, Bethesda, Md. Dr. Nayar, a member of the Cytopathology Committee, is in the Department of Cytopathology, McGaw Medical Center of Northwestern University, Chicago.