Clinical Review

Pap test every year? Not for every woman

OBG Manag. 2004 December;16(12):36-54

References

1. Saslow D, Runowicz CD, Solomon D, et al. American Cancer Society guidelines for the early detection of cervical neoplasia and cancer. CA Cancer J Clin. November-December 2002;52:342-362.

2. American College of Obstetricians and Gynecologists. Practice bulletin No. 45: cervical cytology screening. Obstet Gynecol. 2003;102:417-427.

3. US Preventative Services Task Force. Screening for cervical cancer. Rockville, Md: Agency for Healthcare Research and Quality; 2003. Available at: http://www.ahrq.gov/clinic/3rduspstf/cervcan/cervcanwh.pdf. Accessed November 1, 2004.

4. American College of Obstetricians and Gynecologists. Technical bulletin No. 29: the frequency with which a cervical-vaginal cytology examination should be performed in gynecologic practice. Washington, DC: ACOG; February 1975.

5. Muñoz N, Bosch X, de Sanjosé S, et al. Epidemiologic classification of human papillomavirus types associated with cervical cancer. N Eng J Med. 2003;348:518-527.

6. Walboomers JM, Jacobs MV, Manos MM, et al. Human papillomavirus is a necessary cause of invasive cervical cancer worldwide. J Pathol. 1999;189:12-19.

7. Ho GY, Bierman R, Beardsley L, et al. The natural history of cervical papillomavirus infection in young women. N Engl J Med. 1998;338:423-428.

8. Moscicki AB, Shiboski S., Broering J, et al. The natural history of human papillomavirus infection as measured by repeated DNA testing in adolescent and young women. J Pediatr. 1998;132:277-284.

9. Moscicki AB. Cervical cytology screening in teens. Curr Womens Health Rep. 2003;3:433-437.

10. Reis LAG, Eisner MP, Kosary CL, et al. SEER Cancer Statistics Review, 1975-2001. National Cancer Institute. Available at: http://seer.cancer.gov/csr/1975_2001/. Accessed November 8, 2004.

11. American College of Obstetricians and Gynecologists. Committee opinion No. 300: cervical cancer screening in adolescents. Obstet Gynecol. 2004;104:885-889.

12. Kulasingam SL, Hughes JP, Kiviat NB, et al. Evaluation of human papillomavirus testing in primary screening for cervical abnormalities comparison of sensitivity, specificity, and frequency of referral. JAMA. 2002;288:1749-1757.

13. 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.

14. Moscicki AB, Burt VG, Kanowitz S, et al. The significance of squamous metaplasia in the development of low grade squamous intraepithelial lesions in young women. Cancer. 1999;85:1139-1144.

15. Screening for squamous cervical cancer: duration of low risk after negative results of cervical cytology and its implication for screening policies. IARC Working Group on evaluation of cervical cancer screening programmes. Br Med J (Clin Res Ed). 1986;293:659-664.

16. Sawaya GF, Kerlikowske K, Lee NC, et al. Frequency of cervical smear abnormalities within 3 years of normal cytology. Obstet Gyncol. 2000;96:219-223.

17. NIH Consensus statement: cervical cancer. National Institutes of Health. Bethesda, MD: US Department of Health and Human Services, National Institutes of Health, 1996;14:1-38.

18. Sawaya GF, Grady D, Kerlikowske K, et al. The positive predictive value of cervical smears in previously screened postmenopausal women: the Heart and Estrogen/Progestin Replacement Study (HERS). Ann Intern Med. 2000;133:942-950.

19. Sirovich BE, Welch HG. Cervical cancer screening among women without a cervix. JAMA. 2004;291:2990-2993.

20. Sellors JW, Karwalajtys TL, Kaczorowski JA, et al. Prevalence of infection with carcinogenic human papillomavirus among older women. CMAJ. 2002;167:871-873.

21. Sherman ME, Lorincz AT, Scott DR, et al. Baseline cytology, human papillomavirus testing, and risk for cervical neoplasia: a 10-year cohort analysis. J Natl Cancer Inst. 2003;95:46-52.

22. Wright TC, Jr, Schiffman M, Solomon D, et al. Interim guidance for the use of human papillomavirus DNA testing as an adjunct to cervical cytology for screening. Obstet Gynecol. 2004;103:304-309.

23. ASCUS-LSIL Triage Study (ALTS) Group. Results of a randomized trial on the management of cytology of atypical squamous cells of undetermined significance. Am J Obstet Gynecol. 2003;188:1383-1392.

24. Schlect NF, Kulaga S, Robitaille J, et al. Persistent human papillomavirus infection as a predictor of cervical intraepithelial neoplasia. JAMA. 2001;286:3106-3114.

Why change? How will patients react?

Cumulative findings suggest an age- and risk-based approach

Research over the past few decades has revealed much about the pathogenesis of cervical cancer which supports an age- and risk-based approach to screening for cervical cancer—when to start, when to stop, and how often to perform cervical cytology.

The main questions

In this article, I’ll review some of the data on these concerns:

Why wait 3 years after first intercourse for the first Pap test?
Why is 21 the ‘default’ age for first Pap test?
What are the risks and costs of screening every 2 to 3 years in well-screened women over age 30? Over age 65?
Do most women without a cervix require screening?
What is the role of HPV DNA testing?
How should we deal with abnormal results?
How should we counsel the patient?
What’s the harm in continuing Pap tests in all women?
Will women return for annual exams as we advise, if we change their Pap test routine?

ADOLESCENCEWhy wait 3 years after onset of intercourse for first Pap test?

Care is not compromised

Delaying screening until at least 3 years after coitarche does not compromise the diagnosis of high-grade lesions, yet does allow discovery and eradication long before they become malignant. On the other hand, screening young women sooner than 3 years after first sexual intercourse risks diagnosing numerous self-limited HPV infections and transient low-grade dysplastic lesions, which have very low premalignant potential.

Persistent high-risk HPV must precede cancer. Cervical cancer develops only after persistent HPV infection, many years from the initial HPV exposure.

We now know that at least 15 to 18 types of human papillomavirus (HPV) can cause cervical cancer, and that infection with a high-risk type of HPV is the necessary antecedent—but not by itself a sufficient antecedent—for high-grade cervical dysplasia and cervical cancer.^5,6

We also know that HPV is most often acquired through sexual intercourse and that it is very efficiently acquired by young women.^7,8 For example, a study of young college women who were initially HPV negative acquired HPV at a rate of 14% per year.⁷

HPV infections in young women are usually transient, however. Up to 90% of young women who test positive for HPV DNA will revert to negative within 2 years.⁹

The problems of screening too early. Squamous cancer of the cervix is exceedingly rare in women under age 21.¹⁰ Diagnosis of self-limited HPV infections and transient low-grade dysplastic lesions would likely result in repeat Pap tests and colposcopies. In addition to being costly and anxiety-provoking, these interventions may lead to needless destruction of the immature transformation zone in young women of low parity.

Don’t neglect counseling, STD testing, birth control

Delaying the first Pap test in young women until 3 years after initial intercourse, however, does not mean we should neglect gynecologic examinations in this group. They are at high risk for sexually transmitted infections and at extremely high risk for unintended pregnancies. So, while waiting 3 years to do the first Pap test makes sense, an early visit, before or soon after first intercourse is essential for gynecologic health care, including prevention of pregnancy and sexually transmitted disease.

October 2004 opinion on Gyn visits for young teens. ACOG published a committee opinion¹¹ to clear up confusion over when adolescent girls should have their first Pap test versus when they should have their first gynecologic visit. The opinion advises a first visit at age 13 to 15, for health guidance, screening, and preventive services, and says parents and patients need to understand that this visit does not necessarily include a pelvic exam or a Pap test. The advisory stresses that adolescents are unlikely to acknowledge sexual activity without sensitive and direct questions, and suggested a resource: “Asking the Right Questions,” from the STD/HTD Prevention Training Center of New England.

AGES 21 TO 30Why is age 21 the “default” for first Pap?

Because the incidence of high-grade squamous intraepithelial lesions (HSIL) increases with age,¹² cytology screening should start at age 21, irrespective of sexual history. Saslow et al¹ writing for the American Cancer Society, acknowledged the difficulty of obtaining a reliable sexual history. This may be especially true with patients who may have suffered sexual abuse as adolescents. The default age of 21 for initial Pap test allows the provider to sidestep the question of age at first intercourse. On the other hand, a 21-year-old who has never had vaginal intercourse does not need to be screened for cervical cancer.

Aggressive screening until age 30

Women should be screened every year until age 30 if conventional Pap smears are used.^1,2 During a woman’s 20s, precancerous lesions become more common and invasive cancer, while still rare, is seen with increasing frequency. Both ACOG and ACS consider this period of a woman’s life to be a time for aggressive cervical cancer screening.