A. Recommended Pap Smear Frequency

1. American Collage of Obstetrics and Gynecology (ACOG) Recommendations
2. American Cancer Society (ACS) and US Preventive Task Force Recommendations
3. Standard Pap smear being supplemented with liquid based preparations and HPV testing
4. HPV (human papilloma virus) testing of cervical swabs may replace Pap smears [13]
5. Combination of Pap and HPV testing reduces incidence of grade 2 or 3 cervical intraepithelial neoplasia (CIN) or cervical cancer detected on subsequent screening examinations [14]
6. Overview of Pap Smear Screening [1,8]
   1. Initiate within 3 years of sexual activity or at 21 years of age, whichever is first
   2. Repeat every 1-3 years with standard Pap from then on if normal until menopause
   3. Liquid based cytology screening can be done every 2 years if normal
   4. After age 30, can screen every 2-3 years if normal screens
   5. HPV testing added to Pap can help reduce frequency to every 3 years if non-high risk HPV
   6. HPV testing is more sensitive (94% versus 55%) and about as specific (94.1% versus
7. 8%) for CIN 2 or 3 compared to Pap smear [13]
   1. After menopause, every 2-3 years if normal Pap smear obtained [21]
   2. In sexually inactive post-menopausal women with normal Paps and no high risk HPV, consider stopping Pap smears
   3. In HIV+ and other immunocompromised patients, Pap smears done q6 months [28]
8. Follow up on abnormal smears every 3-6 months (depends on HPV status; see below)
9. Three Consecutive Normal Smears
   1. In such persons who have ONE sex partner, every 2-3 year smears are acceptable
   2. For screening interval of 3 years, there is increased of cervical cancer of 3 per 100,000 persons [2]
   3. Using liquid based Pap or HPV testing, 2-3 year screening intervals are acceptable
   4. Combined HPV and Pap testing leads to reduced CIN 2/3 or cervical cancer [14]
10. Pap Smears Following Hysterectomy
    1. No association between hysterectomy for benign disease and vaginal cancer
    2. Lack of evidence to suggest routine Pap Smear after hysterectomy for benign disease
    3. Pap smear is not beneficial and should not be done after hysterectomy for benign disease [31]
    4. In patients with supracervical hysterectomy, should continue Pap smear screening
    5. After normal Pap, interval should be 2 or more years in post-menopausal women [21]
11. About 2-3% of women of childbearing age will have CIN (pre-cancer) on Pap smear

B. Efficacy

1. Standard screening method for cervical carcinoma [4]
   1. Older smears are no longer standard of care
   2. New liquid-based / thin-layer preparations are generally recommended
   3. Whether liquid-based are superior to conventional cervical cytology is not clear [11]
   4. Computer-assisted screening may also be considered
2. Reduction of Cervical Cancer
   1. Early detection with Pap smear reduces rates of invasive cervical malignancy >50-75%
   2. Combined Pap and HPV testing likely reduces risks even further [14]
3. Instruments for Obtaining Pap Smear
   1. Should include spatula and endocervical brush
   2. Ayre's spatula is the least effective sampling device and should not be used alone
   3. Extended tip spatula or cervex brush are recommended over Ayre's spatula
   4. Newer collection fluids allow monolayer smears to be made (such as ThinPrep) [17]
   5. Monolayer smears can be partially interpreted by computer assisted imaging
4. Test Characteristics [17,22,23]
   1. False positives for squamous cervical cancer 5-15% (mainly ASC-US, LGSIL)
   2. False negatives ~15%, often adenocarcinoma
   3. Intraobserver variability is ~50% for cytologic and histologic readings [22]
   4. Most of this variability is found in mildly to moderately abnormal pathology [22]
   5. Liquid-based screening may have increased incidence of ASC-US versus conventional [11]
5. Computer Assisted Initial Screening [17]
   1. AutoPap Primary Screening System
   2. Uses proprietary computerized algorithms to detect smears with high risk of cytologic abnormalities using liquid-based preparation
   3. Cytotechnologist then reviews the smears/slides selected by the computer
6. HPV Screening (see below)
   1. HPV DNA detection for high and moderate risk strains of HPV available
   2. HPV18, highly oncogenic, does not induce as much cytological change as HPV16 [29]
   3. HPV testing clearly useful following ASCUS (but not LSIL) result on initial cytology
   4. HPV test may be useful for monitoring LSIL: HPV negative LSIL has high regression rate [7]
   5. HPV primary testing is likely to replace Pap smear [13]
7. Self-collected vaginal swab detection of HPV DNA [15]
   1. As sensitive for detection of high-grade servical disease as Pap smear
   2. Less specific (17% false positives) than Pap smear (12% false positives)
   3. HPV DNA testing with self-collected swabs may be used if Pap smear not available

C. Smear Results: 2001 Bethesda Classification [9,23]

1. Adequacy of Smear
   1. Satisfactory: was endocervical material obtained ?
   2. Unsatisfactory: rejected, not processed, other reason
2. General Categorization (Optional)
   1. Negative for intraepithelial lesion or malignancy
   2. Epithelial cell abnormality
   3. Other
3. Negative for Intraepithelial Lesion or Malignancy
   1. Organisms: trichomonas, yeast (Candida), bacterial vaginosis, Actinomyces, herpes
   2. Other non-neoplastic: reactive cellular changes, glandular cells, atrophy
4. Epithelial Cell Abnormalities
   1. Squamous Cell
   2. Glandular Cell
5. Squamous Cell Abnormalities
   1. Atypical Squamous Cells (ASC)
   2. ASC of Undetermined Significance (ASC-US)
   3. ASC and cannot exclude high-grade squamous intraepithelial lesion (HSIL; ASC-H)
   4. Low-grade squamous intraepithelial lesion (LSIL)
   5. LSIL encompassing HPV, mild dysplasia, cervical intraepithelial neoplasia I (CIN 1)
   6. HSIL encompassing moderate or severe dysplasia, carcinoma in situe (CIS)
   7. HSIL with CIN 2 and CIN3
   8. Sqamous cell carcinoma
6. Glandular Cell Abnormalities
   1. Atypical Glandular Cells (AGC) - specify endocervical, endometrial, not specified
   2. AGC, favor neoplastic - specify endocervical or not specified
   3. Endocervical adenocarcinoma in situ (AIS)
   4. Adenocarcinoma

D. Human Papilloma Virus (HPV) Testing [4,6]

1. HPV
   1. Over 95% of all cervical cancers are positive for "high risk" strains of HPV DNA
   2. Initial high levels [18] and persistent high levels [19] of HPV type 16 are strong risk factors for the development of cervical carcinoma in situ (CIS)
   3. Persistence of any known oncogenic HPV >4 months >10X increased risk for any SIL [27]
   4. HPV testing is used to follow up any atypical squamous cells (ASC; see below)
   5. Assessing HPV viral loads in Pap smear samples may have prognostic utility
   6. HPV testing is recommended in patients with HIV for general screening [25]
   7. HPV testing followed by colposcopy for high risk strains is associated with reduced prevalence of CIN2/3 within 6 months of initial evaluation [32]
2. HPV + Pap Testing
   1. Combination of Pap and HPV testing reduces incidence of grade 2 or 3 CIN or cervical cancer detected on subsequent screening examinations [14]
   2. Pap + HPV testing every 2 years until age 65 is cost effective [5]
3. Primary HPV Testing Versus Pap Smear [3,13]
   1. High risk HPV serotype positivity 20% more sensitive for detecting CIN2 or CIN3 and 5% less specific than Pap smear
   2. HPV testing is more sensitive (94% versus 55%) and about as specific (94.1% versus
4. 8%) for CIN 2 or 3 compared to Pap smear [13]
   1. HPV-positive women with normal or borderline followup cytology should undergo repeat HPV testing in 12 months
   2. HPV testing and visual inspection with acetic acid can replace standard Pap smear [13,32]
   3. Immediate colposcopy in patients with high risk HPV or abnormal visual inspection results in reduced rates of CIN2/3 after 6-12 months compared with delayed evaluation [32]
   4. HPV DNA testing detects more CIN III on initial screen than control Pap Smear [33]
   5. On subsequent screen, patients initially tested with HPV DNA had lower CIN III rates than those tested with Pap [33]
   6. Therefore, HPV DNA assessment results in earlier detection of CIN III lesions than Pap [33]

D. Risks for CIN

1. Human Papilloma Virus (HPV) Infection
   1. Early intercourse
   2. Multiple sex partners
   3. Prostitutes
   4. Multiple sexually transmitted diseases
   5. Specific serotypes of HPV (Changes: koilocytosis, perinuclear changes)
   6. Concurrent HIV infection greatly increases risk for progression to cancer [25,28]
   7. HPV testing should be adjunct to standard PAP smear in HIV+ patients [25]
2. HPV Epidemilogy
   1. Some10-25% of women with normal Pap smears are positive for HPV DNA [6]
   2. About 80% HIV negative will only have transient HPV DNA positivity on Pap testing
   3. HIV positive women have highly increased risk of persistent HPV infection and dysplasia
   4. HPV infection is a 6-10X risk factor for development of LGSIL lesions on Pap [24]
   5. High initial and persistently high levels of HPV 16 DNA in Pap are strong risk factors for development of cervical carcinoma in situ (CIS) [18,19]
   6. Majority of HPV infections of ANY type are cleared spontaneously over years [26]
   7. Over 50% of high-risk HPV is cleared at 2 years in patients with non-severe dyskaryosis [26]
   8. HPV testing should be adjunct to standard PAP smear in HIV+ patients [25]
3. HPV Serotypes
   1. Over 65 serotypes known
   2. Benign / Low Risk: 6, 11 (associated with benign genital warts)
   3. High Risk: 16, 18, 31, 33 and 35, 45
   4. Intermediate Risk: most other serotypes
4. HPV and Gynecologic Evaluation Following Pap Smear [12]
   1. Persistence of high risk serotype HPV (DNA testing) predicts CIN 3 morphology
   2. Persistence of high risk HPV AND severe dyskaryosis strongly predicts progression [26]
   3. All women with persistent high risk HPV on second test after 6 months should undergo invasive analysis by gynecologist
   4. All women with mild to moderate cervical dyskaryosis and high risk HPV should undergo a repeat HPV analysis at 6 months
   5. All women with severe cervical dyskaryosis should be evaluated by a gynecologist
5. ASC-US and CIN [10]
   1. Histology in ASC-US patients: normal 80.5%; CIN1 12.8%; CIN2 6.6%; Cancer 0.1%
   2. ASC-US with high-risk human papilloma virus (HPV) serotypes have ~28% risk of SIL
   3. ASC-US with low-risk HPV serotypes or negative for HPV have 7.5% risk of SIL
   4. Thus, HPV DNA detection can help stratify ASC-US smears for high or low risk [12]
6. Low socioeconomic status
7. Severely Immunocompromised patients
   1. AIDS (risk of CIN and cervical cancer increases with decreasing CD4+ T cell counts)
   2. Chemotherapy
   3. These risk factors
8. Exposure to Diethylstilbestrol (DES) in utero
9. Delayed type hypersensitivity to HPV-16 E7 associated with regression of CIN lesions [27]

E. Followup on Abnormal PAP Smear [3,4,9]

1. Management with Atypical Squamous Cells or Atypical Glandular Cells (AGC)
   1. Histology in ASC-US patients: normal 80.5%; CIN1 12.8%; CIN2 6.6%; Cancer 0.1%
   2. Therefore, further evaluation of all ASC-US is required
   3. Options are: repeat cytology in 4-6 months, HPV testing, or immediate colposcopy [8]
   4. Presence of high risk HPV should prompt immediate colposcopy
   5. Absence of high risk HPV can allow repeat cytology within 12 months
   6. Abnormal followup cytology after initial ASC should prompt immediate colposcopy
   7. Immediate colposcopy recommended for ASC-H, LSIL, HSIL and AGC
   8. Note all cases of AGC and AIS should be evaluated by colposcopy
   9. Women with AGC-favor neoplasia or AIS who do not have invasive disease on initial colposcopy should undergo diagnostic excisional procedure (cold-knife conization)
   10. Repeat colsposcopy is performed every 6 months until 4 negative results are obtained
2. HPV Testing [3,12,16]
   1. Reflex HPV DNA testing is recommended for ASC-US or AGC on Pap [1,4,12]
   2. Note that all AGC should by evaluated by colposcopy regardless of HPV status
   3. HPV DNA results on reflex testing have a positive predictive value of 15% and a negative predictive value for 99% for presence of HGSIL on colposcopy
   4. All women with mild to moderate cervical dyskaryosis and high risk HPV should undergo a repeat HPV analysis at 6 months
   5. Specificity of second generation hybrid capture HPV assay for high grade lesions is 89% [22]
   6. Persistent HPV is a 6-10X risk factor for development of LGSIL [24]
   7. High risk HPV serotype positive on Pap smear should prompt colposcopic evaluation
   8. Determination of HPV 16 viral load in Pap smear may have prognostic utility [18,19]
3. LSIL [7]
   1. Regression of LSIL on cytology and colposcopy 60% at 12 months, 90% at 3 years
   2. LSIL and ASC-US with oncogenic HPV type are clinically equivalent
   3. Over 80% of GSIL are positive for oncogenic HPV types
   4. LSIL which is HPV negative has a very high regression rate
   5. LSIL with HPV present is generally referred for colposcopy to avoid missing lesions
   6. Postmenopausal women with LSIL can be treated with intravaginal estrogen and followed by repeat cytology and/or HPV DNA testing
   7. HPV negative LSIL probably does not require immediate treatment
4. HSIL
   1. 98.9% of HSIL have oncogenic HPV types
   2. 75% of non-pregnant women with HSIL have CIN2 or CIN3
   3. Up to 3% of women with HSIL will have invasive cancer
   4. Colposcopy and endocervical biopsy strongly recommended
5. Colposcopy
   1. Visualization of Transformation Zone
   2. Assess sharpness of peripheral margin
   3. Aceto-whitening (application of acetic acid to area stains glycogen in cytoplasm dark)
   4. Color: Increased white implies increased nuclear content (abnormal)
      1. Vascular pattern: punctations, mosaicism, abnormal vessels
      2. Margin: well demarcated (hyperkeratosis) is okay
      3. Atrophic area implies estrogen depletion
   5. If findings are concerning, biopsy may be performed
   6. Colposcopy is not indicated for normal Pap smears in presence of external HPV lesions
   7. Colposcopy is probably unnecessary in patients with ASC-US and negative HPV DNA
6. Biopsy
   1. Endocervical Curettage
   2. Treatment with loop diathermy
   3. Conization will provide tissue also
7. Summary of Clinical Outcomes
   1. Low grade CIN should be followed closely (treatment is optional)
   2. High grade CIN (CIN2 or 3) should be treated aggressively

F. Therapy

1. CIN I
   1. Should be documented on biopsy
   2. Many patients require no further intervention, as most of these will resolve
   3. Cryotherapy - May be considered; N2O or CO2 with probe; often painful
   4. Followup evaluation should document non-progression of disease
2. CIN II and III
   1. Definitive therapy with proof of efficacy should be obtained
   2. Laser vaporization, loop diathermy, conization are options
   3. Demonstration of invasive disease should prompt aggressive management
3. Laser Tissue Vaporization
   1. Least invasive procedure
   2. No increased risk for preterm delivery or premature rupture of membranes (PROM) [30]
4. Loop Diathermy (Loop Electrosurgical Excision Procedure, LEEP)
   1. Tissue sample for pathology (do not change therapy based on margins)
   2. Different Loop sizes available
   3. Procedure can be done in the office
   4. Increases risk of preterm delivery or PROM ~2X [30]
5. Cone Biopsy (Conization) Procedure
   1. Now outpatient surgical procedure with general anesthesia
   2. Indicated if new squamo-columnar junction is not seen, or if
   3. Endocervical curettage is abnormal or if
   4. Two grade discrepancy between cytology and histology or if
   5. Cytologic suspicion of adenocarcinoma
   6. Increases risk of preterm delivery (premature rupture of membranes) ~2.7X [30]
6. Same management in pregnancy, but try not to biopsy as may lead to pre-term labor or miscarriage
7. Vaccinations against HPV are being investigated

References

1. Sawaya GF, Brown AD, Washington AE, Garber AM. 2001. NEJM. 344(21):1603
2. Sawaya GF, McConnell KJ, Kulasingam SL, et al. 2003. 349(16):1501
3. Cuzick J, Szarewski A, Cubie H, et al. 2003. Lancet. 362(9399):1871
4. Wright TC Jr, Cox JT, Massad LS, et al. 2002. JAMA. 287(16):2120
5. Mandelblatt JS, Lawrence WF, Womack SM, et al. 2002. JAMA. 287(18):2372
6. Kulasingam SL, Hughes JP, Kiviat NB, et al. 2002. JAMA. 288(14):1749
7. Moscicki AB, Shiboski S, Hills NK, et al. 2004. Lancet. 364(9446):1678
8. Sawaya GF. 2005. JAMA. 294(17):2210
9. Apgar BS and Brotzman G. 2004. Am Fam Phys. 70(10):1905
10. Goodman A and Wilbur DC. 2003. NEJM. 349(16):1555 (Case Record)
11. Davey E, Barratt A, Irwig L, et al. 2006. Lancet. 367(9505):122
12. Kim JJ, Wright TC, Goldie SJ. 2002. JAMA. 287(18):2382
13. Mayrand MH, Duarte-Franco E, Rodrigues I, et al. 2007. NEJM. 357(16):1579
14. Naucler P, Ryd W, Tornberg S, et al. 2007. NEJM. 357(16):1589
15. Wright TC Jr, Denny L, Kuhn L, et al. 2000. JAMA. 283(1):81
16. Schiffman M, Herrero R, Hildesheim A, et al. 2000. JAMA. 283(1):87
17. Nanda K, McCrory DC, Myers ER, et al. 2000. Ann Intern Med. 132(10):810
18. Josefsson AM, Magnusson PKE, Ylitalo N, et al. 2000. Lancet. 355(9222):2189
19. Ylitalo N, Sorensen P, Josefsson AM, et al. 2000. Lancet. 355(9222):2194
20. Hopfl R, Heim K, Christensen N, et al. 2000. Lancet. 356(9246):1985
21. Sawaya GF, Grady D, Kerlikowske K, et al. 2000. Ann Intern Med. 133(12):942
22. Stoler MH and Schiffman M. 2001. JAMA. 285(11):1500
23. Solomon D, Davey D, Kurman R, et al. 2002. JAMA. 287(16):2114
24. Mosciecki AB, Hills N, Shiboski S, et al. 2001. JAMA. 285(23):2995
25. Goldie SJ, Freedberg KA, Weinstein MC, et al. 2001. Am J Med. 111(2):140
26. Nobbenhuis MAE, Helmerhorst TJM, van den Brule AJC, et al. 2001. Lancet. 358(9295):1782
27. Schlecht NF, Kulaga S, Robitaille J, et al. 2001. JAMA. 286(24):3106
28. Levine AM. 2002. Ann Intern Med. 136(3):228
29. Woodman CBJ, Collins S, Rollason TP, et al. 2003. Lancet. 361(9351):40
30. Sadler L, Saftlas A, Wang W, et al. 2004. JAMA. 291(17):2100
31. Sirovich BE and Welch HG. 2004. JAMA. 291(24):2990
32. Denny L, Kuhn L, De Souza M, et al. 2005. JAMA. 294(17):2173
33. Bulkmans NW, Berkhof J, Rozendaal L, et al. 2007. Lancet. 370(9601):1764