Lab

Pap Smear

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Pap Smear, Cervical Cytology, Cervical Smear, Papanicolaou Smear, Cervical Dysplasia

  • Efficacy
  • Pap Smear
  1. Specificity of Pap Smear: 70%
  2. Sensitivity of Pap Smear: 80%
    1. Thin Prep Pap Smear
      1. Liquid based Pap Smear improves sensitivity
      2. Can be used for HPV DNA testing
      3. Will allow Gonorrhea and Chlamydia testing
      4. Reduces sampling error (e.g. drying artifact)
      5. Use spatula and cytobrush (instead of broom)
        1. Improves endocervical sampling
    2. Repeating Pap Smear improves sensitivity
      1. Repeated in short interval, sensitivity: 96%
      2. Third repeated in short interval: 99.2%
      3. Short interval is approximately 1 year
  • Precautions
  1. Abnormal visible cervical lesions indicate diagnostic Colposcopy (regardless of Pap Smear)
  2. Despite negative Pap Smears, HPV positive status confers higher risk at older ages
    1. Kjaer (2006) Cancer Res 66(21): 10630-6 [PubMed]
  • Prognosis
  • Reassuring findings
  1. Negative HPV test with a negative Pap Smear after age 30
    1. High longterm Negative Predictive Value
    2. Bigras (2005) Br J Cancer 93(5): 575-81 [PubMed]
  • Technique
  1. Preparation: Water-based Speculum lubrication
    1. Does not contaminate conventional Pap Smear slide
      1. Amies (2002) Obstet Gynecol 100:889-92 [PubMed]
      2. Harer (2002) Obstet Gynecol 100:887-8 [PubMed]
    2. Does not affect thin prep Pap Smear
      1. Note that thin-prep manufacturer recommends water
      2. Hathaway (2006) Obstet Gynecol 107:66-70 [PubMed]
  2. Tips to prevent unsatisfactory Pap Smears
    1. Avoid Pap Smear during time of Menses
    2. Avoid tampons and intercourse within 48 hours
    3. Blot Cervix prior to Pap Smear
    4. Focus on endocervical canal in postmenopausal women
  3. Step 1: Clean Cervix (clean only if large discharge)
    1. Gently wipe excess Cervical Mucus from os
    2. Use large cotton tipped swab
    3. Do not rinse Cervix with Saline
    4. Avoid performing Pap Smear during menstruation
  4. Step 2: Sample the Cervix
    1. Order is critical for less blood
      1. First: Chlamydia cultures (if needed)
      2. Option 1: Conventional Pap Smear
        1. Second: Exocervix with Ayres spatula (or similar)
        2. Last: Endocervix with Brush (rotate 180 degrees)
      3. Option 2: Thin prep
        1. Liquid pap (with broom or spatula/brush as above)
        2. Reflex to HPV testing (do not HPV test under age 20 due to low predictive value)
    2. Conventional Pap Smear pointers
      1. Get exo- and endocervix before applying to slide
        1. Prevents one from drying while collecting other
        2. Thin prep eliminates drying risk
      2. Samples may be placed on top of one another
      3. Spread spatula material in one smooth stroke
      4. Roll the brush along slide by twirling handle
    3. Pregnancy
      1. Place brush only 50% into canal and sample sides
  5. Step 3: Fix Pap Smear Sample (except thin prep)
    1. Fix sample immediately to prevent air drying
    2. Air drying is common reason for ASCUS Pap Smear
  • Labs
  1. HPV DNA
    1. Tested at age 30 regardless of Pap Smear results
    2. Directs further management of Cervical Cytology in age over 25-30 years old
    3. Not typically useful prior to age 25-30 years old
    4. Do not obtain more often than every 3 years
    5. Identify HPV Genotype if HPV positive result
  • Findings
  1. Normal
    1. Bethesda: Normal
    2. World Health Organization (WHO): Normal
  2. Inadequate Pap Smear
  3. Negative Pap Smear Cytology but Missing Transformation Zone
  4. Benign Pap Smear Changes
    1. Vaginal Infection
    2. Reactive changes (Inflammation)
  5. ASCUS Pap Smear
    1. Atypical Squamous Cells of Undetermined Significance
  6. AGUS Pap Smear
    1. Atypical Glandular Cells of Undetermined Significance
  7. Cervical Intraepithelial Neoplasia (Dysplasia)
    1. Mild Dysplasia
      1. Bethesda: Low Grade SIL
      2. WHO: CIN I
      3. Risk of progression
        1. Regresses spontaneously in 60% of cases
        2. Persists in 30% of cases
        3. Progresses to CIN III in 10% of cases
        4. Progresses to invasive cancer 1% of cases
    2. Moderate Dysplasia
      1. WHO: CIN II
      2. Risk of progression
        1. Regresses spontaneously in 40% of cases
        2. Persists in 40% of cases
        3. Progresses to CIN III in 15% of cases
        4. Progresses to invasive cancer 5% of cases
    3. Severe dysplasia
      1. Bethesda: High Grade SIL
      2. WHO: CIN III
      3. Risk of progression
        1. Regresses spontaneously in 33% of cases
        2. Persists in 55% of cases
        3. Progresses to invasive cancer >12% of cases
  8. Cervical Adenocarcinoma In-Situ (Pre-invasive Cervical Cancer)
  9. Cervical Cancer
  10. References
    1. Ostor (1993) Int J Gynecol Pathol 12(2): 186-92 [PubMed]
  • Management
  • Primary HPV Screening Protocol
  1. See Pap Smear Intervals
  2. HPV DNA negative
    1. Routine screening
  3. HPV DNA high risk type 16 or 18
    1. Colposcopy
  4. HPV DNA other high risk type (31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68)
    1. Negative Cervical Cytology
      1. Repeat Cervical Cytology in one year
    2. Positive Cervical Cytology for ASCUS or higher
      1. Colposcopy
  5. References
    1. Huh (2015) Gynecol Oncol 136(2): 178-82 [PubMed]
  • Management
  • Abnormal Pap Smear
  • Resources
  1. American Society for Colposcopy and Cervical Pathology
    1. http://www.asccp.org