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The Pap Smear: Technique and Interpretation. Karen James, MD January 28, 2003. Objectives. Outline pap smear as screening toool Review cervical histology Describe proper pap smear technique Review Bethesda 2001 terminology Practice management of pap smear results using case studies.
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The Pap Smear: Technique and Interpretation Karen James, MD January 28, 2003
Objectives • Outline pap smear as screening toool • Review cervical histology • Describe proper pap smear technique • Review Bethesda 2001 terminology • Practice management of pap smear results using case studies
Cytologic screening for cervical cancer • Cervical cancer screening has decreased morbidity and mortality • Deaths from cervical cancer decreased from 26,000 to less than 5,000 between 1941 and 1997 • Between 1973 and 1994, the incidence of cervical cancer decreased from 14.2 to 7.8 cases per 100,000 women
Pap smears are not perfect • For a high grade lesion, the sensitivity of a single pap smear is only 60-80% • Estimated false negative rate is 30-50% • Requires adequate specimen collection • Requires adequate cytological review
Pap smears are not perfect • Requires adequate patient and physician follow-up • 10% of women with cervical cancer had inappropriate follow-up • Requires access to care • 50% of women with cervical cancer were never screened and 10% had not been screened within 5 years of diagnosis
Who to screen • Any woman with a cervix who has ever had sexual intercourse • This includes women who have sex with women • This may mean women who have only had digital vaginal penetration
When to screen • Start within 3 years of onset of sexual activity or by age of 21, whichever is first • Risk factors for cervical dysplasia • Early onset of sexual activity • Multiple sexual partners • Tobacco • Oral contraceptives, a.k.a. no condoms
Screening frequency • Yearly until three consecutive normal pap smears, then may decrease frequency to every three years • ACOG and ACS recommend annual screening for high-risk women
When to stop routine screening • Age 65 and “adequate recent screening” • Three consecutive normal pap smears • No abnormal pap smears in last 10 years • No history of DES exposure • No history of cervical or uterine cancer
When to stop routine screening • Hysterectomy for benign disease • USPSTF recommends discontinuation • Hysterectomy for invasive cervical cancer • ACOG and ACS recommend continued screening
Original Squamous Epithelium • Vagina and outer ectocervix • 4 cell layers • Well-glycogenated (plump and pink) unless atrophic
Columnar Epithelium • Upper and middle endocervical canal • Single layer of columnar cells arranged in folds • Mucin producing (not true glands)
Squamous Metaplasia • Central ectocervix and proximal endocervical canal • Replacement of columnar epithelium by squamous epithelium • Progressive and stimulated by • Acidic environment with onset of puberty • Estrogen surges causing eversion of endocervix
Transformation Zone • Zone between original squamocolumnar junction and the “new” squamocolumnar junction • Nabothian cysts visually identify the transformation zone if present
Original Squamocolumnar Junction • Placement determined between 18-20 weeks gestation • Most often found on ectocervix • Can be found in vagina or vaginal fornices in DES exposed women • Less apparent over time with maturation of epithelium
“New” Squamocolumnar Junction • Border between squamous epithelium and columnar epithelium • Found on ectocervix or in endocervical canal • Majority of cervical cancers and precursor lesions arise in immature squamous metaplasia, i.e. the leading edge of the squamocolumnar junction
Technique • Visualize entire cervix if possible • Carefully remove any obscuring discharge • Sample ectocervix first with spatula • Sample endocervix with gentle cytobrush rotation • Apply material uniformly to slide • Fix rapidly with spray or liquid fixative
Technique • Hold spray fixative 10 inches away from slide • Collect cells before bimanual exam • Avoid contamination with lubricant • Test for GC and Chlamydia after pap smear • For DES patients sample cervix and upper 2/3 of vagina
“Normal” Pap Smear • Negative for intraepithelial lesion or malignancy • Other non-neoplastic findings • Reactive cellular changes • Glandular cells status post hysterectomy • Atrophy • Other • Endometrial cells (women 40 yrs)
Epithelial Cell Abnormalities: Squamous • Atypical squamous cells • ASC-US: undetermined significance • ASC-H: cannot exclude HSIL • LSIL: low grade (CIN 1) • HSIL: high grade (CIN 2 - 3) • Squamous cell carcinoma
Epithelial Cell Abnormalities: Glandular • Atypical endocervical, endometrial or glandular cells (NOS) • Atypical endocervical or glandular - favor neoplastic • Endocervical adenocarcinoma in situ • Adenocarcinoma: endocervical, endometrial or extrauterine