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PekkaNieminen

Pap (Cervical) Smear and Endometrial Biopsy

Pap smear

Indications Interventions to Encourage the Uptake of Cervical Screening, Liquid-Based Versus Conventional Cervical Cytology, Human Papillomavirus Testing Versus Conventional Cytology for Cytological Cervical Lesions

  • The most important indication of Pap smear or, alternatively, high risk HPV testing (hrHPV) is screening to prevent cervical cancer, i.e. diagnostics of the cancer and precancerous lesions.
  • More than 80% of cancer cases that otherwise would occur can be prevented by screening.
  • According to a screening recommendation by the EU and the Finnish Current Care guideline, the screening should be started at the age of 25-30 and it should be continued until at least 65 years of age, at maximum, at 5-year intervals. See tableT1.
  • Pap smears for screening purposes are not warranted in women less than 25 years of age.
  • Pap smears are not warranted in women less than 20 years of age.
  • Diagnostic Pap smear can be taken from a 20-24-year-old woman if there is an obvious need for it due to symptoms, individual risk factors, sexually transmitted diseases or diagnosis of gynaecological infections.
  • In the follow-up of changes detected in a Pap smear and after treatment of premalignant lesions, the testing interval is shorter than in screening. See local recommendations.
  • It is recommended to perform a hrHPV test (hr = high risk) or Pap smear in persons older than the recommended screening age (65 years)
    • at 3-5-year intervals if a premalignant lesion has been treated during the woman's screening history
    • at 5-year intervals if the woman has not regularly participated in the screening during the previous 10 years.
  • Women who have regularly participated in the screening and always with normal results probably will not benefit from continuing the screening after 65 years of age.

Indications of a Pap smear in outpatient care

Screening-like testing in women of 25-29 years if the woman has not participated in mass screening and if, based on a physician's assessment, the test is seen as warranted
  • Pap smears for the purpose of screening to reduce the risk of cervical cancer is not warranted before the age of 25.
Screening-like testing in women ≥ 30 years of age, if the woman has not participated in mass screening and 5 or more years have passed since the previous screening test.
  • In women older than screening age, an hrHPV test or Pap smear is warranted at intervals of, at maximum, 5 years if a premalignant lesion has been treated during the woman's screening history.
Diagnostic Pap smear (in a symptomatic woman) when it is clinically indicated, e.g. in:
  • recurrent postcoital bleeding
  • intermenstrual bleeding or persistent leucorrhoea
  • macroscopic condylomata or other changes in the vaginal part of the cervix
  • prolonged symptoms of the vagina or the external genitalia

Sampling

  • Provide a sufficient amount of clinical details with the request form (at least the date of the last menstrual period and the duration of the cycle, history of abnormal smear results and any subsequent treatment).
  • Collect three samples on the same slide
    • Vaginal sample with the rounded end of the spatula
    • External cervix sample with the convex end of the spatula
    • Internal cervix (endocervix) sample with a cytobrush.
  • Spread the collected material evenly over the slide with a single smooth stroke motion (not with to and fro movements) to avoid damaging the cells. It is important to rotate the brush on the slide.
  • In some regions, a so-called liquid-based Pap method is used. The sample is taken from the cervix with a broom-like brush, and the brush is put in fixation liquid in a tube. Later in a laboratory, the cells are transferred from the container onto a slide for examination.

Fixation

  • Fix the sample as soon as possible.
  • Immerse the slide in 85-90% ethanol for 10 minutes or use an appropriate fixation spray. Keep a sufficient distance when spraying to avoid damage to the sample and clean the spray nozzle before spraying.

Sensitivity of the Pap smear Sensitivity and Specificity of Pap Smears in the Detection of Cervical Cancer, Liquid-Based Versus Conventional Cervical Cytology, Human Papillomavirus Testing Versus Conventional Cytology for Cytological Cervical Lesions

  • Squamous cell carcinoma of the uterine cervix 85-95%
  • Cancer of the body of the uterus (corpus uteri) only 50-60%
  • The Pap smear is not useful in the diagnosis of cancer of the ovary.

Reporting of Pap smears

The Bethesda system

  • The Bethesda system is an internationally accepted reporting system, and its latest version was updated in 2001 and amended in 2014.
  • The 2001 Bethesda System (TBS; table T3) is the recommended reporting system also for mass screening samples. Local recommendations may differ from this.

The 2001 Bethesda system.

ClassificationResult
Sample typeConventional smear, Liquid-based smear
Adequacy of the specimenSatisfactory for evaluation
Satisfactory for evaluation, no glandular cells
Satisfactory, but limited by... (specify reason)
Unsatisfactory for evaluation... (specify reason)
General categorisationNegative for intraepithelial lesion or malignancy
Epithelial cell abnormality
Other, see report
Abnormal microbesBV, clue cells
Mixed flora
Fungal organisms
Actinomyces
Trichomonas vaginalis
Herpes
Reactive changesInflammation
Regeneration
Radiation
Change caused by intrauterine contraceptive device (IUD)
Other non-neoplastic changesEndometrial cells in a woman > 50 years of age
Glandular cells after hysterectomy
Atrophy
Cytolysis
Squamous cell abnormalitiesASC-US - atypical squamous cells of undetermined significance
ASC-H - atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (HSIL)
LSIL - low-grade squamous intraepithelial lesion
HSIL - high-grade squamous intraepithelial lesion
Squamous cell carcinoma
Glandular cell abnormalitiesAGC-NOS, of endocervical origin, of undetermined significance
AGC-FN, of endocervical origin, favour neoplastic
Of endometrial origin, of undetermined significance
Of endometrial origin, favour neoplastic
Of undetermined origin, of undetermined significance
Of undetermined origin, favour neoplastic
Adenocarcinoma in situ
Adenocarcinoma
Hormonal evaluationMaturation index......./......../
Compatible with age and history
Incompatible with age and history (specify)
Hormonal evaluation is not possible due to...
Report

Interpreting the results

  • Measures and follow-up (see table T2)

Infection

  • Clue cells are typical of bacterial vaginosis (BV). Symptomatic patients should be treated. Asymptomatic patients should be treated particularly during pregnancy or when planning such because of the increased risk of premature delivery.
  • Mixed flora is reported in about 10% of the samples. Mixed flora needs no treatment unless it is associated with inflammatory cell changes or symptoms like leucorrhoea with a smell.
  • The diagnosis of trichomonas is reliable. Trichomonas must be treated.
  • The diagnosis of fungal organisms is less accurate. However, the presence of fungal hyphae (approx. 4% of samples) is suggestive of Candida. Usually only symptomatic patients need treatment.
  • Actinomyces is usually only seen in conjunction with an IUD which has been in use for a longer time. The treatment consists of the removal of the IUD. If needed, a new IUD may be inserted after a few months. Actinomyces requires treatment. If there are signs of infection, order a course of penicillin and metronidazole, in addition to removal of the IUD.
  • Herpes may be detected by a Pap smear, which is specific but not very sensitive.
  • HPV infection and associated cellular changes are reported as atypical epithelial cells according to their severity; HPV is a significant factor in the development of atypical changes.
  • For the treatment of vaginitis, see Vulvovaginitis.

Sources of error

  • One of the most common problems is the inadequacy of clinical details provided.
  • Insufficient number of cells: if a cervical sample contains endocervical cells it is likely that the sample collection has been correct.
  • Incorrect sampling, particularly slide material too thick or insufficient, is the largest error source.
  • Infection, abundant blood and cytolysis may disturb the evaluation of cells and hormonal situation, and so does recent topical treatment. The evaluation of hormonal balance done from a Pap smear is, however, always only indicative.
  • Lubricants, oils and gels may also make the interpretation more difficult as they significantly disturb the high-quality staining of the sample. Only normal saline or water should be used for lubrication.

Measures and follow-up in various Pap smear findings

FindingMeasuresFollow-up
Satisfactory for evaluation, no glandular cellsConsider taking a new sample
Evaluation unreliableConsider taking a new sample
Unsatisfactory for evaluationTake a new sample
Negative for intraepithelial lesion or malignancy
InflammationIf necessary, microbe-specific therapy and follow-up as recommended by the cytologist
RegenerationFollow-up as recommended by the cytologist; colposcopy if strong evidence of regeneration persists
Atrophic vaginitisLocal oestrogen therapy is recommended, follow-up as recommended by the cytologist
Change caused by radiationRepeat sample after 4-12 months as recommended by the cytologist; colposcopy if the change is significant and recurring.Annual smear test
Epithelial cell abnormality
ASC-US (atypical squamous cells of undetermined significance)Repeat sample after 12-24 months. Colposcopy if the change recurs 2-3 times during 12-24 months. Further treatment according to findings.According to colposcopy findings
ASC-H (as above but cannot exclude high-grade squamous intraepithelial lesion)Colposcopy within 1-2 months. Treatment is warranted if CIN 2 or 3 is detected, in other cases repeat samples at 6 month intervals until the finding is normal (CIN = cervical intraepithelial neoplasia; CIN 1 = mild dysplasia, CIN 2 = moderate dysplasia, CIN 3 = severe dysplasia or carcinoma-in-situ).According to colposcopy findings
LSIL (low-grade squamous intraepithelial lesion)Women > 30 yrs.: colposcopy within 6 months. The same applies to women < 30 yrs if recommended by the cytologist or when ASC-US or a more marked change is detected in the follow-up sample after 6-12 months. Treatment is warranted if CIN 2 or 3 is detected in colposcopy, otherwise repeat samples at 6-12 month intervals until the finding is normal.According to colposcopy findings. In CIN 1, follow-up for 2 years. Treatment, if not cured during follow-up. Thereafter annual smear tests for 30 months. Later on, the interval between smear tests must not exceed 5 years.
HSIL (high-grade squamous intraepithelial lesion)Colposcopy within 1-2 months. Treatment is warranted if CIN 2 or 3 is detected, in other cases repeat colposcopy after 6 months and take repeat samples at 6 month intervals until the finding is normal.According to colposcopy findings. In CIN 2-3, annual smear tests for 60 months after treatment; thereafter, the interval between smear tests must not exceed 5 years.
Squamous cell carcinomaColposcopy, loop excision and treatment of the carcinoma according to the degree of invasion.Follow-up at an oncology clinic
Atypical glandular cells of endocervical originColposcopy within 1-2 months, in undetermined glandular atypia a repeat smear within 4-6 months may be sufficient as recommended by cytologist.According to colposcopy findings. Annual smear test
Atypical glandular cells of endometrial originVaginal ultrasound and endometrial biopsyPostmenopausal endometrial follow-up
AdenocarcinomaColposcopy, treatment of the carcinoma depending on the caseFollow-up at an oncology clinic
Other malignancyColposcopy and histological samplesFollow-up at an oncology clinic
Hormonal state inconsistent with age and historyDepending on the case; information from the Pap smear is always only indicative (N.B. oestrogen-secreting tumours after menopause)

Endometrial biopsy

  • The condition of the endometrium can be assessed with the use of an endometrial biopsy, for example in bleeding disorders.
  • The collection of the biopsy is relatively easy, and may be carried out at a primary care facility. The diagnostic yield of the examination may be improved with a concurrent intravaginal ultrasound examination.

Indications

  • Postmenopausal bleeding in a patient with an unclear history ("slightly brown discharge", "a bit of spotting") and also if the patient gives a definite history of a bleed
  • Slight but recurring bleeding disorder in a woman below 40 years of age
  • Recurring bleeding disorder in a woman using progestogen-only or combined contraceptives
  • The determination of endometrial response during long-term hormone replacement therapy

Techniques

  • Both disposable and multiple use catheters are available. No local anaesthesia is necessary.
    1. Perform pelvic examination to determine the position of the uterus.
    2. Clean the cervix with saline solution if needed.
    3. If needed, grasp the cervix with a tenaculum and gently pull outwards in order to straighten the uterocervical angle, thus facilitating the insertion of the biopsy catheter.
    4. The direction of the cervix can be probed gently with the sound if necessary, and the distance from the fundus to the external cervical os can be measured at the same time.
    5. Insert the biopsy catheter into the uterine cavity. Aspirate whilst twisting the catheter 360 degrees against the uterine walls.
    6. A good tissue sample is usually collected. It is placed in a container with buffered formalin solution for a histological examination. It is advisable to cut the tip of the catheter with scissors: the quality of the tissue sample is thus better preserved.
      • If the sample is scant or if the pathologist so wishes the sample could be placed into a container with ethanol for cytological examination.

    References

    • Bibbo M (ed). Comprehensive Cytopathology. 2nd ed. Philadelphia, PA: W.B. Saunders 1997.
    • Kohdunkaulan, emättimen ja ulkosynnytinten solumuutokset [Cellular changes of the uterine cervix, vagina and female external genitalia]. A Current Care Guideline. Working group appointed by the Finnish Medical Society Duodecimin and Finnish Assocation for Colposcopy. Helsinki: Finnish Medical Society Duodecim, 2021. Available online (in Finnish only) http://www.kaypahoito.fi/hoi50049.