Pap Smear Abnormality
Pap Smear Abnormality: Excerpt from The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
Stephen Schmidt and Kathryn M. Andolsek
Worldwide, cervical cancer is one of the most common malignancies; 16,000 cases are diagnosed and 4,800 deaths occur annually in the United States (1). An American woman’s lifetime risk of cervical cancer is 0.83%; her risk of dying 0.27%. A 40% decrease in incidence and mortality appear to result from increased screening and early treatment. Pap smears are one of the few interventions awarded an “A” recommendation from the US Preventive Services Task Force, although no randomized trials support its efficacy. In addition to cancer, 5% of the 50 million yearly pap smears performed in the United States reveal low grade abnormalities (2).
Approach
Management of the abnormal pap smear must be individualized.
A. The Bethesda System was developed in 1988 and revised in 1991 by the National Cancer Institute to provide uniform terminology for cervical cytopathology reports (2). Knowledge of the natural history of each abnormality is crucial and is summarized in Table 11.1 (3).
B. Special concerns: frequency of screening, patient reliability, and prevalence of disease. All women who are at least aged 18 years or sexually active (1,4,5) should be screened. The frequency of screening after the initial smear is controversial. Many experts agree that after three annual normal results, the screening interval can be increased to 3 years in low risk patients (1). Some countries and professional organizations recommend discontinuing pap smear screening in older women (age 65) without previous dysplasia. Central to both this decision and the management of abnormal results is the reliability of the patient for follow-up. Aggressive management is recommended for women felt to be less likely to follow-up (2) or with risk factors that increase the prevalence of cancer.
C. New technologies. The sensitivity of traditional pap smear screening may be as low as 50%. Three new devices recently approved by the Food and Drug Administration (ThinPrep, Papnet, and AutoPap) were designed to reduce the rate of false–negative findings. Although these devices improve sensitivity, it is not clear they improve specificity. Further research is needed to determine their appropriate role. They are not useful in the evaluation of a woman with an abnormal pap smear by traditional screening (4).
History
Gynecologic history, which is essential in determining a patient’s risk, should be shared with the cytopathologist. Risk factors include early age at first intercourse or pregnancy, immunosuppression of any cause, human immunodeficiency virus infection, human papilloma virus (HPV), smoking, multiple sexual partners, and a history of lower genital tract neoplasia (5).
Physical examination
The cervix usually appears normal to the naked eye. Gross cervical abnormalities should prompt further evaluation. When present, discharge should be gently removed prior to the pap smear. Tests for sexually transmitted diseases, when indicated, should be obtained after the pap smear. If the cervix appears normal, vaginitis can be treated and the smear obtained after resolution of the discharge (5).
Testing
Evaluation of an abnormal pap smear may involve further testing or an attempt to diagnose and establish the extent of the lesion.
A. Repeat pap smear. Low grade lesions can be followed with serial testing. Although false–negative finding rates of 20% to 45% have been reported, rates as low as 10% have been reported, using conization specimens as the reference (1). Repeat testing at frequent intervals minimizes this risk.
B. Cervicography. Photographic evaluation of the cervix may have a sensitivity comparable to a pap smear, but it has much lower specificity (50%). A 10% to 15% rate of unsatisfactory cervicograms further limits the utility of this test (1). Current recommendations limit its use to experienced physicians who understand its limitations (2).
C. Human papillomavirus typing. HPV types 16, 18, 45, and 56 are strongly correlated with cervical cancer. Screening for HPV and HPV typing have been studied to identify high risk individuals. The positive predictive value of HPV screening is less than 10% (1), limiting its clinical usefulness. The role of typing as an adjunctive triage strategy remains under investigation.
Diagnostic assessment
A. Reactive changes associated with inflammation. Infectious causes (e.g., Candida sp., Trichomonas vaginalis, Gardnerella vaginalis, herpes simplex virus, or Chlamydia trachomatis) are common. The pathologist may be able to identify an offending organism or typical cytologic changes. However, the clinician must provide clinical correlation regarding symptoms and the need for treatment. No data support empiric therapy. The pap smear should be repeated in 3 to 6 months, regardless of cause or treatment (5).
B. Atypical squamous cells of uncertain significance (ASCUS). Multiple options are currently recommended based on the clinical setting and the patient’s risk. In a reliable patient, ASCUS can be followed with repeat cytology every 4 to 6 months for 2 years or until three consecutive, adequate, and negative smears are obtained. Recurrent ASCUS should be evaluated with colposcopy and biopsy (2,5). If the patient is postmenopausal or inflammation is present, a repeat pap smear after estrogen vaginal cream or appropriate antibiotic therapy can be considered (2). Close communication with the cytopathologist can clarify whether this process favors reactive or neoplastic changes and the relative incidence of neoplasia. ASCUS favoring a neoplastic process should be managed as a low grade squamous intraepithelial lesion (2).
C. Low grade squamous intraepithelial lesion frequently reverts to normal. In the appropriate clinical setting with a reliable patient, cytology every 4 to 6 months until three consecutive, adequate, and negative smears is appropriate. However, because of the high rate of false–negative cytology findings, further evaluation with colposcopy, including biopsy and endocervical curettage (ECC) (2,5), is appropriate. Unreliable or high risk patients should undergo more aggressive evaluation. After the entire lesion and transformation zone are visualized, the histologically confirmed lesion can be ablated, excised, or observed (5).
D. High grade squamous intraepithelial lesion. This category includes cancer in situ and moderate to severe dysplasia. Evaluation should include colposcopy, biopsy, and ECC. After identifying the entire lesion, excise or ablate the entire transformation zone (2,5).
E. Cancer. Cytology suggestive of invasive cancer should be evaluated with biopsy and referral to a physician experienced in the management of this disease.
F. Atypical glandular cells. Atypical glandular cells of undetermined significance (AGUS, AGCUS) should be subclassified according to favoring reactive process or neoplasia and by origin (endocervical or endometrial) (2). Endocervical atypia can be followed with colposcopy and ECC (5). If a neoplastic process is suspected, many believe that the best evaluation is diagnostic conization (2,5). Endometrial atypia should be evaluated by biopsy, hysteroscopy, or dilation and curretage (2,5).
References
1. US Preventive Services Task Force. Screening for cervical cancer. Guide to clinical preventive services, 2nd ed. Baltimore: Williams & Wilkins, 1996:105–117.
2. Kurman, RJ, Henson, DE, Herbst, AL, et al. Interim guidelines for management of abnormal cervical cytology. JAMA 1994;271:1866–1869.
3. Melnikow J, Nuovo J, Willan AR, et al. Natural history of cervical squamous intraepithelial lesions: a metaanalysis. Obstet Gynecol 1998;92:727–733.
4. Evaluation of cervical cytology. Summary, evidence report/technology assessment. No. 5. Rockville, MD: AHCPR, January 1999; http://www.ahcpr.gov/clinic/cervsumm.htm
5. American College of Obstetricians and Gynecologists. Cervical cytology: evaluation and management of abnormalities. Technical Bulletin No. 183. Washington, DC: American College of Obstetricians and Gynecologists, 1993.
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Book Source Details
- Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
- Author(s): Robert B. Taylor (editor)
- Year of Publication: 2000
- Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.
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