What is the role of Papanicolaou (Pap) testing in the workup of cervical cancer?

Updated: Feb 12, 2019
  • Author: Cecelia H Boardman, MD; Chief Editor: Warner K Huh, MD  more...
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Answer

For many years, the Pap test has been the standard method for cervical cancer screening. Retrospective data have shown that screening with a Pap test reduces the incidence of cervical cancer by 60-90% and the death rate by 90%.

Because of false negatives, the best that a Pap test can do is to reduce the incidence of cervical cancer to 2-3 per 100,000 women. False-negative tests mostly result from sampling error, which can be reduced by ensuring that adequate material is taken from both the endocervical canal and the ectocervix. Smears without endocervical or metaplastic cells should be repeated. (See Pap Smear.)

The limitations of the conventional Pap test include limited sensitivity (51%) and a significant proportion of inadequate specimens. In addition, accurate interpretation of conventional Pap tests is often compromised by the presence of artifacts (eg, blood, mucus, obscuring inflammation, scant cellular material, or air-drying artifact).

Newer liquid-based Pap test technologies have become available. In a randomized, controlled trial from the Netherlands that compared liquid-based and conventional cervical cytology, liquid-based cytology reduced the proportion of unsatisfactory specimens from 1.1% to 0.3% and eliminated obscuring blood, poor fixation, cytolysis, and insufficient spreading of cells as causes of unsatisfactory results. [60]

With liquid-based cytology, however, older women (primarily those 55-60 years of age) were more likely to have a sample called unsatisfactory. Nevertheless, 18-month follow-up showed that women with unsatisfactory results by either method were not at higher risk for cervical abnormalities. [60]


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