Preliminary comparison of papanicolaou smear and speculoscopy for assessing cervical cancer precursor lesions in pregnant adolescents

New technologies in cervical cancer precursor detection

The current literature reflects three routes toward improving cervical cancer screening. The first is to improve the test qualities of cytology-based screening. The use of liquid-based cytology and computerized analysis of Papanicolaou tests are examples of attempts at this approach. Secondly, through various combinations of parallel or sequential tests, either the sensitivity or the specificity of a given test could be improved depending on the tests chosen and the order in which they were performed (eg, Papanicolaou test followed by human papillomavirus [HPV] or vice versa). Several excellent studies have been published this year on the use of HPV DNA testing as a primary screening modality and as an adjunct to the triage of mildly abnormal cytologic findings. The recent literature also reflects increasing interest in visual inspection of the cervix and self-collected samples for HPV testing as an equally effective and viable alternative to cytology in low-resource settings. A third possibility is to make use of advances in digital and spectroscopic techniques. In these cost-conscious times, a significant number of articles address the cost-effectiveness of these technologies and the real value of cervical cancer screening. This article reviews the current literature concerning both the advent of new cervical cancer screening technologies and the rediscovery of old ones.

Accuracy of the Papanicolaou test in screening for and follow-up of cervical cytologic abnormalities: a systematic review

PURPOSE

To evaluate the accuracy of conventional and new methods of Papanicolaou (Pap) testing when used to detect cervical cancer and its precursors.

DATA SOURCES

Systematic search of English-language literature through October 1999 using MEDLINE, EMBASE, other computerized databases, and hand searching.

STUDY SELECTION

All studies that compared Pap testing (conventional methods, computer screening or rescreening, or monolayer cytology) with a concurrent reference standard (histologic examination, colposcopy, or cytology).

DATA EXTRACTION

Two reviewers independently reviewed selection criteria and completed 2 x 2 tables for each study.

DATA SYNTHESIS

94 studies of the conventional Pap test and three studies of monolayer cytology met inclusion criteria. No studies of computerized screening were included. Data were organized by cytologic and histologic thresholds used to define disease. For conventional Pap tests, estimates of sensitivity and specificity varied greatly in individual studies. Methodologic quality and frequency of histologic abnormalities also varied greatly between studies. In the 12 studies with the least biased estimates, sensitivity ranged from 30% to 87% and specificity ranged from 86% to 100%.

CONCLUSIONS

Insufficient high-quality data exist to estimate test operating characteristics of new cytologic methods for cervical screening. Future studies of these technologies should apply adequate reference standards. Most studies of the conventional Pap test are severely biased: The best estimates suggest that it is only moderately accurate and does not achieve concurrently high sensitivity and specificity. Cost-effectiveness models of cervical cancer screening should use more conservative estimates of Pap test sensitivity.