Page 45 - Screening for Cervical Cancer: Systematic Evidence Review

Chapter III. Results

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Pap test from 79 women within a two-year timeframe. At completion of follow-up, 3 women
had vaginal intraepithelial neoplasia (VAIN) and one had squamous cell carcinoma. This

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translates into 0.42 high-grade lesions per 1,000 Pap tests. These articles are described in
greater detail in Evidence Table 1B.

Summary

The available evidence about age and screening outcomes is observational, from large

population-based retrospective cohorts supported by registry systems, or from smaller

prospective cohort studies. Despite varied study design and populations, the findings are

coherent and support the assessment that risk of high-grade cervical lesions falls with age,

especially among those with prior normal screening results. Because none of these studies

evaluates outcomes among women who did not receive further screening after a designated age,

and because none is experimental, we cannot draw direct conclusions about the anticipated

results of discontinuing screening at a specific age.

Prior USPSTF recommendations to discontinue Pap testing after hysterectomy for benign

disease are supported by a well-conducted study; they should be re-emphasized. Lastly, no

direct comparisons between proposed screening systems, including those based on individual

risk assessment, were identified. This confirms that this literature is substantially less well-

developed than that of other areas of screening tests, such as colorectal cancer screening in which

trials comparing annual fecal occult blood testing to sigmoidoscopy are available to inform

decisionmaking.

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