Page 71 - Screening for Cervical Cancer: Systematic Evidence Review

Chapter IV. Discussion

squamous cells of unknown significance (ASCUS) or greater on cytology among a group of

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menopausal women from a prospective cohort. At the conclusion of these evaluations, a case

of cervical intraepithelial neoplasia 2 and a case of vaginal intraepithelial neoplasia III (not the

target of cervical cancer screening) had been identified.

The literature provides fairly reliable estimates of the number of women who need to be

screened to detect serious lesions. Recommendations can be made to discontinue or substantially

lengthen the interval, beyond 3 years, for screening among women age 65 and older who have a

history of prior normal Pap tests, depending on tolerance for missing rare cases that would have

been detectable under different screening systems. The difficult trade-off between overscreening

and missing rare but potentially preventable cases is a challenge for policy in this area. It

suggests at minimum that women and their providers should be fully informed about the

relatively larger risk of overintervention compared to the much smaller risk of failing to detect a

high-grade lesion that would lead to morbidity or mortality.

Prior recommendations of the US Preventive Services Task Force to discontinue Pap

testing after hysterectomy for benign disease are clearly supported and should be re-emphasized.

Lastly, no direct comparisons between outcomes of proposed screening systems or interval for

screening were identified. These findings confirm 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 use of screening methods over time are available to inform decision-

making.

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