Page 9 - Screening for Cervical Cancer: Systematic Evidence Review

Structured Abstract

values. We used scoring checklists to summarize strengths of the publications; we also

evaluated the validity of each article and the overall quality of the evidence.

Data Synthesis: The evidence about age and hysterectomy is observational,

predominantly from population- or care-based data. The findings are consistent: risk of cervical

cancer or abnormalities falls with age; high-grade and more severe lesions are detected in fewer

than 1 per 1,000 Pap tests among women older than 60 who have had prior screening; and longer

histories of prior normal Pap tests further reduces risk. After hysterectomy, high-grade vaginal

lesions are rare, fewer than 2 to 4 per 10,000 tests. The literature about new diagnostic tools is

limited by lack of histologically validated performance. Using tools such as liquid cytology,

neural-net rescreening, and computer-based review algorithms improves sensitivity; however,

this improvement is predominantly for detection of low-grade lesions. The impact on specificity

is poorly documented. Sensitivity of HPV testing for screening detection of high-grade lesions is

competitive with conventional cytology (roughly 82%); specificity is lower (78%); and negative

predictive value is good (99%). For triage of women with abnormal Pap tests, sensitivity for

detecting high-grade lesions is 85%, specificity is 60%, and negative predictive value is 97%.

Conclusion: The yield of screening among older women who have been previously

screened decreases with age; if recommendations are not modified, older women are

disproportionately likely to have evaluations for false-positive findings. The prior

recommendation of the US Preventive Services Task Force to discontinue Pap testing after

hysterectomy for benign disease is supported. For making decisions about screening modality in

US populations, evidence about these new technologies for cytology screening and HPV testing

is currently limited. Controlled trials and prospective cost evaluation of new screening strategies

x