Screening With the Papanicolaou Test
Benefits
Based on solid evidence, regular screening of appropriate women for cervical cancer with the Papanicolaou (Pap) test reduces mortality from cervical cancer. Screening is effective when started within 3 years after first vaginal intercourse.
Description of the Evidence
- Study Design: Evidence obtained from population-based and cohort studies.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: Regular Pap screening decreases cervix cancer incidence and mortality by at least 80%.
- External Validity: Good.
Harms
Based on solid evidence, regular screening with the Pap test leads to additional diagnostic procedures (e.g., colposcopy) and treatment for low-grade squamous intraepithelial lesions (LSIL) with uncertain long-term consequences on fertility and pregnancy. These harms are greatest for younger women, who have a higher prevalence of LSIL, lesions that often regress without treatment.
Description of the Evidence
- Study Design: Evidence obtained from cohort or case-control studies.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: Additional diagnostic procedures were performed in 50% of women undergoing regular Pap testing. Approximately 5% were treated for LSIL. The number with impaired fertility and pregnancy complications is unknown.
- External Validity: Good.
Screening Women Without a Cervix
Based on solid evidence, screening is not helpful in women who do not have a cervix as a result of a hysterectomy for a benign condition.
Description of the Evidence
- Study Design: Evidence obtained from a single cohort study.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: Among women without cervices, fewer than 1 per 1,000 had an abnormal Pap test.
- External Validity: Good.
Screening Elderly Women
Based on solid evidence, continued screening in elderly women who have had negative Pap tests is of minimal value.
Description of the Evidence
- Study Design: Evidence obtained from cohort studies.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: Women aged 60 years and older who have a negative test are very unlikely to have abnormal Pap tests on repeat screening.
- External Validity: Good.