Screening With the Papanicolaou Test
        Benefits
         Harms
Screening Women Without a Cervix

Note: Separate PDQ summaries on Cervical Cancer Prevention ¹, Cervical Cancer Treatment ², and Levels of Evidence for Cancer Screening and Prevention Studies ³ are also available.

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 after age 25 years [1] but is of little value in women older than 60 years who have previously had negative tests.[2]

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.

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.

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.

References

1. Sasieni P, Castanon A, Cuzick J: Effectiveness of cervical screening with age: population based case-control study of prospectively recorded data. BMJ 339: b2968, 2009.  [PUBMED Abstract]
   
   
2. Sawaya GF, McConnell KJ, Kulasingam SL, et al.: Risk of cervical cancer associated with extending the interval between cervical-cancer screenings. N Engl J Med 349 (16): 1501-9, 2003.  [PUBMED Abstract]