What are the recommended Pap smear (cervical cytology) screening guidelines for women, including age groups, intervals, and special circumstances?

Pap Smear Screening Guidelines

When to Start Screening

Begin cervical cancer screening at age 21 years, regardless of sexual history or age at first intercourse. 1, 2, 3

• Screening before age 21 causes more harm than benefit because cervical abnormalities are common in adolescents but clinically important lesions are extremely rare 1, 2
• The high rate of spontaneous regression in young women leads to unnecessary colposcopies, biopsies, and treatments that can cause psychological distress and potential obstetric complications 1

Screening Strategy by Age Group

Ages 21-29 Years

Screen with cervical cytology (Pap test) alone every 3 years. 1, 2, 3

• HPV testing (either alone or as cotesting) is not recommended for routine screening in this age group due to the high prevalence of transient HPV infections that clear spontaneously 1, 2
• Reflex HPV testing may be used for triage of ASC-US results in women aged 25-29 years, but is not part of primary screening 1, 2
• Annual screening is explicitly not recommended at any age 1

Ages 30-65 Years

Three equally acceptable options exist, with cotesting every 5 years or primary HPV testing every 5 years preferred over cytology alone: 1, 2, 3

1. Cotesting (cytology + HPV) every 5 years (preferred by ACOG and NCCN) 1, 2
2. Primary HPV testing alone every 5 years (preferred by ACS 2020, FDA-approved) 2, 3
3. Cytology alone every 3 years (acceptable but less preferred) 1, 2, 3

The rationale for extended intervals with HPV-based strategies is that women with negative HPV tests have an extremely low 5-year risk of CIN 2+ (0.27% for negative cotesting, 0.34% for negative HPV alone) 1, 2

When to Stop Screening

Discontinue screening at age 65 years if ALL of the following criteria are met: 1, 2, 3

• Adequate prior screening: Either 3 consecutive negative cytology results OR 2 consecutive negative cotests within the past 10 years 1, 2
• Most recent test within the past 5 years 1, 2
• No history of CIN 2/3, adenocarcinoma in situ, or cervical cancer 1, 2

Continue screening beyond age 65 if: 1, 2

• History of CIN 2/3 or cervical cancer (continue for at least 20 years after treatment, even if this extends beyond age 65) 1, 2
• HIV infection or immunosuppression 1, 2
• In utero diethylstilbestrol (DES) exposure 1, 2
• Inadequate prior screening history 1, 2

Post-Hysterectomy

Discontinue all cervical cancer screening after total hysterectomy with removal of the cervix if: 1, 2, 3

• No history of CIN 2/3 or more severe disease in the past 25 years 2
• No history of cervical cancer 1, 2
• Hysterectomy was performed for benign indications 1

Continue screening if: 1, 2

• Subtotal hysterectomy (cervix retained) 2
• History of CIN 2/3, adenocarcinoma in situ, or cervical cancer 1, 2

High-Risk Populations Requiring Modified Screening

The following groups require more intensive, individualized surveillance (often annual screening): 1, 2

• HIV-positive women 1, 2
• Immunocompromised patients (organ transplant recipients, chronic corticosteroid users, chemotherapy patients) 1, 2
• History of CIN 2/3 or cervical cancer 1, 2
• In utero DES exposure 1, 2

These populations should not follow standard screening intervals and require consultation with specialists 2

HPV Vaccination Status

Women who received HPV vaccination should follow the same screening recommendations as unvaccinated women. 2

• Vaccination does not eliminate the need for screening because vaccines do not cover all oncogenic HPV types 1, 2
• Current vaccines protect against HPV 16/18 (causing ~70% of cervical cancers) but not all high-risk types 2

Common Pitfalls to Avoid

Do not screen women under age 21, regardless of sexual history - this is a grade D recommendation (harms outweigh benefits) 1, 2, 3

Do not perform annual screening - screening more frequently than every 3 years provides minimal additional benefit with substantial increases in false positives, unnecessary colposcopies, and overtreatment 1

Do not use HPV testing (alone or cotesting) in women under age 30 for primary screening - the high prevalence of transient HPV infections leads to excessive false positives 1, 2

Do not continue screening after adequate negative results beyond age 65 unless high-risk factors are present - this represents low-value care with persistent harms 1

Do not screen women after total hysterectomy for benign disease - the yield is extremely low and represents unnecessary testing 1, 3