What are the next steps after an abnormal Pap (Papanicolau) smear result?

Management of Abnormal Pap Smear Results

The next steps after an abnormal Pap smear depend critically on the specific cytology result: high-grade lesions (HSIL) require immediate colposcopy or expedited treatment, low-grade lesions (LSIL) typically require colposcopy in most cases, and atypical cells (ASC-US) should be triaged with HPV testing. 1

High-Grade Squamous Intraepithelial Lesion (HSIL)

For patients ≥25 years with HSIL who are not pregnant, expedited treatment is preferred over colposcopy with biopsy after shared decision-making. 1

• Immediate colposcopy is always required for HSIL results 2, 1
• If HPV 16 is positive with HSIL cytology, expedited treatment should be strongly considered 1
• Research supports this aggressive approach, showing 84% of HSIL (CIN 2) Pap smears have CIN 2 or CIN 3 on histology, with only 16% overtreatment rate 3
• Pregnant women should not receive expedited treatment; colposcopy with biopsy is appropriate management 1

Atypical Squamous Cells - Cannot Exclude HSIL (ASC-H)

• Immediate colposcopy is recommended for all ASC-H results 1
• This category carries significant risk and should be managed similarly to HSIL 1

Low-Grade Squamous Intraepithelial Lesion (LSIL)

Colposcopy is recommended in most cases for LSIL. 1

• For women <21 years with LSIL, colposcopy is not recommended due to high rates of spontaneous clearance; repeat Pap testing at 12 and 24 months is recommended instead 1
• If preceded by negative HPV test or cotest within past 5 years, follow-up in 1 year instead of immediate colposcopy may be appropriate 1
• Research shows 13.3% of LSIL cases have CIN 2/3 on colposcopic biopsy, supporting the need for colposcopy rather than routine cytological follow-up 4

A critical pitfall: The older 1998 CDC guidelines suggested repeat Pap smears every 4-6 months for low-grade SIL could be acceptable in certain circumstances 2, but current evidence strongly favors colposcopy in most cases for LSIL 1.

Atypical Squamous Cells of Undetermined Significance (ASC-US)

For women ≥21 years with ASC-US, three management options exist: high-risk HPV DNA testing (preferred), repeat Pap tests, or immediate colposcopy. 1

HPV-Based Triage for ASC-US:

• If HPV positive with ASC-US, refer for colposcopy 1
• If HPV negative with ASC-US, repeat Pap test in 12 months 1
• Research demonstrates 38.89% of cytologically detected ASC-US cases are diagnosed as CIN 1-3 on histology, emphasizing the importance of proper triage 5

Alternative Management Without HPV Testing:

• Repeat Pap smears every 4-6 months for 2 years until three consecutive smears are negative 2
• If persistent abnormalities on repeat smears, colposcopy should be considered 2
• Women with ASC-US associated with severe inflammation should be reevaluated with repeat Pap smear after 2-3 months, then every 4-6 months for 2 years 2

Atypical Glandular Cells (AGC)

• All subcategories of AGC require colposcopy with endocervical sampling and HPV DNA testing 1
• AGC detected in postmenopausal women signifies underlying pathology and requires thorough investigation 5

HPV-Positive Results with Normal or Minimally Abnormal Cytology

HPV 16 or 18 Positive:

• Colposcopy is required regardless of cytology results, even if cytology is normal 1
• For HPV 18 positive cases, endocervical sampling is acceptable at colposcopy due to association with adenocarcinoma 1

Other High-Risk HPV Types (Non-16/18) with Normal Cytology:

• Return in 1 year for repeat testing is recommended in most cases 1
• Approximately 60% of high-risk HPV infections clear spontaneously within one year 6
• Colposcopy is always recommended for two consecutive HPV-positive tests, regardless of previous Pap test results 1

Long-Term Surveillance After Treatment

Surveillance should continue for at least 25 years after initial treatment for high-grade precancer, even beyond age 65. 1

Initial Post-Treatment Testing:

• HPV test or cotest at 6,18, and 30 months, OR 1
• Cytology alone at 6,12,18,24, and 30 months 1

Long-Term Surveillance:

• Every 3 years if using HPV testing or cotesting 1
• Annual testing if using cytology alone 1
• If hysterectomy occurs during surveillance period, vaginal screening should continue 1

Critical Pitfalls to Avoid

• The Pap smear is not an effective screening test for STDs 2, 1
• Postpone Pap smear if the woman is menstruating 1
• Mucopurulent discharge might compromise interpretation; remove carefully before testing if follow-up is unlikely 1
• Women with external genital warts do not need more frequent Pap smears unless otherwise indicated 1
• Women who have had a hysterectomy do not require annual Pap smears unless the hysterectomy was related to cervical cancer or its precursor lesions 1
• Never use HPV tests that detect low-risk HPV types (e.g., types 6 and 11) as they are not beneficial in this setting 1
• All repeat Pap smears must not only be negative but also interpreted by the laboratory as "satisfactory for evaluation" 2

Practical Implementation Considerations

• Clinics that cannot provide colposcopy services should establish clear referral protocols to facilities that can promptly evaluate and treat patients 2, 1
• Referral services should report results back to the referring clinician 2
• Develop protocols to identify women who miss initial appointments for rescheduling 2
• Documentation of Pap results, follow-up appointments, and results should be clearly maintained in the clinic record 2, 1
• Patients should receive printed information about their Pap smear results and a copy for their records when possible 2
• HPV testing or cotesting is preferred to cytology testing alone for follow-up after abnormal results 1