What is involved in a colposcopy procedure and when is it recommended?

Colposcopy: Procedure and Indications

Colposcopy is a diagnostic procedure that involves magnified visual examination of the cervix after application of dilute acetic acid, with directed biopsies of abnormal areas, and is primarily indicated for evaluation of abnormal cervical cancer screening results, particularly high-risk HPV infections and abnormal cytology. 1, 2

What the Procedure Involves

The colposcopic examination is an office-based procedure performed without general anesthesia that includes the following steps: 2

• Illumination and magnification of the cervix using a colposcope to visualize the transformation zone 2
• Application of 3-5% dilute acetic acid to the cervix, which causes abnormal cells to appear white (acetowhite changes) 2
• Identification of abnormal features including acetowhite epithelium, abnormal vascular patterns (punctation, mosaicism), and areas that fail to uptake iodine stain 2
• Directed biopsies of suspicious lesions with characteristics suggesting premalignancy or malignancy 2, 3
• Endocervical sampling may be performed, particularly when evaluating atypical glandular cells (AGC) or adenocarcinoma in situ (AIS), and is specifically acceptable for HPV 18-positive patients due to adenocarcinoma risk 1, 2
• Satisfactory colposcopy requires complete visualization of the entire squamocolumnar junction and all margins of any visible lesions 2

When Colposcopy is Recommended

Immediate Colposcopy Required

The following scenarios mandate immediate colposcopy referral: 1, 4

• HPV 16 or 18 positive results, regardless of cytology - even if the Pap test is completely normal, colposcopy is required because HPV 16 is the highest-risk type and HPV 18 has high association with adenocarcinoma 1, 4
• High-grade cytology results including HSIL (high-grade squamous intraepithelial lesion) or ASC-H (atypical squamous cells cannot exclude HSIL) 1, 4
• Two consecutive HPV-positive tests - previous Pap results do not modify this recommendation 1, 4
• History of high-grade lesions (CIN 2 or CIN 3, histologic or cytologic HSIL, ASC-H, AGC, or AIS) 1
• Atypical glandular cells (AGC) or adenocarcinoma in situ (AIS) on cytology 1

Alternative Management (Deferred Colposcopy)

For lower-risk scenarios, repeat testing in 1 year is acceptable: 1, 4

• HPV positive (non-16/18) with normal cytology - return in 1 year for repeat HPV testing with or without concurrent Pap test 1, 4
• If abnormal cytology or persistent HPV positivity at 1-year follow-up, then proceed to colposcopy 4

Special Considerations for ASC-US

For women aged ≥21 years with ASC-US (atypical squamous cells of undetermined significance), three management options exist: 1

• Prompt colposcopy (appropriate if concerns about adherence or other clinical indications) 1
• Repeat Pap tests at 6 and 12 months until two consecutive negative results 1
• High-risk HPV DNA testing (if negative, repeat Pap at 12 months; if positive, immediate colposcopy) 1

Critical Post-Treatment Surveillance

After treatment for high-grade precancer (CIN 2/3 or moderate/severe dysplasia), surveillance must continue for at least 25 years, even if this extends beyond age 65 years: 1, 4

• Initial intensive surveillance: HPV test or cotest at 6,18, and 30 months (or cytology alone at 6,12,18,24, and 30 months if HPV testing unavailable) 1, 4
• Long-term surveillance: Every 3 years with HPV testing/cotesting, or annually with cytology alone 1, 4
• If hysterectomy occurs during surveillance period, vaginal screening must continue 1

Important Clinical Pitfalls

Common errors to avoid in colposcopy management: 1, 2

• Never defer colposcopy for HPV 16/18 positive results - even normal cytology requires colposcopy because these are the highest-risk types 1, 4
• Negative HPV test or cotest only reduces risk sufficiently to defer colposcopy if performed for screening purposes within the last 5 years - colposcopy is still warranted if negative results occurred during surveillance for a previous abnormality 1
• Unsatisfactory colposcopy (inability to visualize entire squamocolumnar junction) requires additional evaluation and cannot rule out disease 2
• Multiple biopsies of two or more sites are recommended to increase diagnostic accuracy 3