What are the indications for colposcopy and how is the procedure performed?

Colposcopy: Indications and Procedure

Primary Indications for Colposcopy

Colposcopy is indicated for all women with high-grade squamous intraepithelial lesion (HSIL) cytology, atypical glandular cells (AGC), adenocarcinoma in situ (AIS), and atypical squamous cells-cannot exclude HSIL (ASC-H). 1

The key indications include:

• High-grade cytology abnormalities (HSIL, ASC-H) - immediate colposcopy required 1
• All subcategories of AGC and AIS - colposcopy with endocervical sampling mandatory 1
• Abnormal cervical cancer screening results - approximately 4% of screened women require colposcopy after one screening round 2
• Persistent HPV-16 or HPV-18 infection with abnormal cytology 3
• ASC-US (atypical squamous cells of undetermined significance) - only if high-risk HPV positive 1, 3

Age-Specific Considerations

For women ≥35 years with AGC or AIS, endometrial sampling must be performed in conjunction with colposcopy and endocervical sampling 1. Women <35 years require endometrial sampling only if they have unexplained vaginal bleeding or conditions suggesting chronic anovulation 1.

In pregnant women, colposcopy is recommended for HSIL, but endocervical curettage is unacceptable 1. The evaluation should preferably be conducted by clinicians experienced with pregnancy-induced colposcopic changes 1.

How the Procedure is Performed

Pre-Procedure Requirements

The colposcope provides illumination and magnification to examine the cervix 4. A satisfactory colposcopy requires complete visualization of the squamocolumnar junction and margins of any visible lesions 4, 5.

Step-by-Step Procedure

1. Initial cervical examination under magnification before any application 6

2. Application of 3-5% dilute acetic acid to the cervix 4

   • This causes abnormal cells to appear white (acetowhite changes)
   • Allows identification of lesions with malignant/premalignant characteristics 4

3. Systematic evaluation documenting 5:

   • Cervix visibility
   • Squamocolumnar junction visibility (critical for adequacy)
   • Presence and characteristics of acetowhitening
   • Abnormal vascular patterns
   • Lesion size and location

4. Iodine staining (Schiller's test) 4

   • Normal tissue uptakes iodine
   • Abnormal tissue fails to stain

5. Directed biopsies of suspicious lesions showing 4:

   • Dense acetowhite changes
   • Abnormal vascular patterns (punctation, mosaicism)
   • Failure to uptake iodine stain

6. Endocervical sampling when indicated 1, 7:

   • Recommended for: high-grade cytology, HPV-16/18 infection, age >40 years, unsatisfactory colposcopy (squamocolumnar junction not visualized), previous treatment for cervical precancer 7
   • Unacceptable in pregnancy 1, 7
   • May be omitted in nulliparous women <30 years with ASC-US or LSIL if squamocolumnar junction fully visualized 7

Documentation Requirements

Minimum reporting criteria 5:

• Squamocolumnar junction visibility
• Presence of acetowhitening
• Presence of lesion(s)
• Colposcopic impression

Comprehensive reporting should additionally include lesion visibility, size, location, vascular changes, and other lesion features 5.

Critical Procedural Pitfalls

The most common error is performing colposcopy when the squamocolumnar junction is not fully visualized - this results in an unsatisfactory examination and requires endocervical sampling or excisional procedure 4, 5.

Among women undergoing colposcopy with biopsy, 28% experience moderate or severe pain and 22% have at least moderate postprocedure bleeding 2. Patients should be counseled about these expected outcomes.

HPV DNA testing alone or repeat cytology is unacceptable for initial triage of AGC and AIS - these patients require colposcopy 1. This is a critical management error that can delay cancer diagnosis.