What is Colposcopy?
Colposcopy is a diagnostic examination of the cervix, vagina, and sometimes vulva using a specialized microscope (colposcope) after applying 3-5% acetic acid solution, typically coupled with directed biopsies of any lesions suspected of representing neoplasia. 1
Purpose and Clinical Role
Colposcopy serves as the primary diagnostic approach following abnormal cervical cancer screening results. 1 The procedure is specifically indicated for:
- Evaluation of abnormal cervical cytology including LSIL or more severe findings 1
- HPV-positive atypical squamous cells of undetermined significance (ASC-US) 1
- Positive HPV 16 or 18 results, even with normal cytology, due to high cancer association 2
- Persistent HPV positivity at 12-month follow-up testing 2
The Colposcopic Procedure
Technical Components
The examination involves viewing the cervix through a long focal-length dissecting microscope with 10x-16x magnification. 1 Key procedural steps include:
- Application of 3-5% acetic acid solution to the cervix before viewing 1
- Observation of coloration changes induced by the acid and blood vessel patterns 1
- Directed biopsies of all lesions suspected of representing neoplasia 1
- Endocervical sampling when endocervical canal extension is suspected, particularly for atypical glandular cells or adenocarcinoma in situ 1
Documentation Requirements
A comprehensive colposcopy examination should document: 3
- Cervix visibility and squamocolumnar junction visibility
- Presence of acetowhitening
- Presence, size, and location of lesion(s)
- Vascular changes and other lesion features
- Colposcopic impression
Satisfactory colposcopy requires visualization of the entire squamocolumnar junction and the margin of any visible lesion. 1
Diagnostic Performance
Colposcopy performance is inherently variable due to subjectivity in biopsy technique. 1 The sensitivity ranges significantly:
The reproducibility of colposcopy is poor with high inter- and intra-operator variability, and overall sensitivity and specificity are limited. 1
Current Practice Guidelines
Biopsy Recommendations
- No biopsies in low-risk women without visible acetowhite lesions 1
- Biopsy all acetowhite lesions when present 1
- Consider forgoing colposcopy in favor of treatment in very high-risk women (those with at least two high-grade cytology results, high-grade colposcopy findings, and/or positive HPV16/18) 1
Special Considerations for HPV 18
For HPV 18-positive results, endocervical sampling is acceptable at the time of colposcopy due to its specific association with adenocarcinoma. 2, 4 This is critical because HPV 18-related lesions may develop higher in the endocervical canal. 4
Potential Harms
While relatively few, harms from colposcopy include: 1
- Bleeding and infection
- Minor discomfort from prolonged speculum examination, acetic acid application, and biopsy
- Patient anxiety before, during, and after the procedure
- Risk of overtreatment: Colposcopy identifies CIN2, which may regress spontaneously, but typically triggers excisional treatment that can increase preterm birth risk two-fold 1
Timing Recommendations
Colposcopy should be performed within 90 days of a positive cervical screening result based on expert consensus and pragmatic health system considerations. 1 Longer delays result in decreased screening benefit, with 1.4% fewer cancers prevented at 90 days compared to immediate follow-up. 1
Common Pitfalls
- Inadequate visualization: The diagnosis is unreliable if the superior limit of the lesion cannot be seen; endocervical curettage should be added in such cases 1
- Low-quality procedures with insufficient biopsies may lead to false reassurance 1
- Overlooking endocervical sampling in HPV 18-positive cases, missing adenocarcinoma that develops higher in the canal 4