Colposcopy and treatment of CIN/CGIN

A 31-year-old is referred because her cervical screening test is HPV-positive with a high-grade squamous intraepithelial lesion on cytology. You are the colposcopist. The decision you make next — biopsy only, see-and-treat, or observe — sets her oncologic course and her future obstetric risk. This is one of the few encounters where overtreatment is measurable in premature babies. This topic is that encounter, written from the published evidence.[2][3]

Overview and definition

Colposcopy is a magnified, illuminated examination of the cervix (and vagina and vulva) after the application of acetic acid. Its purpose is to localise premalignant change in the transformation zone, biopsy it, and direct treatment. The whole subject turns on one fact that the published reviews state plainly: most cervical cancers develop in the transformation zone, the area of squamous metaplasia at the squamocolumnar junction (SCJ).[13][17]

Cervical intraepithelial neoplasia (CIN) describes the atypical squamous changes that arise in the transformation zone, graded by the depth of epithelial involvement — CIN 1, CIN 2 and CIN 3, from mild to severe. Local treatment is by ablation or excision, and the choice depends on the grade and extent of the disease.[14]

Cytology is reported using the Bethesda system, which has standardised reporting terminology and provided the basis for risk-based management strategies.[7]

References18Show ledgerHide ledger

1. [1]Perkins RB, Guido RS, Castle PE, Chelmow D, Einstein MH, Garcia F, et al. 2019 ASCCP Risk-Based Management Consensus Guidelines: Updates Through 2023 J Low Genit Tract Dis, 2024.PMID 38117563
2. [2]Kyrgiou M, Koliopoulos G, Martin-Hirsch P, Arbyn M, Prendiville W, Paraskevaidis E Obstetric outcomes after conservative treatment for intraepithelial or early invasive cervical lesions: systematic review and meta-analysis Lancet, 2006.PMID 16473126
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