Academic articles, March

Kamaitorn Tientong, M.D.
Department of Obstetrics and Gynecology, Rajavithi Hospital

Colposcopy: A Critical Diagnostic Tool in Gynecologic Oncology

          Colposcopy is a diagnostic procedure that uses a high-magnification, illuminated microscope to examine the cervix, vagina, vulva, and anus. Its primary goal is to detect pre-cancerous and cancerous lesions early, enabling timely treatment. Compared to gross examination, colposcopy improves the identification of abnormal epithelial changes, enhancing biopsy precision and diagnostic accuracy.

Colposcopy is indicated in the following clinical scenarios:
1.Evaluation of abnormal cervical cancer screening results: It is performed as a follow-up for abnormal findings in Pap smears and/or HPV tests, as well as for assessing visible abnormalities in the cervix, vagina, or vulva.
2.Colposcopy is used to evaluate the completeness of lesion removal, detect residual or additional lesions in adjacent tissues, and facilitate post-treatment surveillance for disease recurrence.

Step of cervical colposcopy procedure
     1.Repeat cervical cytology and/or HPV testing (if indicated)
     2.Gross examination of the vulva, vagina, and cervix
          The initial assessment is conducted under bright illumination without diagnostic solutions, focusing on abnormalities such as erosion, ulceration, irregular surfaces, leukoplakia, pigmented lesions, and exophytic growths. Any detected abnormalities should be biopsied for histopathological evaluation.
     3.Colposcopic examination of the cervix and upper one-third of the vagina
          3.1 Application of acetic acid
The cervix is first examined without acetic acid, then with a 3–5% solution. Within 30–60 seconds, acetic acid dehydrates cells, causing acetowhite change in squamous cells with enlarged or dense nuclei, such as metaplastic, dysplastic, or HPV-infected cells. Blood vessels and columnar cells remain unaffected but become more visible. Acetowhite changes fade within three minutes, requiring reapplication if needed.
          3.2 Use of green filter
          A green filter enhances the visualization of abnormal vasculature by making blood vessels appear darker, improving contrast with the surrounding epithelium.
          3.3 Application of Lugol’s Iodine solution (if indicated)
          If no lesions are found after acetic acid application, lugol’s iodine solution may be used. Glycogen-containing squamous cells absorb iodine and appear dark brown, while non-glycogenated cells (e.g., columnar cells, high-grade lesions) remain light yellow, aiding lesion detection.
          3.4 Examination of the upper one-third of the vagina
          After assessing the cervix, the upper third of the vagina, including the lateral fornices, is examined. Abnormal findings may include adenosis, polyps, cysts, Diethylstilbestrol (DES)-related changes, condyloma, and lesions suggestive of pre-invasive or invasive disease.
     4.Biopsy and/or Endocervical Sampling (as indicated)
          The ASCCP recommends targeted biopsies for all acetowhite areas, with at least 2–4 samples for accurate evaluation. Untargeted biopsies are not advised for low-risk patients (e.g., those with LSIL or less on cervical cytology and negative for HPV 16/18) if no visible lesions are found.
     5.Documentation of Findings

Complications of colposcopy
          Colposcopy is generally a safe procedure with minimal risk. However, potential complications of biopsy may include bleeding and infection.

References
     1.Pierce JG Jr, Bright S. Performance of a colposcopic examination, a loop electrosurgical procedure, and cryotherapy of the cervix. Obstet Gynecol Clin North Am 2013; 40:731.
     2.Wentzensen N, Massad LS, Mayeaux EJ Jr, et al. Evidence-Based Consensus Recommendations for Colposcopy Practice for Cervical Cancer Prevention in the United States. J Low Genit Tract Dis 2017; 21:216.
     3.MacLean AB. Acetowhite epithelium. Gynecol Oncol 2004; 95:691.
     4.Marina OC, Sanders CK, Mourant JR. Effects of acetic acid on light scattering from cells. J Biomed Opt 2012; 17:085002.
     5.Hilal Z, Tempfer CB, Burgard L, et al. How long is too long? Application of acetic acid during colposcopy: a prospective study. Am J Obstet Gynecol 2020; 223:101.e1.
      6.Perkins RB, Guido RS, Castle PE, et al. 2019 ASCCP Risk-Based Management Consensus Guidelines for Abnormal Cervical Cancer Screening Tests and Cancer Precursors. J Low Genit Tract Dis 2020; 24:102.