Colposcopia

Chapter 4
An introduction to colposcopy: indications for colposcopy, instrumentation, principles, and documentation of results
• A colposcope is a low-power, stereoscopic, binocular field microscope with a powerful light source used for magnified visual examination of the uterine cervix to help in the diagnosis of cervical neoplasia. • The most common indication of referral for colposcopy ispositive screening tests (e.g., positive cytology, positive on visual inspection with acetic acid (VIA) etc.). • The key ingredients of colposcopic examination are the observation of features of the cervical epithelium after application of normal saline, 3-5% dilute acetic acid, and Lugol’s iodine solution in successive steps. • The characteristics of acetowhite changes, if any, on the cervixfollowing the application of dilute acetic acid are useful in colposcopic interpretation and in directing biopsies. • The colour changes in the cervix, following the application of Lugol’s iodine solution, depends on the presence or absence of glycogen in the epithelial cells. Areas containing glycogen turn brown or black; areas lacking glycogen remain colourless or pale or turn mustard or saffronyellow. • It is important to carefully document the findings of colposcopic examination, immediately after the procedure, in a colposcopic record.

This chapter describes the indications for carrying out colposcopic examination of women, the instrumentation used for colposcopy, the basis of different colposcopic investigations and the methods of documentation of colposcopic findings. Thestep-bystep procedure of doing the colposcopic examination is described in the next chapter.

Indications for colposcopy
Given the availability of a colposcope and a trained colposcopist, there are a number of indications for this examination, of which positive cervical screening tests constitute the most frequent indication for colposcopy. The most common reason for referral of women for colposcopyis abnormal cervical cytology, usually discovered as a result of cytological screening (Table 4.1). Cytologically reported high-grade abnormalities such as high-grade cervical intraepithelial neoplasia

(CIN 2 and CIN 3) may be associated with an underlying invasive squamous cell cervical cancer or adenocarcinoma. It is important that all women with high-grade abnormalities be referredimmediately for diagnostic colposcopy. However, there is considerable variation in the management of women with low-grade abnormalities such as low-grade cervical intraepithelial neoplasia (CIN 1). The referral criteria in some centres, for example in developing countries where colposcopy is available, allow for the immediate referral of women with lowgrade abnormalities, whereas in other regions, forexample in developed countries, they are called back for repeat cytology smears every six months for up to two years and only those with persistent or progressive abnormalities are referred. It should be emphasized that women with low-grade lesions (CIN 1) on their cytology smears have a higher probability of having a

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Chapter 4

Table 4.1: Indications for colposcopy
Suspicious-lookingcervix Invasive carcinoma on cytology CIN 2 or CIN 3 on cytology Persisting (for more than 12-18 months) low-grade (CIN 1) abnormalities on cytology CIN 1 on cytology Persistently unsatisfactory quality on cytology Infection with oncogenic human papillomaviruses (HPV) Acetopositivity on visual inspection with acetic acid (VIA) Acetopositivity on visual inspection with acetic acid usingmagnification (VIAM) Positive on visual inspection with Lugol’s iodine (VILI)

high-grade lesion that would be found at colposcopy; perhaps 15% for those with atypia and 20% with CIN 1 on cytology may harbour higher-grade lesions (Shafi et al., 1997). It is advisable that women with any grade of CIN on cytology be referred for colposcopy in developing countries, in view of the possibility of reporting...