Introduction Different approaches to screening and treatment of cervical precancer Anatomical considerations

Anatomical considerations Gross anatomy of female genital organs, External genitalia Internal genital organs Gross anatomy of the cervix Cervical epithelium Squamous epithelium Columnar epithelium Squamocolumnar junction (SCJ)

Physiological changes of the cervical epithelium

Ectropion Squamous metaplasia Transformation zone of the cervix Changes induced by pregnancy Atrophic changes Congenital transformation zone (CTZ)

Neoplastic changes of the cervical epithelium

Genesis of cervical cancer – Role of HPV HPV structure and types Genesis of precancerous lesions and cervical cancer Cervical intraepithelial neoplasia (CIN) Adenocarcinoma in situ (AIS) Cervical cancers

HPV tests – Variation between tests Instruments, consumables, and setup required

for collection of samples for HPV testing (provider-collected) for self-collection of samples for HPV testing

Procedure to collect samples for HPV testing

Sample collected by a health provider Counselling of a woman undergoing HPV testing History taking Preparation for sample collection for HPV testing Steps for inspection of the external genitalia Steps for insertion of the speculum and exposure of the cervix Steps for collection of cervical samples Steps for self-collection of samples Storage of the samples after collection, and transportation to the laboratory

Interpretation of HPV test results Management of women with a positive HPV test result

Management of women with a positive HPV test result The different strategies Triage with cytology Triage with VIA Triage with colposcopy

Treatment of cervical intraepithelial neoplasia – principles Steps to determine eligibility for ablative treatment

Criteria used to determine eligibility for ablative treatment Steps to determine eligibility for ablative treatment

Role of Lugol’s iodine in identifying the transformation zone for treatment

Role of Lugol’s iodine in identifying the transformation zone for treatment Steps for applying Lugol’s iodine to the cervix Pre-treatment assessment

Treatment by cryotherapy

Principles Cryosurgical unit Ancillary instruments and consumables Steps Side-effects and complications Post-treatment advice and follow-up Video

Treatment by thermal ablation

Principles The benchtop model The battery-operated model Complications Video

Using an HPV test as the test of cure in women treated for cervical abnormalities or cervical intraepithelial neoplasia (CIN) Infection prevention

Standard procedures for protection from infection Essential steps for infection prevention in a cervical cancer screening clinic Preparation of 0.5% chlorine solution

Case studies

VIA triage outcome (applicable in screen-and-treat setting only) – negative cases VIA triage outcome – positive cases VIA triage outcome – suspicious of cancer cases

Foreword Acknowledgement Authors Suggested citation Copyright

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Using HPV tests for cervical cancer screening and managing HPV-positive women – a practical online guide

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Physiological changes of the cervical epithelium – Squamous metaplasia

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The vaginal environment is acidic, because of the dominant presence of Lactobacillus bacteria. Exposure of the everted columnar epithelium to the acidic environment of the vagina leads to destruction of the cells, which are eventually replaced by newly formed (immature) squamous epithelium from the periphery. This process of physiological replacement of the columnar epithelium by immature squamous epithelium is known as squamous metaplasia.
Metaplasia starts from the distal limit of the ectropion; that is, from the SCJ located at the periphery of the ectropion, and progresses towards the external os. The newly formed immature metaplastic squamous epithelium gradually replaces the columnar epithelium and forms a new SCJ, which lies closer to the external os.
The SCJ that was originally at the distal limit of the ectropion and from where metaplasia started is known as the original SCJ. The newly formed SCJ, which is located closer to the external os, is known as the new SCJ. The original SCJ ultimately becomes a squamosquamous junction (the junction between the original squamous epithelium and the new squamous epithelium) and is no longer distinguishable after the metaplastic process progresses. Hence, the new SCJ is simply known as the SCJ. Henceforth, the new SCJ will always be referred to as the SCJ.

During the process of squamous metaplasia, the immature metaplastic squamous epithelium may occlude some of the crypt openings of the columnar epithelium. This results in entrapment of the mucus secreted by the columnar cells, with the formation of retention cysts known as nabothian cysts. Some of the openings of the crypts may remain uncovered by the metaplastic epithelium. These crypt openings remain patent and visible, and some of the crypts keep secreting mucin. The nabothian cysts and the patent crypt openings are the features of the metaplastic epithelium that may be visible during examination of the cervix.

The next section discusses how the physiological changes lead to the formation of a very important landmark on the cervix: the transformation zone.

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