Overview
This specialist Guidelines summary covers recommendations from the World Health Organization (WHO) on the use of thermal ablation for the treatment of pre-cancerous cervical lesions. These recommendations apply to women who have histologically confirmed cervical intraepithelial neoplasia 2 and above (CIN2+) or women who have screened positive in a screen-and-treat strategy.
This summary is intended for use by oncologists working in a secondary care setting.
Please refer to the full document for background information, dissemination, updating and implementation, and research implications.
Eligibility for Thermal Ablation and Cryotherapy
- Eligibility for treatment requires a visual assessment which includes colposcopy (if available) or naked eye examination of cervix after applying 3–5% acetic acid for 1 minute
- Clinicians usually describe what they see when performing visual inspection (for example, if the transformation zone (TZ) is fully visible; if the whole lesion is visible; if the lesion extends into the endocervix), and then consider if the probe can reach the whole lesion. Clinicians can also consider the following classification from the International Federation for Cervical Pathology and Colposcopy according to the visibility of the TZ:
- A type 1 TZ is completely ectocervical and is therefore fully visible
- A type 2 TZ is partially endocervical but is still fully visible. It may be shallow and within range of an ablative probe or may extend beyond reach of an ablative probe
- A type 3 TZ extends out of view up the endocervical canal; the squamocolumnar junction (SCJ) is not fully visible
- Following assessment as described above, women who screen positive are eligible for ablative therapy if there is no suspicion of invasive or glandular disease, and if:
- the TZ is fully visible, the whole lesion is visible, and it does not extend into the endocervix, or
- the lesion is type 1 TZ, or
- the lesion is type 2 TZ where the probe tip will achieve complete ablation of the SCJ epithelium, where it can reach the upper limit of the TZ. Sometimes the SCJ can be seen high in the canal, but a probe tip would not reach it
- Women who screen positive are not eligible for ablative therapy if there is any suspicion of invasive or glandular disease (adenocarcinoma or adenocarcinoma in situ), and:
- the TZ is not fully visible because it is endocervical (type 3 TZ), or
- it is a type 2 TZ where the SCJ is out of reach of the probe tip.
Intervals for Follow Up
- Intervals for follow up should be conducted according to the WHO guidelines for treatment of CIN2–3 and adenocarcinoma in situ, and the WHO guideline for screening and treatment of cervical pre-cancer lesions for cervical cancer prevention. According to those recommendations, all women who have received treatment should receive post-treatment follow up at 1 year to ensure effectiveness of treatment. Post-treatment follow up is critical, in particular for women living with HIV or women of unknown HIV status in areas with high endemic HIV infection.
Recommendations
- WHO suggests either large loop excision of the transformation zone (LLETZ), cryotherapy, or thermal ablation to treat all women who have histologically confirmed CIN2+ disease and who are eligible for thermal ablation or cryotherapy
- the choice of LLETZ, cryotherapy, or thermal ablation depends on the expertise, training, equipment and consumables available, infrastructure and resources in a programme. This recommendation applies to all women, including women living with HIV
- WHO suggests thermal ablation be provided at a minimum of 100°C for 20–30 seconds using as many applications as needed to cover the entire TZ in overlapping fields
- In exceptional conditions when LLETZ is not available for women who have histologically confirmed CIN2+ disease or are not eligible for cryotherapy or thermal ablation, the Guideline Development Group (GDG) recommends an alternative treatment. The choice of alternative treatment will be dependent on the skills and resources available and referral to a higher level of care where a cone biopsy, trachelectomy, or hysterectomy can be performed
- this applies to all women, including women living with HIV
- WHO suggests providing either thermal ablation or cryotherapy to women screened positive with high-risk human papillomavirus (hrHPV), or visual inspection with acetic acid (VIA), or hrHPV followed by VIA, with no histological confirmation and who are eligible for ablative treatment, or providing LLETZ when the woman is not eligible for cryotherapy or thermal ablation
- this applies to all women, including women living with HIV. The choice of screening tests is based on WHO recommendations for screening and treatment
- WHO suggests that prophylactic antibiotics are not used when providing thermal ablation
- WHO suggests that trained nurses, midwives, or health care workers, as well as physicians, may perform thermal ablation to ensure the availability and accessibility of treatment
- In settings where LLETZ is available and accessible, WHO suggests LLETZ rather than thermal ablation or cryotherapy for women who test positive after prior thermal ablation or cryotherapy
- In settings where LLETZ is unavailable or inaccessible, the GDG recommends thermal ablation or cryotherapy rather than no treatment for women who test positive after prior thermal ablation or cryotherapy
- this is consistent with the recommendation to provide LLETZ after prior cryotherapy.
Terms used in this Guideline
The term LLETZ represents a therapeutic intervention to excise the TZ. LLETZ is the original terminology used for excision of the TZ; however, in some countries this terminology was changed to loop electro excision procedure (LEEP) and the two terms are often used interchangeably. The term LEEP has also been used to refer to a diagnostic procedure, requiring the excision of up to 2 cm of tissue from the cervix for the pathologist to make an accurate diagnosis. These guidelines therefore use LLETZ to represent a therapeutic intervention to excise the TZ.
References
References