|Treatment by LLETZ Principles and indications|| |
Large loop excision of the transformation zone (LLETZ), also known as loop electrosurgical excision procedure (LEEP), is an excisional method for treatment of CIN.
- A wire loop electrode powered by an electrosurgical unit (ESU) is used to resect the transformation zone along with the lesion.
- It is important to remove the entire transformation zone (not just the lesion) along with an adequate length of the endocervix to ensure at least 23 mm of tumour-free margin and removal of the full depths of the crypts in the transformation zone.
- Depending on the type of transformation zone and the length of the endocervix removed, the excision can be of type 1, type 2, or type 3. Type 1 excision is adequate for a purely ectocervical lesion, whereas type 3 excision is required if the endocervical extent of the lesion is not visible or if LLETZ is performed for glandular abnormalities or microinvasive cancer.
- The cervical tissue is cut as the heat from the electrical arc between the fine wire (active electrode) and the cervix vaporizes the tissue. Therefore, the loop should not be forced into the cervix; rather, it should be guided to melt the tissue (like a hot knife in butter). Bending of the loop will result in a shallow cone.
- A blend of cutting and coagulation current is used. The wattage required varies from machine to machine, but it should be started at 40 W coagulation and 40 W cutting current and gradually increased if necessary.
- The width of the loop ranges from 10 mm to 30 mm, and the depth ranges from 10 mm to 20 mm. The appropriate size of the loop should be selected to achieve an adequate depth and width of cut depending on the size and the position of the lesion. Loops that are too small should not be used, because there will be charring of the tissue.
- Ideally, the transformation zone should be removed as a single piece of tissue. However, a bigger lesion may require multiple passes of the loop to remove the transformation zone in pieces. The central part of the lesion should always be excised first.
- The tissue removed must be subjected to histopathological examination to determine the severity of the disease and whether the margins of the cone are free of disease.
Indications for LLETZ
- A CIN1 lesion that is persistent beyond 2 years
- CIN2 or CIN3 lesions
- CIN lesions that cannot be treated by cryotherapy or thermal ablation
- Cervical glandular intraepithelial neoplasia (CGIN) (adenocarcinoma in situ) (cold-knife conization preferred)
- Microinvasive cancer (cold-knife conization preferred)
- Cytology ASC-H or HSIL with a type 3 transformation zone and no visible lesion on colposcopy
- Persistently abnormal cytology in the absence of any lesion visible on colposcopy
- VIA- or HPV-positive lesions that cannot be treated by cryotherapy or thermal ablation (only in settings where the screen-and-treat algorithm is practised)
- Cytology and/or endocervical curettage shows glandular abnormalities
LLETZ should be regarded as a therapeutic procedure if the lesion is on the ectocervix or if the upper limit of the lesion is visible inside the endocervical canal and there is no suspicion of invasive or glandular disease. For other indications, LLETZ is essentially a diagnostic procedure to remove a cone for histopathological evaluation.
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