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A Study of Two Cone Biopsy Techniques For Women With Cervical Pre-Invasive Disease. LLETZ Cone and SWETZ.

Phase 3
Not Enrolling
Cervical Intraepithelial Neoplasia

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Trial Information

A Study of Two Cone Biopsy Techniques For Women With Cervical Pre-Invasive Disease. LLETZ Cone and SWETZ.

The treatment of precancerous lesions hinges on the destruction, or more commonly, the
excision of the cervical transformation zone (TZ). When the TZ contains squamous precancer
and is completely ectocervical and therefore full visible, excision or destruction is an
effective and relatively straightforward therapeutic entity. However in a small proportion
of women a cone biopsy is necessary. A cone biopsy often requires the excision of 20-30 mms
of endocervical canal.


1. The standard procedure, LLETZ - cone ( also called LEEP), is performed with a large
loop electrode of 20-25 mm depth. The activated loop is applied to the cervix outside
the lateral margin of TZ and brought slowly to the controlateral TZ margin with the
objective to acquire 20-25 mm up the canal.

2. The experimental intervention is SWETZ, a method of excision using a 1cm straight
disposal of 0.20 wire to remove the endocervical transformation zone or glandular
disease. The activated wire is used as a knife, fashioning a cone with desired

This technique may be able to excise the endocervical TZ with a lower rate of morbidity and
incomplete excision rate than LLETZ cone biopsy.

The hypothesis to be tested in this trial is that SWETZ is superior to LLETZ cone biopsy
in the management of endocervical pre-invasive disease.

Inclusion Criteria:

- Incompletely visible transformation zone in women with High grade Squamous
Intraepithelial Lesion (HSIL)

- Suspicion of microinvasive carcinoma or occult invasive carcinoma

- Suspicion of glandular disease

Exclusion Criteria:

- Pregnancy

- Coagulation disorders

- Cervicitis were present

- Refusal to participate in the study

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Treatment

Outcome Measure:

Endocervical Margin Not Free of Disease.

Outcome Description:

Primary outcome is the incidence of incomplete excision of dysplasia at the endocervical excision margin as recognized histologically.

Outcome Time Frame:

3 months after the surgery is performed.

Safety Issue:


Principal Investigator


Investigator Role:

Study Director

Investigator Affiliation:

British Society of Colposcopy


Brazil: National Committee of Ethics in Research

Study ID:




Start Date:

November 1999

Completion Date:

December 2010

Related Keywords:

  • Cervical Intraepithelial Neoplasia
  • Cone biopsy
  • Conization
  • LEEP
  • Loop electrosurgical excisional procedures
  • Large Loop Excision of Transformation Zone
  • NETZ
  • Needle Excision of Transformation Zone
  • Straight Wire Excision of Transformation Zone
  • Electrosurgery
  • Neoplasms
  • Cervical Intraepithelial Neoplasia
  • Carcinoma in Situ