Comparing surgical techniques for treating endometriomas

BLAST: a Randomized Controlled Trial on Conservative Endometrioma Surgery Using the CO2 Laser: the Combined Technique Versus CO2 Laser Vaporization Only

Not applicable Interventional Universitaire Ziekenhuizen KU Leuven · NCT04151433

This study is testing which of two surgical methods is better at preserving a woman's ability to have children while treating endometriomas.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment92 (estimated)
Ages18 Years to 40 Years
SexFemale
SponsorUniversitaire Ziekenhuizen KU Leuven Academic / other
Locations4 sites (Antwerp and 3 other locations)
Trial IDNCT04151433 on ClinicalTrials.gov

What this trial studies

This study aims to evaluate which of two conservative surgical techniques is more effective in preserving ovarian reserve during the treatment of endometriomas. The techniques being compared are a combined approach and CO2 laser vaporization. Ovarian reserve will be assessed through measurements of AMH serum levels taken before and after the surgery. The study targets patients who are undergoing laparoscopic surgery for endometriotic cysts.

Who should consider this trial

Good fit: Ideal candidates are women aged 18 to 40 with unilateral endometriotic cysts between 2.5 cm and 8 cm in diameter who are experiencing infertility or pain.

Not a fit: Patients with a history of hysterectomy, prior unilateral oophorectomy, or those with suspected malignancy may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved surgical outcomes and better preservation of ovarian function for patients with endometriomas.

How similar studies have performed: Other studies have shown promising results with similar conservative surgical approaches, indicating potential for success in this trial.

Eligibility criteria

Show full inclusion / exclusion criteria
Population: patients planned for laparoscopic CO2 laser surgery for endometriotic cysts.

Inclusion Criteria:

* Age: 18 - 40 years (both inclusive)
* Unilateral endometriotic cysts with a mean diameter of \>=2.5cm and ≤8 cm, measured in 3 dimensions.
* Presence of a contralateral endometrioma of ≤ 2cm is allowed
* Complaining of infertility and/or pain
* BMI ≤35
* Use of contraception (combined or Progesteron only) for at least 4 weeks before surgery

Exclusion Criteria:

* Incomplete surgery for the pelvis
* Contra-indication for the use of contraception (combined or Progesteron only)
* Use of GnRH analogues preoperatively and in the first 3 months postoperatively
* (History of) hysterectomy
* Prior unilateral oophorectomy
* Pituitary/hypothalamic disorders
* Suspected malignancy
* Contralateral endometrioma of \>2 cm
* AMH \<0.7 preoperatively
* Pregnancy

Where this trial is running

Antwerp and 3 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Endometriosis OvaryEndometrioma
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.