Non-Invasive Tests in the Diagnosis of Endometriosis

• Endometriosis is a chronic painful disease condition affecting 10% of the reproductive age women.
• Laparoscopy is useful to diagnose endometriosis with great accuracy. But the surgical risks and high costs are disadvantages.
• A significant delay in the diagnosis of endometriosis is due to the absence of good non-invasive tests.
• A review was conducted to find if there is any combination of non-invasive tests which can accurately diagnose endometriosis.

Researchers at the University of Adelaide published a review that assessed the diagnostic accuracy of different combinations of non-invasive tests for diagnosing endometriosis. The innermost lining of the uterus is called the endometrium. Endometriosis is a condition where the endometrial glands and stroma are present outside the uterus. Endometriosis frequently involves ovaries, peritoneum, bowel and sometimes beyond the pelvis. Endometriosis involving the ovaries can cause a cystic condition called endometrioma.

In endometriosis, the ectopic endometrial tissue acts like the tissue in the uterus. It grows, breaks downs and sheds to bleed with each menstrual cycle. The tissues around the ectopic endometrium get irritated, scar and form adhesions. The condition causes impaired fertility and pain-related symptoms like cyclic pelvic pain, dysmenorrhea or painful menstruation, dyspareunia or painful sex, dyschezia or difficulty with passing stools and dysuria or painful urination.

The diagnosis of endometriosis is made based on the history, physical examination, pelvic examination, vaginal ultrasound, Magnetic Resonance Imaging (MRI), serum markers, endometrial markers, urinary markers and diagnostic laparoscopy. Laparoscopy is an invasive method that diagnoses endometriosis with great accuracy. Researchers tried to find out if a combination of non-invasive tests could replace the need for laparoscopy while providing the same degree of accuracy.

The study reviewed eleven studies, which included 1339 women in the reproductive age group who were suspected to have ovarian, peritoneal or deep infiltrative endometriosis (DIE).   Three authors collected the data and performed a quality assessment using the QUADAS-2 tool. To find the combined estimates of sensitivity and specificity of the different combinations of various non-invasive tests, the bivariate model was used. The possibility of the non-surgical tests replacing laparoscopy was based on the sensitivity and specificity of the tests.

The following combinations met the criteria for being replacement tests in diagnosing endometriosis:

Pelvic Endometriosis:

• IL-6 (>15.4pg/ml) and Endometrial PGP 9.5 - sensitivity 1.0 and specificity 0.93.

Rectal Endometriosis:

• Vaginal examination and transvaginal ultrasound (TVUS) - sensitivity 0.96 and specificity 0.98.

The following combinations meet the criteria for SpIN (in case of positive result the test rules in the diagnosis with accuracy) triage test in diagnosing the following types of endometriosis:

Advertisement

Pelvic Endometriosis:

• Multiplication of urine vitamin-D-binding protein (VDBP) and serum CA-125 (>2755) – Sensitivity 0.74 and Specificity 0.97.
• Serum CA-125 (>35U/ml), the length of the menses and endometrial leukocytes – Sensitivity 0.61 and Specificity 0.95.

Endometrioma:

• TVUS and Serum CA-125 (greater than equal to 25U/ml) or CA 19.9 (greater than equal to 12U/ml) – Sensitivity 0.79 and Specificity 0.97.
• TVUS and Serum CA 19.9 (greater than equal to 12U/ml) – Sensitivity 0.54 and Specificity 0.97.
• TVUS and Serum CA-125 (greater than equal to 20U/ml or 25U/ml) – Sensitivity 0.69 and 0.96.
• TVUS and Serum CA-125 (greater than equal to 35U/ml) – Sensitivity 0.52 and Specificity 0.97.

Obliterated pouch of Douglas:

• Vaginal examination and TUVS – Sensitivity 0.87 and Specificity 0.98.

Vaginal wall endometriosis:

• Vaginal Examination and TUVS – Sensitivity 0.82 and Specificity 0.99.

Rectovaginal septum endometriosis:

• Vaginal Examination and TUVS – Sensitivity 0.88 and Specificity 0.99.

The studies included in the review had a poor methodological quality. Hence, the results of this review are not reliable. Finally, there is no strong evidence to prove the benefit of the combinations of multiple non-invasive tests in clinical practice over the gold standard laparoscopy in endometriosis. To find the importance of non-invasive tests or their combinations in the diagnosis of endometriosis, high-quality research studies are essential.

References:

1. Nisenblat, V., et al., Combination of the non-invasive tests for the diagnosis of endometriosis. Cochrane Database Syst Rev, 2016. 7: p. Cd012281.
2. http://www.mayoclinic.org/diseases-conditions/endometriosis/basics/definition/con-20013968?p=1
3. Hsu, A. L., Khachikyan, I., & Stratton, P. (2010). Invasive and non-invasive methods for the diagnosis of endometriosis. Clinical Obstetrics and Gynecology, 53(2), 413–419. http://doi.org/10.1097/GRF.0b013e3181db7ce8

Source-Medindia