Is laparoscopy the gold standard for the diagnosis of endometriosis?

Liquid Biopsy in Endometriosis: A Systematic Review

Despite laparoscopy being a standardized option to diagnose pelvic endometriotic implants, non-invasive biomarkers are necessary to avoid the discomfort of invasive procedures. Recent evidence suggests a potential role of microRNAs (miRNAs) as feasible biomarkers for the early diagnosis of endometriosis. Following the recommendations in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we systematically searched PubMed, EMBASE, Scopus, Cochrane Library, and Science Direct in January 2023. We provided no restriction on the country and year of publication, and considered English published articles. We selected studies including patients with endometriosis and describing miRNA regulation in the context of endometriosis. Overall, 45 studies fulfilled the inclusion criteria, and 2045 patients with endometriosis and 1587 controls were screened. Patients were analyzed concerning miRNAs expression and sources, stage of disease, and symptoms, and compared to controls. Among DEMs, the ones with the widest delta between endometriosis patients and controls-Relative Expression ≥ 4 Log2(ratio)-were miR-145, miR-191, miR-195, miR-21-5p, miR-106b-5p, miR-195-5p, miR-451a, miR-200c, miR-20a-5p, and miR-15a-5p. Although the epigenetic regulation is partially unclear, miRNAs are valid biomarkers to diagnose endometriotic lesions in symptomatic and non-symptomatic women. MiRNAs modulation should be clarified, especially during therapies or relapse, to plan targeted management protocols.

Translational Applications of Linear and Circular Long Noncoding RNAs in Endometriosis

Endometriosis is a chronic gynecologic disease that negatively affects the quality of life of many women. Unfortunately, endometriosis does not have a cure. The current medical treatments involve hormonal manipulation with unwanted side effects and high recurrence rates after stopping the medication. Sadly, a definitive diagnosis for endometriosis requires invasive surgical procedures, with the risk of complications, additional surgeries in the future, and a high rate of recurrence. Both improved therapies and noninvasive diagnostic tests are needed. The unique molecular features of endometriosis have been studied at the coding gene level. While the molecular components of endometriosis at the small RNA level have been studied extensively, other noncoding RNAs, such as long intergenic noncoding RNAs and the more recently discovered subset of long noncoding RNAs called circular RNAs, have been studied more limitedly. This review describes the molecular formation of long noncoding and the unique circumstances of the formation of circular long noncoding RNAs, their expression and function in endometriosis, and promising preclinical studies. Continued translational research on long noncoding RNAs, including the more stable circular long noncoding RNAs, may lead to improved therapeutic and diagnostic opportunities.

Circulating serum miR-200c and miR-34a-5p as diagnostic biomarkers for endometriosis

OBJECTIVE

Endometriosis is defined by the presence of endometrial glands and stroma grow in areas outside the uterus. A simple blood test for endometriosis-specific biomarkers would offer a more timely accurate diagnosis of the disease and could lead to earlier treatment intervention. Alterations in microRNA (miRNA) levels in blood may reflect changes during normal physiologic processes and have been related to several pathologic conditions, including gynecologic diseases. In the present study, we aim to evaluate the level of serum miR-34a-5p and miR-200c from women with and without endometriosis, and to explore the potential of miRNAs as reliable non-invasive biomarkers in the diagnosis of endometriosis.

METHODS

Expression levels of miRNAs were performed by quantitative real-time polymerase chain reaction (qRT-PCR). Serum cancer antigen 125 (CA-125) levels were analyzed by autoanalyzer.

RESULTS

miR-34a-5p expression levels were decreased and miR-200c expression levels were increased in the endometriosis patients compared to the control group. According to the areas under the ROC curve (AUC) values, miR-200c and miR-34a-5p may serve as biomarkers for the diagnosis of endometriosis. Serum miR-34a-5p and miR-200c had a sensitivity of 78.95 % and 100 % and a specificity of 49.12 % and 100 %, respectively, for the detection of endometriosis.

CONCLUSION

Serum miRNAs may provide a promising opportunity for diagnosis of endometriosis. Understanding the role of circulating miRNAs will serve a better comprehension of the systemic effects of endometriosis and offer options for new treatments. It is clear that more work is needed in this area.

Asymmetric dimethylarginine (ADMA), nitric oxide metabolite, and estradiol levels in serum and peritoneal fluid in women with endometriosis

BACKGROUND

Increase in nitric oxide (NO) concentration accompanied by alteration in peritoneal immune defense reactions is involved in the pathogenesis of endometriosis. Asymmetric dimethylarginine is an endogenous competitive inhibitor of NO synthase. This study was designed to compare NO metabolite (nitrite), asymmetric dimethylarginine, and estradiol concentrations in serum and peritoneal fluid (PF) of patients with and without endometriosis.

MATERIALS AND METHODS

Subjects were assigned to two groups based on their laparoscopic results. The groups consisted of women with and without endometriosis (90 and 89 participants, respectively). The serum and peritoneal levels of nitrite (stable NO metabolite), asymmetric dimethylarginine, and estradiol were measured using enzyme-linked immunosorbent assay (ELISA) kits. These parameters were analyzed and compared between the groups statistically using SPSS software version 16.

RESULTS

Both nitrite and asymmetric dimethylarginine levels were significantly higher in the serum of the participants from both groups than those in the PF group (P < 0.05). However, no significant difference in the asymmetric dimethylarginine level was detected between the two groups. In addition, the PF level of nitrite increased significantly in patients with endometriosis when compared with non-endometriosis subjects (P < 0.05). The PF levels of estradiol in both groups were significantly higher than the serum levels of estradiol (P < 0.05).

CONCLUSIONS

The NO metabolite level of PF implies the possible role of NO in the pathogenesis of endometriosis.

Circulating Micro-RNAs as Diagnostic Biomarkers for Endometriosis: Privation and Promise

Endometriosis represents a major medical concern in women of reproductive age. One of the remaining major hurdles for successful treatment of endometriosis is the limitation of the process of timely disease diagnosis. A simple blood test for endometriosis-specific biomarkers would offer a more timely accurate diagnosis for the disease, thus allowing for earlier treatment intervention. Although there have been considerable efforts to identify such biomarkers, no clear choice for such noninvasive diagnostic tools has been identified. Micro-RNAs are small noncoding RNAs that have been evaluated intensively as biomarkers for several diseases, and they may hold promise for a diagnosis of endometriosis. In this review, we highlight the need for noninvasive testing for endometriosis, discuss the potential use of micro-RNAs as diagnostic tools for this disease, and consider potential limitations in the use of these small RNA molecules as diagnostic markers for endometriosis.

Estimating diagnostic accuracy of raters without a gold standard by exploiting a group of experts

In diagnostic medicine, estimating the diagnostic accuracy of a group of raters or medical tests relative to the gold standard is often the primary goal. When a gold standard is absent, latent class models where the unknown gold standard test is treated as a latent variable are often used. However, these models have been criticized in the literature from both a conceptual and a robustness perspective. As an alternative, we propose an approach where we exploit an imperfect reference standard with unknown diagnostic accuracy and conduct sensitivity analysis by varying this accuracy over scientifically reasonable ranges. In this article, a latent class model with crossed random effects is proposed for estimating the diagnostic accuracy of regional obstetrics and gynaecological (OB/GYN) physicians in diagnosing endometriosis. To avoid the pitfalls of models without a gold standard, we exploit the diagnostic results of a group of OB/GYN physicians with an international reputation for the diagnosis of endometriosis. We construct an ordinal reference standard based on the discordance among these international experts and propose a mechanism for conducting sensitivity analysis relative to the unknown diagnostic accuracy among them. A Monte Carlo EM algorithm is proposed for parameter estimation and a BIC-type model selection procedure is presented. Through simulations and data analysis we show that this new approach provides a useful alternative to traditional latent class modeling approaches used in this setting.

Endometriosis

Az endometriosis (ectopiás endometrium) szövettanilag benignus kórkép, de sok panaszt (meddőség, dysmenorrhoea, fájdalom) és súlyos szövődményeket okozhat. A nemi teljesség korában lévő nők megbetegedése, de ritka kivételként a menarche előtt is kialakul. Korábban feltételezett gyakoriságát (1-2%) a laparoszkópia alkalmazása óta 6-10%-ban adják meg. Keletkezésében közvetlen ráterjedés (például endometriosis interna, seu adenomyosis), retrográd menstruáció, embolizáció, metaplasia mellett immunológiai és genetikai folyamatok szerepét is bizonyították. Felismerésében a laparoszkópiának van fő szerepe, továbbá a képalkotó eljárásoknak és a fizikális vizsgálatnak. Kezelésében hormonális és műtéti megoldások mellett palliatív gyógymódokkal segíthetünk.

Sonorectovaginography: a new sonographic technique for imaging of the posterior compartment of the pelvis

OBJECTIVE

We describe the use of a new sonographic technique for imaging of the posterior compartment of the pelvis: sonorectovaginography.

METHODS

Sonorectovaginography uses instillation of fluids (saline solution and ultrasound gel) in the vagina, pouch of Douglas, and rectum for the purpose of creating acoustic interfaces between the vagina, cervix, rectum, and pouch of Douglas. We performed sonorectovaginography in a woman with chronic pelvic pain during laparoscopy. Urinary catheters were introduced into the rectum and vagina. Sterile saline solution was introduced into the abdominal cavity through a laparoscopic trocar and in the rectum via a rectal catheter. The transvaginal probe was then inserted, and sterile ultrasound gel was introduced into the vagina through the vaginal catheter under sonographic guidance.

RESULTS

Sonorectovaginography has helped us create acoustic interfaces and enhanced simultaneous visualization of the vaginal walls, posterior vaginal fornix, retrocervical area, rectovaginal septum, rectal wall, and pouch of Douglas.

CONCLUSIONS

Imaging of the posterior compartment of the pelvis is of paramount importance for identification of potentially difficult endometriosis cases, such as those complicated by obliteration of the pouch of Douglas or infiltration of the retrocervical area, rectovaginal septum, or vaginal or rectal wall. Sonorectovaginography may prove helpful in evaluating this compartment of the pelvis in women with suspected deep endometriosis. Its reproducibility, tolerability, and accuracy, however, need to be validated prospectively, and normative data for the rectovaginal septum also need to be established.

Serum cytokines as biomarkers for nonsurgical prediction of endometriosis

OBJECTIVE

To test the ability of a group of serum cytokines, either individually or in combination, to serve as biomarkers for the nonsurgical diagnosis of endometriosis.

STUDY DESIGN

Subjects were allocated to two groups according to their laparoscopic diagnosis. The first group consisted of patients with endometriosis and the second group was made up of infertile women with no pelvic pathology (controls). Blood samples were collected preoperatively and stored. Cytokines were measured in the serum of all participants using the Bio-Plex Protein Array System. Nonparametric statistics and the Mann-Whitney test were used to compare groups. Subjects were seen at the Gynecologic endoscopy unit.

RESULTS

Three cytokines were significantly higher in the serum of subjects with endometriosis than in the control group: interleukin-6 (IL-6) [4.41 pg/ml (range: 1.47-15.01) versus 0.97 pg/ml (range: 0.29-2.98), respectively; p<0.001], monocyte chemotactic protein-1 (MCP-1) [37.91 pg/ml (range: 24.54-94.74) versus 22.13 pg/ml (range: 13.85-39.45), respectively; p<0.001], and interferon-gamma (INF-gamma) [19.01 pg/ml (range: 1.19-73.52) versus 0.30 pg/ml (range: 0.00-13.05), respectively; p<0.001]. There was no statistically significant difference between subjects with endometriosis and controls in the serum concentration of vascular endothelial growth factor (VEGF), tumor necrosis factor-alpha (TNF-alpha), or granulocyte macrophage colony stimulating factor (GM-CSF). Interleukin-2 (IL-2), interleukin-8 (IL-8), and interleukin-15 (IL-15) were undetectable in the serum of both groups. None of the measured cytokines showed significant correlation with the cycle phase or stage of endometriosis. In a multivariate analysis, serum interleukin-6 provided a sensitivity of 71% and a specificity of 66% to discriminate between endometriosis patients and controls at a cutoff point of 1.9 pg/ml. Adding monocyte chemotactic protein-1 and interferon-gamma to interleukin-6 did not increase the discriminative ability over that achieved by measuring serum interleukin-6 alone.

CONCLUSIONS

Serum of subjects with endometriosis contains significantly higher levels of interleukin-6, monocyte chemotactic protein-1, and interferon-gamma than control women. Serum interleukin-6 measurements discriminate between women with endometriosis and controls. Interleukin-6 provides a promising serum marker for the nonsurgical prediction of endometriosis.

Defining endometrial cells: the need for improved identification at ectopic sites and characterization in eutopic sites for developing novel methods of management for endometriosis

Endometriosis is classically defined as ectopic growth of endometrial glands and stroma. Currently, histologic confirmation of laparoscopic findings is paramount for diagnosis of endometriosis and evidence is evolving suggesting that the pathogenesis of endometriosis is related to endometrial anomalies.

Diagnosis of pelvic endometriosis with use of macroscopic versus histologic findings

OBJECTIVE

To obtain histologic confirmation of lesions suspected of endometriosis at laparoscopy.

DESIGN

Prospective clinical study.

SETTING

Patients in an academic hospital.

PATIENT(S)

Women of reproductive age who complained of chronic pelvic pain.

INTERVENTION(S)

A total of 122 biopsies were obtained from 54 patients undergoing laparoscopy, after exclusion of other potential causes of pelvic pain.

MAIN OUTCOME MEASURE(S)

Lack of consistency between laparoscopic and histologic diagnosis of endometriosis, in particular for minimal/mild stages.

RESULTS

Endometriosis was confirmed by histology in 54% of the excised lesions. Diagnosis was more often confirmed among classic lesions than for all atypical lesions considered together. The histologic diagnosis of fibrosis was the most common among those biopsies, which lacked the presence of endometriosis. The revised American Fertility Association (AFS) scores before and after histologic confirmation differed significantly. In particular, 20 patients in either revised AFS class I or II were down-graded to stage 0. No single anatomical site turned out to be particularly prone to misdiagnosis at laparoscopy, in comparison to the other sites.

CONCLUSION(S)

These results confirm the need of histologic confirmation to obtain a diagnosis of endometriosis. However, the clinical impact of such findings remains a matter of debate.

Development of a nonsurgical diagnostic tool for endometriosis based on the detection of endometrial leukocyte subsets and serum CA-125 levels

OBJECTIVE

To determine whether the proportion of several leukocyte subsets is modulated in the endometrium of patients with endometriosis and, if yes, whether it can be used for diagnostic purposes.

DESIGN

Case-control study.

SETTING

Eight clinical institutions of the Montreal area.

PATIENT(S)

Women who underwent laparoscopy or laparotomy between 1997 and 2001, who had regular menstrual cycles and were not under hormone treatment for the previous 3 months were selected. This study included 368 women, 173 with surgically confirmed endometriosis and 195 controls with no surgical evidence of endometriosis.

INTERVENTIONS

MAIN OUTCOME MEASURE(S)

Cytometry analysis was used to measure the proportion of several leukocyte subsets among CD45(+) endometrial cells.

RESULT(S)

The proportion of CD3(+), CD16(+), CD3(-)HLADR(-), CD3(-)CD45RA(-), CD3(+)CD16(-), CD3(+)CD56(-), CD56(-)CD16(+), and CD16b(+) leukocytes was significantly altered in the endometrium of cases compared with controls. A multiple logistic regression model was adjusted with these endometrial leukocytes, serum CA-125 levels, risk factors, and confounders. The diagnostic performance of this predictive model was defined by a specificity of 95% and a sensitivity of 61%. Furthermore, the positive and negative predictive values were 91% and 75%, respectively.

CONCLUSION(S)

This predictive model represents a novel diagnostic tool to identify women with a high likelihood of suffering from endometriosis.