Increased risk for ovarian cancer and borderline ovarian tumours in subfertile women with endometriosis

Endometriosis-Associated Ovarian Cancer: From Molecular Pathologies to Clinical Relevance

Endometriosis is a chronic condition affecting reproductive-aged women, characterized by the growth of ectopic endometrial tissue. Despite being benign, endometriosis is associated with an increased risk of certain cancers, including endometriosis-associated ovarian cancer (EAOC). Ovarian cancer is rare, but more common in women with endometriosis, particularly endometrioid and clear-cell carcinomas. Factors such as hormonal imbalance, reproductive history, environmental exposures, and genetic predisposition contribute to the malignant transformation of endometriosis. Thus, understanding potential risk factors causing malignancy is crucial. Over the past few decades, various genetic mutations, microRNAs, as well as tumor microenvironmental factors have been identified, impacting pathways like PI3K/AKT/mTOR, DNA repair mechanisms, oxidative stress, and inflammation. Thus, this review aims to summarize molecular studies involved in EAOC pathogenesis as potential therapeutic targets. However, further research is needed to better understand the molecular and environmental factors driving EAOC development, to target the susceptibility of endometriotic lesions to malignant progression, and to identify effective therapeutic strategies.

Ovarian Cancer: From Precursor Lesion Identification to Population-Based Prevention Programs

Epithelial ovarian cancer (EOC) is a heterogeneous group of malignancies, including high-grade serous ovarian cancer (HGSC). HGSC is often diagnosed at advanced stages and is linked to TP53 variants. While BRCA variants elevate risk, most HGSC cases occur in individuals without known genetic variants, necessitating prevention strategies for people without known high-risk genetic variants. Effective prevention programs are also needed due to the lack of traditional screening options. An emerging primary prevention strategy is opportunistic salpingectomy, which involves removing fallopian tubes during another planned pelvic surgery. Opportunistic salpingectomy offers a safe and cost-effective preventative option that is gaining global adoption. With the publication of the first cohort study of patients who underwent salpingectomy, specifically for cancer prevention, attention has turned to broadening opportunities for salpingectomy in addition to more targeted approaches. Prevention opportunities are promising with increasing adoption of salpingectomy and the increased understanding of the etiology of the distinct histotypes of ovarian cancer. Yet, further research on targeted risk-reducing salpingectomy with thoughtful consideration of equity is necessary to reduce death and suffering from ovarian cancer.

Insights from Mendelian randomization and genetic correlation analyses into the relationship between endometriosis and its comorbidities

BACKGROUND

Endometriosis remains a poorly understood disease, despite its high prevalence and debilitating symptoms. The overlap in symptoms and the increased risk of multiple other traits in women with endometriosis is becoming increasingly apparent through epidemiological data. Genetic studies offer a method of investigating these comorbid relationships through the assessment of causal relationships with Mendelian randomization (MR), as well as identification of shared genetic variants and genes involved across traits. This has the capacity to identify risk factors for endometriosis as well as provide insight into the aetiology of disease.

OBJECTIVE AND RATIONALE

We aim to review the current literature assessing the relationship between endometriosis and other traits using genomic data, primarily through the methods of MR and genetic correlation. We critically examine the limitations of these studies in accordance with the assumptions of the utilized methods.

SEARCH METHODS

The PubMed database was used to search for peer-reviewed original research articles using the terms 'Mendelian randomization endometriosis' and '"genetic correlation" endometriosis'. Additionally, a Google Scholar search using the terms '"endometriosis" "mendelian randomization" "genetic correlation"' was performed. All relevant publications (n = 21) published up until 7 October 2022 were included in this review. Upon compilation of all traits with published MR and/or genetic correlation with endometriosis, additional epidemiological and genetic information on their comorbidity with endometriosis was sourced by searching for the trait in conjunction with 'endometriosis' on Google Scholar.

OUTCOMES

The association between endometriosis and multiple pain, gynaecological, cancer, inflammatory, gastrointestinal, psychological, and anthropometric traits has been assessed using MR analysis and genetic correlation analysis. Genetic correlation analyses provide evidence that genetic factors contributing to endometriosis are shared with multiple traits: migraine, uterine fibroids, subtypes of ovarian cancer, melanoma, asthma, gastro-oesophageal reflux disease, gastritis/duodenitis, and depression, suggesting the involvement of multiple biological mechanisms in endometriosis. The assessment of causality with MR has revealed several potential causes (e.g. depression) and outcomes (e.g. ovarian cancer and uterine fibroids) of a genetic predisposition to endometriosis; however, interpretation of these results requires consideration of potential violations of the MR assumptions.

WIDER IMPLICATIONS

Genomic studies have demonstrated that there is a molecular basis for the co-occurrence of endometriosis with other traits. Dissection of this overlap has identified shared genes and pathways, which provide insight into the biology of endometriosis. Thoughtful MR studies are necessary to ascertain causality of the comorbidities of endometriosis. Given the significant diagnostic delay of endometriosis of 7-11 years, determining risk factors is necessary to aid diagnosis and reduce the disease burden. Identification of traits for which endometriosis is a risk factor is important for holistic treatment and counselling of the patient. The use of genomic data to disentangle the overlap of endometriosis with other traits has provided insights into the aetiology of endometriosis.

Effects of Infertility Drug Exposure on the Risk of Borderline Ovarian Tumors: A Systematic Review and Meta-Analysis

Whether infertility drug exposure increases the risk of borderline ovarian tumors (BOTs) remains controversial. The present study was conducted with a comprehensive search for studies published from January 1990 to December 2021 in the online databases Cochrane Library, PubMed, Web of Science and EMBASE. We considered the first diagnosis of a BOT as the primary outcome. The odds ratio (OR) was calculated with corresponding 95% confidence intervals (CIs) for the risk of BOTs in patients who were treated with infertility drugs. Ten studies, a total of 2,779,511 women, qualified for inclusion in this meta-analysis. The pooled OR of 1.56 (95% CI: 1.09-2.22) revealed a significant positive association between infertility drugs and an increased risk for BOTs, but for specific drugs, only CC plus Gn had statistical significance. No publication bias was detected using the Egger and Begg tests (p > 0.05). A significant difference in BOT incidence was observed among infertile women and nulliparous women who were treated with or without infertility drugs. In conclusion, the use of infertility drugs may increase the risk of BOTs, but a dose-dependent relationship was not observed between the number of assisted reproduction technology cycles and the risk of BOTs, and infertile women who successfully became pregnant might have a reduced risk. Registration: PROSPERO, CRD42022330775.

Ovulation induction drug and ovarian cancer: an updated systematic review and meta-analysis

OBJECTIVE

To explore the association between ovulation induction drugs and ovarian cancer.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Women without ovarian cancer who ever or never underwent ovarian induction.

INTERVENTION(S)

An extensive electronic search of the following databases was performed: PubMed, EMBASE, MEDLINE, Google Scholar, Cochrane Library and CNKI, from inception until January 2022. A total of 34 studies fulfilled our inclusion criteria and were included in the final meta-analysis. The odds ratio (OR) and random-effects model were used to estimate the pooled effects. The Newcastle-Ottawa Scale was used to assess the quality of included studies. Funnel plots and Egger tests were used to assess publication bias.

MAIN OUTCOMES

New diagnosed borderline ovarian tumor (BOT) and invasive ovarian cancer (IOC) between ovulation induction (OI) group and control (CT) group considering fertility outcome, OI cycles and specific OI drugs.

RESULTS

Primarily, there was no significant difference in the incidence of IOC and BOT between the OI and CT groups. Secondly, OI treatment did not increase the risk of IOC and BOT in the multiparous women, nor did it increase the risk of IOC in the nulliparous women. However, the risk of BOT appeared to be higher in nulliparous women treated with OI treatment. Thirdly, among women exposed to OI, the risk of IOC and BOT was higher in nulliparous women than in multiparous women. Fourthly, the risk of IOC did not increase with increasing OI cycles. Lastly, exposure to specific OI drugs also did not contribute to the risk of IOC and BOT.

CONCLUSION

Overall, OI treatment did not increase the risk of IOC and BOT in most women, regardless of OI drug type and OI cycle. However, nulliparous women treated with OI showed a higher risk of ovarian cancer, necessitating their rigorous monitoring and ongoing follow-up.

Endometriosis-Associated Ovarian Cancer: What Are the Implications for Women with Intact Endometrioma Planning for a Future Pregnancy? A Reproductive Clinical Outlook

Endometriosis is a chronic, universal, and prevalent disease estimated to affect up to 1:10 women of reproductive age. Endometriosis-associated ovarian cancer (EAOC) developing at reproductive age is challenging and of concern for women and practitioners alike. This outlook review focuses on the occurrence of EAOC, especially in infertile women or those planning for a future pregnancy, from the perspective of a reproductive endocrinologist, based on recent evidence. Contemporary pathogenesis, genetic profiles, evidence of causality, clinical diagnosis, prognosis, and up-to-date management are discussed. EAOC seems to be merely associated with endometrioma and includes clear-cell and endometrioid ovarian carcinoma. Although endometrioma is frequently found in women of reproductive age (up to 1:18 of women), EAOC appears to be a rare occurrence. These women are of more advanced reproductive age, nulliparous, and hyperestrogenic, with a large-sized unilateral endometrioma (>9 cm) containing solid components and papillary projections. Each case suspected to have EAOC has specific characteristics, and a multidisciplinary discussion and appropriate patient counseling should be conducted to reach an optimal therapeutic plan. Since most of these cases are diagnosed at an early stage with a favorable prognosis, fertility-sparing surgery may be feasible. The pros and cons of fertility preservation techniques should be discussed.

A multi-level investigation of the genetic relationship between endometriosis and ovarian cancer histotypes

Endometriosis is associated with increased risk of epithelial ovarian cancers (EOCs). Using data from large endometriosis and EOC genome-wide association meta-analyses, we estimate the genetic correlation and evaluate the causal relationship between genetic liability to endometriosis and EOC histotypes, and identify shared susceptibility loci. We estimate a significant genetic correlation (r_g) between endometriosis and clear cell (r_g = 0.71), endometrioid (r_g = 0.48), and high-grade serous (r_g = 0.19) ovarian cancer, associations supported by Mendelian randomization analyses. Bivariate meta-analysis identified 28 loci associated with both endometriosis and EOC, including 19 with evidence for a shared underlying association signal. Differences in the shared risk suggest different underlying pathways may contribute to the relationship between endometriosis and the different histotypes. Functional annotation using transcriptomic and epigenomic profiles of relevant tissues/cells highlights several target genes. This comprehensive analysis reveals profound genetic overlap between endometriosis and EOC histotypes with valuable genomic targets for understanding the biological mechanisms linking the diseases.

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Endometriosis is genetically correlated with CCOC, ENOC, and HGSOC

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Genetic liability to endometriosis confers risk of these EOC histotypes

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Profound colocalization of genetic associations at endometriosis and EOC risk loci

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Functional annotation highlights shared target genes elucidating the genetic link

Accuracy of MRI Pelvis in the Diagnosis of Ovarian Endometrioma: Using Histopathology as Gold Standard

Background

Endometriosis is defined as the ectopic presence of endometrial mucosa at locations other than the uterine cavity. It results in significant morbidity and is a leading cause of infertility as well. Magnetic resonance imaging (MRI) is establishing its role in the diagnosis of endometriosis and its complications. The objective of this study was to assess the accuracy of MRI in the diagnosis of ovarian endometriosis using histopathology as the gold standard.

Materials and methods

All patients presenting with clinical complaints and suspicion of endometriosis, undergoing MRI followed by surgical resection and confirmation by histopathology, were included in the study. Data were analyzed on a predefined proforma and parameters of accuracy were calculated.

Results 

A total of 170 patients were included in this study, having a mean age of 36.8 years with a standard deviation of 10.4 years. The mean parity for included subjects was 2.25, with a standard deviation of 1.3. Overall, the sensitivity of MRI was 86.7% and the specificity was 81.9%. The positive predictive value (PPV) of MRI was 83.3%, while the negative predictive value (NPV) was 81.9%. Overall, the diagnostic accuracy of MRI was 84.7%.

Conclusion

The accuracy of MRI in the diagnosis of endometriosis was found to be acceptable and comparable to most of the worldwide published literature. The routine use of MRI for diagnosis and preoperative planning is justified by the results of this study.

Endometriosis and gynaecological cancers: molecular insights behind a complex machinery

Endometriosis is described as the presence of both endometrial glandular and stromal cells outside the uterine cavity. A major characterization of this disease is ectopic implantation of endometrial cells with increased migration. It is one of the leading causes of morbidity among premenopausal women, with a prevalence of 10-16% of women of reproductive age. Despite over century of intensive research, none of the current treatment options represents a real cure. Based on the current knowledge, endometriosis, particularly its atypical version, is considered to be a transitional form from benign disease to tumour. However, the exact mechanisms of this conversion are still not fully established.

Infiltrating T lymphocytes and programmed cell death protein-1/programmed death-ligand 1 expression in endometriosis-associated ovarian cancer

OBJECTIVE

To characterize T lymphocyte infiltration and programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) expression in early-stage endometriosis-associated ovarian cancer (EAOC), ovarian endometriosis (OE), atypical endometriosis (AE), and deep endometriosis (DE).

DESIGN

Case-control, retrospective study.

SETTING

Research University Hospital.

PATIENT(S)

A total of 362 patients with a histologic diagnosis of EAOC, OE, AE, or DE were identified between 2000 and 2019 from Fondazione Policlinico Universitario Agostino Gemelli IRCCS and Gemelli Molise SpA tissue data banks. A 1:1 propensity score-matched method yielded matched pairs of 55 subjects with EAOC, 55 patients with OE, 12 patients with AE, and 42 patients with DE, resulting in no differences in family history of cancer, parity, and use of oral contraceptives.

INTERVENTION(S)

Immunohistochemistry assays using the following primary antibodies: CD3+; CD4+; CD8+; PD-1; and PD-L1.

MAIN OUTCOME MEASURE(S)

To characterize T lymphocyte infiltration and PD-1/PD-L1 expression in 4 different endometriosis-related diseases.

RESULT(S)

Endometriosis-associated ovarian cancer cases displayed significantly higher levels of PD-1/PD-L1 expression compared with all other endometriosis-related diseases (vs. OE vs. AE vs. DE). Moreover, a significantly lower count of infiltrating T lymphocytes was observed in EAOC cases compared with OE ones. Finally, one-third of OE cases showed a cancer-like PD-1/PD-L1 expression profile.

CONCLUSION(S)

Endometriosis-associated ovarian cancer is characterized by higher levels of PD-1/PD-L1 expression compared with benign endometriosis-related diseases. This profile was found in one-third of clinically benign cases, suggesting that it develops early in the carcinogenesis process.

The relation between endometrioma and ovarian cancer

INTRODUCTION

The relationship between endometrioma and ovarian cancer is a topic of discussion in the field of endometriosis and to date it is still debated whether ovarian endometriosis may represent a risk factor for ovarian cancers.

EVIDENCE ACQUISITION

A literature search was carried out using Cochrane Library, EMBASE, Medline and Google Scholar up to October 2020. Primary outcome of interest was ovarian cancer incidence in patients with endometriosis. Secondary outcome was ovarian cancer prognosis in patients with endometriosis compared to patient without endometriosis.

EVIDENCE SYNTHESIS

Patients with ovarian endometriosis has a slight increase risk of developing ovarian cancer (merely 1.8%), being the general population risk for ovarian cancer 1.31%. In patient at postmenopausal age, long-lasting endometriosis, early-age diagnosis, infertility and/or infertility treatment the risk of developing ovarian cancer is higher. Endometriosis-related ovarian cancers are generally clear cell and endometrioid and are diagnosed at early stage compared to non-endometriosis related ovarian cancer.

CONCLUSIONS

The lifetime risk for ovarian cancer is low in endometriosis patients in general and higher in subgroups of patients allowing a tailored management based on patient characteristics. Endometriosis is a chronic disease negatively affecting the quality of life, nonetheless, concerns on ovarian cancer should be avoided in order to reduce the burden of the disease on women's health.

Fertility treatment and cancers-the eternal conundrum: a systematic review and meta-analysis

STUDY QUESTION

Does fertility treatment (FT) significantly increase the incidence of breast, ovarian, endometrial or cervical cancer?

SUMMARY ANSWER

Overall, FT does not significantly increase the incidence of breast, ovarian or endometrial cancer and may even reduce the incidence of cervical cancer.

WHAT IS KNOWN ALREADY

Infertility affects more than 14% of couples. Infertility and nulliparity are established risk factors for endometrial, ovarian and breast cancer, yet the association with FT is more contentious.

STUDY DESIGN, SIZE, DURATION

A literature search was carried out using Cochrane Library, EMBASE, Medline and Google Scholar up to December 2019. Peer-reviewed studies stating cancer incidence (breast, ovarian, endometrial or cervical) in FT and no-FT groups were identified. Out of 128 studies identified, 29 retrospective studies fulfilled the criteria and were included (n = 21 070 337).

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the final meta-analysis, 29 studies were included: breast (n = 19), ovarian (n = 19), endometrial (n = 15) and cervical (n = 13), 17 studies involved multiple cancer types and so were included in each individual cancer meta-analysis. Primary outcome of interest was cancer incidence (breast, ovarian, endometrial and cervical) in FT and no-FT groups. Secondary outcome was cancer incidence according to specific fertility drug exposure. Odds ratio (OR) and random effects model were used to demonstrate treatment effect and calculate pooled treatment effect, respectively. A meta-regression and eight sub-group analyses were performed to assess the impact of the following variables, maternal age, infertility, study size, outliers and specific FT sub-types, on cancer incidence.

MAIN RESULTS AND THE ROLE OF CHANCE

Cervical cancer incidence was significantly lower in the FT group compared with the no-FT group: OR 0.68 (95% CI 0.46-0.99). The incidences of breast (OR 0.86; 95% CI 0.73-1.01) and endometrial (OR 1.28; 95% CI 0.92-1.79) cancers were not found to be significantly different between the FT and no-FT groups. Whilst overall ovarian cancer incidence was not significantly different between the FT and no-FT groups (OR 1.19; 95% CI 0.98-1.46), separate analysis of borderline ovarian tumours (BOT) revealed a significant association (OR 1.69; 95% CI 1.27-2.25). In further sub-group analyses, ovarian cancer incidence was shown to be significantly higher in the IVF (OR 1.32; 95% CI 1.03-1.69) and clomiphene citrate (CC) treatment group (OR 1.40; 95% CI 1.10-1.77), respectively when compared with the no-FT group. Conversely, the incidences of breast (OR 0.75; 95% CI 0.61-0.92) and cervical cancer (OR 0.58; 95% CI 0.38-0.89) were significantly lower in the IVF treatment sub-group compared to the no-FT group.

LIMITATIONS, REASONS FOR CAUTION

The large, varied dataset spanning a wide study period introduced significant clinical heterogeneity. Thus, results have to be interpreted with an element of caution. Exclusion of non-English citations, unpublished work and abstracts, in order to ensure data accuracy and reliability was maintained, may have introduced a degree of selection bias.

WIDER IMPLICATIONS OF THE FINDINGS

The results for breast, ovarian, endometrial and cervical cancer are reassuring, in line with previously published meta-analyses for individual cancers but the association between IVF and CC treatment and an increase in ovarian cancer incidence requires additional work to understand the potential mechanism driving this association. In particular, focusing on (i) discriminating specific treatments effects from an inherent risk of malignancy; (ii) differential risk profiles among specific patient sub-groups (refractory treatment and obesity); and (iii) understanding the impact of FT outcomes on cancer incidence.

STUDY FUNDING/COMPETING INTEREST(S)

This study did not receive any funding. The authors have no financial, personal, intellectual and professional conflicts of interest to declare.

PROSPERO REGISTRATION NUMBER

CRD42019153404.

Ovarian cancer prognosis in women with endometriosis: a retrospective nationwide cohort study of 32,419 women

BACKGROUND

Contradicting results regarding ovarian cancer prognosis in women with endometriosis have been reported in the literature. Owing to the small sample size of previous studies, larger studies are required to elucidate the role of endometriosis in ovarian cancer prognosis.

OBJECTIVE

This study aimed to evaluate the survival rate in women with ovarian cancer with or without histologically proven endometriosis in a Dutch population-based cohort.

STUDY DESIGN

All women with ovarian cancer diagnosed between 1990 and 2015 were identified from the Netherlands Cancer Registry. We linked these women with the Dutch nationwide registry of histopathology and cytopathology (Pathologisch-Anatomisch Landelijk Geautomatiseerd Archief) to identify all women with histologically proven endometriosis. We compared the prognosis of patients with ovarian cancer with and without histologically proven endometriosis. Primary outcome was the overall survival with subgroup analyses stratified by histologic ovarian cancer subtype and stage. Multivariable Cox proportional hazard analysis was used to estimate hazard ratios with 95% confidence intervals.

RESULTS

We included 32,419 patients with ovarian cancer, of whom 1979 (6.1%) had histologically proven endometriosis. The median age of histologic endometriosis diagnosis was 53 years (interquartile range, 46-62). Of all women with ovarian cancer and endometriosis, 81.2% received a diagnosis of synchronous endometriosis and ovarian cancer. The endometriosis cohort was younger at ovarian cancer diagnosis, had more favorable tumor characteristics, and more often had surgical treatment for ovarian cancer than the women without endometriosis. These variables were included in the multivariable model as confounders. Women with histologically proven endometriosis had a significantly better prognosis in both crude and adjusted analyses (hazard ratio, 0.46; 95% confidence interval, 0.43-0.49; P<.0005, and adjusted hazard ratio, 0.89; 95% confidence interval, 0.83-0.95; P<.05, respectively).

CONCLUSION

Women with ovarian cancer and histologically proven endometriosis had longer overall survival than women with ovarian cancer without endometriosis, even after adjustment for confounders. Future studies on ovarian cancer treatment and prognosis should consider stratifying by endometriosis status to elucidate its role. Furthermore, women diagnosed as having ovarian cancer and concurrent endometriosis should be explained the role of endometriosis in ovarian cancer survival.

Endometriosis and cancer: a systematic review and meta-analysis

BACKGROUND

Endometriosis is an often chronic, inflammatory gynaecologic condition affecting 190 million women worldwide. Studies have reported an elevated cancer risk among patients with endometriosis. However, prior research has included methodologic issues that impede valid and robust interpretation.

OBJECTIVE AND RATIONALE

We conducted a meta-analysis of studies investigating the association between endometriosis and cancer risk and analysed the results by methodologic characteristics. We discuss the implications of cancer screening in patients and management challenges faced by clinicians.

SEARCH METHODS

We searched PubMed and Embase databases for eligible studies from inception through 24 October 2019. We included cohort and case-control studies examining the association between endometriosis and cancer risk; cross-sectional studies and case reports were excluded. Publications had to present risk/rate/odds estimates with 95% CI. Random effects meta-analysis was used to estimate summary relative risks (SRR) and CIs. Heterogeneity across studies was assessed by the Q test and I2 statistics, and publication bias using Egger's and Begg's tests. Risk of bias and quality of the included studies were assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) tool.

OUTCOMES

Forty-nine population-based case-control and cohort studies were included. Twenty-six studies were scored as having a 'serious'/'critical' risk of bias, and the remaining 23 'low'/'moderate'. Cancer-specific analyses showed a positive association between endometriosis and ovarian cancer risk (SRR = 1.93, 95% CI = 1.68-2.22; n = 24 studies) that was strongest for clear cell (SRR = 3.44, 95% CI = 2.82-4.42; n = 5 studies) and endometrioid (SRR = 2.33, 95% CI = 1.82-2.98; n = 5 studies) histotypes (Pheterogeneity < 0.0001), although with significant evidence of both heterogeneity across studies and publication bias (Egger's and Begg's P-values < 0.01). A robust association was observed between endometriosis and thyroid cancer (SRR = 1.39, 95% CI =1.24-1.57; n = 5 studies), a very small association with breast cancer (SRR = 1.04, 95% CI =1.00-1.09; n = 20 studies) and no association with colorectal cancer (SRR = 1.00, 95% CI =0.87-1.16; n = 5 studies). The association with endometrial cancer was not statistically significant (SRR = 1.23, 95% CI =0.97-1.57; n = 17 studies) overall and wholly null when restricted to prospective cohort studies (SRR = 0.99, 95% CI =0.72-1.37; n = 5 studies). The association with cutaneous melanoma was also non-significant (SRR = 1.17, 95% CI =0.97-1.41; n = 7 studies) but increased in magnitude and was statistically significant when restricted to studies with low/moderate risk of bias (SRR = 1.71, 95% CI = 1.24-2.36, n = 2 studies). The most robust finding both in terms of statistical significance and magnitude of effect was an inverse association with cervical cancer (SRR = 0.68, 95% CI =0.56-0.82; n = 4 studies); however, this result has a high potential to reflect heightened access to detection of dysplasia for women who reached an endometriosis diagnosis and is thus likely not causal. Several additional cancer types were explored based on <4 studies.

WIDER IMPLICATIONS

Endometriosis was associated with a higher risk of ovarian and thyroid, and minimally (only 4% greater risk) with breast cancer, and with a lower risk of cervical cancer. However, this meta-analysis confirms that: a majority of studies had severe/critical risk of bias; there is impactful heterogeneity across studies-and for ovarian cancer, publication bias; and causal inference requires temporality, which in many studies was not considered. We discuss the implications of these potential associations from the perspectives of patients with endometriosis, clinicians involved in their care, and scientists investigating their long-term health risks.

Incidence of endometrioid and clear-cell ovarian cancer in histological proven endometriosis: the ENOCA population-based cohort study

BACKGROUND

Several studies have suggested that endometriosis is associated with an increased risk of ovarian cancer, especially for the clear-cell and endometrioid subtypes. However, previous studies lack sufficient power or diagnostic certainty.

OBJECTIVE

The objective of the study was to assess the association between histologically proven endometriosis and ovarian cancer in a large population-based cohort study.

STUDY DESIGN

We identified 131,450 women with a histological diagnosis of endometriosis between 1990 and 2015 from the Dutch nationwide registry of histopathology and cytopathology (PALGA). For the control cohort 132,654 women with a benign dermal nevus were matched on age and inclusion year with the endometriosis cases. Histological diagnoses of ovarian, fallopian tubes, and peritoneal cancers between January 1990 and July 2017 were retrieved. Incidence rate ratios were estimated for ovarian cancer and its subtypes for the whole follow-up period as well as for women with more than 1 person-year at risk.

RESULTS

We found a crude incidence rate ratio of 4.79 (95% confidence interval, 4.33-5.31) and an age-adjusted incidence rate ratio of 7.18 (95% confidence interval, 6.17-8.36) for ovarian cancer overall. Endometrioid and clear-cell ovarian cancer had the highest age-adjusted incidence rate ratio of 29.06 (95% confidence interval, 20.66-40.87) and 21.34 (95% confidence interval, 14.01-32.51), respectively. Median age at ovarian cancer diagnosis was 56 years (interquartile range, 49-63) for the endometriosis cohort and 60 years (interquartile range, 53-67) for the nevus cohort, (P < .05). After excluding women with less than 1 person-year at risk following an endometriosis diagnosis, we found a crude incidence rate ratio of 1.04 (95% confidence interval, 0.91-1.19) and an age-adjusted incidence rate ratio of 1.08 (95% confidence interval, 0.87-1.35) for ovarian cancer overall. However, statistically significant age-adjusted incidence rate ratios of 2.29 (95% confidence interval, 1.24-4.20) for clear-cell ovarian cancer and 2.56 (95% confidence interval, 1.47-4.47) for endometrioid ovarian cancer were found.

CONCLUSION

A significantly higher incidence of clear-cell and endometrioid ovarian cancer was found in women with histologically proven endometriosis. Additionally, we found an increased incidence of all ovarian cancer subtypes in histologically proven endometriosis; however, in many of these women, endometriosis and ovarian cancer were diagnosed synchronously after the average menopausal age, which may suggest that the risk of ovarian cancer in endometriosis patients remains, even when clinical endometriosis symptoms are no longer present.

Subsequent Development of Epithelial Ovarian Cancer After Ovarian Surgery for Benign Ovarian Tumor: A Population-Based Cohort Study

Purpose

The goal of the current study is to determine the risk of subsequent development of epithelial ovarian cancer (EOC) in women after ovarian surgery for benign ovarian tumors.

Patients and Methods

We conducted the nationwide population-based historic cohort study using the National Health Insurance Research Database (NHIRD) of Taiwan. Eleven thousand six hundred twenty women who underwent ovarian surgery for ovarian benign diseases were analyzed. The collected data included age, types of ovarian surgery, medical history by Charlson comorbidity index (CCI), infertility (yes/no), pelvic inflammatory disease (PID) (yes/no), tubal ligation (yes/no), total/subtotal hysterectomy (TH/STH) (yes/no), and endometrioma (yes/no). We used the Kaplan-Meier method and the Log-rank test to evaluate the risk factors. Cox proportional hazard methods were used to evaluate risk factors for the subsequent development of EOC. Multivariate analysis using Cox stepwise forward regression was conducted for the covariate selected in univariate analysis. Hazard ratio (HR) and 95% confidence interval (CI) were calculated using the Wald test.

Results

Subsequent EOC incidence rate (IR, incidence per 10,000 person-years) of women after ovarian surgery for benign ovarian tumors was 2.98. Separating into four groups based on different age, IR of EOC was 1.57 (<30 years), 4.71 (30-39 years), 3.59 (40-49 years) and 0.94 (≥50 years), respectively. Univariate and multivariate analyses identified only high level of CCI (≥2 or more) as an independent risk factor for subsequent development of EOC in women after ovarian surgery for benign ovarian tumors (HR 59.17, 95% CI 7.50-466.80 in women with CCI level of 2 and HR 190.68, 95% CI 24.33-2494.19, in women with CCI level ≥3, respectively).

Conclusion

Our results, if confirmed, suggest that women with other comorbidities (CCI) should be well informed that they may have a higher risk of subsequent development of EOC when ovarian surgery is planned even though the final pathology showed a benign ovarian tumor.

Increased association of ovarian cancer in women with histological proven endosalpingiosis

BACKGROUND

Few studies have investigated the possible association between endosalpingiosis and ovarian cancer, therefore we assessed whether there is an association between histological confirmed endosalpingiosis and ovarian cancer.

METHODS

We identified all women with a histological diagnosis of endosalpingiosis between 1990 and 2015 from the Dutch nationwide registry of histopathology and cytopathology (PALGA). We used women with a benign dermal nevus as controls. Histology results for cancer of the ovaries, fallopian tubes and peritoneum between January 1990 and July 2017 were retrieved. Incidence rate ratios (IRR) were estimated for ovarian cancer and its subtypes.

RESULTS

We found 2490 women with a histological diagnosis of endosalpingiosis, of which 1005 women 40.4 %) had concurrent endometriosis. The age-adjusted IRR for ovarian cancer in endosalpingiosis patients (including endometriosis) was 43.7 (95 %CI 35.1-54.3). Excluding cases with concurrent endometriosis, resulted in an age-adjusted IRR of 38.8 (95 %CI 29.3-50.4). IRRs were 2.4 (95 %CI 1.4-3.9) and 1.8 (95 %CI 0.8-4.0) respectively when excluding synchronously diagnosed cases. The increased IRRs seem to be caused by an increased risk of clear cell and endometrioid ovarian cancer subtypes.

CONCLUSIONS

This study shows an association between histological diagnosed endosalpingiosis and ovarian cancer. The association with endometrioid and clear cell subtypes seems most outspoken. Additionally, this study shows that this association is independent of histological endometriosis diagnosis, making it important for pathologists to report endosalpingiosis accurately and for gynaecologists to be more aware of the increased association of ovarian cancer in women with endosalpingiosis.

Association between endometriosis and gynecological cancers: a critical review of the literature

BACKGROUND

Endometriosis is one of the most common benign gynecological diseases with an occurrence approximately 10% in reproductive age. Endometriosis has been proposed as a possible precursor of certain ovarian carcinomas such as clear cell and endometrioid ovarian carcinomas. In addition to this pathogenic link, the association with other gynecological tumors and breast cancer has been studied on an epidemiological basis in several studies.

OBJECTIVE

The aim of this review was to critically present the recent published evidence on the association of endometriosis with gynecological cancer, and with a special emphasis on ovarian cancer.

MATERIALS AND METHODS

A search for eligible studies was conducted in three electronic databases, MEDLINE, EMBASE and CINAHL, for original research in humans published in any language.

RESULTS

The present review includes studies examining the association between endometriosis and different types of gynecological cancer (i.e., 25 studies on ovarian cancer, 8 studies on breast cancer, 8 studies on endometrial cancer and 2 studies on cervical cancer).

CONCLUSION

The present literature supports the pre-existing evidence suggesting an association between ovarian cancer and endometriosis and specifically its two histologic subtypes (endometrioid and ovarian clear cell cancer). The most recent population-based epidemiological studies cannot provide a clear association between endometriosis and endometrial, cervical or breast cancer.

[Borderline Ovarian Tumours: CNGOF Guidelines for Clinical Practice - Epidemiological Aspects and Risk Factors]

The incidence (rate/100,000) of BOT gradually increases with age from 15-19 years of age and peaks at nearly 4.5 cases/100,000 for the 55-59 year age group (NP3). In the presence of a benign ovarian mass, the standardized risk ratio of serous and mucinous BOT is 1.69, (95% CI 1.39-2.03) and 1.75, (95% CI 1.45-2.10), respectively (NP2). At diagnosis, a median age of diagnosis of OFA is 46 years, unilateral forms (79.7% of cases) are predominant compared to cancers (45.3%) (<0.001) and FIGO I stages represent nearly 63.7% of cases (NP3). The 5-year survival rates for FIGO I, II, III, IV stages are: 99.7% (95% CI: 96.2-100%), 99.6% (95% CI: 92.6-100%), 95.3% (95% CI: 91.8-97.4%), 77.1% (95% CI: 58.0-88.3%), respectively (NP3). Survivors at 5 years for serous and mucinous tumours are 99.7% (95% CI: 99.2-99.9%), 98.5% (95% CI: 96.9-99.3%), respectively (NP3). An epidemiological association exists between personal BOT risk and: (1) a familial history of BOT/certain cancers (pancreas, lung, bone, leukemia) (NP3), (2) a personal history of benign ovarian cyst (NP2), (3) a personal history of pelvic inflammatory disease (IGH), (4) the use of intrauterine device levonorgestrel (NP3), (5) the use of oral contraceptive pills (NP3), (6) multiparity (NP3), (7) hormone replacement therapy (NP3), (8) high consumption of coumestrol (NP4), (9) medical treatment of infertility with progesterone (NP3), (10) non-steroidal anti-inflammatory drug (NSAID). An epidemiological association exists between previous/actual tabacco consumption and the risk of mucinous ovarian BOT (NP2). Relative risk (RR) varies between 2.2 and 2.7, however the relationship is not necessarily a causal one. An epidemiological association exists between overweight/obesity and the risk of serous BOT (NP2). RR varies between 1.2 to 1.8. The high Vitamin D was inversely associated to the risk of serous BOT (NP4). The risk of mucinous BOT was lowered with paracetamol use (OR=0.77; 95% CI: 0.60-0.98) (NP3). However, the relationship between these factors and BOT is not necessarily a causal one and no screening modality can be proposed in the general population (gradeC).

Assisted reproductive technology and risk of ovarian cancer and borderline tumors in parous women: a population-based cohort study

The study aimed to investigate if assisted reproductive technology (ART) treatment or a diagnosis of infertility were associated with the risk of ovarian cancer or borderline ovarian tumors (BOT) in parous women. In a population-based register study of 1,340,097 women with a first live birth in Sweden 1982–2012, the relationship between ART treatments, infertility and incidence of ovarian cancer or BOT were investigated using Cox regression analysis. In the cohort, 38,025 women gave birth following ART, 49,208 following an infertility diagnosis but no ART and 1,252,864 without infertility diagnosis or ART. During follow-up, 991 women were diagnosed with ovarian cancer and 747 with BOT. Women who gave birth following ART had higher incidence of both ovarian cancer (adjusted hazard ratio [aHR] 2.43, 95% confidence interval [CI] 1.73–3.42) and BOT (aHR 1.91, 95% CI 1.27–2.86), compared to women without infertility. Compared to women with infertility diagnoses and non-ART births, women with ART births also had a higher incidence of ovarian cancer (aHR 1.79, 95% CI 1.18–2.71) and BOT (aHR 1.48, 95% CI 0.90–2.44). Our results suggest that women who have gone through ART have a higher risk of ovarian cancer and BOT. At least part of that risk seems to be due to the underlying infertility and not the treatment per se, since the increased risk was smaller when comparing to other infertile women. As ART treatments are becoming more common and ovarian cancer usually occur in women of advanced age, larger studies with longer follow-up are needed in order to confirm or refute our findings.

The risk of breast and gynecological cancer in women with a diagnosis of infertility: a nationwide population-based study

Some studies have suggested that infertility is a risk factor for endometrial, ovarian and breast cancer. The study aimed to create a comprehensive picture of the association between infertility and the risk of ovarian, endometrial and breast cancer, and whether any association could be explained by ovulatory disturbances, endometriosis or nulliparity. In a population-based cohort of 2,882,847 women, cox regression analysis was used to investigate cancer incidence among infertile women. Overall, infertility was associated with a higher incidence rate of ovarian (adjusted hazard ratio [aHR] 1.53, 95% confidence interval [CI] 1.38-1.71) and endometrial cancer (aHR 1.25, 95% CI 1.11-1.40), but not of breast cancer (aHR 0.96, 95% CI 0.92-1.01). Ovarian cancer incidence was higher in women diagnosed with endometriosis, and in nulliparous women with ovulatory disturbances, compared to women with none of the diagnoses. Endometrial cancer incidence was higher in women with ovulatory disturbances, but not in women with endometriosis. These findings suggest that infertility could have long-term consequences of importance to physicians and public health workers.

The role of menopausal hormone therapy in women with or at risk of ovarian and breast cancers: Misconceptions and current directions

For women who are candidates for menopausal hormone therapy (MHT), estrogen can provide relief from symptomatic menopause, decrease rates of chronic illnesses, and improve health-related quality of life. However, confusion surrounds the evidence regarding the impact of exogenous estrogen and progesterone on the breast and ovary. Available data regarding the risks of MHT (estrogen and/or progestin) related to the development of breast and ovarian cancer are often inconsistent or incomplete. Modern molecular and genetic techniques have improved our understanding of the heterogeneity of breast and ovarian cancer. This enhanced understanding of the disease has impacted our understanding of carcinogenesis. Treatment options have evolved to be more targeted toward hormonal therapy for certain subtypes of disease, whereas cytotoxic chemotherapy remains the standard for other histological and molecular subtypes. The role of MHT in the breast and ovarian cancer survivor, as well as women who are at high risk for the development of hereditary breast and ovarian cancer, remains controversial despite evidence that this treatment can improve quality of life and survival outcomes. Through this article, we examine the evidence for and against the use of MHT with a focus on women who have or are at high risk for breast and ovarian cancer.

Impact of endometriosis on risk of ovarian, endometrial and cervical cancers: a meta-analysis

PURPOSE

The risks of gynecologic cancer have not been well established in women with endometriosis. The objective of the present study was to investigate the influence of endometriosis on the risk for three gynecologic cancer (ovarian cancer, endometrial cancer and cervical cancer).

METHODS

We gathered updated evidence about the risk relationship between endometriosis and gynecologic cancers by conducting a comprehensive search of several medical literature electronic databases, including PubMed, Embase and the Cochrane Library. The design and quality of all studies were evaluated using the Newcastle-Ottawa Scale (NOS), and a random-effects model was used to calculate pooled risk ratio (RR).

RESULTS

Of the 8538 articles our search produced, we selected 25 qualified studies, including 16 cohort studies and 9 case-control studies. Patients with endometriosis had both an increased risk of ovarian cancer [RR  1.964; 95% CI (1.685, 2.290)]. The risk of endometrial cancer (EC) is not necessarily higher in patients with endometriosis [RR 1.176, 95% CI (0.878, 1.575)]. Endometriosis was not associated with an increased risk for cervical cancer (CC) [RR 0.670, 95% CI (0.537, 0.838)].

CONCLUSIONS

Patients with endometriosis need to be closely observed and rechecked regularly to prevent malignant changes.

Association of Pelvic Inflammatory Disease with Risk of Endometriosis: A Nationwide Cohort Study Involving 141,460 Individuals

Endometriosis occurs when endometrial tissue exists outside the uterine cavity. The presence of ectopic endometrial tissue and resultant inflammation cause serious symptoms, including chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. Pelvic inflammatory disease is caused by the ascension of pathogenic bacteria from the vagina to the uterus, Fallopian tubes, and ovaries. The factors involved in the pathogenesis of the two conditions are not clearly understood, but recent studies have suggested that disturbances of the female reproductive tract microbiota and inflammatory processes influence the development of both diseases. Using data from the National Health Insurance Research Database (NHIRD), we conducted a study to assess the association of pelvic inflammatory disease (PID) with endometriosis. An age-matched control group including patients without PID was selected. Patients with a pre-existing diagnosis of endometriosis were excluded. This nationwide retrospective cohort study, involving a total of 141,460 patients, demonstrated that patients with PID had a three-fold increase in the risk of developing endometriosis (HR = 3.02, 95% CI = 2.85–3.2).

Comparative study of endometrioid borderline ovarian tumor with and without endometriosis

Background

Synchronous endometriosis has been poorly studied in women with endometrioid borderline ovarian tumors (EBOTs). The aims of this study were to compare the clinicopathological features and prognosis of EBOTs with or without endometriosis.

Results

Of 52 patients diagnosed with EBOTs, no death was observed and only one case had successful pregnancy during the follow-up period. Older, menopausal EBOT patients, EBOT patients with small tumors and relatively low CA125 level probably had better progression-free survival (PFS) outcomes. About 1/3 of EBOTs had concomitant endometrial lesions. Approximately 1/3 of EBOTs were associated with endometriosis. Patients were divided into two groups according to the presence or not of endometriosis in this retrospective cohort study. Patients with endometriosis-associated endometrioid borderline ovarian tumor (EAEBOT) were more likely to be younger and premenopausal. Variables such as PFS outcomes, endometrial lesions did not differ statistically between groups. However, in specific EBOT patients like parous patients, patients with CA125 ≥ 140 U/ml or patients without fertility sparing surgery, coexisting endometriosis perhaps predicted worse PFS outcomes.

Conclusion

We considered EAEBOT as an entity similar to non-EAEBOT. Closely follow-up for some particular patients with concomitant endometriosis was necessary.

New knowledge and insights about the malignant transformation of endometriosis

Endometriosis may be a definitive risk factor for ovarian cancer, the most fatal gynecological cancer. The ability of endometriosis to transform into malignancy, first described by Dr. Sampson in 1925, is considered a rare occurrence, affecting approximately 1% of ovarian endometriomas. Recently we conducted a retrospective study regarding the malignant transformation of endometriosis in Japanese women. Many studies have reported a consistent correlation between endometriosis and ovarian cancer according to histological subtypes. However, the existing epidemiological evidence linking this association is insufficient to define the role of endometriosis as a cause of ovarian cancer and to influence changes to current clinical practice. Prospective cohort studies are therefore needed to clarify this issue. Additionally, the results of many molecular studies are conflicting, and earlier studies showing the molecular aberrations involved in genomic instability and mutation that enable malignant transformation have not been replicated in later studies. Careful long-term observation of a patient with endometrioma is required to detect possible subsequent incidence of malignant transformation. More importantly, a precise strategy should be set up for better prevention, early detection, specific diagnosis and treatment targeting molecular pathogenesis to understand the mechanisms of endometriosis-associated ovarian cancer. Clinicians need to be aware of the increased ovarian cancer risk in women with endometriosis.

Improved clinical outcomes of patients with ovarian carcinoma arising in endometriosis

BACKGROUND

Despite enormous efforts to dissect the role of endometriosis in ovarian cancer development, the difference in prognosis between ovarian cancer patients with or without endometriosis remains elusive. The purpose of this study is to assess the association between endometriosis and the prognosis in patients with ovarian cancer.

RESULTS

Ovarian cancer arising in endometriosis tended to be presented as clear cell histology, early stage, less intraperitoneal metastasis and ascites, and lower CA125 level compared with those without endometriosis. Multivariate Cox regression analysis identified endometriosis as an independent prognostic factor for progression free survival (P = 0.002) and overall survival (P = 0.009) in all patients and especially for early stage. A nomogram integrating endometriosis, FIGO stage and CA125 was established to predict progression free survival and overall survival.

MATERIALS AND METHODS

This study retrospectively enrolled 196 ovarian cancers arising or not in endometriosis judged by adjunctive use of CD10 immunohistochemistry in conjunction with H&E staining specimens. Clinicopathologic variables, progression-free survival (PFS) and overall survival (OS) were recorded. Kaplan-Meier analysis was performed to compare survival curves. Cox regression models were used to analyze the effect of endometriosis on PFS and OS. A prognostic nomogram was constructed based on the independent prognostic factors identified by multivariate analysis.

CONCLUSIONS

Endometriosis is an independent predictor of prognosis in ovarian cancer patients.

Ovarian Cancer Prevention in High-risk Women

Ovarian carcinoma is the most lethal malignancy of the female genital tract. Population-based trials in the general population have not demonstrated that screening improves early detection or survival. Therefore, application of prevention strategies is vital to improving outcomes from this disease. Surgical prevention reduces risk and prophylactic risk-reducing salpingo-oophorectomy is the most effective means to prevent ovarian carcinoma in the high-risk patient although the risks do not outweigh the benefits in average risk patients. Other surgical and medical options have unknown or limited efficacy in the high-risk patient. In this review, we define the patient at high risk for ovarian cancer, discuss how to identify these women and weigh their available ovarian cancer prevention strategies.

Clinical implication for endometriosis associated with ovarian cancer

We reviewed current literature regarding the association of endometriosis and epithelial ovarian cancer based on epidemiology studies, molecular researches and clinical observations. Our methods include a review of literature research of MEDLINE, PubMed, Cochrane Library of Systematic Reviews and reference search in selected papers. The life time risk of epithelial ovarian cancer in women with endometriosis is low, yet there might be a cluster of individuals who have higher risk of developing epithelial ovarian cancer from endometriosis. Endometriosis associated ovarian cancer (EAOC) is predominant in particular histological subtypes of epithelial ovarian carcinoma and are related to some specific molecular aberrations. Clinical observations showed age as an important variable to the development of EAOC. Rapid growth of tumor and solid components in sonography are key features to detect malignant transformation of endometriosis. Evidence is not clear about prophylactic oophorectomy in preventing EAOC in patients with endometriosis. This review provided rationale data for identifying, monitoring, counseling and management of women with endometriosis who are potentially high risk for malignant transformation.

miRNA expression profiling in formalin-fixed paraffin-embedded endometriosis and ovarian cancer samples

Endometriosis is an inflammatory pathology associated with a negative effect on life quality. Recently, this pathology was connected to ovarian cancer, in particular with endometrioid ovarian cancer. microRNAs (miRNAs) are a class of RNA transcripts ~19–22 nucleotides in length, the altered miRNA pattern being connected to pathological status. miRNAs are highly stable transcripts, and these can be assessed from formalin-fixed paraffin-embedded (FFPE) samples leading to the identification of miRNAs that could be developed as diagnostic and prognostic biomarkers, in particular those involved in malignant transformation. The aim of our study was to evaluate miRNA expression pattern in FFPE samples from endometriosis and ovarian cancer patients using PCR-array technology and also to compare the differential expression pattern in ovarian cancer versus endometriosis. For the PCR-array study, we have used nine macrodissected FFPE samples from endometriosis tissue, eight samples of ovarian cancers and five normal ovarian tissues. Quantitative real-time PCR (qRT-PCR) was used for data validation in a new patient cohort of 17 normal samples, 33 endometriosis samples and 28 ovarian cancer macrodissected FFPE samples. Considering 1.5-fold expression difference as a cut-off level and a P-value <0.05, we have identified four miRNAs being overexpressed in endometrial tissue, while in ovarian cancer 15 were differentially expressed (nine overexpressed and six downregulated). The expression level was confirmed by qRT-PCR for miR-93, miR-141, miR-155, miR-429, miR-200c, miR-205 and miR-492. Using the interpretative program Ingenuity Pathway Analysis revealed several deregulated pathways due to abnormal miRNA expression in endometriosis and ovarian cancer, which in turn is responsible for pathogenesis; this differential expression of miRNAs can be exploited as a therapeutic target. A higher number of altered miRNAs were detected in endometriosis versus ovarian cancer tissue, most of them being linked with epithelial-to-mesenchymal transition.

Endometriosis and risk of ovarian and endometrial cancers in a large prospective cohort of U.S. nurses

PURPOSE

Endometriosis is associated with ovarian cancer, but the relation with endometrial cancer is unclear. Prior studies generally were retrospective and had potential limitations, including use of self-reported endometriosis, failure to account for delays between symptom onset and endometriosis diagnosis, and changes in risk factors post-endometriosis diagnosis. We evaluated whether these limitations obscured a weak association with endometrial cancer and the extent to which these limitations impacted associations with ovarian cancer.

METHODS

Cox proportional hazards regression models were used to assess associations between endometriosis and cancer risk, evaluating the impacts of self-reported vs. laparoscopically confirmed endometriosis, delayed diagnosis, and post-endometriosis diagnosis changes in risk factor exposures on relative risk estimates.

RESULTS

Over 18 years of follow-up, we identified 228 ovarian and 166 endometrial cancers among 102,025 and 97,109 eligible women, respectively. Self-reported endometriosis was associated with ovarian cancer [relative risk (RR): 1.81; 95% confidence interval (CI): 1.26-2.58]; this association was stronger for laparoscopically confirmed endometriosis (HR: 2.14; 95% CI 1.45-3.15). No association was observed with endometrial cancer (self-report RR: 0.78; 95% CI 0.42-1.44; laparoscopic-confirmation RR: 0.76; 95% CI 0.35-1.64). Accounting for diagnosis delays or post-endometriosis diagnosis changes in risk factors had a little impact.

CONCLUSIONS

This study adds to the evidence that endometriosis is not strongly linked to endometrial cancer risk and that the association with ovarian cancer is robust to misclassification, diagnostic delay, and changes in exposures post-endometriosis diagnosis. Our analysis suggests that confounding and misclassification do not obscure a weak association for endometrial cancer risk, although our results should be replicated.

Synchronous endometrial and ovarian carcinomas: predictors of risk and associations with survival and tumor expression profiles

PURPOSE

Synchronous endometrial and ovarian tumors (SEOs) are diagnosed in 10% of ovarian cancer patients. We examined predictors of SEOs, evaluated associations of SEOs with survival and characterized ovarian tumor profiles using immunohistochemistry.

METHODS

We included patients with endometrioid (n = 180) and clear cell (n = 165) ovarian carcinoma identified from the Alberta Cancer Registry between 1979 and 2010 for whom we abstracted medical records and constructed tumor tissue microarrays (TMAs). A concurrent diagnosis of endometrial cancer was obtained from the medical chart. We used unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) and Cox proportional hazards models to estimate hazard ratios (HRs) and 95% CIs. Protein expression in ovarian tumors of patients with and without SEOs was evaluated using Fisher's exact test.

RESULTS

Comparing 52 patients with SEO tumors to 293 patients with endometrioid or clear cell ovarian carcinomas, endometriosis at the ovary (OR = 0.45, 95% CI = 0.23-0.87, p = 0.02) was the strongest predictor of decreased risk in multivariable models. Premenopausal status (OR = 2.17, 95% CI = 0.92-5.13, p = 0.08) and lower pre-treatment CA125 levels (OR = 0.17, 95% CI = 0.02-1.32, p = 0.09) showed weaker associations. There were no significant differences in survival between patients with or without SEO tumors. More patients with SEO tumors compared to endometrioid ovarian carcinoma were deficient in MLH1, PMS2 and PTEN (p ≤ 0.03).

CONCLUSIONS

Endometriosis may not be the mechanism by which SEO cancers arise. Altered tumor oncoprotein expression between women with and without SEOs indicates important biological differences although this did not translate into prognostic differences.

Endometriosis and Ovarian Cancer: an Integrative Review (Endometriosis and Ovarian Cancer)

Despite being initially considered a benign disease, it is widely thought nowadays that endometriosis and especially ovarian endometriomas are neoplastic conditions with the potential to become malignant. This review was conducted to summarize, in a concise and systematic manner, the available scientific data relating endometriosis to ovarian cancer, published in the past five years. After reading abstracts and applying our predefined inclusion and exclusion criteria, a final list of 11 scientific papers was obtained and subjected to review. Endometriosis is associated with an increased risk of developing epithelial ovarian cancer (EOC), mainly of endometrioid and clear cell subtypes. This might be by virtue of the high estrogen concentration with the disease, which leads to malignant proliferation of endometriotic cysts, or be due to mutations in the ARID1A gene and consequent loss of BAF250a expression. The iron produced in the fluid of endometriotic cysts promotes oxidative stress, which in turn may cause genetic mutations and malignant progression of ovarian cysts.

Women's Reproductive History Before the Diagnosis of Incident Endometriosis

BACKGROUND

Endometriosis is a gynecologic disease reported to be associated with infertility and, possibly, adverse pregnancy outcomes. While considerable research focuses on pregnancy outcomes following diagnosis and/or treatment, few data actually describe women's reproductive history before diagnosis for a more complete understanding of endometriosis and reproduction.

MATERIALS AND METHODS

The study sample comprised 473 women (aged 18-44 years) undergoing laparoscopies or laparotomies, irrespective of surgical indication at 14 clinical sites, during the period 2007-2009. Upon enrollment and before surgery, women were queried about pregnancy intentions and the time required to become pregnant for planned pregnancies. Endometriosis was defined as surgically visualized disease. Using discrete time survival analysis, we estimated fecundability odds ratios (FORs) and 95% confidence intervals (CIs) to assess time to pregnancy (TTP) after adjusting for potential confounders (age, body composition, cigarette smoking, site). Generalized estimating equations accounted for multiple pregnancy attempts per woman. FORs <1.0 denote a longer TTP or diminished fecundity.

RESULTS

Approximately 66% and 69% of women with and without endometriosis, respectively, reported having a planned pregnancy before surgery, respectively. After adjustment, an endometriosis diagnosis was associated with ≈29% reduction in fecundity or a longer TTP across all pregnancy-trying attempts (adjusted FOR = 0.71; 95% CI 0.46-1.10). While FORs were consistently <1.0, irrespective of endometriosis staging, CIs included 1.

CONCLUSIONS

Women with endometriosis had a longer TTP than unaffected women, irrespective of disease severity, although the findings did not achieve significance. Prior reproductive history may be informative for predicting fecundity and pregnancy outcomes following diagnosis/treatment.

Endometriosis-associated Malignancy

Endometriosis is a common condition in women of reproductive age. According to several epidemiological studies endometriosis may be associated with increased risk of various malignancies. However, endometriosis-associated malignancy (EAM) is defined by certain histological criteria. About 80 % of EAM have been found in the ovary, whereas 20 % are localized in extragonadal sites like intestine, rectovaginal septum, abdominal wall, pleura and others. Some authors suggest that EAM arise from atypical endometriosis as an intermediate lesion between endometriosis and cancer. Moreover, a number of genetic alterations, like loss of heterozygosity (LOH), PTEN, ARID1 A and p53 mutations have been found in both endometriosis and EAM. Endometriosis-associated ovarian cancer (EAOC) is mostly a well or intermediately differentiated tumor of endometrioid or clear cell histological sub-type. Women affected by EAOC are on average five to ten years younger than non-EAOC patients; in most of the cases EAOC is a low stage disease with favorable clinical outcome. Since EAM is a rare condition systematic data on EAM are still missing. A systematic retrospective study on endometriosis-associated malignancies (EAM study) is currently being conducted by the Endometriosis Research Foundation together with the study groups on ovarian and uterine tumors of the working group for gynecological oncology (AGO) (gyn@mlk-berlin.de).

Clinicopathologic analysis with immunohistochemistry for DNA mismatch repair protein expression in synchronous primary endometrial and ovarian cancers

OBJECTIVE

Synchronous primary endometrial and ovarian cancers have been an important topic in clinical medicine because it is sometimes difficult to distinguish whether there are 2 primary tumors or a single primary tumor and an associated metastasis. In addition, although these tumors are recommended for either immunohistochemistry for DNA mismatch repair (MMR) proteins or a microsatellite instability test in the Bethesda guidelines as Lynch syndrome-associated cancers, few studies have completed these analyses. In this study, we characterized the clinicopathologic features and the expression pattern of MMR proteins in synchronous primary endometrial and ovarian cancers.

METHODS

Clinicopathologic features and the expression pattern of MMR proteins (MLH1, MSH2, and MSH6) were characterized and analyzed in 32 synchronous primary endometrial and ovarian cancers.

RESULTS

Most synchronous cancers are endometrioid type (endometrioid/endometrioid) (n = 24, 75%), grade 1 (n = 19, 59.4%), and diagnosed as stage I (n = 15, 46.9%) in both endometrium and ovary. It is worth mentioning that 75% of the patients (n = 24) had endometriosis, which was more common (n = 21, 87.5%) in endometrioid/endometrioid cancers, whereas only 3 cases (37.5%) were of different histology (P = 0.018). Loss of expression of at least 1 MMR protein was observed in 17 (53.1%) of the endometrial tumors and in 10 (31.3%) of ovarian tumors. Only 4 cases (12.5%) that had specific MMR protein loss showed the same type of loss for both endometrial and ovarian tumors, in which 3 of the cases were losses in MLH1. One case showed concordant MSH6 protein loss, although the cases did not meet the Amsterdam criteria II.

CONCLUSIONS

These results suggest that most synchronous primary endometrial ovarian cancers are not hereditary cancers caused by germ line mutations but rather sporadic cancers.

The Risk of Epithelial Ovarian Cancer of Women With Endometriosis May be Varied Greatly if Diagnostic Criteria Are Different: A Nationwide Population-Based Cohort Study

This article aims to test the hypothesis that the risk of epithelial ovarian cancer (EOC) in women with endometriosis might be changed by enrolling different population. A nationwide 14-year historic cohort study using the National Health Insurance Research Database (NHIRD) of Taiwan and the Registry for Catastrophic Illness Patients was conducted. A total of 239,385 women aged between 20 and 51 years, with at least 1 gynecologic visit after 2000, were analyzed. Cases included women with a diagnosed endometriosis, which was established along a spectrum from at least 1 medical record of endometriosis (recalled endometriosis) to tissue-proved ovarian endometriosis (n = X). Controls included women without any diagnosis of endometriosis (n = 239,385 - X). We used Cox regression, and computed hazard ratios (HRs) with 95% confidence intervals (95% CI) to determine the risk of EOC in patients. The EOC incidence rates (IRs, per 10,000 person-years) of women with endometriosis ranged from 1.90 in women with recalled endometriosis to 18.70 in women with tissue-proved ovarian endometrioma, compared with those women without any diagnosis of endometriosis (0.77-0.89), contributing to crude HRs ranging from 2.59 (95% CI, 2.09-3.21; P < 0.001) to 24.04 (95% CI, 17.48-33.05; P < 0.001). After adjustment for pelvic inflammatory disease, infertility, Charlson co-morbidity index, and age, adjusted HRs were ranged from the lowest of 1.90 (95% CI, 1.51-2.37; P < 0.001) in recalled endometriosis to the highest of 18.57 (95% CI, 13.37-25.79; P < 0.001) in tissue-proved ovarian endometrioma, which was inversely related to the prevalence rate of endometriosis (from the highest of 30.80% in recalled endometriosis to the lowest of 1.54% in tissue-proved ovarian endometrioma). The risk of EOC in women with endometriosis varied greatly by different criteria used. Women with endometriosis might have a more apparently higher risk than those reported by systematic review and meta-analysis.

Endometriosis and ovarian cancer: potential benefits and harms of screening and risk-reducing surgery

Although endometriosis is well recognized as a benign gynecologic condition, its association with ovarian cancer (OVCA) has frequently been reported. Review articles on this topic are voluminous, yet there seems to be no consensus as to whether endometriosis is truly a precursor of OVCA and whether any screening or risk-reducing surgery should be instituted, on the basis of our current knowledge. In this review, published data are compiled and critically appraised. Through this critical appraisal, it seems clear that the strongest evidence seems to come from prevalence data. This type of data also suggests a reduced risk of certain histotypes (mainly type II) of OVCA in women with endometriosis. This may explain the rather moderate increase in risk as shown in epidemiologic studies. Even with this moderate increase in OVCA risk, caution should be exercised because of apparent bias in favor of publication of positive results, extensive heterogeneities among prevalence estimates, and inverse relationship between estimates and sizes of the studies. Many molecular studies are conflicting, and earlier studies showing molecular aberrations involved in genomic instability and mutation that enable malignant transformation are not replicated in later studies. Given the low incidence of OVCA and the rather moderate increase in risk of mostly type I tumors, screening seems to be ill-advised, and risk-reducing surgery such as salpingectomy with or without oophorectomy does not seem to yield any substantial benefit to women with endometriosis.

Endometriosis: a high-risk population for major chronic diseases?

BACKGROUND

Despite an estimated prevalence of 10% in women, the etiology of endometriosis remains poorly understood. Over recent decades, endometriosis has been associated with risk of several chronic diseases, such as cancer, autoimmune diseases, asthma/atopic diseases and cardiovascular diseases. A deeper understanding of these associations is needed as they may provide new leads into the causes or consequences of endometriosis. This review summarizes the available epidemiological findings on the associations between endometriosis and other chronic diseases and discusses hypotheses for underlying mechanisms, potential sources of bias and methodological complexities.

METHODS

We performed a comprehensive search of the PubMed/Medline and ISI Web of Knowledge databases for all studies reporting on the associations between endometriosis and other diseases published in English through to May 2014, using numerous search terms. We additionally examined the reference lists of all identified papers to capture any additional articles that were not identified through computer searches.

RESULTS

We identified 21 studies on the associations between endometriosis and ovarian cancer, 14 for breast cancer, 8 for endometrial cancer, 4 for cervical cancer, 12 for cutaneous melanoma and 3 for non-Hodgkin's lymphoma, as well as 9 on the links between endometriosis and autoimmune diseases, 6 on the links with asthma and atopic diseases, and 4 on the links with cardiovascular diseases. Endometriosis patients were reported to be at higher risk of ovarian and breast cancers, cutaneous melanoma, asthma, and some autoimmune, cardiovascular and atopic diseases, and at decreased risk of cervical cancer.

CONCLUSIONS

Increasing evidence suggests that endometriosis patients are at higher risk of several chronic diseases. Although the underlying mechanisms are not yet understood, the available data to date suggest that endometriosis is not harmless with respects to women's long-term health. If these relationships are confirmed, these findings may have important implications in screening practices and in the management and care of endometriosis patients.

The Risks for Ovarian, Endometrial, Breast, Colorectal, and Other Cancers in Women With Newly Diagnosed Endometriosis or Adenomyosis: A Population-Based Study

OBJECTIVE

Recent studies report a link between endometriosis and ovarian cancer (OC). Using a population-based cohort study to confirm the association between endometriosis and cancer is desirable. We thus examined the magnitude of the risks of OC, endometrial cancer (EC), breast cancer, colorectal cancer (CRC), and other cancers in women with newly diagnosed endometriosis or adenomyosis (internal endometriosis).

METHODS/MATERIALS

Women older than 20 years with claims data between 2003 and 2005 were identified from the Longitudinal Health Insurance Dataset containing 1 million individuals randomly sampled from the National Health Insurance Research Database. Those with preexisting malignancies, hysterectomy, or oophorectomy were excluded. The endometriosis cohort (n = 2266, including 768 cases of pure adenomyosis) and comparison cohort (n = 9064), formed by 1:4 matching, were followed up until incidence cancer, dropout, or December 31, 2008. Outcome measures included cancer incidence and adjusted hazard ratio by Cox model adjusted for age group, comorbidities, and endometriosis medication use.

RESULTS

With 9842 person-years of follow-up in endometriosis cohort and 36,274 person-years of follow-up in comparison cohort, there were increased risks of all cancers (adjusted hazard ratio, 1.8; 95% confidence interval, 1.4-2.4), OC (4.56, 1.72-12.11), and EC (4.05, 1.20-13.66). The ovarian endometriosis group was associated with increased risk of subsequent OC (4.37, 1.07-17.83). The adenomyosis group was strongly associated with both OC (5.50, 1.95-15.50) and EC (5.13, 1.36-19.40). Increased risk of subsequent CRC was observed in women with adenomyosis with coexistent endometriosis at other sites (13.04, 2.21-77.04). However, no statistically significant increased risk of breast or other cancers was observed.

CONCLUSIONS

Having limitations such as lacking of parity information which may affect the magnitude of risk estimates, this study demonstrates that ovarian endometriosis has a 4-fold increased risk of OC. Adenomyosis may associate with a 4- to 5-fold increased risk of OC and EC, and unexpectedly, a 13-fold increased risk of CRC.

The Impact of Endometriosis across the Lifespan of Women: Foreseeable Research and Therapeutic Prospects

In addition to estrogen dependence, endometriosis is characterized by chronic pelvic inflammation. The impact of the chronic pelvic inflammatory state on other organ systems and women's health is unclear. Endometriosis associated chronic inflammation and potential adverse health effects across the lifespan render it imperative for renewed research vigor into the identification of novel biomarkers of disease and therapeutic options. Herein we propose a number of opportunities for research and development of new therapeutics to address the unmet needs in the treatment of endometriosis per se and its ancillary risks for other diseases in women across the lifespan.

Comparative Analysis of Differentially Expressed miRNAs and their Downstream mRNAs in Ovarian Cancer and its Associated Endometriosis

Objective

There is an increased risk of developing ovarian cancer (OC) in patients with endometriosis. Hence, development of new biomarkers may provide a positive clinical outcome for early detection. MicroRNAs (miRNAs) are small non-coding RNAs that play an important role in biological and pathological process and are currently used as diagnostic and prognostic markers in various cancers. In the current study, we assessed the differential expression of miRNAs from 19 paired ovarian cancer and its associated endometriosis tissue samples. In addition we also analyzed the downstream targets of those miRNAs.

Methods

Nineteen paired cases of ovarian cancer and endometriosis foci were identified by a gynecologic pathologist and macro-dissected. The total RNAs were extracted and subjected to comprehensive miRNA profiling from the pooled samples of these two different entities using microarray analysis. Later, the abnormal expressions of few selected miRNAs were validated in individual cases by quantitative real-time PCR (qRT-PCR). Ingenuity pathway analysis revealed target mRNAs which were validated by qRT-PCR.

Results

The miRNA profiling identified deregulation of greater than 1156 miRNAs in OC, of which the top seven were further validated by qRT-PCR. The expression of miR-1, miR-133a, and miR-451 were reduced significantly (p<0.0001) in the OC patients compared to its associated endometriosis. In contrast, the expression of miR-141, miR-200a, miR-200c, and miR-3613 were elevated significantly (p<0.05) in most of the OC patients. Furthermore, among the downstream mRNAs of these miRNAs, the level of PTEN expression was significantly (p<0.05) reduced in OC compared to endometriosis while no significant difference was observed in NF-κB expression.

Conclusion

The expression of miRNAs and mRNAs in OC were significantly different compared to its concurrent endometriosis. These differential expressed miRNAs may serve as potential diagnostic and prognostic biomarkers for OC associated with endometriosis.

Endometriosis and ovarian cancer

Endometriosis is the leading cause of morbidity among premenopausal women and the complex pathogenesis of this disease remains controversial despite extensive research. This disease represents one of the most common gynecological problems. It is generally believed that this disease is due primarily to retrograde menstruation or transplantation of shed endometrium. Based on overwhelming data, ovarian endometrioma is considered a neoplastic process, since most endometriosis-associated ovarian carcinoma occur in the presence of atypical ovarian endometriosis. A study comparing patients with typical epithelial ovarian cancer with endometriosis-associated ovarian cancer demonstrated that the patients with the latter disease strongly differ in both biological and histological characteristics. The prevelance of this disease is not completely established, but approximately 15 percent of women suffer from this disease. In addition, we know about the possible links between endometriosis and cancer for almost 100 years. Despite clear evidence revealing that endometriosis increases ovarian cancer risks, it is possible that it may not affect disease progression after the appearance of ovarian cancer. However, despite clear evidence revealing that endometriosis increases ovarian cancer risk, our knowledge of the risk factors is far from established. In our review, we focused on the most recent approaches including possible biomarkers and genetic approaches.

An increased risk of epithelial ovarian cancer in Taiwanese women with a new surgico-pathological diagnosis of endometriosis

Background

Epidemiological evidence of relationships between endometriosis and epithelial ovarian cancer (EOC) has been obtained mainly from Western countries. Our goal was to determine the risk of EOC due to endometriosis in Taiwanese women.

Methods

A retrospective cohort study was performed by linking to the National Health Insurance Research Database (NHIRD) of Taiwan. A total of 5,945 women with a new surgico-pathological diagnosis of endometriosis from 2000 to 2010 and 23,780 multivariable-matched controls (1:4) were selected. The Cox regression model adjusted for potential confounders was used to assess the risk of EOC due to endometriosis.

Results

The EOC incidence rate (IR) of the women with and without endometriosis was 11.64 and 2.66 per 10,000 person-years, contributing to a crude hazard ratio (HR) of 4.48 (95% confidence interval [CI] 2.84-7.06), and HR after adjustment for all confounders (adjusted HR) of 5.62 (95% CI 3.46-9.14); the risk was higher in clear-cell carcinoma subtypes (adjusted HR 7.36, 95% CI 1.91-28.33). The EOC IR of women with endometriosis consistently increased with increasing age, ranging from 4.99 (<30 years) to 35.81 (≥50 years) per 10,000 person-years, contributing to a progressively increased risk of EOC (crude HRs ranging from 2.80 to 6.74 and adjusted HRs ranging from 3.34 to 9.63) compared to age-matched women without endometriosis, whose EOC IR also increased with age. The older women (≥50 years) with endometriosis had a risk of EOC that was higher than both the age-matched women without endometriosis (adjusted HR 9.63, 95% CI 3.27-28.37) and the youngest women (<30 years) with endometriosis (adjusted HR 4.97, 95% CI 1.03-24.09).

Conclusions

These significant findings corroborate the previously reported association between endometriosis and increased risk of EOC. Since the risk of EOC in women with a new surgico-pathological diagnosis of endometriosis constantly increased with age and this increased risk of EOC was more significant in women aged ≥50 years, active and intensive surgical intervention should be taken into consideration for older women with endometriosis.

Novel insights on the malignant transformation of endometriosis into ovarian carcinoma

The malignant transformation of endometriosis is an uncommon event, which happens in 0.7-2.5% of the cases, and, when occurs, it usually involves the ovary. A 2 to 3-fold higher risk of ovarian endometrioid and clear cell carcinoma has been reported in women with endometriosis. Pathological studies have detected a morphological continuum of sequential steps from normal endometriotic cyst epithelium to atypical endometriosis and finally to invasive carcinoma. Ovarian endometrioid carcinoma harbors mutations of CTNNB1 in 16-53.3%, of PTEN in 14-20% and of ARID1A in 30-55% of the cases. Ovarian clear cell carcinoma harbors mutations of PIK3CA in 20-40% and of ARID1 in 15-75% of the cases. Whereas estrogen receptors and progesterone receptors are quite always absent, HNF-1b is often over-expressed in this histotype. Atypical endometriosis and endometriosis-related ovarian neoplasms share molecular alterations, such as PTEN mutations, ARID1A mutations and up-regulation of HNF-1b. Moreover, ARID1A mutations have been noted in clear cell tumors and contiguous atypical endometriosis, but not in distant endometriotic lesions. The loss of BAF250a protein expression is suggestive for the presence of ARID1A mutations, and represents an useful marker of malignant transformation of endometriosis.