Endometriosis as a prognostic factor for cancer survival

Causal effects of endometriosis on cancer risk: A Mendelian randomization study

Endometriosis has been reported in epidemiological studies to be associated with certain types of cancer. However, the presence of reverse causality and residual confounding due to common risk factors introduces uncertainty regarding the extent to which endometriosis itself contributes to the development of cancer. We performed the Mendelian randomization (MR) to investigate the causal associations between endometriosis and 34 different types of cancers. The results of the inverse-variance-weighted (IVW) model suggested that genetic predisposition to endometriosis was causally associated with an increased risk for ovarian cancer (OR = 3.2913; p-value = .0320). The genetic liabilities to endometriosis had causal associations with the decreased risk for skin cancer (OR = 0.9973; p-value = .0219), hematological cancer (OR = 0.9953; p-value = .0175) and ER- breast cancer (OR = 0.6960; p-value = .0381). The causal association of the above combinations were robust by test of heterogeneity and pleiotropy. Together, our study suggests that endometriosis had causal effect on cancer risk.

Identification of fallopian tube microbiota and its association with ovarian cancer

Investigating the human fallopian tube (FT) microbiota has significant implications for understanding the pathogenesis of ovarian cancer (OC). In this large prospective study, we collected swabs intraoperatively from the FT and other surgical sites as controls to profile the microbiota in the FT and to assess its relationship with OC. Eighty-one OC and 106 non-cancer patients were enrolled and 1001 swabs were processed for 16S rRNA gene PCR and sequencing. We identified 84 bacterial species that may represent the FT microbiota and found a clear shift in the microbiota of the OC patients when compared to the non-cancer patients. Of the top 20 species that were most prevalent in the FT of OC patients, 60% were bacteria that predominantly reside in the gastrointestinal tract, while 30% normally reside in the mouth. Serous carcinoma had higher prevalence of almost all 84 FT bacterial species compared to the other OC subtypes. The clear shift in the FT microbiota in OC patients establishes the scientific foundation for future investigation into the role of these bacteria in the pathogenesis of OC.

Identification of fallopian tube microbiota and its association with ovarian cancer: a prospective study of intraoperative swab collections from 187 patients

Investigating the human fallopian tube (FT) microbiota has significant implications for understanding the pathogenesis of ovarian cancer (OC). In this large prospective study, we collected swabs intraoperatively from the FT and other surgical sites as controls to profile the microbiota in the FT and to assess its relationship with OC. 81 OC and 106 non-cancer patients were enrolled and 1001 swabs were processed for 16S rRNA gene PCR and sequencing. We identified 84 bacterial species that may represent the FT microbiota and found a clear shift in the microbiota of the OC patients when compared to the non-cancer patients. Of the top 20 species that were most prevalent in the FT of OC patients, 60% were bacteria that predominantly reside in the gastrointestinal tract, while 30% normally reside in the mouth. Serous carcinoma had higher prevalence of almost all 84 FT bacterial species compared to the other OC subtypes. The clear shift in the FT microbiota in OC patients establishes the scientific foundation for future investigation into the role of these bacteria in the pathogenesis of ovarian cancer. .

Causal effects of genetically predicted endometriosis on breast cancer: a two-sample Mendelian randomization study

This study used a Mendelian randomization (MR) approach to investigate the causal relationship between genetically predicted endometriosis (EMS) and breast cancer risk. A total of 122,977 cases and 105,974 controls were included in the analysis, with gene-level summary data obtained from the Breast Cancer Association Consortium (BCAC). An inverse variance-weighting approach was applied to assess the causal relationship between EMS and breast cancer risk, and weighted median and MR-Egger regression methods were used to evaluate pleiotropy. Results showed a causal relationship between EMS and a decreased risk of overall breast cancer (odds ratio [OR] 0.95; 95% CI 0.90-0.99, p = 0.02). Furthermore, EMS was associated with a lower risk for estrogen receptor (ER)-positive breast cancer in a subgroup analysis based on immunohistochemistry type (OR 0.91; 95% CI 0.86-0.97, p = 0.005). However, there was no causal association between ER-negative breast cancer and survival (OR 1.00; 95% CI 0.94-1.06, p = 0.89). Pleiotropy was not observed. These findings provide evidence of a relationship between EMS and reduced breast cancer risk in invasive breast cancer overall and specific tissue types, and support the results of a previous observational study. Further research is needed to elucidate the mechanisms underlying this association.

Does endometriosis increase the risks of endometrial hyperplasia and endometrial cancer?

OBJECTIVE

The risk of developing endometrial hyperplasia after diagnosis of endometriosis has not been determined. Moreover, the risk of endometrial cancer associated with endometriosis is unclear. This nationwide population-based study investigated the associations of endometrial hyperplasia and endometrial cancer with endometriosis, after adjusting for covariates.

METHODS

This population-based observational study analyzed data from the Korean National Health Insurance (NHI) database, including 147,869 women who were diagnosed with endometriosis from 2002 to 2017, with each patient matched to 20 control women without endometriosis. Cox proportional hazard regression analyses were performed to estimate the hazard ratios (HRs) of endometrial hyperplasia, endometrial cancer, and mortality from endometrial cancer.

RESULTS

Among three million women in this population, 16,377 women were diagnosed with endometrial hyperplasia, and 1795 women were diagnosed with endometrial cancer over 19,931,794 person-years of follow-up. Women with endometriosis were at significantly higher risks of endometrial hyperplasia (adjusted hazard ratio [aHR] 1.85, 95% confidence interval [CI] 1.75-1.95), and endometrial cancer (aHR 1.35, 95% CI 1.12-1.63) were compared with control women after adjustment for covariates. A diagnosis of endometriosis did not affect survival in patients with endometrial cancer.

CONCLUSION

The risks of endometrial hyperplasia and endometrial cancer were found to be significantly higher in women with than without endometriosis. The presence of endometriosis did not affect overall survival in women with endometrial cancer. Additional long-term prospective studies with adequate control of confounders are needed.

A Presentation of Synchronous Ovarian and Endometrial Endometrioid Adenocarcinoma From a Case of Suspected Ruptured Ectopic Pregnancy

A 32-year-old woman of child-bearing age who initially underwent surgical laparoscopy for suspected ruptured ectopic pregnancy with elevated serum β-human chorionic gonadotropin (hCG) levels was unexpectedly found to have histologically diagnosed synchronous ovarian and endometrial endometrioid adenocarcinoma. She subsequently underwent another full completion staging surgery and adjuvant chemotherapy as she was unsuitable for fertility-sparing surgery. An elevated serum β-hCG level accompanied by clinical signs of acute abdominal pain, per vaginal bleeding, ultrasound features of abdominal free fluid in the pelvis and an adnexal mass warrants a high clinical suspicion for a ruptured ectopic pregnancy. However, it is important to recognize ovarian malignancy as a rare but differential diagnosis to suspected ectopic pregnancy in patients with acute abdomen. Fertility-sparing surgery may be considered for young patients seeking fertility, without compromising patient survival in women without synchronous gynecological cancers.

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.

Endometriosis-associated Ovarian Cancer is a Subset With a More Favorable Outcome and Distinct Clinical-pathologic Characteristics

There is a controversy about whether endometriosis-associated ovarian cancer (EAOC) might represent a different entity from the corresponding ovarian cancer occurring de novo, in the absence of endometriosis. This study investigated the clinical-pathologic characteristics and outcome of EAOC compared with other ovarian carcinomas that are not associated with endometriosis (non-EAOC) in a large cohort. Seven hundred two patients meeting the inclusion criteria were further subclassified as group I when patients had ovarian carcinoma associated with or arising within endometriosis (EAOC) and group II when patients had non-EAOC. Age, gross features, histologic type, International Federation of Gynecology and Obstetrics stage, and disease-free survival (DFS) were compared between the groups. One hundred sixty-eight (23.9%) patients had EAOC, whereas 534 (76.1%) patients had non-EAOC. EAOCs were mostly endometrioid and clear cell type. Patients with EAOC were younger, present early, and had a lower rate of recurrence when compared with patients with non-EAOC, P<0.001. Patients with EAOC had longer DFS time, 51.9 mo (95% confidence interval, 44.9-58.8) versus 30.5 mo (95% confidence interval, 27.7-33.3) in non-EAOC patients. The 5 yr Kaplan-Meier estimate of DFS rate was 70% in 166 patients of group I and was 39.3% in 532 patients of group II, P<0.001. On multivariate analysis, International Federation of Gynecology and Obstetrics staging, histologic type, and treatment were the only significant factors affecting the hazards of recurrence. Patients with tumors associated with endometriosis are usually, younger, present early, have lower rate of recurrence, longer DFS, and their tumors are of lower grade and are more likely endometrioid or clear cell carcinoma.

Factors associated with ovarian endometriosis malignancy and its recurrence in Chinese women

In this study, the risk factors for ovarian endometriosis (OE) malignancy and its recurrence were explored in Chinese women. For OE malignancy occurrence, the age of marriage, abortion times, course of OE, body mass index (BMI), other benign uterine complications, and shorter parturition times were identified as risk factors using univariate analyses. Among them, age at marriage, course of OE, BMI, and decreased parturition times were identified as risk factors using multivariate analyses. For OE malignancy recurrence, the risk factors included clinical staging, histological classification, and chemotherapy by univariate analysis; and clinical stage, clear-cell carcinoma, and fewer chemotherapy cycles by multivariate analyses. In summary, we concluded that higher ages at marriage, longer courses of ovarian endometriosis, shorter parturition times, and additional benign uterine complications may increase the risk of OE malignancy. Advanced clinical stages, clear-cell carcinomas, and fewer chemotherapy cycles may promote OE malignancy recurrence. Impact statement What is already known on this subject? Endometriosis is one of the most common gynaecological diseases. Although endometriosis is not a malignant disease, endometriosis cells have characteristics similar to cancer cells. The risk of malignant transformation rates of ovarian endometriosis is said to be 1:18. However, epidemiological evidence based on large population research in ovarian endometriosis malignancy is lacking. In addition, there were few studies focussing on the long-term prognosis of ovarian endometriosis malignancies. What do the results of this study add? This study revealed the possible occurrence and recurrence risk factors of ovarian endometriosis malignancy using univariate and multivariate statistics analyses. What are the implications of these findings for clinical practice and/or further research? A clinical retrospective study with a longer follow-up period is suggested for assessing the occurrence and recurrence risk factors for ovarian endometriosis malignancies.

Mortality of midlife women with surgically verified endometriosis—a cohort study including 2.5 million person-years of observation

STUDY QUESTION

Is all-cause and cause-specific mortality increased among women with surgically verified endometriosis?

SUMMARY ANSWER

The all-cause and cause-specific mortality in midlife was lower throughout the follow-up among women with surgically verified endometriosis compared to the reference cohort.

WHAT IS KNOWN ALREADY

Endometriosis has been associated with an increased risk of comorbidities such as certain cancers and cardiovascular diseases. These diseases are also common causes of death; however, little is known about the mortality of women with endometriosis.

STUDY DESIGN, SIZE, DURATION

A nationwide retrospective cohort study of women with surgically verified diagnosis of endometriosis was compared to the reference cohort in Finland (1987–2012). Follow-up ended at death or 31 December 2014. During the median follow-up of 17 years, 2.5 million person-years accumulated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Forty-nine thousand nine hundred and fifty-six women with at least one record of surgically verified diagnosis of endometriosis in the Finnish Hospital Discharge Register between 1987 and 2012 were compared to a reference cohort of 98 824 age- and municipality-matched women. The age (mean ± standard deviation) of the endometriosis cohort was 36.4 ± 9.0 and 53.6 ± 12.1 years at the beginning and at the end of the follow-up, respectively. By using the Poisson regression models the crude and adjusted all-cause and cause-specific mortality rate ratios (MRR) and 95% confidence intervals (CI) were assessed. Calendar time, age, time since the start of follow-up, educational level, and parity adjusted were considered in the multivariate analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1656 and 4291 deaths occurred in the endometriosis and reference cohorts, respectively. A lower all-cause mortality was observed for the endometriosis cohort (adjusted MRR, 0.73 [95% CI 0.69 to 0.77])—there were four deaths less per 1000 women over 10 years. A lower cause-specific mortality contributed to this: the adjusted MRR was 0.88 (95% CI 0.81 to 0.96) for any cancer and 0.55 (95% CI 0.47 to 0.65) for cardiovascular diseases, including 0.52 (95% CI 0.42 to 0.64) for ischemic heart disease and 0.60 (95% CI 0.47 to 0.76) for cerebrovascular disease. Mortality due to alcohol, accidents and violence, respiratory, and digestive disease-related causes was also decreased.

LIMITATIONS, REASONS FOR CAUSATION

These results are limited to women with endometriosis diagnosed by surgery. In addition, the study does not extend into the oldest age groups. The results might be explained by the characteristics and factors related to women’s lifestyle, and/or increased medical attention and care received, rather than the disease itself.

WIDER IMPLICATIONS OF THE FINDINGS

These reassuring data are valuable to women with endometriosis and to their health care providers. Nonetheless, more studies are needed to address the causality.

STUDY FUNDING/COMPETING INTEREST

This research was funded by the Hospital District of Helsinki and Uusimaa and The Finnish Medical Foundation. None of the authors report any competing interest in relation to the present work; all the authors have completed the disclosure form.

Endometriosis and ovarian cancer: Their association and relationship

Objectives

To study endometriosis-associated borderline or malignant ovarian epithelial tumors by analyzing their differential clinical features, as well as the histological pattern, survival and immunohistochemical data compared with those without associated endometriosis.

Study design

Setting: Hospital Marina Baixa and San Juan University Hospital, Alicante, Spain. This retrospective study included clinical and pathological data from 36 operated cases with endometriosis-associated ovarian epithelial tumors and 305 cases of ovarian epithelial tumors without endometriosis, including borderline and invasive tumors. We also studied hormonal receptors and p53 protein expression in 13 cases with endometriosis-associated endometrioid and clear cell tumors, and report two cases with histologically-confirmed previous endometriosis.

Results

Associated endometriosis was observed in 10.5% of patients with borderline or invasive ovarian epithelial tumor, 53% of those with endometrioid, and 22% with clear cell tumors. Patients with endometriosis-associated ovarian epithelial tumors were younger, had lower parity, were more frequently premenopausal, had a lower tumor stage or were borderline, and in general had better prognosis and longer survival, although they also more frequently had an associated endometrial carcinoma. Associated endometriosis and endometrioid tumors were generally estrogen-receptor positive, whereas they were negative in the clear cell tumor component. p53 protein positivity was generally observed in clear cell tumors and in associated endometriosis. Two reported cases with previous, known endometriosis were followed in their evolution to borderline endometrioid carcinoma and clear cell carcinoma, respectively.

Conclusions

Our results and review of the literature suggest that the association of ovarian epithelial tumors and endometriosis is a factor for good prognosis for ovarian cancer and that this association might correspond in many cases to an intermediate stage in the development of endometriosis to endometrioid, clear cell, or other invasive carcinomas.

A Nationwide Cohort Study on the risk of non-gynecological cancers in women with surgically verified endometriosis

We assessed the association of surgically verified endometriosis and risk of non-gynecological cancers according to the type of endometriosis (i.e., ovarian, peritoneal and deep infiltrating endometriosis). All diagnoses of endometriosis combined with relevant procedural codes were identified from the Finnish Hospital Discharge Register 1987-2012. Non-gynecological cancers diagnosed after the endometriosis diagnosis were obtained from the Finnish Cancer Registry. The cohort of 49,933 women with surgically verified endometriosis and the sub-cohorts of ovarian (n = 23,210), peritoneal (n = 20,187), and deep infiltrating (n = 2,372) endometriosis were analyzed separately. The endometriosis cohort contributed 838,685 person-years of follow-up and the Finnish female population served as the reference cohort. The standardized incidence ratio (SIR) and 95% confidence interval (95%CI) was calculated for each cancer separately. The follow-up ended at emigration, death or on the 31st of December 2014. The non-gynecological cancer risk was not increased among women with endometriosis (SIR 1.03, 95%CI 0.98-1.08). Endometriosis was associated with an increased risk of thyroid cancer in the entire cohort (SIR 1.43, 95%CI 1.23-1.64) and in the sub-cohorts of ovarian and peritoneal endometriosis. We found a decreased risk of mouth and pharynx cancer (SIR 0.60, 95%CI 0.41-0.80), and of pancreatic cancer (SIR 0.76, 95%CI 0.58-0.96). The incidence of basal cell carcinoma was elevated in the entire cohort (SIR 1.18, 95%CI 1.10-1.25) and in the sub-cohorts of ovarian and peritoneal endometriosis. In conclusion, women with surgically verified endometriosis have an altered risk of only few non-gynecological cancers.

The Endometriotic Tumor Microenvironment in Ovarian Cancer

Women with endometriosis are at increased risk of developing ovarian cancer, specifically ovarian endometrioid, low-grade serous, and clear-cell adenocarcinoma. An important clinical caveat to the association of endometriosis with ovarian cancer is the improved prognosis for women with endometriosis at time of ovarian cancer staging. Whether endometriosis-associated ovarian cancers develop from the molecular transformation of endometriosis or develop because of the endometriotic tumor microenvironment remain unknown. Additionally, how the presence of endometriosis improves prognosis is also undefined, but likely relies on the endometriotic microenvironment. The unique tumor microenvironment of endometriosis is composed of epithelial, stromal, and immune cells, which adapt to survive in hypoxic conditions with high levels of iron, estrogen, and inflammatory cytokines and chemokines. Understanding the unique molecular features of the endometriotic tumor microenvironment may lead to impactful precision therapies and/or modalities for prevention. A challenge to this important study is the rarity of well-characterized clinical samples and the limited model systems. In this review, we will describe the unique molecular features of endometriosis-associated ovarian cancers, the endometriotic tumor microenvironment, and available model systems for endometriosis-associated ovarian cancers. Continued research on these unique ovarian cancers may lead to improved prevention and treatment options.

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.

Trends in the incidence rate, type and treatment of surgically verified endometriosis - a nationwide cohort study

INTRODUCTION

To study the trends in incidence rate, type and surgical treatment, and patient characteristics of surgically verified endometriosis during 1987-2012.

MATERIAL AND METHODS

This is a register-based cohort study. We identified women receiving their first diagnosis of endometriosis in surgery from the Finnish Hospital Discharge Register (FHDR). Quality of the FHDR records was assessed bidirectionally. The age-standardized incidence rates of the first surgically verified endometriosis was assessed by calendar year.

RESULTS

The cohort comprises 49 956 women. The quality assessment suggested the FHDR data to be of good quality. The most common diagnosis, ovarian endometriosis (46%), was associated with highest median age 38.5 years (interquartile range 31.0-44.8) and the second most common diagnosis, peritoneal endometriosis (40%), with median age 34.9 years (28.6-41.7). Between 1987 and 2012, a decrease was observed in the median age, from 38.8 (32.3-43.6) to 34.0 (28.9-41.0) years, and in the age-standardized incidence rate from 116 [95% confidence interval (CI) 112-121] to 45 (42-48) per 100 000 women. The proportion of hysterectomy as a first surgical treatment decreased from 38 to 19%, whereas that of laparoscopy increased from 42 to 73% when comparing 1987-1995 with 1996-2012.

CONCLUSIONS

This nationwide cohort of surgically verified endometriosis showed a decrease in the incidence rate and in the patient age at the time of first diagnosis, even though the proportion of laparoscopy has increased. The number of hysterectomies has decreased. These changes are likely to reflect the evolving diagnostics, increasing awareness of endometriosis, and effective use of medical treatment before surgery.

Role of endometriosis as a prognostic factor for post-progression survival in ovarian clear cell carcinoma

The clinical significance of coexistence of endometriosis (EM) in ovarian clear cell carcinoma (CCC) has not yet been determined. The aim of the present study was to analyze the correlation of endometriosis with clinicopathological factors in CCC. The cases with CCC that received primary debulking surgery at the present hospital between 1990 and 2013 were identified. Retrospective analysis was conducted to evaluate the association between complications with EM and clinicopathological features in CCC. Of the 105 cases enrolled in the study, 45 cases were complicated with EM, and 60 cases did not have EM (non-EM). The patients with EM were diagnosed at a younger age (P=0.03), and at earlier stages (P<0.01) compared with non-EM cases. Although there was no significant difference of progression-free survival (P=0.36), complications with EM were identified as an independent prognostic factor for overall survival (OS; P<0.01) by multivariate analysis. A total of 48 patients (45.7%) developed recurrence: 18 patients in EM-group and 30 patients in non-EM group. There were no significant differences of clinicopathological factors in the treatment at recurrence between both groups. Recurrent cases in EM had significantly worse post-progression survival (PPS) compared with recurrent non-EM group (P<0.01). Multivariate analysis for PPS demonstrated that complications with EM (P<0.01) were identified as a worse prognostic factor. In CCC, the complication with EM was identified as a significant worse prognostic factor for PPS in recurrent cases. Additionally, EM was significantly associated with OS in all cases with CCC. Novel treatment strategies are therefore necessary for recurrent CCC, particularly for cases exhibiting EM.

Reproductive and hormonal factors in relation to survival and platinum resistance among ovarian cancer cases

Background:

Ovarian cancer survival is poor, particularly for platinum-resistant cases. The previous literature on pre-diagnostic reproductive factors and ovarian cancer survival has been mixed. Therefore, we evaluated pre-diagnostic reproductive and hormonal factors with overall survival and, additionally, platinum-chemotherapy resistance.

Methods:

We followed 1649 invasive epithelial ovarian cancer cases who were enrolled between 1992 and 2008 for overall mortality within the New England Case-Control Study and abstracted chemotherapy data on a subset (n=449). We assessed pre-diagnostic reproductive and hormonal factors during in-person interviews. We calculated hazard ratios (HRs) using Cox-proportional hazards models.

Results:

We observed 911 all-cause deaths among 1649 ovarian cancer cases. Self-reported endometriosis and longer duration of hormone therapy use were associated with improved survival (HR: 0.72; 95% confidence interval (CI): 0.54–0.94 and HR, ⩾5 years vs never: 0.70; 95% CI: 0.55–0.90, respectively). Older age at menopause and menarche were associated with worse survival (HR, ⩽50 vs >50 years: 1.23; 95% CI: 1.03–1.46 and HR, 13 vs <13 years: 1.24; 95% CI: 1.06–1.44, respectively). We observed no association between oral contraceptive use, parity and tubal ligation, and overall survival. No significant associations were observed for any of the reproductive and hormonal factors and platinum resistance.

Conclusions:

These results suggest that pre-diagnostic exposures such as endometriosis and HT use may influence overall survival among ovarian cancer patients.

Diagnostics and Therapy for Malignant (Degenerate) Colon Endometriosis - Three Case Reports

Malignant degeneration of colon endometriosis is a very rare event. We report here on three cases. A 48-year-old woman with a 10-year history of endometriosis was treated for a rectal adenocarcinoma, a 61-year-old G1P1, who was operated at the age of 40 years for ovarian endometriosis and again at the age of 53 years for an endometriosis-associated endometroid ovarian carcinoma, presented for therapy for a lymph node recurrence of the ovarian cancer and, secondly, due to a malignantly degenerated rectum-sigmoid colon endometriosis; furthermore a 54-year old woman with a 21-year history of endometriosis was operated for malignant colon endometriosis. The tumour occurred during an adjuvant anti-oestrogen treatment with an aromatase inhibitor following surgical and radiotherapy for breast cancer. In all cases a radical cancer operation was followed by adjuvant chemotherapy and in one case with an additional radiotherapy. In the follow-up periods of 18 months, 2 and 5 years, respectively, all women remained free of recurrences. Although this is not a randomised controlled study due to the rare occurrence of such cases, a radical operation followed by individualised adjuvant therapy appears to be the treatment of choice.

Low-grade epithelial ovarian cancer: a number of distinct clinical entities?

PURPOSE OF REVIEW

The purpose of this study is to summarize the contemporary understanding of low-grade epithelial ovarian cancers.

RECENT FINDINGS

Low-grade serous ovarian cancer is biologically distinct from high-grade serous ovarian cancer. It is associated with a high incidence of K-RAS and B-RAF mutations. Although described as indolent due to median progression-free and overall survivals of 20 and 99 months, respectively, with a median age of diagnosis of 43 years, it accounts for a significant number of patient-years lost. Retrospective studies suggest response rates of 5% for chemotherapy and 9% for antioestrogen therapy. A prospective study of the mitogen-activated protein kinase kinase inhibitor selumetinib (response rate 15%) and retrospective bevacizumab studies suggest that these may be more effective approaches.Limited retrospective clinical data and even more sparse molecular data suggest that similar distinctions may exist between low-grade endometrioid and mucinous ovarian cancers and their respective high-grade counterparts, but more research is required in order to clarify the biological differences and the implications that these have for management.

SUMMARY

The results of phase III mitogen-activated protein kinase kinase inhibitor studies in low-grade serous ovarian cancer and further clinical and biological assessment of low-grade endometrioid and mucinous ovarian cancers are urgently required.

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).

(Partial) Loss of BAF250a (ARID1A) in rectovaginal deep-infiltrating endometriosis, endometriomas and involved pelvic sentinel lymph nodes

STUDY HYPOTHESIS

Loss of protein BAF250a (ARID1A) expression is present in women with rectovaginal deep-infiltrating endometriosis (DIE) and endometriosis affecting the pelvic sentinel lymph nodes (PSLN).

STUDY FINDING

Partial loss of protein BAF250a was found in some of our patient samples, comprising all endometriosis entities, including rectovaginal DIE and endometriosis affecting the PSLN.

WHAT IS KNOWN ALREADY

Loss of BAF250a (BRG-associated factor 250a)/ARIDIA (AT-rich interactive domain 1A) protein expression was identified among endometriosis-associated ovarian carcinomas and ovarian endometriosis, and this phenomenon was described as a possible early event in the transformation of endometriosis into cancer. DIE affecting the bowel/rectovaginal site is the most aggressive presentation of endometriosis and its 'risk' of malignant transformation has not been studied so far.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

We evaluated the immunohistochemical expression of BAF250a protein in 70 samples from patients enrolled in this study who were surgically treated at a tertiary center, university Hospital. The samples submitted to investigation were from rectovaginal DIE (n= 25/30), endometriosis affecting the PSLN (n= 5/7), ovarian endometriosis (n= 20/20) and endometrium from patients without endometriosis used as controls (n= 20/20).

MAIN RESULTS AND THE ROLE OF CHANCE

Partial loss (i.e. in one tissue section some cells stained positive for BAF250a while other cells, usually an adjacent group, were negative) of BAF250a protein was identified in 36% (9/25) of rectovaginal DIE samples, 40% (2/5) of endometriosis lesions involving the PSLN, 30% (6/20) of endometriomas, and also in 25% (5/20) of endometrium from controls. We found no statistical correlation between occurrence of partial loss of BAF250a protein and the use or not of hormone medications (P = 0.106), cycle phase (P = 0.917) and stage of disease (P = 0.717).

LIMITATIONS, REASONS FOR CAUTION

We only found partial loss of BAF250a protein expression, and in a small population of women, with relatively high frequency in all benign tissues assessed in the present analysis. Therefore, this finding alone should not be correlated directly with the risk of malignant transformation in these lesions.

WIDER IMPLICATIONS OF THE FINDINGS

The occurrence of partial loss of BAF250a protein expression in women with rectovaginal DIE and endometriosis affecting the PSLN is described for the first time. The value of this finding as a predictor of malignant transformation in endometriosis must still be clarified and further studied in association with other molecular events, such as PTEN (phosphatase and tensin homolog) deletion and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) mutation. We might then be able to identify in the future which patients with endometriosis are at higher risk of cancer.

STUDY FUNDING AND COMPETING INTERESTS

This study was supported by an internal Charité grant to the Endometriosis Research Center and the authors declare no conflicts of interest.

Endometriosis and breast cancer: A survey of the epidemiological studies

Endometriosis is a chronic gynecological disease with a wide spectrum of clinical manifestations that affects approximately 10% of women of reproductive age. Recent reviews have demonstrated the connection between endometriosis and breast cancer, which represents the most frequently diagnosed female cancer and the most common cause of cancer-related mortality among women worldwide. The aim of this study was to conduct a survey of available published epidemiological studies indicating the association between endometriosis and breast cancer, and simultaneously to categorize the results based on the strength of the association, with the intention of the critical evaluation of the existing data. We performed a rigorous search of the PubMed/Medline database, using the key words 'endometriosis' and 'breast cancer' for all studies published in the English language until September 2015. We found 4 retrospective cohort studies, 4 case-control studies and 3 case-cohort studies that demonstrated a notable risk for developing breast cancer among women with endometriosis. By contrast, we also found 5 case-control studies, 1 prospective cohort study, 1 case-cohort study and 1 cross-sectional study that demonstrated a negative association between endometriosis and breast cancer. In conclusion, as regards the clarification of a 'robust' or 'weak' association between endometriosis and breast cancer, no definite conclusions could be drawn, due to the limited number of studies and the limitations of each of these studies. New well-designed, prospective cohort or randomized control trials with long-term follow-up are warranted in order to provide evidence-based clinical recommendations for proper counseling, screening and treatment strategies for patients with endometriosis, and hence to improve public health.

Synchronous endometrioid endometrial and ovarian cancer in a 34-year-old woman

Ovarian cancer is the leading cause of death from gynaecological malignancy in developed countries. Synchronous endometrioid endometrial and ovarian cancer in patients appears with different clinical characteristics compared to patients with isolated endometrial cancer. A 34-year-old woman with lower abdominal pain of 1 year duration presented at the emergency department. On gynaecological examination, she had a left and midline pelvic mass. A transvaginal ultrasound showed it to be a complex hypervascularised mass, with cystic and solid components on left adnexal region. Ectopic pregnancy and pelvic inflammatory disease were excluded. Serum levels of tumour marker CA125 and ROMA were increased. The MR showed a complex mass, suggestive of primary fallopian tube or ovarian tumour. The patient underwent a total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic and para-aortic lymph node dissection and subcolonic omentectomy. Histopathology revealed a synchronous endometrioid endometrial and ovarian cancer.

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.

Association of endometriosis and breast cancer: mini review of the literature

BACKGROUND

Endometriosis is a common, estrogen-dependent, gynecological disease, which is defined as the presence of endometrial tissue outside the uterine cavity. Current data have associated endometriosis with specific malignancies, including ovarian and breast cancer.

PURPOSE

The purpose of our study is to summarize and present published literature providing evidence regarding the possible relationship between endometriosis and breast cancer.

METHODS

Pubmed and Scopus databases were searched systematically for studies that sought to identify a potential association of endometriosis and breast cancer. 15 relevant articles were retrieved and included in the present review.

RESULTS

A small number of observational studies have shown a correlation of endometriosis and breast cancer. Other studies found that the risk of breast cancer increases with age. The scenario of an early interruption of the inflammatory process, derived from endometriosis, by oophorectomy and a possible consequent decrease in the risk of breast cancer has also been proposed. The hypothesis that both conditions could be related through common mutations on BRAC1 and BRAC2 genes has also been investigated.

CONCLUSION

The available published evidence is inconclusive. Further studies are needed to evaluate the association of endometriosis and breast cancer and the possible pathogenetic pathways that relate the two disorders.

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.

Malignant neoplasia arising from ovarian remnants following bilateral salpingo-oophorectomy (Review)

Ovarian remnant syndrome (ORS) is a rare, but well-known gynecological complication, most often induced by difficult bilateral salpingo-oophorectomy (BSO) procedures that leave residual ovarian tissue on the pelvic wall. The most common preexisting conditions for this complication include endometriosis, pelvic inflammatory disease and prior abdominal surgery. The residual ovarian tissue may eventually cause malignant development. A total of 12 cases of malignant and benign tumors (clear cell adenocarcinoma in 1 case, mucinous-type tumors in 2, endometrioid-type tumors in 5, adenocarcinoma in 3 and border serous neoplasia in 1) and 21 benign cysts developing from an ovarian remnant have been described in the literature to date. Endometriosis, known to increase the risk of ovarian cancer, predisposes patients to ORS, with an incidence rate of 30 to 50% in ORS patients with ovarian carcinoma. Although the true incidence of ORS remains unknown, when endometriotic adhesions are diagnosed during BSO, the possibility of ORS and subsequent ovarian malignant transformation may mandate complete surgical resection.

Theories on the pathogenesis of endometriosis

Endometriosis is a common, chronic inflammatory disease defined by the presence of extrauterine endometrial tissue. The aetiology of endometriosis is complex and multifactorial, where several not fully confirmed theories describe its pathogenesis. This review examines existing theories on the initiation and propagation of different types of endometriotic lesions, as well as critically appraises the myriad of biologically relevant evidence that support or oppose each of the proposed theories. The current literature suggests that stem cells, dysfunctional immune response, genetic predisposition, and aberrant peritoneal environment may all be involved in the establishment and propagation of endometriotic lesions. An orchestrated scientific and clinical effort is needed to consider all factors involved in the pathogenesis of this multifaceted disease and to propose novel therapeutic targets to reach effective treatments for this distressing condition.

Risk and prognosis of ovarian cancer in women with endometriosis: a meta-analysis

Background:

The risk and prognosis of ovarian cancer have not been well established in women with endometriosis. Thus, we investigated the impact of endometriosis on the risk and prognosis for ovarian cancer, and evaluated clinicopathologic characteristics of endometriosis-associated ovarian cancer (EAOC) in comparison with non-EAOC.

Methods:

After we searched an electronic search to identify relevant studies published online between January 1990 and December 2012, we found 20 case–control and 15 cohort studies including 444 255 patients from 1 625 potentially relevant studies. In the meta-analysis, ovarian cancer risk by endometriosis and clinicopathologic characteristics were evaluated using risk ratio (RR) or standard incidence ratio (SIR), and prognosis was investigated using hazard ratio (HR) with 95% confidence interval (CI). Heterogeneity was evaluated using Higgins I² to select fixed-effect (I² ⩽50%) or random effects models (I²>50%), and found no publication bias using funnel plots with Egger's test (P>0.05). Furthermore, we performed subgroup analyses based on study design, assessment of endometriosis, histology, disease status, quality of study and adjustment for potential confounding factors to minimise bias.

Results:

Endometriosis increased ovarian cancer risk in case–control or two-arm cohort studies (RR, 1.265; 95% CI, 1.214–1.318) and single-arm cohort studies (SIR, 1.797; 95% CI, 1.276–2.531), which were similar in subgroup analyses. Although progression-free survival was not different between EAOC and non-EAOC (HR, 1.023; 95% CI, 0.712–1.470), EAOC was associated with better overall survival than non-EAOC in crude analyses (HR, 0.778; 95% CI, 0.655–0.925). However, progression-free survival and overall survival were not different between the two groups in subgroup analyses. Stage I–II disease, grade 1 disease and nulliparity were more common in EAOC (RRs, 1.959, 1.319 and 1.327; 95% CIs, 1.367–2.807, 1.149–1.514 and 1.245–1.415), whereas probability of optimal debulking surgery was not different between the two groups (RR, 1.403; 95% CI, 0.915–2.152). Furthermore, endometrioid and clear cell carcinomas were more common in EAOC (RRs, 1.759 and 2.606; 95% CIs, 1.551–1.995 and 2.225–3.053), whereas serous carcinoma was less frequent in EAOC than in non-EAOC (RR, 0.733; 95% CI, 0.617–0.871), and there was no difference in the risk of mucinous carcinoma between the two groups (RR, 0.805; 95% CI, 0.584–1.109). These clinicopathologic characteristics were also similar in subgroup analyses.

Conclusions:

Endometriosis is strongly associated with the increased risk of ovarian cancer, and EAOC shows favourable characteristics including early-stage disease, low-grade disease and a specific histology such as endometrioid or clear cell carcinoma. However, endometriosis may not affect disease progression after the onset of ovarian cancer.

Lipocalin 2 induces the epithelial–mesenchymal transition in stressed endometrial epithelial cells: possible correlation with endometriosis development in a mouse model

Lipocalin 2 (LCN2) is an induced stressor that promotes the epithelial–mesenchymal transition (EMT). We previously demonstrated that the development of endometriosis in mice correlates with the secretion of LCN2 in the uterus. Here, we sought to clarify the relationship between LCN2 and EMT in endometrial epithelial cells and to determine whether LCN2 plays a role in endometriosis. Antibodies that functionally inhibit LCN2 slowed the growth of ectopic endometrial tissue in a mouse model of endometriosis, suggesting that LCN2 promotes the formation of endometriotic lesions. Using nutrient deprivation as a stressor, LCN2 expression was induced in cultured primary endometrial epithelial cells. As LCN2 levels increased, the cells transitioned from a round to a spindle-like morphology and dispersed. Immunochemical analyses revealed decreased levels of cytokeratin and increased levels of fibronectin in these endometrial cells, adhesive changes that correlate with induction of cell migration and invasion.Lcn2knockdown also indicated that LCN2 promotes EMT and migration of endometrial epithelial cells. Our results suggest that stressful cellular microenvironments cause uterine tissues to secrete LCN2 and that this results in EMT of endometrial epithelial cells, which may correlate with the development of ectopic endometriosis. These findings shed light on the role of LCN2 in the pathology of endometrial disorders.

Genome-wide expressions in autologous eutopic and ectopic endometrium of fertile women with endometriosis

BACKGROUND

In order to obtain a lead of the pathophysiology of endometriosis, genome-wide expressional analyses of eutopic and ectopic endometrium have earlier been reported, however, the effects of stages of severity and phases of menstrual cycle on expressional profiles have not been examined. The effect of genetic heterogeneity and fertility history on transcriptional activity was also not considered. In the present study, a genome-wide expression analysis of autologous, paired eutopic and ectopic endometrial samples obtained from fertile women (n=18) suffering from moderate (stage 3; n=8) or severe (stage 4; n=10) ovarian endometriosis during proliferative (n=13) and secretory (n=5) phases of menstrual cycle was performed.

METHODS

Individual pure RNA samples were subjected to Agilent's Whole Human Genome 44K microarray experiments. Microarray data were validated (P<0.01) by estimating transcript copy numbers by performing real time RT-PCR of seven (7) arbitrarily selected genes in all samples. The data obtained were subjected to differential expression (DE) and differential co-expression (DC) analyses followed by networks and enrichment analysis, and gene set enrichment analysis (GSEA). The reproducibility of prediction based on GSEA implementation of DC results was assessed by examining the relative expressions of twenty eight (28) selected genes in RNA samples obtained from fresh pool of eutopic and ectopic samples from confirmed ovarian endometriosis patients with stages 3 and 4 (n=4/each) during proliferative and secretory (n=4/each) phases.

RESULTS

Higher clustering effect of pairing (cluster distance, cd=0.1) in samples from same individuals on expressional arrays among eutopic and ectopic samples was observed as compared to that of clinical stages of severity (cd=0.5) and phases of menstrual cycle (cd=0.6). Post hoc analysis revealed anomaly in the expressional profiles of several genes associated with immunological, neuracrine and endocrine functions and gynecological cancers however with no overt oncogenic potential in endometriotic tissue. Dys-regulation of three (CLOCK, ESR1, and MYC) major transcription factors appeared to be significant causative factors in the pathogenesis of ovarian endometriosis. A novel cohort of twenty-eight (28) genes representing potential marker for ovarian endometriosis in fertile women was discovered.

CONCLUSIONS

Dysfunctional expression of immuno-neuro-endocrine behaviour in endometrium appeared critical to endometriosis. Although no overt oncogenic potential was evident, several genes associated with gynecological cancers were observed to be high in the expressional profiles in endometriotic tissue.

Unraveling the two entities of endometrioid ovarian cancer: a single center clinical experience

OBJECTIVE

Due to the increasing prevalence of the benign condition, ovarian carcinoma arising from endometriosis is emerging as a relevant clinical entity with an unclear biological signature. We have investigated clinical and histologic features of endometriosis-associated endometrioid ovarian cancer using an institutional retrospective database.

METHODS

Patients diagnosed with endometrioid ovarian cancer at our institution were divided into two groups according to the fulfillment or not of Sampson's and Scott's criteria for the detection of endometriosis-associated ovarian cancer. Clinical and histological data were reported and compared. Survival analysis was obtained using the log-rank test in an unadjusted Kaplan-Meier method. Multivariate analysis was performed using the Cox proportional hazards regression model to establish independent factors associated with endometriosis-associated endometrioid ovarian cancer and to identify predictors of survival. The degree of concordance was evaluated by Cohen's Kappa measures.

RESULTS

Patients with endometriosis-associated endometrioid ovarian cancer were significantly younger, had a lower disease stage (62% vs 23%; p=0.003), a less prevalent high grade tumor (38% vs 82%; p=0.002) and a higher prevalence of squamous and mucinous metaplasia. The rate of endometrial cancer diagnosis was significantly higher in women with endometriosis-associated endometrioid ovarian cancer (33%) than in other patients (11%) (p=0.04) with a 92% concordance between ovarian and endometrial histologic tumor grade. A significant difference in survival rate could not be demonstrated between patients with or without endometriosis.

CONCLUSIONS

The analysis of a retrospective endometrioid ovarian cancer database may allow to suggest a 40 molecular, morphological and clinical parallelism between endometrial and endometrioid ovarian cancers.

The association between endometriosis and gynecological cancers and breast cancer: a review of epidemiological data

OBJECTIVE

This article critically reviews the literature on the association between endometriosis and gynecological cancers and breast cancer, based on epidemiologic data.

METHODS

Literature review of the English language literature based on searching in the MEDLINE (PubMed) database and additional collection of reports by systematically reviewing all references from retrieved papers.

RESULTS

Data from large cohort and case-control studies indicate that endometriosis patients only have an increased risk of ovarian cancer among the gynecological malignancies and breast cancer, although most of the observed associations are modest. Data on the association between endometriosis and breast cancer are inconsistent. Endometriosis patients have a reduced risk of cervical cancer, and there is no association between endometriosis and endometrial cancer. Endometriosis-associated ovarian cancer seems to be a distinct clinical entity; patients are younger, diagnosed in earlier stages, have lower grade lesions and a better survival. Further, endometriosis-associated ovarian cancers are predominantly clear cell and endometrioid histologic subtypes.

CONCLUSIONS

Endometriosis seems to be a precursor of epithelial ovarian cancer, especially clear cell and endometrioid adenocarcinomas. However, current evidence is insufficient to draw any definitive conclusions whether this association represents causality or the sharing of similar risk factors and/or antecedent mechanisms.