Menopausal hormone therapy and risk of ovarian cancer in the European prospective investigation into cancer and nutrition

Global epidemiology of epithelial ovarian cancer

Globally, ovarian cancer is the eighth most common cancer in women, accounting for an estimated 3.7% of cases and 4.7% of cancer deaths in 2020. Until the early 2000s, age-standardized incidence was highest in northern Europe and North America, but this trend has changed; incidence is now declining in these regions and increasing in parts of eastern Europe and Asia. Ovarian cancer is a very heterogeneous disease and, even among the most common type, namely epithelial ovarian cancer, five major clinically and genetically distinct histotypes exist. Most high-grade serous ovarian carcinomas are now recognized to originate in the fimbrial ends of the fallopian tube. This knowledge has led to more cancers being coded as fallopian tube in origin, which probably explains some of the apparent declines in ovarian cancer incidence, particularly in high-income countries; however, it also suggests that opportunistic salpingectomy offers an important opportunity for prevention. The five histotypes share several reproductive and hormonal risk factors, although differences also exist. In this Review, we summarize the epidemiology of this complex disease, comparing the different histotypes, and consider the potential for prevention. We also discuss how changes in the prevalence of risk and protective factors might have contributed to the observed changes in incidence and what this might mean for incidence in the future.

Use of menopausal hormone therapy and ovarian cancer risk in a French cohort study

BACKGROUND

Epidemiological studies have found that menopausal hormone therapy (MHT) use is associated with an increased ovarian cancer risk. However, whether different MHT types confer the same level of risk is unclear. We estimated the associations between different MHT types and the risk of ovarian cancer in a prospective cohort.

METHODS

The study population included 75 606 postmenopausal women from the E3N cohort. Exposure to MHT was identified from self-reports in biennial questionnaires between 1992 and 2004 and from drug claim data matched to the cohort between 2004 and 2014. Hazard ratios and 95% confidence intervals (CIs) of ovarian cancer were estimated using multivariable Cox proportional hazards models with MHT as a time-varying exposure. Tests of statistical significance were 2-sided.

RESULTS

Over an average 15.3 years follow-up, 416 ovarian cancers were diagnosed. Hazard ratios of ovarian cancer associated with ever use of estrogens combined with progesterone or dydrogesterone and ever use of estrogens combined with other progestagen were equal to 1.28 (95% CI = 1.04 to 1.57) and 0.81 (95% CI = 0.65 to 1.00), respectively (Phomogeneity = .003), compared with never use. The hazard ratio for unopposed estrogen use was 1.09 (95% CI = 0.82 to 1.46). We found no trend according to duration of use or time since last use except for estrogens combined with progesterone or dydrogesterone, which showed decreasing risk with increasing time since last use.

CONCLUSION

Different MHT types may impact ovarian cancer risk differentially. The possibility that MHT containing progestagens other than progesterone or dydrogesterone may confer some protection should be evaluated in other epidemiological studies.

Effects of menopausal hormone therapy on the risk of ovarian cancer: Health Insurance Database in South Korea-based cohort study

OBJECTIVE

This study aimed to evaluate the risk of ovarian cancer associated with hormone therapy regimens using a Korean population-based study.

METHODS

This retrospective cohort study used national health checkup and insurance data from January 1, 2002, to December 31, 2019, provided by Korea's National Health Insurance Service. Women older than 40 years who recorded "menopause" in the questionnaire from 2002 to 2011 were included in this study. Menopausal hormone therapy (MHT) preparations were classified into tibolone, combined estrogen plus progestin by the manufacturer, combined estrogen plus progestin by physician, estrogen, and topical estrogen groups. The number of participants recorded as menopausal during the national health examination between 2002 and 2011 was 2,506,271. The MHT and non-MHT groups consisted of 373,271 and 1,382,653 patients, respectively. The hazard ratios (HR) of ovarian cancer according to MHT type, age at inclusion, body mass index, region, socioeconomic status, Charlson comorbidity index, age at menarche, age at menopause, parity, smoking, alcohol consumption, physical exercise, and period from menopause to inclusion were evaluated.

RESULTS

The risk of ovarian cancer was reduced in the tibolone group (HR, 0.84; 95% confidence interval, 0.75-0.93; P = 0.003) and in patients in rural areas (HR, 0.90; 95% confidence interval, 0.845-0.98; P = 0.013). The risk of ovarian cancer was not related to the other MHT treatments.

CONCLUSION

Tibolone was associated with a lower risk of ovarian cancer. No other MHT was associated with ovarian cancer.

Hysterectomy and risk of epithelial ovarian cancer by histologic type, endometriosis, and menopausal hormone therapy

BACKGROUND

This nationwide, register-based case-control study investigated the association between hysterectomy and risk of epithelial ovarian cancer according to histology and by history of endometriosis and menopausal hormone therapy (MHT) use.

METHODS

From the Danish Cancer Registry, all women registered with epithelial ovarian cancer at age 40-79 years during 1998-2016 were identified (n = 6738). Each case was sex- and age-matched to 15 population controls using risk-set sampling. Information on previous hysterectomy on benign indication and potential confounders was retrieved from nationwide registers. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between hysterectomy and ovarian cancer according to histology, endometriosis, and use of MHT.

RESULTS

Hysterectomy was not associated with risk of epithelial ovarian cancer overall (OR=0.99; 95% CI 0.91 -1.09) but was associated with reduced risk of clear cell ovarian cancer (OR=0.46; 95% CI 0.28-0.78). In stratified analyses, decreased ORs associated with hysterectomy were seen in women with endometriosis (OR=0.74; 95% CI 0.50-1.10) and in non-users of MHT (OR=0.87; 95% CI 0.76-1.01). In contrast, among long-term MHT users, hysterectomy was associated with increased odds for ovarian cancer (OR=1.20; 95% CI 1.03-1.39).

CONCLUSION

Hysterectomy was not associated with epithelial ovarian cancer overall but with reduced risk of clear cell ovarian cancer. Our findings may suggest a reduced risk of ovarian cancer after hysterectomy in women with endometriosis and in MHT non-users. Interestingly our data pointed to an increased ovarian cancer risk associated with hysterectomy among long-term users of MHT.

Risk Factors for Ovarian Cancer: An Umbrella Review of the Literature

Several non-genetic factors have been associated with ovarian cancer incidence or mortality. To evaluate the strength and validity of the evidence we conducted an umbrella review of the literature that included systematic reviews/meta-analyses that evaluated the link between non-genetic risk factors and ovarian cancer incidence and mortality. We searched PubMed, EMBASE, Cochrane Database of Systematic Reviews and performed a manual screening of references. Evidence was graded into strong, highly suggestive, suggestive or weak based on statistical significance of the random effects summary estimate and the largest study in a meta-analysis, the number of cases, between-study heterogeneity, 95% prediction intervals, small study effects, and presence of excess significance bias. We identified 212 meta-analyses, investigating 55 non-genetic risk factors for ovarian cancer. Risk factors were grouped in eight broad categories: anthropometric indices, dietary intake, physical activity, pre-existing medical conditions, past drug history, biochemical markers, past gynaecological history and smoking. Of the 174 meta-analyses of cohort studies assessing 44 factors, six associations were graded with strong evidence. Greater height (RR per 10 cm 1.16, 95% confidence interval (CI) 1.11-1.20), body mass index (BMI) (RR ≥ 30 kg/m² versus normal 1.27, 95% CI 1.17-1.38) and three exposures of varying preparations and usage related to hormone replacement therapy (HRT) use increased the risk of developing ovarian cancer. Use of oral contraceptive pill reduced the risk (RR 0.74, 95% CI 0.69-0.80). Refining the significance of genuine risk factors for the development of ovarian cancer may potentially increase awareness in women at risk, aid prevention and early detection.

A nomogram model based on clinical markers for predicting malignancy of ovarian tumors

OBJECTIVE

The aim of this study was to build a nomogram based on clinical markers for predicting the malignancy of ovarian tumors (OTs).

METHOD

A total of 1,268 patients diagnosed with OTs that were surgically removed between October 2017 and May 2019 were enrolled. Clinical markers such as post-menopausal status, body mass index (BMI), serum human epididymis protein 4 (HE4) value, cancer antigen 125 (CA125) value, Risk of Ovarian Malignancy Algorithm (ROMA) index, course of disease, patient-generated subjective global assessment (PG-SGA) score, ascites, and locations and features of masses were recorded and analyzed (p 0.05). Significant variables were further selected using multivariate logistic regression analysis and were included in the decision curve analysis (DCA) used to assess the value of the nomogram model for predicting OT malignancy.

RESULT

The significant variables included post-menopausal status, BMI, HE4 value, CA125 value, ROMA index, course of disease, PG-SGA score, ascites, and features and locations of masses (p 0.05). The ROMA index, BMI (≥ 26), unclear/blurred mass boundary (on magnetic resonance imaging [MRI]/computed tomography [CT]), mass detection (on MRI/CT), and mass size and features (on type B ultrasound [BUS]) were screened out for multivariate logistic regression analysis to assess the value of the nomogram model for predicting OT malignant risk (p 0.05). The DCA revealed that the net benefit of the nomogram's calculation model was superior to that of the CA125 value, HE4 value, and ROMA index for predicting OT malignancy.

CONCLUSION

We successfully tailored a nomogram model based on selected clinical markers which showed superior prognostic predictive accuracy compared with the use of the CA125, HE4, or ROMA index (that combines both HE and CA125 values) for predicting the malignancy of OT patients.

Characterization of diphenyl phthalate as an agonist for estrogen receptor: an in vitro and in silico study

Phthalate esters (PAEs) are important pollutants in the environment, which can interfere with the endocrine system by mimicking estrogen. However, limited information is available on modulating the estrogen receptor (ER) of five PAEs including di (2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), benzyl butyl phthalate (BBP), diphenyl phthalate (DPhP) and dicyclohexyl phthalate (DCHP). This study evaluated the agonistic effects of PAEs on human ER. The cytotoxicity assay showed that there were a significant inhibition of the cell proliferation with treatment of five PAEs. Moreover, DPhP does-dependently enhanced ER-mediated transcriptional activity in the reporter gene assay. The increased expression of estrogen-responsive genes (TFF1, CTSD, and GREB1) was also observed in MCF-7 cells treated with DPhP. The result of molecular docking showed that DPhP tended to bind to the agonist conformation of ER compared with the antagonist conformation of ER, demonstrating its agonist characteristic that has been confirmed in the reporter gene assay. Thus, we found that DPhP may be evaluated as an ER agonist in vitro and it can interfere with the normal function of human ER.

Association of Endogenous Pregnenolone, Progesterone, and Related Metabolites with Risk of Endometrial and Ovarian Cancers in Postmenopausal Women: The BFIT Cohort

BACKGROUND

Postmenopausal pregnenolone and/or progesterone levels in relation to endometrial and ovarian cancer risks have been infrequently evaluated. To address this, we utilized a sensitive and reliable assay to quantify prediagnostic levels of seven markers related to endogenous hormone metabolism.

METHODS

Hormones were quantified in baseline serum collected from postmenopausal women in a cohort study nested within the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT). Women using exogenous hormones at baseline (1992-1993) were excluded. Incident endometrial (n = 65) and ovarian (n = 67) cancers were diagnosed during 12 follow-up years and compared with a subcohort of 345 women (no hysterectomy) and 413 women (no oophorectomy), respectively. Cox models with robust variance were used to estimate cancer risk.

RESULTS

Circulating progesterone levels were not associated with endometrial [tertile (T)3 vs. T1 HR (95% confidence interval): 1.87 (0.85-4.11); P _trend = 0.17] or ovarian cancer risk [1.16 (0.58-2.33); 0.73]. Increasing levels of the progesterone-to-estradiol ratio were inversely associated with endometrial cancer risk [T3 vs. T1: 0.29 (0.09-0.95); 0.03]. Increasing levels of 17-hydroxypregnenolone were inversely associated with endometrial cancer risk [0.40 (0.18-0.91); 0.03] and positively associated with ovarian cancer risk [3.11 (1.39-6.93); 0.01].

CONCLUSIONS

Using sensitive and reliable assays, this study provides novel data that endogenous progesterone levels are not strongly associated with incident endometrial or ovarian cancer risks. 17-hydroxypregnenolone was positively associated with ovarian cancer and inversely associated with endometrial cancer.

IMPACT

While our results require replication in large studies, they provide further support of the hormonal etiology of endometrial and ovarian cancers.

Posttraumatic Stress Disorder and Likelihood of Hormone Therapy Use among Women in the Nurses' Health Study II: A 26-Year Prospective Analysis

BACKGROUND

Posttraumatic stress disorder (PTSD) is associated with higher risk of certain chronic diseases, including ovarian cancer, but underlying mechanisms remain unclear. Although prior work has linked menopausal hormone therapy (MHT) use with elevated ovarian cancer risk, little research considers PTSD to likelihood of MHT use. We examined whether PTSD was prospectively associated with greater likelihood of initiating MHT use over 26 years.

METHODS

Using data from the Nurses' Health Study II, with trauma and PTSD (symptoms and onset date) assessed by screener in 2008 and MHT assessed via biennial survey (from 1989), we performed Cox proportional regression models with women contributing person-years from age 36 years. Relevant covariates were assessed at biennial surveys. We considered potential effect modification by race/ethnicity, age at baseline, and period (1989-2002 vs. 2003-2015).

RESULTS

Over follow-up, 22,352 of 43,025 women reported initiating MHT use. For example, compared with women with no trauma, the HR for initiating MHT was 1.18 for those with trauma/1-3 PTSD symptoms [95% confidence interval (CI), 1.13-1.22] and 1.31 for those with trauma/4-7 PTSD symptoms (95% CI, 1.25-1.36; P trend < 0.001), adjusting for sociodemographic factors. Associations were maintained when adjusting for reproductive factors and health conditions. We found evidence of effect modification by age at baseline.

CONCLUSIONS

Trauma and number of PTSD symptoms were associated with greater likelihood of initiating MHT use in a dose-response manner.

IMPACT

MHT may be a pathway linking PTSD to altered chronic disease risk. It is important to understand why women with PTSD initiate MHT use.

Tibolone as Hormonal Therapy and Neuroprotective Agent

Tibolone (TIB), a selective tissue estrogenic activity regulator (STEAR) in clinical use by postmenopausal women, activates hormonal receptors in a tissue-specific manner. Estrogenic activity is present mostly in the brain, vagina, and bone, while the inactive forms predominate in the endometrium and breast. Conflicting literature on TIB's actions has been observed. While it has benefits for vasomotor symptoms, bone demineralization, and sexual health, a higher relative risk of hormone-sensitive cancer has been reported. In the brain, TIB can improve mood and cognition, neuroinflammation, and reactive gliosis. This review aims to discuss the systemic effects of TIB on peri- and post-menopausal women and its role in the brain. We suggest that TIB is a hormonal therapy with promising neuroprotective properties.

Prior uterine myoma and risk of ovarian cancer: a population-based case-control study

Objective

Uterine myoma which results in the magnitude of ovarian cancer remains uncertain. This study aimed to assess the association between women with previous uterine myoma and the risk of ovarian cancer.

Methods

This population-based case-control study was conducted using the Taiwan National Health Insurance Research Database between 2006 and 2010. We identified 4,088 adult women with newly diagnosed ovarian cancer with 16,348 women without ovarian cancer matched for age, urbanization level, income and initial diagnosis date. Logistic regression analyses were used to evaluate the variables associated with ovarian cancer. In addition, the effect of surgical interventions on the risk of ovarian cancer was also evaluated.

Results

Women with previous uterine myoma were more likely than those who did not to have ovarian cancer (adjusted odds ratio [aOR]=2.26; 95% confidence interval [CI]=2.06−2.49). Patients with uterine myoma who either received (aOR=1.79; 95% CI=1.51−2.13) or did not receive hormone replacement therapy (aOR=2.51; 95% CI=2.24−2.82) experienced a significantly higher risk of ovarian cancer than those without uterine myoma, respectively. However, patients with uterine myoma who underwent either myomectomy (aOR=0.55; 95% CI=0.39−0.77) or hysterectomy (aOR=0.33; 95% CI=0.26−0.42) had a significantly lower risk of ovarian cancer.

Conclusion

The results revealed that a significantly higher risk of ovarian cancer in women with previous uterine myoma, through an indirect mechanism. Furthermore, a lower risk of ovarian cancer was observed in women who underwent surgical removal of the uterine myoma.

Environmental toxin exposure in polycystic ovary syndrome women and possible ovarian neoplastic repercussion

Purpose: Over the last two decades, increasing attention has been paid to environmental toxins and their effects on the female reproductive system. Endocrine disrupting chemicals (EDCs) are exogenous substances or mixtures that can mimic the action of steroid hormones and interfere with their metabolism. Advanced glycation end products (AGEs) are proinflammatory molecules that can interact with cell surface receptors and mediate the triggering of proinflammatory pathways and oxidative stress. The purpose of this review is to explore the effects of environmental toxin exposure in the pathogenesis of both polycystic ovary syndrome (PCOS) and OC (ovarian cancer), considered separately, and also to evaluate possible neoplastic ovarian repercussion after exposure in patients diagnosed with PCOS.Materials and methods: We searched PubMed for articles published in the English language with the use of the following MeSH search terms: "polycystic ovary syndrome" and "ovarian cancer" combined with "endocrine disruptors". Titles and abstracts were examined and full articles that met the selection criteria were retrieved. A manual search of review articles and cross-references completed the search.Results: Extensive data from different studies collected in recent years concerning the effects of EDC/AGE exposure have confirmed their role in the pathophysiology of both PCOS and OC. They favor PCOS/OC development through different mechanisms that finally lead to hormonal and metabolic disruption and epigenetic modifications.Conclusions: Environmental toxin exposure in PCOS women could favor neoplastic transformation by exacerbating and potentiating some PCOS features. Further research, although difficult, is needed in order to prevent further diffusion of these substances in the environment, or at least to provide adequate information to the population considered at risk.

The Association Between Hysterectomy and Ovarian Cancer Risk: A Population-Based Record-Linkage Study

BACKGROUND

Recent studies have called into question the long-held belief that hysterectomy without oophorectomy protects against ovarian cancer. This population-based longitudinal record-linkage study aimed to explore this relationship, overall and by age at hysterectomy, time period, surgery type, and indication for hysterectomy.

METHODS

We followed the female adult Western Australian population (837 942 women) across a 27-year period using linked electoral, hospital, births, deaths, and cancer records. Surgery dates were determined from hospital records, and ovarian cancer diagnoses (n = 1640) were ascertained from cancer registry records. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between hysterectomy and ovarian cancer incidence.

RESULTS

Hysterectomy without oophorectomy (n = 78 594) was not associated with risk of invasive ovarian cancer overall (HR = 0.98, 95% CI = 0.85 to 1.11) or with the most common serous subtype (HR = 1.05, 95% CI = 0.89 to 1.23). Estimates did not vary statistically significantly by age at procedure, time period, or surgical approach. However, among women with endometriosis (5.8%) or with fibroids (5.7%), hysterectomy was associated with substantially decreased ovarian cancer risk overall (HR = 0.17, 95% CI = 0.12 to 0.24, and HR = 0.27, 95% CI = 0.20 to 0.36, respectively) and across all subtypes.

CONCLUSIONS

Our results suggest that for most women, having a hysterectomy with ovarian conservation is not likely to substantially alter their risk of developing ovarian cancer. However, our results, if confirmed, suggest that ovarian cancer risk reduction could be considered as a possible benefit of hysterectomy when making decisions about surgical management of endometriosis or fibroids.

Genetic epidemiology of ovarian cancer and prospects for polygenic risk prediction

Epithelial ovarian cancer (EOC) is a heterogeneous disease with a major heritable component. The different histotypes of invasive disease - high grade serous, clear cell, endometrioid and mucinous - are associated with different underlying genetic susceptibility and epidemiological and lifestyle risk factors, all of which contribute to the different biology and clinical characteristics of each histotype. A combination of familial and population based sequencing studies, and genome wide association studies (GWAS) have identified a range of genetic susceptibility alleles for EOC comprising rare but highly penetrant genes (e.g. BRCA1, BRCA2) that are responsible for familial clustering of ovarian cancer cases; more moderate penetrance susceptibility genes (e.g. BRIP1, RAD51C/D, MSH6); and multiple common but low penetrance susceptibility alleles identified by GWAS. Identifying genetic risk alleles for ovarian cancer has had a significant impact on disease prevention strategies; for example it is now routine clinical practice for individuals with germline BRCA1 and BRCA2 mutations to undergo risk reducing salpingo-oophorectomy. Because ovarian cancers are commonly diagnosed at a late clinical stage when the prognosis is poor, the continued development of genetic risk prediction and prevention strategies will represent an important approach to reduce mortality due to ovarian cancer. Advances in genomics technologies that enable more high-throughput genetic testing, combined with research studies that identify additional EOC risk alleles will likely provide further opportunities to establish polygenic risk prediction approaches, based on combinations of rare high/moderate penetrance susceptibility genes and common, low penetrance susceptibility alleles. This article reviews the current literature describing the genetic and epidemiological components of ovarian cancer risk, and discusses both the opportunities and challenges in using this information for clinical risk prediction and prevention.

Novel biomolecule lycopene-reduced graphene oxide-silver nanoparticle enhances apoptotic potential of trichostatin A in human ovarian cancer cells (SKOV3)

Background

Recently, there has been much interest in the field of nanomedicine to improve prevention, diagnosis, and treatment. Combination therapy seems to be most effective when two different molecules that work by different mechanisms are combined at low dose, thereby decreasing the possibility of drug resistance and occurrence of unbearable side effects. Based on this consideration, the study was designed to investigate the combination effect of reduced graphene oxide-silver nanoparticles (rGO-AgNPs) and trichostatin A (TSA) in human ovarian cancer cells (SKOV3).

Methods

The rGO-AgNPs were synthesized using a biomolecule called lycopene, and the resultant product was characterized by various analytical techniques. The combination effect of rGO-Ag and TSA was investigated in SKOV3 cells using various cellular assays such as cell viability, cytotoxicity, and immunofluorescence analysis.

Results

AgNPs were uniformly distributed on the surface of graphene sheet with an average size between 10 and 50 nm. rGO-Ag and TSA were found to inhibit cell viability in a dose-dependent manner. The combination of rGO-Ag and TSA at low concentration showed a significant effect on cell viability, and increased cytotoxicity by increasing the level of malondialdehyde and decreasing the level of glutathione, and also causing mitochondrial dysfunction. Furthermore, the combination of rGO-Ag and TSA had a more pronounced effect on DNA fragmentation and double-strand breaks, and eventually induced apoptosis.

Conclusion

This study is the first to report that the combination of rGO-Ag and TSA can cause potential cytotoxicity and also induce significantly greater cell death compared to either rGO-Ag alone or TSA alone in SKOV3 cells by various mechanisms including reactive oxygen species generation, mitochondrial dysfunction, and DNA damage. Therefore, this combination chemotherapy could be possibly used in advanced cancers that are not suitable for radiation therapy or surgical treatment and facilitate overcoming tumor resistance and disease progression.

Effects of Endocrine-Disrupting Chemicals and Epigenetic Modifications in Ovarian Cancer: A Review

Ovarian cancer (OC) is a relatively fatal female reproductive malignancy. Since the underlying causes are uncertain, it brings us to believe that both genetic and external factors contribute toward development of this lethal disorder. Exposure to endocrine-disrupting chemicals (EDCs) in the form of occupational usage of pesticides, fungicides, herbicides, plasticizers, cosmetics, and so on is potentially carcinogenic and their ability to cause epigenetic modifications has led us to hypothesize that they may play a catalytic role in OC progression. In response to synthetic chemicals, animal models have demonstrated disturbances in the development of ovaries and steroid hormonal levels but in humans, more research is required. The present review is an attempt to address the impact of EDCs on the hormonal system and gene methylation levels that may lead to malfunctioning of the ovaries which may consequently develop in the form of cancer. It can be concluded that endocrine disruptors do have a potential carcinogenicity and their high proportions in human body may cause epigenetic modifications, prompting ovarian surface epithelium to grow in an abnormal manner.

Epidemiology of ovarian cancer: a review

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

Epidemiology of ovarian cancer: a review

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

Epidemiology of ovarian cancer: a review

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

A prospective study of reproductive factors and exogenous hormone use in relation to ovarian cancer risk among Black women

PURPOSE

Extensive data in White women have linked oral contraceptive use, tubal ligation, and parity to reduced risk of ovarian cancer; results on postmenopausal female hormone use are mixed. Few studies, all of which are case-control studies, have been undertaken among Black women. The aim of the present study was to prospectively assess associations of reproductive factors and exogenous hormones with ovarian cancer among Black women.

METHODS

During follow-up from 1995 to 2013 in the Black Women's Health Study, a prospective cohort study, 115 incident cases of ovarian cancer were identified. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the relation of the factors of interest to risk of ovarian cancer, with control for covariates.

RESULT

Oral contraceptive use was inversely associated with ovarian cancer risk: The HR for ≥10 years of use relative to <1 year was 0.50 (95% CI 0.30-0.98). For postmenopausal female hormone use, the HRs for ever use of estrogen with progestin and of estrogen alone were 1.37 (0.73-2.55) and 1.66 (0.90-3.07), respectively. The HRs for parity and tubal ligation were below 1.0, but were not statistically significant.

CONCLUSION

Overall, the findings indicate that the relation of reproductive factors and exogenous hormone use to risk of ovarian cancer is similar among Black and White women. The results on estrogen-only supplements and estrogen with progestin supplements add to evidence from Whites, indicating that use of hormone supplements may be associated with increased risk of ovarian cancer.

Hormone therapy for ovarian cancer survivors: systematic review and meta-analysis

OBJECTIVE

Hormone therapy (HT) alleviates menopausal symptoms, but there is a lack of consensus regarding its use among premenopausal ovarian cancer survivors.

METHODS

We systematically reviewed the literature and searched the Medline (1966-2014), Scopus (2004-2014), Popline (1974-2014), ClinicalTrials.gov (2008-2014), and Cochrane Central Register of Controlled Trials CENTRAL (1999-2014) databases and the reference lists of electronically retrieved studies. Statistical meta-analysis was performed using RevMan 5.1 software.

RESULTS

Six studies were included in our systematic review, which involved 1,521 women. Among them, 451 women (29.6%) received HT, whereas the remaining 1,070 women (70.4%) did not receive any treatment. We noticed a statistically significant reduction of ovarian cancer-related deaths among women who received HT (odds ratio, 0.47; 95% CI, 0.28-0.80); however, disease recurrence rates did not differ between the two groups (odds ratio, 0.71; 95% CI, 0.45-1.14). Studies included in the present systematic review did not report a significant difference in overall survival and disease-free survival rates among women receiving HT and controls.

CONCLUSIONS

Based on the results of meta-analysis, HT does not influence the odds of ovarian cancer recurrence; however, this conclusion must be confirmed separately because of significant limitations in the methodological quality of the studies included.

Association Between Menopausal Estrogen-Only Therapy and Ovarian Carcinoma Risk

OBJECTIVE

To describe the association between postmenopausal estrogen-only therapy use and risk of ovarian carcinoma, specifically with regard to disease histotype and duration and timing of use.

METHODS

We conducted a pooled analysis of 906 women with ovarian carcinoma and 1,220 women in a control group; all 2,126 women included reported having had a hysterectomy. Ten population-based case-control studies participating in the Ovarian Cancer Association Consortium, an international consortium whose goal is to combine data from many studies with similar methods so reliable assessments of risk factors can be determined, were included. Self-reported questionnaire data from each study were harmonized and conditional logistic regression was used to examine estrogen-only therapy's histotype-specific and duration and recency of use associations.

RESULTS

Forty-three and a half percent of the women in the control group reported previous use of estrogen-only therapy. Compared with them, current or recent estrogen-only therapy use was associated with an increased risk for the serous (51.4%, odds ratio [OR] 1.63, 95% confidence interval [CI] 1.27-2.09) and endometrioid (48.6%, OR 2.00, 95% CI 1.17-3.41) histotypes. In addition, statistically significant trends in risk according to duration of use were seen among current or recent postmenopausal estrogen-only therapy users for both ovarian carcinoma histotypes (Ptrend<.001 for serous and endometrioid). Compared with women in the control group, current or recent users for 10 years or more had increased risks of serous ovarian carcinoma (36.8%, OR 1.73, 95% CI 1.26-2.38) and endometrioid ovarian carcinoma (34.9%, OR 4.03, 95% CI 1.91-8.49).

CONCLUSION

We found evidence of an increased risk of serous and endometrioid ovarian carcinoma associated with postmenopausal estrogen-only therapy use, particularly of long duration. These findings emphasize that risk may be associated with extended estrogen-only therapy use.

European Code against Cancer 4th Edition: Medical exposures, including hormone therapy, and cancer

The 4th edition of the European Code against Cancer recommends limiting - or avoiding when possible - the use of hormone replacement therapy (HRT) because of the increased risk of cancer, nevertheless acknowledging that prescription of HRT may be indicated under certain medical conditions. Current evidence shows that HRT, generally prescribed as menopausal hormone therapy, is associated with an increased risk of cancers of the breast, endometrium, and ovary, with the risk pattern depending on factors such as the type of therapy (oestrogen-only or combined oestrogen-progestogen), duration of treatment, and initiation according to the time of menopause. Carcinogenicity has also been established for anti-neoplastic agents used in cancer therapy, immunosuppressants, oestrogen-progestogen contraceptives, and tamoxifen. Medical use of ionising radiation, an established carcinogen, can provide major health benefits; however, prudent practices need to be in place, with procedures and techniques providing the needed diagnostic information or therapeutic gain with the lowest possible radiation exposure. For pharmaceutical drugs and medical radiation exposure with convincing evidence on their carcinogenicity, health benefits have to be balanced against the risks; potential increases in long-term cancer risk should be considered in the context of the often substantial and immediate health benefits from diagnosis and/or treatment. Thus, apart from HRT, no general recommendations on reducing cancer risk were given for carcinogenic drugs and medical radiation in the 4th edition of European Code against Cancer. It is crucial that the application of these measures relies on medical expertise and thorough benefit-risk evaluation. This also pertains to cancer-preventive drugs, and self-medication with aspirin or other potential chemopreventive drugs is strongly discouraged because of the possibility of serious, potentially lethal, adverse events.

Environmental (nongenetic) factors in gynecological cancers: update and future perspectives

Globally, gynecological cancers comprise three of the seven most common female cancers and are responsible for more than 1,000,000 new cases and 500,000 deaths annually. This review summarizes current knowledge regarding the role of environmental factors in gynecological cancer etiology and survival, focusing on those that are potentially amenable to intervention. Strong associations with use of exogenous hormones are countered by opposing risks of breast cancer, thus current hormonal preparations are not an option for prevention. Weight control would reduce risk of endometrial cancer but this and other lifestyle modifications are unlikely to have a major effect on gynecological cancer mortality rates. There is little information regarding the potential for lifestyle changes to improve outcomes for women with gynecological cancer.

Baseline and lifetime alcohol consumption and risk of differentiated thyroid carcinoma in the EPIC study

BACKGROUND

Results from several cohort and case-control studies suggest a protective association between current alcohol intake and risk of thyroid carcinoma, but the epidemiological evidence is not completely consistent and several questions remain unanswered.

METHODS

The association between alcohol consumption at recruitment and over the lifetime and risk of differentiated thyroid carcinoma was examined in the European Prospective Investigation into Cancer and Nutrition. Among 477 263 eligible participants (70% women), 556 (90% women) were diagnosed with differentiated thyroid carcinoma over a mean follow-up of 11 years. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox proportional hazards models.

RESULTS

Compared with participants consuming 0.1-4.9 g of alcohol per day at recruitment, participants consuming 15 or more grams (approximately 1-1.5 drinks) had a 23% lower risk of differentiated thyroid carcinoma (HR=0.77; 95% CI=0.60-0.98). These findings did not differ greatly when analyses were conducted for lifetime alcohol consumption, although the risk estimates were attenuated and not statistically significant anymore. Similar results were observed by type of alcoholic beverage, by differentiated thyroid carcinoma histology or according to age, sex, smoking status, body mass index and diabetes.

CONCLUSIONS

Our study provides some support to the hypothesis that moderate alcohol consumption may be associated with a lower risk of papillary and follicular thyroid carcinomas.

An epidemiologic risk prediction model for ovarian cancer in Europe: the EPIC study

BACKGROUND

Ovarian cancer has a high case-fatality ratio, largely due to late diagnosis. Epidemiologic risk prediction models could help identify women at increased risk who may benefit from targeted prevention measures, such as screening or chemopreventive agents.

METHODS

We built an ovarian cancer risk prediction model with epidemiologic risk factors from 202,206 women in the European Prospective Investigation into Cancer and Nutrition study.

RESULTS

Older age at menopause, longer duration of hormone replacement therapy, and higher body mass index were included as increasing ovarian cancer risk, whereas unilateral ovariectomy, longer duration of oral contraceptive use, and higher number of full-term pregnancies were decreasing risk. The discriminatory power (overall concordance index) of this model, as examined with five-fold cross-validation, was 0.64 (95% confidence interval (CI): 0.57, 0.70). The ratio of the expected to observed number of ovarian cancer cases occurring in the first 5 years of follow-up was 0.90 (293 out of 324, 95% CI: 0.81-1.01), in general there was no evidence for miscalibration.

CONCLUSION

Our ovarian cancer risk model containing only epidemiological data showed modest discriminatory power for a Western European population. Future studies should consider adding informative biomarkers to possibly improve the predictive ability of the model.

Effects of oestrogen on long noncoding RNA expression in oestrogen receptor alpha-positive ovarian cancer cells

Although oestrogen (E2) signalling has long been implicated in epithelial ovarian cancer (EOC) progression, the underlying mechanisms remain unknown. Long noncoding RNAs (lncRNAs) play a major role in cancer progression; therefore, our aim was to explore whether any lncRNA is regulated by E2 and plays some potential roles in the hormonal regulation of EOC progression. Here, we reported that E2 significantly dysregulated 115 lncRNAs (fold change ≥1.5, P<0.05) in E2 receptor (ER) alpha (ERα)-positive EOC SKOV3 cells compared with E2-untreated controls based on the microarray analysis. E2 regulation of the expression of 58 lncRNAs was bioinformatics predicted to be ERα-mediated; this was confirmed for two candidates. Both TC0101441 and TC0101686 were dysregulated by E2 in another ERα-positive PEO1 cells but not in ERα-negative A2780 cells. Additionally, the modulation of TC0101441 and TC0101686 expression by E2 was abrogated by the ER inhibitor ICI 182, 780 and short hairpin RNAs targeting ERα (ERα-shRNA). Further study of the two lncRNA expression indicated that ERα-positive EOC tissues had lower expression of TC0101686 and higher expression of TC0101441 compared to ERα-negative tissues. Particularly, elevated TC0101441 expression was correlated with lymph node metastasis, showing a metastatic potential. Results of in vitro assays further confirmed the pro-metastatic effect of TC0101441 and revealed that knockdown of TC0101441 also impaired E2-induced EOC cell migration/invasion by at least partly, regulating MMP2 and MMP3. Together, our findings demonstrate, for the first time, that E2 modulates lncRNA expression in ERα-positive EOC cells and that this regulation is sometimes ERα-mediated. Furthermore, our findings reveal that TC0101441contributes to E2-induced EOC cell migration/invasion. These results may shed a new insight into estrogenic effect on EOC progression by providing a perspective of lncRNA.

Expression and clinical significance of estrogen-regulated long non-coding RNAs in estrogen receptor α-positive ovarian cancer progression

Estrogen (E2) has long been implicated in epithelial ovarian cancer (EOC) progression. The effects of E2 on cancer progression can be mediated by numerous target genes, including coding RNAs and, more recently, non-coding RNAs (ncRNAs). Among the ncRNAs, long ncRNAs (lncRNAs) have emerged as new regulators in cancer progression; therefore, our aim was to determine whether the expression of any lncRNAs is regulated by E2 and, if so, whether a subset of these lncRNAs have some clinical significance in EOC progression. A microarray was performed to identify E2-regulated lncRNAs in E2 receptor (ER) α-positive EOC cells. Bioinformatics analyses of lncRNAs were conducted, focusing on gene ontology and pathway analyses. Quantitative real-time polymerase chain reactions were performed to confirm the expression of certain lncRNAs in ERα-positive EOC tissues. The correlation between certain lncRNA expression and clinicopathological factors as well as prognosis in ERα-positive EOC patients was then analyzed. We showed that 115 lncRNAs exhibited significant changes in E2-treated SKOV3 cells compared with untreated controls. Most of these lncRNAs were predicated to have potential to contribute to cancer progression. Notably, three candidates (TC0100223, TC0101686 and TC0101441) were aberrantly expressed in ERα-positive compared to ERα-negative EOC tissues, showing correlations with some malignant cancer phenotypes such as advanced FIGO stage and/or high histological grade. Furthermore, multivariate analysis indicated that TC0101441 was an independent prognostic factor for overall survival. Taken together, these results indicate for the first time that E2 can modulate lncRNA expression in ERα-positive EOC cells and that certain lncRNAs are correlated with advanced cancer progression and suggestive of a prognostic indicator in ERα-positive EOC patients. Knowledge of these E2-regulated lncRNAs could aid in the future understanding of the estrogenic effect on EOC progression and may assist in the clinical design of new target therapies based on a perspective of lncRNA.

Conjugated estrogens for the treatment of menopausal symptoms: a review of safety data

INTRODUCTION

Conjugated equine estrogens (CEE) are widely used for the treatment of menopausal symptoms, such as vasomotor symptoms and vulvovaginal atrophy, and for the prevention of bone loss, in postmenopausal women. The safety profile of CEE has been extensively published over the past 20 years.

AREAS COVERED

Data from randomized controlled trials and from observational studies on the effects of CEE on the risk of breast cancer, endometrial cancer or hyperplasia, other cancers, cardiovascular outcomes, and cognitive function are reviewed. When used alone, CEE are not associated with an increased risk of breast cancer and may be associated with reduced mortality. The risk of cardiovascular events with CEE may be reduced in women who are more recently postmenopausal.

EXPERT OPINION

Numerous clinical studies have evaluated the safety of CEE. The data reviewed in this article describe the breast, endometrial, and cardiovascular safety of unopposed CEE. International recommendations describe CEE as the menopausal symptom treatment of choice, particularly in young or recently postmenopausal hysterectomized women.

Ovarian cancer incidence trends in relation to changing patterns of menopausal hormone therapy use in the United States

PURPOSE

After a report from the Women's Health Initiative (WHI) in 2002, a precipitous decline in menopausal hormonal therapy (MHT) use in the United States was linked to a decline in breast cancer incidence rates. Given that MHT use is also associated with increased ovarian cancer risk, we tested whether ovarian cancer incidence rates changed after 2002.

METHODS

Using the North American Association of Central Cancer Registries database (1995 to 2008; N = 171,142 incident ovarian cancers), we applied standard analytic approaches and age-period-cohort (APC) models to estimate ovarian cancer incidence rate changes before (1995 to 2002) and after (2003 to 2008) the WHI report.

RESULTS

Among women age ≥ 50 years, age-standardized ovarian cancer incidence declined by 0.8% per year (95% CI, -1.8% to -0.5% per year) before the WHI announcement; after the WHI report, the rate declined by 2.4% per year (95% CI, -2.5% to -2.2% per year). APC models confirmed an accelerated decline in ovarian cancer incidence after the WHI report, adjusted for age and birth cohort effects. This sudden change was notable among women most likely to have used MHT (ie, women age 50 to 69 years, white women, and residents of regions with highest MHT prescription frequency). The largest changes were found for the endometrioid histologic subtype.

CONCLUSION

After a marked reduction in MHT use around 2002, ovarian cancer incidence rates demonstrated an accelerated decline, with the largest changes for endometrioid carcinomas. This strong temporal association, although not proving a causal role of hormones in ovarian carcinogenesis, suggests that future analytic research supporting cancer control efforts should clarify the role of hormonal exposures on the development and behavior of subtypes of ovarian cancer.

Ovarian epithelial tumors and reproductive factors: a systematic review

PURPOSE

The aim of this systematic review is to summarize the current knowledge about the etiology and pathogenesis of borderline tumors ovarian cancer with special emphasis on the role of endocrine treatments and reproductive factors to establish a foundation for future studies.

METHODS

We performed a systematic review on the relation between ovarian epithelial tumors (OET) and reproductive factors using the keywords: ovarian cancer, ovarian tumor, ovarian borderline tumor, age at menarche, age at menopause, parity, infertility, PCO syndrome, oral contraception, menopausal hormone therapy, fertility treatment. Totally, 3,290 abstracts were scanned for their relevance in this publication and 127 were finally included.

RESULTS

The incidence of ovarian epithelial cancer and ovarian borderline tumors is influenced by certain reproductive factors. The strongest protective effects are conferred by parity and use of oral contraceptive pills. Recent molecular biologic and histopathologic studies prove that OET represent a diverse group of tumors, each histologic type with a different genetic background. This is at least partly reflected in epidemiologic and clinical studies showing different risk modulating effects of reproductive factors and endocrine therapies on OET.

CONCLUSIONS

The etiology and pathogenesis of ovarian cancer are still not fully understood. None of the so far proposed hypothesis on the development of OET can fully account for the epidemiologic and clinical findings in the context of reproductive factors and OET development. Further research approaches are warranted and need to put more weight on the clinical and genetical diversity of OET to yield a more detailed insight into their pathogenesis.

Ovarian cancer and menopausal hormone therapy in the NIH-AARP diet and health study

Background:

Women using unopposed estrogens during menopause are at increased risk of ovarian cancer. It is uncertain whether oestrogen plus progestin therapy exerts similar effects.

Methods:

We evaluated menopausal hormone use and incident ovarian cancer (n=426) in 92 601 post-menopausal women enrolled in the National Institutes of Health-AARP (NIH-AARP) Diet and Health Study. Participants were administered questionnaires in 1996–1997 and followed through 2006. Hazard rate ratios (RR) and 95% confidence intervals (CIs) were estimated using Cox regression.

Results:

Increased risks were associated with long duration (10+ years) use of unopposed oestrogen (RR 2.15, 95% CI: 1.30–3.57 among women with a hysterectomy) and oestrogen plus progestin (RR 1.68, 95% CI: 1.13–2.49 among women with intact uteri) therapy. Similar risks were associated with progestins that were used sequentially (<15 days progestin per month) (RR 1.60, 95% CI: 1.10–2.33) or continuously (>25 days progestin per month) (RR 1.43, 95% CI: 1.032–2.01; P-value for heterogeneity=0.63).

Conclusion:

Our findings suggest that long duration use of both unopposed estrogens and oestrogen plus progestins are associated with increased risks of ovarian cancer, and that risk associated with oestrogen plus progestin use does not vary by regimen (sequential or continuous).