Reproductive risk factors and endometrial cancer: the European Prospective Investigation into Cancer and Nutrition

Case Report: Synchronous primary malignancy including the breast and endometrium

Breast and endometrial cancer are the most common types of female cancers, but the incidence of both of these malignancies in a single patient is a rare event. Multiple primary malignancy has been increasingly reported over the past decade, and double primary cancer is considered as the most common type.  In this study, we present a 53-year-old woman with synchronous primary malignancy of breast and endometrium. This patient had a history of breast and endometrial cancer in her family. Mammography and chest CT of the patient revealed a mass in the right breast and left supraclavicular region. However, the patient did not want to initiate treatment. Subsequently, the patient returned with a chief complaint of persistent abnormal vaginal bleeding. Abdominopelvic CT scan of the patient revealed a huge soft tissue mass in the pelvic cavity. She underwent hysterectomy, and pathology revealed endometrioid carcinoma, which had invaded the full thickness of uterine wall. Since this type of malignancy is rare and several risk factors are associated with it, it is worth being considered by clinicians when making decisions about screening or strategy for prevention.

Changes in Uterine Cancer Incidence Rates in Egypt

Background

Uterine cancer is one of the top-ranking cancers in women with wide international variations in incidence rates. Developed countries have higher incidence rates than the developing countries. Egypt has significantly lower incidence of uterine cancer than other countries in the Middle East. This study aimed at verifying the incidence rate of uterine cancer and characterizing the demographic and clinical profiles of patients residing in the Gharbiah province in the Nile delta region of Egypt.

Methods

Data from 660 uterine cancer patients diagnosed during the period of 1999 to 2010 were abstracted from the Gharbiah Cancer Registry, the only population-based registry in Egypt. The data included age, marital status, number of children, residence, smoking, occupation, date and basis of diagnosis, tumor topography, morphology, stage and grade, and treatment. Crude rate, age-standardized rate (ASR), and age-specific rate were calculated and associated with demographic and clinical characteristics of patients.

Results

The study confirmed the low ASR of uterine cancer in Egypt, (4.1 per 100,000 (95% CI: 3.8-4.4)). The incidence rate increased significantly over the 12-year period. The crude rate (CR) was 1.95, 95% CI (1.64-2.25) in 1999-2002; 2.9, 95% CI (2.5-3.2) in 2003-2006; and 3.5, 95% CI (3.1-3.9) in 2007-2010. The rate ratio was 1.5, 95% CI (1.2-1.8) in 2003-2006 and 1.8, 95% CI (1.5-2.2) in 2007-2010 compared to 1999-2002. The majority of patients (83%) were postmenopausal with the highest age-specific rate in the 60-69-year age group (22.07 per 100,000 (95% CI: 19.3-25.2). The majority of patients were diagnosed at early stages (60% localized and 5% regional), had adenocarcinoma (68%), and resided in urban areas (54%).

Conclusions

The study confirmed the low incidence rate of uterine cancer in the Gharbiah province of Egypt and significant increase in incidence in recent years. Future studies should focus on verifying the possible effect of hysterectomy on lowering the incidence, the factors related to the changes in rates between rural and urban areas, and the possible impact of nutritional and epidemiologic transitions on the increasing rates.

Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study

INTRODUCTION

Lifetime number of years of menstruation (LNYM) reflects a woman's cumulative exposure to endogenous estrogen and can be used as a measure of the combined effect of reproductive factors related to endometrial cancer (EC) risk.

MATERIAL AND METHODS

We aimed to study the association between LNYM and EC risk among postmenopausal women and calculate the population attributable fraction of EC for different LNYM categories. Our study sample consisted of 117 589 women from the Norwegian Women and Cancer (NOWAC) Study. All women were aged 30-70 years at enrollment and completed a baseline questionnaire between 1991 and 2006. Women were followed up for EC to December 2014 through linkages to national registries. We used Cox proportional hazards models to estimate hazard ratios with 95% confidence intervals (95% CIs), adjusted for potential confounders.

RESULTS

In all, 720 women developed EC. We found a statistically significant, positive dose-response relationship between LNYM and EC, with a 9.1% higher risk for each additional year of LNYM (P for trend < .001). Using the LNYM category ≥40 as a reference, the hazard ratios for LNYM <25, 25-29, 30-34, 35-39 were 0.17 (95% CI 0.22-0.27), 0.25 (95% CI 0.17-0.36), 0.43 (95% CI 0.32-0.58), and 0.68 (95% CI 0.51-0.92), respectively. The association between LNYM and EC was independent of incomplete pregnancies, menopausal hormone therapy, diabetes, and body mass index. When considering the population attributable fraction, 67% of EC was estimated to be attributable to LNYM ≥25 years.

CONCLUSIONS

Our study supports that increasing LNYM is an important and independent predictor of EC risk.

Associations Between Maternal Obesity and Pregnancy Hyperglycemia and Timing of Puberty Onset in Adolescent Girls: A Population-Based Study

Early puberty is associated with adverse health outcomes. We investigated whether in utero exposure to maternal obesity is associated with daughters' pubertal timing using 15,267 racially/ethnically diverse Kaiser Permanente Northern California members aged 6-11 years with pediatrician-assessed Tanner staging (2003-2017). We calculated maternal body mass index (BMI; weight (kg)/height (m)2) during pregnancy from the electronic health record data. Using a proportional hazards model with interval censoring, we examined the associations between maternal obesity and girls' pubertal timing, as well as effect modification by race/ethnicity and mediation by prepubertal BMI. Maternal obesity (BMI ≥30) and overweight (BMI 25-29.9) were associated with earlier onset of breast development in girls (hazard ratio (HR) = 1.39 (95% confidence interval (CI): 1.30, 1.49) and HR = 1.21 (95% CI: 1.13, 1.29), respectively), after adjustment for girl's race/ethnicity, maternal age, education, parity, and smoking during pregnancy. There was interaction by race/ethnicity for associations between maternal obesity and girls' pubic hair onset: Associations were strongest among Asian and non-Hispanic white girls (HR = 1.53 (95% CI: 1.24, 1.90) and HR = 1.34 (95% CI: 1.18, 1.52), respectively) and absent for African-American girls. Adjustment for girl's prepubertal BMI only slightly attenuated associations. Our results suggest the importance of maternal metabolic factors during pregnancy in the timing of girls' puberty and potential differences in the associations by race/ethnicity.

The relation of age at menarche with age at natural menopause: a population study of 336 788 women in Norway

STUDY QUESTION

Is age at menarche associated with age at menopause or with duration of the reproductive period (interval between menarche and menopause)?

SUMMARY ANSWER

The association of age at menarche with age at menopause was weak and non-linear, and the duration of the reproductive period decreased by increasing age at menarche.

WHAT IS KNOWN ALREADY

It remains uncertain whether age at menarche is associated with age at menopause. Some studies report that women with early menarche also have early menopause. Other studies report that women with early menarche have late menopause, or they report no association. The duration of the reproductive period may be an indicator of the cumulative endogenous exposure to estrogens and progestogens during life course and is associated with risk of breast cancer and endometrial cancer.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 336 788 women, aged 48-71 years, in the BreastScreen Norway during the years 2006-2014 was performed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Information about age at menarche and menopausal status was obtained by self-administered questionnaires. We used time to event approaches to estimate the associations.

MAIN RESULTS AND THE ROLE OF CHANCE

Median age at menopause was 51 years in most menarche groups. Women with menarche at age 16 years or age ≥ 17 years had menopause 1 year later [median: 52 years, interquartile range (IQR): 49-54 years] than women with menarche at age 13 years (median: 51 years, IQR: 49-54 years, reference) (crude hazard ratio (HR) = 0.95; 95% CI: 0.93-0.97 and 0.95; 95% CI: 0.92-0.99, Pnon-linearity < 0.001). The reproductive period decreased with increasing age at menarche (Pnon-linearity < 0.001), and women with menarche at age ≤ 9 years had 9 years longer median reproductive period than women with menarche at age ≥ 17 years (median: 43 versus 34 years). Adjustment for year of birth did not change the HR estimates notably.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

Information about age at menarche and age at menopause was based on self-reports. Particularly for age at menarche, the long time interval between the event and data collection may have caused imprecise reporting.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that age at menarche is a strong indicator for the duration of women's reproductive period. Our findings should encourage studies of the independent role of duration of the reproductive period on the risk of breast cancer and endometrial cancer, since these cancers have been associated with exposure to estrogens and progestogens.

STUDY FUNDING/COMPETING INTEREST(S)

The present study was funded by the Norwegian Cancer Society [Grant number 6863294-2015]. The authors declare no conflicts of interest.

Influence of YKL-40 gene RNA interference on the biological behaviors of endometrial cancer HEC-1A cells

The present study aimed to investigate the effects of chitinase-3-like protein 1 (YKL-40) gene RNA interference on the biological behaviors and enhanced chemosensitivity of endometrial cancer (EC) HEC-1A cells. YKL-40 small interfering (si)RNA was transduced into EC HEC-1A cells using a lentivirus. The experiment was divided into three groups: The experimental group was transfected with YKL-40 siRNA (si-YKL-40); the mock-treatment group was transfected with transfection reagent only; and the blank control group was left untreated. A reverse transcription-quantitative polymerase chain reaction was performed to investigate the mRNA expression levels of YKL-40. The biological behaviors, including cell proliferation, migration, invasion and apoptosis, were detected by MTT and Transwell assays, and flow cytometry (FCM) analysis, respectively. The results of the present study demonstrated that the mRNA expression levels of YKL-40 were downregulated within HEC-1A cells upon transfection with si-YKL-40 (P<0.05). The proliferative, migratory and invasive abilities of HEC-1A cells were inhibited by si-YKL-40 (P<0.05). The mRNA expression levels of YKL-40 were upregulated within HEC-1A cells following treatment with cisplatin (P<0.05). FCM analysis revealed that the average cellular apoptosis rate increased following the inhibition of YKL-40 gene expression via siRNA (P<0.05). Therefore, the YKL-40 gene may be associated with the proliferative, migratory, invasive and anti-apoptotic ability of HEC-1A cells. YKL-40 downregulation may enhance the sensitivity of human EC HEC-1A cells to chemotherapy.

The role of pregnancy, perinatal factors and hormones in maternal cancer risk: a review of the evidence

An understanding of the origin of cancer is critical for cancer prevention and treatment. Complex biological mechanisms promote carcinogenesis, and there is increasing evidence that pregnancy-related exposures influence foetal growth cell division and organ functioning and may have a long-lasting impact on health and disease susceptibility in the mothers and offspring. Nulliparity is an established risk factor for breast, ovarian, endometrial and possibly pancreatic cancer, whilst the risk of kidney cancer is elevated in parous compared with nulliparous women. For breast, endometrial and ovarian cancer, each pregnancy provides an additional risk reduction. The associations of parity with thyroid and colorectal cancers are uncertain. The timing of reproductive events is also recognized to be important. Older age at first birth is associated with an increased risk of breast cancer, and older age at last birth is associated with a reduced risk of endometrial cancer. The risks of breast and endometrial cancers increase with younger age at menarche and older age at menopause. The mechanisms, and hormone profiles, that underlie alterations in maternal cancer risk are not fully understood and may differ by malignancy. Linking health registries and pooling of data in the Nordic countries have provided opportunities to conduct epidemiologic research of pregnancy exposures and subsequent cancer. We review the maternal risk of several malignancies, including those with a well-known hormonal aetiology and those with less established relationships. The tendency for women to have fewer pregnancies and at later ages, together with the age-dependent increase in the incidence of most malignancies, is expected to affect the incidence of pregnancy-associated cancer.

Exogenous Hormone Use and Endometrial Cancer in U.S. Black Women

Background: Although endometrial cancer risk differs among white and black women, few data on its associations with exogenous hormone use in the latter group are available. Studies have reported lower endometrial cancer risk among users of oral contraceptives (OCs), but higher risk among users of estrogen-only female menopausal hormones (FMHs). Evidence for the risk among estrogen plus progestin FMHs users is equivocal.Methods: We followed 47,555 Black Women's Health Study participants with an intact uterus from 1995 through 2013. Data on exogenous hormone use, covariates, and endometrial cancer were obtained biennially. Self-reported incident cases of endometrial cancer were confirmed by medical records or cancer registries whenever possible. We estimated incidence rate ratios (IRRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression.Results: We observed 300 endometrial cancer cases during 689,546 person-years of follow-up. Compared with never use, ≥10 years' duration of OC use was associated with lower risk (multivariable IRR = 0.45, 95% CI, 0.27-0.74), but risk was higher among current users of estrogen-only (IRR = 3.78, 95% CI, 1.69-8.43) and estrogen plus progestin FMH (IRR = 1.55, 95% CI, 0.78-3.11). Risk was not increased among former users of estrogen-only (IRR = 0.87, 95% CI, 0.44-1.72) or estrogen plus progestin FMH (IRR = 0.63, 95% CI, 0.36-1.09).Conclusions: Current use of estrogen-only and estrogen plus progestin FMH was associated with increased risk of endometrial cancer. Risk appeared lower among former users of estrogen plus progestin FMH. Long-term OC use was associated with reduced risk.Impact: Our results are generally consistent with those among white women. Cancer Epidemiol Biomarkers Prev; 27(5); 558-65. ©2018 AACR.

Is the positivity of estrogen receptor or progesterone receptor different between type 1 and type 2 endometrial cancer?

Endometrial cancer is a major cancer in women and traditionally divided into type 1 and type 2. It is well known that type 2 endometrial cancer has a poor prognosis. Studies have suggested that estrogen receptor (ER) or progesterone receptor (PR) positive are positively associated with endometrial cancer survive. However whether the positivity of ER or PR is different between cancer types has not been investigated yet. In this retrospective study, the positivity of ER or PR was analysed in 1054 women with primary diagnosed endometrial cancer taking into account cancer types and menopausal status from the largest university teaching women's hospital in China. The positivity of ER or PR (over 90%) was significantly higher in type 1 compared to that in type 2 endometrial cancer (71% or 64%) in both premenopausal and postmenopausal women. There was no different in positivity of ER or PR in type 1 endometrial cancer between premenopausal and postmenopausal women. However, in type 2 endometrial cancer, the positivity of ER or PR in premenopausal women was significantly higher compared to that in postmenopausal women. Our data demonstrate that both ER and PR positivity are significantly higher in type 1 endometrial cancer (92%) compared to type 2 (72% ER positive, 65% PR positive). Menopausal status is not associated with the positivity of ER or PR in type 1 endometrial cancer. Our data may provide some novel insights why Asian women have better outcomes of endometrial cancer which was reported in the literature.

Faster ticking rate of the epigenetic clock is associated with faster pubertal development in girls

Epigenetic age is an indicator of biological aging, capturing the impact of environmental and behavioral influences across time on cellular function. Deviance between epigenetic age and chronological age (AgeAccel) is a predictor of health. Pubertal timing has similarly been associated with cancer risk and mortality rate among females. We examined the association between AgeAccel and pubertal timing and adolescent breast composition in the longitudinal Growth and Obesity Cohort Study. AgeAccel was estimated in whole blood using the Horvath method at breast Tanner 2 (B2) and 4 (B4). Total breast volume, absolute fibro-glandular volume (FGV), and %FGV were evaluated at B4 using dual X-ray absorptiometry. The impact of AgeAccel (mean: 0; SD: 3.78) across puberty on the time to breast development (thelarche), menarche, and pubertal tempo (thelarche to menarche) was estimated using accelerated failure time models; generalized estimating equations were used to evaluate associations with breast density. A five-year increase in average adolescent AgeAccel was associated with a significant decrease in time to menarche [hazard ratio (HR): 1.37; 95% confidence interval (CI): 1.04, 1.80] adjusting for birth weight, maternal pre-pregnancy body mass index, maternal height, maternal education, B2 height, fat percentage, and cell composition. AgeAccel displayed a stronger inverse association with pubertal tempo (HR: 1.48; 95% CI: 1.10, 1.99). A five-year increase in AgeAccel was associated with 5% greater %FGV, adjusting for B4 percent body fat, and maternal traits (95% CI: 1.01, 1.10). Our study provides unique insight into the influence of AgeAccel on pubertal development in girls, which may have implications for adult health.

Timing of spermarche and menarche among urban students in Guangzhou, China: trends from 2005 to 2012 and association with Obesity

In Guangzhou, China, whether the trend of a decreasing pubertal age has continued in recent years remained unknown, and the association between obesity and early puberty was still controversial. Herein, we conducted a serial cross-sectional study using data from physical fitness surveillance (2005–2012), to determine the recent trends in age at spermarche and menarche among students in Guangzhou, and to investigate whether elevated BMI modified timing of spermarche and menarche. This study included 1,278,258 urban students. In boys, no significant differences were observed in median ages of spermarche (MAS) from 2005 to 2012, with overlapping 95% CIs. Similar results were observed for median ages of menarche (MAM) in girls. The Cox-Stuart trend test showed neither upward nor downward shift in MAS and MAM over time (P = 0.625; 1.000). Each year, both MAS and MAM decreased with increasing BMI. Furthermore, a higher BMI was associated with early age at spermarche and menarche, with ORs of 1.052 (95% CI = 1.045–1.059) and 1.233 (95% CI = 1.220–1.247) in 2012 for boys and girls, respectively. In conclusion, the pubertal timing has been stable in urban students from 2005 to 2012. Furthermore, obesity was associated with early timing of spermarche and menarche.

Could ALDH2*2 be the reason for low incidence and mortality of ovarian cancer for East Asia women?

It is curious that East Asian women have a low incidence and mortality of ovarian cancer in various epidemiological studies. Although different explanations were given, they appear unsubstantial. We notice that East Asian population usually are inactive aldehyde dehydrogenase 2 mutation (ALDH2 ^* 2) carriers, and ALDH plays an important role in the resistance of ovarian cancer to chemotherapeutics, especially in ovarian cancer stem cells. Therefore, we hypothesize whether ALDH2 mutation is the major reason for low incidence and mortality of ovarian cancer in East Asian women, and use the evidence from literature, transcriptomic data with average 5-year overall survival to confirm our hypothesis.

The positivity of estrogen receptor and progesterone receptor may not be associated with metastasis and recurrence in epithelial ovarian cancer

The estrogen (ER) or progesterone receptors (PR) is positively associated with better clinical outcomes in ovarian cancer. Whether metastasis or recurrence of ovarian cancer is correlated with this association has not been investigated. Data on 894 women with epithelial ovarian cancer were collected and the association between ER or PR positivity and peritoneal or lymph node metastases or recurrence was analysed. ER or PR positivity was higher in high-grade, low-grade serous and endometrioid carcinoma, but lower in mucinous and clear-cell carcinoma. Significantly higher ER or PR positivity was seen in endometrioid carcinoma or high-grade serous carcinoma with peritoneal metastases, respectively, but not other subtypes. In addition, there was no significant difference in ER or PR positivity between cases with and without lymph node metastasis in these five subtypes. In recurrent high-grade serous carcinoma with peritoneal metastases (n = 103), the positivity of ER or PR was 86% and 55% respectively. Our data demonstrate that the association between ER or PR positivity and peritoneal metastases was only seen in endometrioid or high grade serous carcinoma, respectively. There was no association of ER or PR positivity and lymph node metastases. The majority of recurrent high-grade serous carcinoma with peritoneal metastases (86%) were ER positive.

The prevalence of malignant and borderline ovarian cancer in pre- and post-menopausal Chinese women

The incidence of ovarian cancer depends on the ethnicity and geographical area. Menopausal status is a well-known risk factor for ovarian cancer and most cases occur after menopause in Caucasians. However, it is less clear how the status of menopause or age at diagnosis is associated with ovarian cancer including its subtypes in Chinese women. Data on 1,283 women with primary malignant or borderline ovarian cancer including age at diagnosis, age at menopause and histology from the largest women's hospital in China was analysed. The median age at diagnosis was 53, 44 and 23 years for epithelial ovarian cancer or sex-cord tumors or germ cell tumors respectively. 58% of epithelial ovarian cancers were diagnosed after menopause, while 58% and 95% of sex-cord tumors and germ cell tumors were diagnosed before menopause. Around 60% of serous, endometrioid and clear-cell carcinoma of epithelial ovarian cancer were diagnosed after menopause, while 23% of mucinous carcinoma was diagnosed after menopause. The median age at diagnosis was 35 years for borderline ovarian cancer and 80% of patients were diagnosed before menopause. Our data demonstrates that the median age at diagnosis of ovarian cancer is younger in our study population than Caucasians reported in the literature regardless of malignant or borderline ovarian cancers, and regardless of subtypes of epithelial ovarian cancer. The prevalence of ovarian cancer is proportionately higher in our study population before menopause than Caucasians. Our results suggest clinicians to be more aware of the symptoms of ovarian cancer in premenopausal Chinese women.

Hormone receptors expression in ovarian cancer taking into account menopausal status: a retrospective study in Chinese population

Ovarian cancer is a major gynaecological cancer with different subtypes and studies have suggested that estrogen receptor (ER) or progesterone receptor (PR) positivity are associated with better clinical outcomes. Furthermore, the clinical outcomes of ovarian cancer are better in Asian compared to Caucasian. To date, studies investigating the ER or PR positivity in all subtypes of ovarian cancer, including borderline epithelial, are limited. In this retrospective study we investigated ER and PR positivity in Chinese women with malignant epithelial ovarian cancer (n=577), sex cord-stromal tumor (n=26) and borderline epithelial ovarian cancer (n=98) taking into account menopausal status. The positivity of ER (>85%) or PR (>58%) was higher in serous and endometrioid carcinoma of malignant epithelial ovarian cancer than that in mucinous and clear-cell carcinoma (<19% of ER or 24% of PR). The majority of serous carcinomas of borderline epithelial ovarian cancerwere ER or PR positive, but in contrast less than 33% of mucinous carcinomas of borderline epithelial ovarian cancerswere ERor PR positive.Furthermore, there was no association between the ER or PR positivity and menopausal status in both malignant and borderline epithelial ovarian cancer. We also found that the age at diagnosis with ovarian cancer was younger in Chinese women. Our data suggest that ER or PR positivity in Chinese women with ovarian cancer is similar to that of other ethnicities reported in literature, suggesting that the better clinical outcomes seen in Asian may be associated with other factors such as age at diagnosis of ovarian cancer.

Commonly used medications and endometrial cancer survival: a population-based cohort study

BACKGROUND

Increasing incidence and new indications for existing drugs make it important to identify new adjuvant therapies for endometrial cancer (EC).

METHODS

This is a prospective cohort study of 3058 newly diagnosed EC cases from 1998 to 2010, identified through record linkages between the UK Clinical Practice Research Datalink, the National Cancer Research Datalink and death registrations from the Office of National Statistics. Using Cox regression models, unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for EC-specific survival.

RESULTS

Over a mean 6.1 (range 1-16) years of follow-up, there were 394 EC-specific deaths. There was no evidence of a significant association between post-diagnostic use of statins (adjusted HR 0.83, 95% CI 0.64, 1.08), β-blockers (adjusted HR 0.86, 95% CI 0.65, 1.13) or low-dose aspirin (adjusted HR 0.91, 95% CI 0.69, 1.20) and EC survival before or after adjustment for confounders. There were also no evidence of a dose-response association between these drug groups and EC survival.

CONCLUSIONS

In this large UK population-based study, no significant associations were observed for post-diagnostic use of statins, β-blockers or low-dose aspirin and EC survival.

Breastfeeding and Endometrial Cancer Risk: An Analysis From the Epidemiology of Endometrial Cancer Consortium

OBJECTIVE

To investigate the association between breastfeeding and endometrial cancer risk using pooled data from 17 studies participating in the Epidemiology of Endometrial Cancer Consortium.

METHODS

We conducted a meta-analysis with individual-level data from three cohort and 14 case-control studies. Study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for the association between breastfeeding and risk of endometrial cancer using multivariable logistic regression and pooled using random-effects meta-analysis. We investigated between-study heterogeneity with I  and Q statistics and metaregression.

RESULTS

After excluding nulliparous women, the analyses included 8,981 women with endometrial cancer and 17,241 women in a control group. Ever breastfeeding was associated with an 11% reduction in risk of endometrial cancer (pooled OR 0.89, 95% CI 0.81-0.98). Longer average duration of breastfeeding per child was associated with lower risk of endometrial cancer, although there appeared to be some leveling of this effect beyond 6-9 months. The association with ever breastfeeding was not explained by greater parity and did not vary notably by body mass index or histologic subtype (grouped as endometrioid and mucinous compared with serous and clear cell).

CONCLUSION

Our findings suggest that reducing endometrial cancer risk can be added to the list of maternal benefits associated with breastfeeding. Ongoing promotion, support, and facilitation of this safe and beneficial behavior might therefore contribute to the prevention of this increasingly common cancer.

Current Evidence on Associations of Nutritional Factors with Ovarian Reserve and Timing of Menopause: A Systematic Review

Ovarian aging is thought to be influenced by environmental factors, including nutrition. The aim of this study was to systematically review current evidence on the associations between nutritional factors, ovarian reserve, and age at menopause. PubMed and Scopus were structurally searched until May 2016. Original studies, with either observational or interventional designs, that examined the associations of nutritional factors (serum or dietary nutrients, food groups, and/or dietary patterns) with different ovarian reserve markers and/or timing of menopause were considered eligible. Twenty-six studies met the inclusion criteria: 17 studies on ovarian reserve markers and 9 studies on menopausal age. Significant diversity was observed in nutritional factors examined across studies. In the study of nutritional factors, associations of serum 25-hydroxyvitamin D [25(OH)D] concentration and intakes of soy or soy products with ovarian reserve have been the most investigated. For associations with menopausal age, intakes of total fat, fiber, and soy products have been mainly examined. Significant associations with ovarian reserve markers were found in 4 of 7 studies on serum 25(OH)D, 2 of 6 studies on soy or soy products, 1 of 2 studies on fiber intake, 1 study on serum zinc and copper concentrations, and 1 study on serum antioxidant concentrations. Studies on nutritional factors and menopausal age provided inconsistent findings, some of which suggested modest associations. Although there is some promising evidence on the influential role of nutrition in ovarian aging, a limited number of studies, heterogeneous in their design and study of nutritional factors, makes it difficult to draw definite conclusions. To better understand this issue, examination of associations of dietary intakes or dietary patterns with more precise markers of ovarian reserve, such as anti-mullerian hormone and antral follicle count, with age at menopause is needed. In addition, to explore whether nutritional factors alter the process of ovarian aging, an examination of changes in ovarian reserve markers should be considered.

EMP2 is a novel therapeutic target for endometrial cancer stem cells

Previous studies have suggested that overexpression of the oncogenic protein epithelial membrane protein-2 (EMP2) correlates with endometrial carcinoma progression and ultimately poor survival from disease. To understand the role of EMP2 in the etiology of disease, gene analysis was performed to show transcripts that are reciprocally regulated by EMP2 levels. In particular, EMP2 expression correlates with and helps regulate the expression of several cancer stem cell associated markers including aldehyde dehydrogenase 1 (ALDH1). ALDH expression significantly promotes tumor initiation and correlates with the levels of EMP2 expression in both patient samples and tumor cell lines. As therapy against CSCs in endometrial cancer is lacking, the ability of anti-EMP2 IgG1 therapy to reduce primary and secondary tumor formation using xenograft HEC1A models was determined. Anti-EMP2 IgG1 reduced the expression and activity of ALDH and correspondingly reduced both primary and secondary tumor load. Our results collectively suggest that anti-EMP2 therapy may be a novel method of reducing endometrial cancer stem cells.

Use of acetaminophen and risk of endometrial cancer: evidence from observational studies

Previous meta-analyses suggested that aspirin was associated with reduced risk of endometrial cancer. However, there has been no study comprehensively summarize the evidence of acetaminophen use and risk of endometrial cancer from observational studies. We systematically searched electronic databases (PubMed , EMBASE, Web of Science, and Cochrane Library) for relevant cohort or case-control studies up to February 28, 2017. Two independent authors performed the eligibility evaluation and data extraction. All differences were resolved by discussion. A random-effects model was applied to estimate summary relative risks (RRs) with 95% CIs. All statistical tests were two-sided. Seven observational studies including four prospective cohort studies and three case-control studies with 3874 endometrial cancer cases were included for final analysis. Compared with never use acetaminophen, ever use this drug was not associated with risk of endometrial cancer (summarized RR = 1.02; 95% CI: 0.93-1.13, I2 = 0%). Similar null association was also observed when compared the highest category of frequency/duration with never use acetaminophen (summarized RR = 0.88; 95% CI: 0.70-1.11, I2 = 15.2%). Additionally, the finding was robust in the subgroup analyses stratified by study characteristics and adjustment for potential confounders and risk factors. There was no evidence of publication bias by a visual inspection of a funnel plot and formal statistical tests. In summary, the present meta-analysis reveals no association between acetaminophen use and risk of endometrial cancer. More large scale prospective cohort studies are warranted to confirm our findings and carry out the dose-response analysis of aforementioned association.

Reproductive factors and incidence of endometrial cancer in U.S. black women

PURPOSE

Previous studies have shown that reproductive history is a strong determinant of endometrial cancer risk among white women. Less is known about how reproductive history affects endometrial cancer risk among black women, whose incidence and mortality differ from white women. We investigated the associations of age at menarche, parity, timing of births, and menopausal age with endometrial cancer in the Black Women's Health Study, a prospective cohort study.

METHODS

Every 2 years from 1995 to 2013, 47,555 participants with intact uteri at baseline in 1995 completed questionnaires on reproductive and medical history, and lifestyle factors. Self-reported cases of endometrial cancer were confirmed by medical record, cancer registry, or death certificate when available. Cox proportional hazards regression was used to estimate multivariable incidence rate ratios (IRR) and 95% confidence intervals (CI).

RESULTS

During 689,501 person-years of follow-up, we identified 300 incident cases of endometrial cancer. The strongest associations with endometrial cancer were found for early age at menarche (<11 vs. 12-13 years: IRR 1.82, 95% CI 1.31, 2.52), and later age at first birth (≥30 vs. <20 years: IRR 0.26, 95% CI 0.13, 0.50). Parous women were less likely than nulliparous women to develop endometrial cancer (IRR 0.77, 95% CI 0.57, 1.05), but there was little evidence of a dose-response relationship for number of births.

CONCLUSION

Associations between reproductive factors and endometrial cancer among black women were generally consistent with those in studies of white women.

Epidemiology of Endometrial Carcinoma: Etiologic Importance of Hormonal and Metabolic Influences

Endometrial carcinoma is the most common gynecologic cancer in developed nations, and the annual incidence is projected to increase, secondary to the high prevalence of obesity, a strong endometrial carcinoma risk factor. Although endometrial carcinomas are etiologically, biologically, and clinically diverse, hormonal and metabolic mechanisms are particularly strongly implicated in the pathogenesis of endometrioid carcinoma, the numerically predominant subtype. The centrality of hormonal and metabolic disturbances in the pathogenesis of endometrial carcinoma, combined with its slow development from well-characterized precursors in most cases, offers a substantial opportunity to reduce endometrial carcinoma mortality through early detection, lifestyle modification, and chemoprevention. In this chapter, we review the epidemiology of endometrial carcinoma, emphasizing theories that link risk factors for these tumors to hormonal and metabolic mechanisms. Future translational research opportunities related to prevention are discussed.

The levels of the sex hormones are not different between type 1 and type 2 endometrial cancer

The involvement of hormonal factors in developing endometrial cancer is well documented. In particular, excess or unopposed estrogen is a major risk factor. Endometrial cancer is divided into estrogen-dependent and estrogen-independent types. Studies suggested that the subtypes of endometrial cancer share many common risk factors. Whether the levels of sex hormones differ between types 1 and 2 endometrial cancer has not been investigated. In this study, levels of estrogen, progesterone, testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) were investigated between type 1 and type 2 endometrial cancer taking into account menopausal status and parity. The sex hormones levels and estrogen and progesterone receptors were measured in 187 women with endometrial cancer. The levels of estradiol (E2), progesterone, testosterone, FSH and LH were not different between the subtypes of endometrial cancer regardless of menopausal status. In addition, the sex hormones were not different between patients of different party regardless of the menopausal status. The majority of type 1 (96%) and type 2 (82%) endometrial cancers were estrogen and progesterone receptor positive. Our data suggest that type 2 endometrial cancer is not completely estrogen independent, and type 1 and type 2 endometrial cancers may have a similar pathogenesis.

Risk Factors for Endometrial Cancer: Results from a Hospital-Based Case-Control Study

Objectives: The purpose of this investigation was to examine the association between endometrial cancer and possible etiological agents. Methods: A case-control study was conducted in Iran between March 2012 and May 2016. The demographic and reproductive factors of 205 women with endometrial cancer were compared, and 590 healthy cases were participated in the control group. For each endometrial cancer case, there were three controls, who were matched in terms of age and residence. The data were considered significant at p ≤0.05. Results: After adjusting the variables, the nulliparity (OR 6.23, 95% CI 2.86-13.59), the nulligravidity (OR 5.94, 95% CI 2.51-14.06), the positive family history of reproductive cancer (OR 4.97, 95% CI 2.33-10.59), the infertility history (OR 2.38, 95%CI 1.32-4.31), the obesity (BMI ≥25) (OR 1.71, 95% CI 1.16-2.52), the early menarche age (<12 years) (OR 2.10, 95% CI 1.17-3.75), and the hormonal contraception use (OR 1.69, 95% CI 1.15-2.49) were found to be associated with an increased risk of endometrial cancer. Nevertheless, the education level, the job of women, the marital age, the leisure activities, and the breast feeding were not found to be associated with the endometrial cancer after adjusting the variables. Conclusion: Scheduling of the screening program is vitally indispensable to identify endometrial cancer in women with nulliparity, nulligravidity and the positive family history of cancer. In addition, women with early menarche, those with the history of infertility, the obese ones, and those who use contraception pills need to be particularly aware of the potential risks.

Breastfeeding and the incidence of endometrial cancer: A meta-analysis

Several epidemiological studies have investigated the association between breastfeeding and endometrial cancer (EC). However, the results of the studies are controversial. Thus, we conduct this meta-analysis to explore the association between breastfeeding and EC and to evaluate the possible does-response relationship between duration of breastfeeding and EC. PubMed, Web of Science, Chinese National Knowledge Infrastructure, China biology medical literature database, Wan fang databases and Database of Chinese Scientific and Technical Periodicals were searched for eligible observational studies up to 11 July 2015. Random effects model was used to calculate the pooled relative risks (RRs) and restricted cubic spline model was adopted for the does-response analysis.

Fifteen articles with 623570 participants were identified. The RRs of these studies suggested that breastfeeding was associated with the reduced risk of EC (high versus low/no: RR = 0.74; 95% confidence interval (CI), 0.58–0.95). In subgroup analyses, a significant association of breastfeeding with EC risk was found in Asia (RR = 0.57, 95% CI 0.37–0.87), and an inverse association of breastfeeding with EC risk was found in cohort studies (RR = 0.62, 95% CI 0.41–0.94). The results were also significant after adjusted for hormone use (RR = 0.63, 95% CI 0.41–0.97) and body mass index (RR=0.65, 95% CI 0.44–0.96). A linear relationship was found of breastfeeding with EC (p for nonlinearity = 0.93), and it indicated that EC risk decreased by 1.2% for one month increment of breastfeeding. This meta-analysis indicates that long term breastfeeding might be associated with decreased risk of EC.

Cancers in Australia in 2010 attributable to and prevented by the use of combined oral contraceptives

OBJECTIVES

To estimate the proportion and number of cancers occurring in Australia in 2010 attributable to combined oral contraceptive pill (OCP) use.

METHODS

We estimated the population attributable fraction (PAF) for cancers causally associated with combined OCP use (breast, cervix), and the proportion of endometrial and ovarian cancers prevented (prevented fraction [PF]). We used standard formulae incorporating prevalence of combined OCP use in the Australian population, relative risks of cancer associated with this exposure and cancer incidence.

RESULTS

An estimated 105 breast and 52 cervical cancers (0.7% and 6.4% of each cancer, respectively) in Australia in 2010 were attributable to current use of combined OCP. Past combined OCP use was estimated to have prevented 1,032 endometrial and 308 ovarian cancers in 2010, reducing the number of cancers that would otherwise have occurred by 31% and 19%, respectively.

CONCLUSIONS

A small proportion of breast and cervical cancers is attributable to combined OCP use; OCP use is likely to have prevented larger numbers of endometrial and ovarian cancers.

IMPLICATIONS

Women seeking contraceptive advice should be told of potential adverse effects, but should also be told that - along with reproductive health benefits - combined OCP use can reduce long-term risks of ovarian and endometrial cancers.

Body Mass Index Is Positively Associated with Endometrial Cancer in Chinese Women, Especially Prior to Menopause

Objective: Obesity is a well-known risk factor for developing endometrial cancer. However, the incidence and survival rate of endometrial cancer are associated with ethnicity and geographical area. In addition, whether menopausal status is associated with developing endometrial cancer in obese women and whether obesity is associated with subtypes of endometrial cancer have not been fully investigated. Here, we investigated the effect of BMI on developing endometrial cancer in Chinese women taking into account menopausal status and cancer subtypes.

Methods: Data on 1,127 women with endometrial cancer including body mass index (BMI), age at diagnosis, parity, menopausal status and cancer subtype were collected from the largest obstetrics & gynaecology hospital in China and analysed.

Results: After adjusting for age and parity, the odds for developing endometrial cancer in overweight or obese perimenopausal women was significantly higher than that in women with normal weight (OR=2.6 with 95%CI:1.9-3.5, and OR=3.5 with 95%CI: 2.2-5.4, respectively). The odds of developing endometrial cancer in overweight postmenopausal women were significantly higher than that in women who were normal weight (OR=2.4 with 95%CI: 1.8-3.1), however this was not the case for obese postmenopausal women. We further found that BMI, menopausal status, age and parity were not associated with subtypes of endometrial cancer.

Conclusion: Our data demonstrate that obesity is positively associated with the incidence of developing endometrial cancer in Chinese women, with more significant effects in perimenopausal women.

Insulin/IGF and sex hormone axes in human endometrium and associations with endometrial cancer risk factors

PURPOSE

Experimental and observational data link insulin, insulin-like growth factor (IGF), and estrogens to endometrial tumorigenesis. However, there are limited data regarding insulin/IGF and sex hormone axes protein and gene expression in normal endometrial tissues, and very few studies have examined the impact of endometrial cancer risk factors on endometrial tissue biology.

METHODS

We evaluated endometrial tissues from 77 premenopausal and 30 postmenopausal women who underwent hysterectomy for benign indications and had provided epidemiological data. Endometrial tissue mRNA and protein levels were measured using quantitative real-time PCR and immunohistochemistry, respectively.

RESULTS

In postmenopausal women, we observed higher levels of phosphorylated IGF-I/insulin receptor (pIGF1R/pIR) in diabetic versus non-diabetic women (p value =0.02), while women who reported regular nonsteroidal anti-inflammatory drug use versus no use had higher levels of insulin and progesterone receptors (both p values ≤0.03). We also noted differences in pIGF1R/pIR staining with OC use (postmenopausal women only), and the proportion of estrogen receptor-positive tissues varied by the number of live births and PTEN status (premenopausal only) (p values ≤0.04). Compared to premenopausal proliferative phase women, postmenopausal women exhibited lower mRNA levels of IGF1, but higher IGFBP1 and IGFBP3 expression (all p values ≤0.004), and higher protein levels of the receptors for estrogen, insulin, and IGF-I (all p values ≤0.02). Conversely, pIGF1R/pIR levels were higher in premenopausal proliferative phase versus postmenopausal endometrium (p value =0.01).

CONCLUSIONS

These results highlight links between endometrial cancer risk factors and mechanistic factors that may contribute to early events in the multistage process of endometrial carcinogenesis.

An epidemiological model for prediction of endometrial cancer risk in Europe

Endometrial cancer (EC) is the fourth most frequent cancer in women in Europe, and as its incidence is increasing, prevention strategies gain further pertinence. Risk prediction models can be a useful tool for identifying women likely to benefit from targeted prevention measures. On the basis of data from 201,811 women (mostly aged 30-65 years) including 855 incident EC cases from eight countries in the European Prospective Investigation into Cancer and Nutrition cohort, a model to predict EC was developed. A step-wise model selection process was used to select confirmed predictive epidemiologic risk factors. Piece-wise constant hazard rates in 5-year age-intervals were estimated in a cause-specific competing risks model, five-fold-cross-validation was applied for internal validation. Risk factors included in the risk prediction model were body-mass index (BMI), menopausal status, age at menarche and at menopause, oral contraceptive use, overall and by different BMI categories and overall duration of use, parity, age at first full-term pregnancy, duration of menopausal hormone therapy and smoking status (specific for pre, peri- and post-menopausal women). These variables improved the discriminating capacity to predict risk over 5 years from 71% for a model based on age alone to 77% (overall C statistic), and the model was well-calibrated (ratio of expected to observed cases = 0.99). Our model could be used for the identification of women at increased risk of EC in Western Europe. To achieve an EC-risk model with general validity, a large-scale cohort-consortium approach would be needed to assess and adjust for population variation.

Reproductive factors and risk of mortality in the European Prospective Investigation into Cancer and Nutrition; a cohort study

BACKGROUND

Reproductive events are associated with important physiologic changes, yet little is known about how reproductive factors influence long-term health in women. Our objective was to assess the relation of reproductive characteristics with all-cause and cause-specific mortality risk.

METHODS

The analysis was performed within the European Investigation into Cancer and Nutrition prospective cohort study, which enrolled >500,000 women and men from 1992 to 2000, who were residing in a given town/geographic area in 10 European countries. The current analysis included 322,972 eligible women aged 25-70 years with 99 % complete follow-up for vital status. We assessed reproductive characteristics reported at the study baseline including parity, age at the first birth, breastfeeding, infertility, oral contraceptive use, age at menarche and menopause, total ovulatory years, and history of oophorectomy/hysterectomy. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for mortality were determined using Cox proportional hazards regression models adjusted for menopausal status, body mass index, physical activity, education level, and smoking status/intensity and duration.

RESULTS

During a mean follow-up of 12.9 years, 14,383 deaths occurred. The HR (95 % CI) for risk of all-cause mortality was lower in parous versus nulliparous women (0.80; 0.76-0.84), in women who had ever versus never breastfed (0.92; 0.87-0.97), in ever versus never users of oral contraceptives (among non-smokers; 0.90; 0.86-0.95), and in women reporting a later age at menarche (≥15 years versus <12; 0.90; 0.85-0.96; P for trend = 0.038).

CONCLUSIONS

Childbirth, breastfeeding, oral contraceptive use, and a later age at menarche were associated with better health outcomes. These findings may contribute to the development of improved strategies to promote better long-term health in women.

Joint Effect of Genotypic and Phenotypic Features of Reproductive Factors on Endometrial Cancer Risk

Prolonged estrogen exposure is believed to be the major cause of endometrial cancer. As possible markers of estrogen exposure, various menstrual and reproductive features, e.g., ages at menarche and menopause, are found to be associated with endometrial cancer risk. In order to assess their combined effects on endometrial cancer, we created the total number of menstrual cycles (TNMC) that a woman experienced during her life or up to the time of study and two genetic risk scores, GRS1 for age at menarche and GRS2 for age at menopause. Comparing 482 endometrial cancer patients with 571 population controls, we found TNMC was associated with endometrial cancer risk and that the association remained statistically significant after adjustment for obesity and other potential confounders. Risk increased by about 2.5% for every additional 10 menstrual-cycles. The study also showed that high GRS1 was associated with increased risk. This relationship, however, was attenuated after adjustment for obesity. Our study further indicated women with high TNMC and GRS1 had twice the risk of endometrial cancer compared to those low in both indices. Our results provided additional support to the involvement of estrogen exposure in endometrial cancer risk with regard to genetic background and lifestyle features.

Parity and endometrial cancer risk: a meta-analysis of epidemiological studies

The association between parity and endometrial cancer risk is inconsistent from observational studies. We aimed to quantitatively assess the relationship by summarizing all relevant epidemiological studies. PubMed (MEDLINE), Embase and Scopus were searched up to February 2015 for eligible case–control studies and prospective studies. Random-effects model was used to pool risk estimations. Ten prospective studies, 35 case-control studies and 1 pooled analysis of 10 cohort and 14 case-control studies including 69681 patients were identified. Pooled analysis revealed that there was a significant inverse association between parity and risk of endometrial cancer (relative risk (RR) for parous versus nulliparous: 0.69, 95% confidence interval (CI) 0.65–0.74; I² = 76.9%). By evaluating the number of parity, we identified that parity number of 1, 2 or 3 versus nulliparous demonstrated significant negative association (RR = 0.73, 95% CI 0.64–0.84, I² = 88.3%; RR = 0.62, 95% CI 0.53–0.74, I² = 92.1%; and RR = 0.68, 95% CI 0.65–0.70, I² = 20.0% respectively). The dose-response analysis suggested a nonlinear relationship between the number of parity and endometrial cancer risk. The RR decreased when the number of parity increased. This meta-analysis suggests that parity may be associated with a decreased risk of endometrial cancer. Further studies are warranted to replicate our findings.

Age at menarche and endometrial cancer risk: a dose-response meta-analysis of prospective studies

Evidence between age at menarche and endometrial cancer risk have been controversial. Therefore, we conducted a meta-analysis of prospective studies to analyze the aforementioned association. Relevant studies were identified by searching PubMed and EMBASE databases until the end of June 2015. A random-effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs) for associations between menarcheal age and endometrial cancer risk. Our meta-analysis included eight prospective studies involving 4553 subjects with endometrial cancer. The summarized RRs of endometrial cancer for menarcheal age were 0.68 (95%CI = 0.58-0.81, I(2) = 41.9%, P = 0.099, n = 8) when comparing women with oldest category of menarcheal age with women with youngest category of menarcheal age. Notably, there was an 4% reduction in risk for per 2 years delay in menarcheal age (summarized RR = 0.96; 95%CI = 0.94-0.98, I(2) = 45.7%, P = 0.101, n = 6). Additionally, significant inverse associations were consistent within all stratified analyses. There was no evidence of publication bias or significant heterogeneity between subgroups detected by meta-regression analyses. Our findings support the hypothesis that late menarcheal age is inversely associated with endometrial cancer risk. Further larger prospective or pooled studies are warranted to fully adjust for potential confounders and distinguish whether the associations differ by histological subtypes of endometrial cancer.

Parity Correlates with the Timing of Developing Endometrial Cancer, But Not Subtype of Endometrial Cancer

Parity is one of well-known risk factors of endometrial cancer, but it is less clear whether parity is associated with the timing of developing endometrial cancer, and with the incidence of subtype of endometrial cancer. Data on 902 patients including age at diagnosis, age at menarche and menopause, parity and age at last birth from two obstetrics and gynaecology hospitals in China was analysed. 5.6% patients were nulliparous, 53.4% patients had one live birth, 27.7% patients had two live births and 13.3% patients had three or more live births. Patients at diagnosis who had three or more live births were significantly older than patients who were nulliparous or had one or two live births with the median age at diagnosis of 63 versus 51 or 52 or 59 years respectively. The percentage of patients with three or more live births at diagnosis before menopause was significantly lower than patients who were nulliparous, had one live birth or had two live births (10% versus 52%, or 51.9% or 22.4%). Furthermore, time from last birth to endometrial cancer was significantly longer in patients who had three or more live births than patients who had two live births or had one live birth (35 versus 31, or 24 years). However, there was no difference in the incidence of subtypes of endometrial cancer according to parity. Our data suggests parity is negatively correlated with the time onset of endometrial cancer and not associated with the incidence of endometrial cancer subtypes.

Reproductive and hormone-related risk factors for epithelial ovarian cancer by histologic pathways, invasiveness and histologic subtypes: Results from the EPIC cohort

Whether risk factors for epithelial ovarian cancer (EOC) differ by subtype (i.e., dualistic pathway of carcinogenesis, histologic subtype) is not well understood; however, data to date suggest risk factor differences. We examined associations between reproductive and hormone-related risk factors for EOC by subtype in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Among 334,126 women with data on reproductive and hormone-related risk factors (follow-up: 1992-2010), 1,245 incident cases of EOC with known histology and invasiveness were identified. Data on tumor histology, grade, and invasiveness, were available from cancer registries and pathology record review. We observed significant heterogeneity by the dualistic model (i.e., type I [low grade serous or endometrioid, mucinous, clear cell, malignant Brenner] vs. type II [high grade serous or endometrioid]) for full-term pregnancy (phet  = 0.02). Full-term pregnancy was more strongly inversely associated with type I than type II tumors (ever vs. never: type I: relative risk (RR) 0.47 [95% confidence interval (CI): 0.33-0.69]; type II, RR: 0.81 [0.61-1.06]). We observed no significant differences in risk in analyses by major histologic subtypes of invasive EOC (serous, mucinous, endometrioid, clear cell). None of the investigated factors were associated with borderline tumors. Established protective factors, including duration of oral contraceptive use and full term pregnancy, were consistently inversely associated with risk across histologic subtypes (e.g., ever full-term pregnancy: serous, RR: 0.73 [0.58-0.92]; mucinous, RR: 0.53 [0.30-0.95]; endometrioid, RR: 0.65 [0.40-1.06]; clear cell, RR: 0.34 [0.18-0.64]; phet  = 0.16). These results suggest limited heterogeneity between reproductive and hormone-related risk factors and EOC subtypes.

Prospective study of body size throughout the life-course and the incidence of endometrial cancer among premenopausal and postmenopausal women

Although adult obesity is known to increase endometrial cancer risk, evidence for childhood obesity is limited. We prospectively examined the association between body fatness throughout life and endometrial cancer risk. 47,289 participants in the Nurses' Health Study (NHS) and 105,386 of the Nurses' Health Study II (NHS II) recalled their body fatness at ages 5, 10 and 20 using a pictogram. Childhood and adolescent body fatness were derived as the average at ages 5 and 10 and ages 10 and 20, respectively. We obtained adult weight from concurrent questionnaires. We calculated hazard ratios (HR) of endometrial cancer using Cox proportional hazards models. During follow-up, 757 incident cases of endometrial cancer were diagnosed. Body fatness in childhood, at age 10, in adolescence and at age 20 were positively associated with endometrial cancer risk (HR for ≥ Level 5 versus ≤ Level 2 in adolescence: 1.83 (95% CI 1.41-2.37). After adjusting for most recent BMI, none of the associations persisted. Weight change since age 18 was positively associated with endometrial cancer risk [HR for ≥ 25 kg gain versus stable: 2.54 (95% CI 1.80-3.59). Adult BMI was strongly associated with endometrial cancer risk [HR BMI ≥ 35 kg/m(2) versus BMI ≤ 25 kg/m(2) : 4.13 (95% CI 3.29-5.16)]. In postmenopausal women, the association with BMI was significantly stronger among non-users of hormone therapy. In conclusion, obesity throughout life is positively associated with endometrial cancer risk, with adult obesity one of the strongest risk factors. Maintaining a healthy weight throughout life remains important.

Childhood Passive Smoking Exposure and Age at Menarche in Chinese Women Who Had Never Smoked: The Guangzhou Biobank Cohort Study

OBJECTIVE

We examined the associations between childhood passive smoking exposure and age at menarche in women who had never smoked in southern China.

METHODS

Among 30,518 participants in Guangzhou Biobank Cohort Study (GBCS) from 2003-2008, 20,061 women who had never smoked and had complete outcome data were included. Childhood passive smoking exposure was defined as living with 1 or more smokers in the same household during childhood. Data on the number of smokers in the household and frequency of exposure (density and frequency) were also obtained. Age at menarche was measured as a continuous variable.

RESULTS

11,379 (56.7%) participants were exposed to passive smoking during childhood. Compared to those with no passive smoking exposure during childhood, those with exposure ≥ 5 days/week had menarche 0.19 year (95% confidence interval (CI): 0.13-0.25) earlier on average. Those exposed to more than two smokers had menarche 0.38 year earlier (95% CI: 0.29-0.47). Childhood exposure was associated with early age at menarche (≤ 13 vs. >13 years), with an adjusted odds ratio of 1.34 (95% CI: 1.21-1.48) for high density, and 1.17 (95% CI: 1.09-1.26) for high frequency of exposure.

CONCLUSION

Childhood passive smoking exposure was associated with earlier age at menarche, with a dose-response relationship in Chinese women who had never smoked. If causal, the results support the promotion of smoking cessation in families with children, particularly young girls.

Association between Breastfeeding and Endometrial Cancer Risk: Evidence from a Systematic Review and Meta-Analysis

Quantification of the association between breastfeeding and risk of endometrial cancer is still conflicting. We therefore conducted a meta-analysis to assess the association between breastfeeding and endometrial cancer risk. Pertinent studies were identified by a search of PubMed and Web of Knowledge through April 2015. A random effect model was used to combine the data for analysis. Sensitivity analysis and publication bias were conducted. Dose-response relationships were assessed by restricted cubic spline and variance-weighted least squares regression analysis. Fourteen articles involving 5158 endometrial cancer cases and 706,946 participants were included in this meta-analysis. Pooled results suggested that breastfeeding significantly reduced the risk of endometrial cancer (summary relative risk (RR): 0.77, 95% CI: 0.62–0.96, I²: 63.0%), especially in North America (summary RR: 0.87, 95% CI: 0.79–0.95). A linear dose-response relationship was found, with the risk of endometrial cancer decreased by 2% for every one-month increase in the duration of breastfeeding (summary RR: 0.98, 95% CI: 0.97–0.99). Our analysis suggested that breastfeeding, particularly a longer duration of breastfeeding, was inversely associated with the risk of endometrial cancer, especially in North America, but not in Europe and Asia, probably due to the small number of cases included. Due to this limitation, further studies originating in other countries are required to assess the association between breastfeeding and endometrial cancer risk.

Female Hormonal Factors and the Risk of Endometrial Cancer in Lynch Syndrome

IMPORTANCE

Apart from hysterectomy, there is no consensus recommendation for reducing endometrial cancer risk for women with a mismatch repair gene mutation (Lynch syndrome).

OBJECTIVE

To investigate the association between hormonal factors and endometrial cancer risk in Lynch syndrome.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study included 1128 women with a mismatch repair gene mutation identified from the Colon Cancer Family Registry. Data were analyzed with a weighted cohort approach. Participants were recruited between 1997 and 2012 from centers across the United States, Australia, Canada, and New Zealand.

EXPOSURES

Age at menarche, first and last live birth, and menopause; number of live births; hormonal contraceptive use; and postmenopausal hormone use.

MAIN OUTCOMES AND MEASURES

Self-reported diagnosis of endometrial cancer.

RESULTS

Endometrial cancer was diagnosed in 133 women (incidence rate per 100 person-years, 0.29; 95% CI, 0.24 to 0.34). Endometrial cancer was diagnosed in 11% (n = 70) of women with age at menarche greater than or equal to 13 years compared with 12.6% (n = 57) of women with age at menarche less than 13 years (incidence rate per 100 person-years, 0.27 vs 0.31; rate difference, -0.04 [95% CI, -0.15 to 0.05]; hazard ratio per year, 0.85 [95% CI, 0.73 to 0.99]; P = .04). Endometrial cancer was diagnosed in 10.8% (n = 88) of parous women compared with 14.4% (n = 40) of nulliparous women (incidence rate per 100 person-years, 0.25 vs 0.43; rate difference, -0.18 [95% CI, -0.32 to -0.04]; hazard ratio, 0.21 [95% CI, 0.10 to 0.42]; P < .001). Endometrial cancer was diagnosed in 8.7% (n = 70) of women who used hormonal contraceptives greater than or equal to 1 year compared with 19.2% (n = 57) of women who used contraceptives less than 1 year (incidence rate per 100 person-years, 0.22 vs 0.45; rate difference, -0.23 [95% CI, -0.36 to -0.11]; hazard ratio, 0.39 [95% CI, 0.23 to 0.64]; P < .001). There was no statistically significant association between endometrial cancer and age at first and last live birth, age at menopause, and postmenopausal hormone use.

CONCLUSIONS AND RELEVANCE

For women with a mismatch repair gene mutation, some endogenous and exogenous hormonal factors were associated with a lower risk of endometrial cancer. These directions and strengths of associations were similar to those for the general population. If replicated, these findings suggest that women with a mismatch repair gene mutation may be counseled like the general population in regard to hormonal influences on endometrial cancer risk.

Infertility and incident endometrial cancer risk: a pooled analysis from the epidemiology of endometrial cancer consortium (E2C2)

BACKGROUND

Nulliparity is an endometrial cancer risk factor, but whether or not this association is due to infertility is unclear. Although there are many underlying infertility causes, few studies have assessed risk relations by specific causes.

METHODS

We conducted a pooled analysis of 8153 cases and 11 713 controls from 2 cohort and 12 case-control studies. All studies provided self-reported infertility and its causes, except for one study that relied on data from national registries. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Nulliparous women had an elevated endometrial cancer risk compared with parous women, even after adjusting for infertility (OR=1.76; 95% CI: 1.59-1.94). Women who reported infertility had an increased risk compared with those without infertility concerns, even after adjusting for nulliparity (OR=1.22; 95% CI: 1.13-1.33). Among women who reported infertility, none of the individual infertility causes were substantially related to endometrial cancer.

CONCLUSIONS

Based on mainly self-reported infertility data that used study-specific definitions of infertility, nulliparity and infertility appeared to independently contribute to endometrial cancer risk. Understanding residual endometrial cancer risk related to infertility, its causes and its treatments may benefit from large studies involving detailed data on various infertility parameters.

Risk factors for endometrial cancer in black and white women: a pooled analysis from the Epidemiology of Endometrial Cancer Consortium (E2C2)

PURPOSE

Endometrial cancer (EC) is the most common gynecologic cancer in the USA. Over the last decade, the incidence rate has been increasing, with a larger increase among blacks. The aim of this study was to compare risk factors for EC in black and white women.

METHODS

Data from seven cohort and four case-control studies were pooled. Unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95 % confidence intervals for each risk factor in blacks and whites separately.

RESULTS

Data were pooled for 2,011 black women (516 cases and 1,495 controls) and 19,297 white women (5,693 cases and 13,604 controls). BMI ≥ 30 was associated with an approximate threefold increase in risk of EC in both black and white women (ORblack 2.93, 95 % CI 2.11, 4.07 and ORwhite 2.99, 95 % CI 2.74, 3.26). Diabetes was associated with a 30-40 % increase in risk among both groups. Increasing parity was associated with decreasing risk of EC in blacks and whites (p value = 0.02 and <0.001, respectively). Current and former smoking was associated with decreased risk of EC among all women. Both black and white women who used oral contraceptives for 10 +years were also at reduced risk of EC (OR 0.49, 95 % CI 0.27, 0.88 and OR 0.69, 95 % CI 0.58, 0.83, respectively). Previous history of hypertension was not associated with EC risk in either group.

CONCLUSIONS

The major known risk factors for EC exert similar effects on black and white women. Differences in the incidence rates between the two populations may be due to differences in the prevalence of risk factors.

A microsatellite polymorphism in IGF1 gene promoter and timing of natural menopause in Caucasian women

BACKGROUND

Genes involved in the IGF-1 aging pathways in the human ovary can be considered strong candidates for predictors of the natural menopause timing. This study evaluates the association between a cytosine-adenine (CA) microsatellite polymorphism in the IGF1 gene promoter P1 and age at natural menopause.

METHODS

Genomic DNA was extracted from the peripheral blood, PCR was performed using primers designed to amplify the polymorphic (CA) n repeat of the human IGF1 gene, an allele dose effect for the most common (CA)19 repeats allele, Cox proportional hazard regression models and the Kaplan-Meier cumulative survivorship method with the log-rank test were used to determine statistical significance of studied associations in a sample of 257 Polish women aged 40-58 years.

RESULTS

Crude Cox proportional hazard regression analysis confirmed the association between the IGF1 gene polymorphism and the menopause timing (p=0.038). This relationship remained statistically significant after controlling for other menopause confounders in multivariate modelling. Out of the input variables, the (CA)n polymorphism in the IGF1 gene promoter, age at menarche and smoking status were independent covariates of the natural menopause timing (χ2=12.845; df=3; p=0.034). The onset of menopause at a younger age was likely associated with the IGF1 genotype variant not carrying the (CA)19 repeats allele, menarche before the age of 12 and a current cigarette smoker status (HR=1.6).

CONCLUSION

This study provides evidence that a common cytosine-adenine (CA) microsatellite repeat polymorphism in the P1 promoter region of the IGF1 gene is an independent predictive factor for age at natural menopause in Caucasian women also after adjusting for other menopause covariates.

Noncontraceptive benefits of the estradiol valerate/dienogest combined oral contraceptive: a review of the literature

Combined oral contraceptives formulated to include estradiol (E2) have recently become available for the indication of pregnancy prevention. A combined estradiol valerate and dienogest pill (E2V/DNG), designed to be administered using an estrogen step-down and a progestin step-up regimen over 26 days of active treatment followed by 2 days of placebo (26/2-day regimen), has also undergone research to assess the potential for additional noncontraceptive benefits. Randomized, placebo-controlled studies have demonstrated that E2V/DNG is an effective treatment for heavy menstrual bleeding - a reduction in median menstrual blood loss approaching 90% occurs after 6 months of treatment. To date, E2V/DNG is the only oral contraceptive approved for this indication. Comparator studies have also demonstrated a reduction in hormone withdrawal-associated symptoms in users of E2V/DNG compared with a conventional 21/7-day regimen of ethinylestradiol/levonorgestrel. Other potential noncontraceptive benefits associated with E2V/DNG, like improvement in dysmenorrhea, sexual function, and quality of life, are comparable with those associated with other combined oral contraceptives and are discussed further in this review.

Association between diabetes, diabetes treatment and risk of developing endometrial cancer

Background:

A growing body of evidence suggests that diabetes is a risk factor for endometrial cancer incidence. However, most of these studies used case-control study designs and did not adjust for obesity, an established risk factor for endometrial cancer. In addition, few epidemiological studies have examined the association between diabetes treatment and endometrial cancer risk. The objective of this study was to assess the relationships among diabetes, diabetes treatment and endometrial cancer risk in postmenopausal women participating in the Women's Health Initiative (WHI).

Methods:

A total of 88 107 postmenopausal women aged 50–79 years who were free of cancer and had no hysterectomy at baseline were followed until date of endometrial cancer diagnosis, death, hysterectomy or loss to follow-up, whichever came first. Endometrial cancers were confirmed by central medical record and pathology report review. Multivariate Cox proportional hazards regression models were used to estimate hazard ratios (HRs) (95% confidence interval (CI)) for diagnosis of diabetes and metformin treatment as risk factors for endometrial cancer.

Results:

Over a mean of 11 years of follow-up, 1241 endometrial cancers developed. In the primary analysis that focused on prevalent diabetes at enrolment, compared with women without diabetes, women with self-reported diabetes, and the subset of women with treated diabetes, had significantly higher risk of endometrial cancer without adjusting for BMI (HR=1.44, 95% CI: 1.13–1.85 for diabetes, HR=1.57, 95% CI: 1.19–2.07 for treated diabetes). However after adjusting for BMI, the associations between diabetes, diabetes treatment, diabetes duration and the risk of endometrial cancer became non-significant. Elevated risk was noted when considering combining diabetes diagnosed at baseline and during follow-up as time-dependent exposure (HR=1.31, 95% CI: 1.08–1.59) even after adjusting for BMI. No significant association was observed between metformin use and endometrial cancer risk.

Conclusions:

Our results suggest that the relationship observed in previous research between diabetes and endometrial cancer incidence may be largely confounded by body weight, although some modest independent elevated risk remains.

Benign breast and gynecologic conditions, reproductive and hormonal factors, and risk of thyroid cancer

The higher incidence of thyroid cancer in women compared with men suggests an influence of sex steroid hormones in the etiology of this malignancy. We investigated a comprehensive set of potential indicators of lifetime sex steroid hormone exposure in relation to thyroid cancer risk. Using data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, which enrolled 70,047 women, 50 to 78 years old, we prospectively examined associations of self-reported history of benign breast and gynecologic conditions, reproductive factors, and exogenous sex hormone use with thyroid cancer risk. Multivariable-adjusted HRs and 95% confidence intervals (CI) were calculated in models using age as the time metric. During follow-up (median, 11 years), 127 women were diagnosed with first primary thyroid cancer. Older age at natural menopause (≥55 vs. <50 years; HR, 2.24; 95% CI, 1.20-4.18), greater estimated lifetime number of ovulatory cycles (≥490 vs. <415 cycles; HR, 2.40; 95% CI, 1.33-4.30), greater number of live births (≥5 vs. 1-2; HR, 1.72; 95% CI, 1.05-2.82), and history of uterine fibroids (HR, 1.72; 95% CI, 1.18-2.50) were associated with an increased risk of thyroid cancer. Earlier age at menarche, greater number of reproductive years, history of a tubal ligation, and history of ovarian cysts were nonsignificantly associated with increased thyroid cancer risk. No associations were observed for oral contraceptive use, menopausal hormone therapy, or history of benign breast disease or endometriosis. In general, we found that factors reflecting a greater length of exposure to endogenous hormones, particularly during the reproductive years, were associated with risk of postmenopausal thyroid cancer.

Immunosuppressive Glycodelin A is an independent marker for poor prognosis in endometrial cancer

Background

Knowledge on immunosuppressive factors in the pathogenesis of endometrial cancer is scarce. The aim of this study was to assess Glycodelin (Gd) and its immunosuppressive isoform Glycodelin A (GdA) in endometrial cancer tissue and to analyze its impact on clinical and pathological features and patient outcome.

Methods

292 patients diagnosed and treated for endometrial cancer were included. Patient characteristics, histology and follow-up data were available. Gd and GdA was determined by immunohistochemistry and in situ hybridization was performed for Gd mRNA.

Results

Endometrial cancer shows intermediate (52.2%) or high (20.6%) expression for Gd in 72.8%, and GdA in 71.6% (intermediate 62.6%, high 9.0%) of all cases. The glycosylation dependent staining of GdA is tumour specific and correlates with the peptide-specific Gd staining though neither of the two is associated with estrogen receptor, progesterone receptor or clinic-pathological features. Also Gd protein positively correlates with Gd mRNA as quantified by in situ hybridization. Gd positive cases have a favourable prognosis (p = 0.039), while GdA positive patients have a poor outcome (p = 0.003). Cox-regression analysis proofed GdA to be an independent prognostic marker for patient survival (p = 0.002), besides tumour stage, grade and the concomitant diagnosis of hypertension.

Conclusion

Gd and GdA are commonly expressed in endometrial cancer tissue and seem to be of relevance in tumourigenesis. They differ not only in glycosylation but also in their biological activity, since only GdA holds prognostic significance for a poor overall survival in endometrial cancer patients. This finding might be explained by GdAs immunosuppressive capacity.

Latitude and ultraviolet radiation dose in the birthplace in relation to menarcheal age in a large cohort of French women

BACKGROUND

Age at menarche is an important determinant of hormonal-related neoplasia and other chronic diseases. Spatial and temporal variations in age at menarche have been observed in industrialised countries and several environmental factors were reported to have an influence.

METHOD

We examined geographical variations in self-reported age at menarche and explored the effects of both latitude and ultraviolet radiation (UVR) dose on the onset of menarche in 88,278 women from the French E3N cohort (aged 40-65 years at inclusion).

RESULTS

The mean age at menarche was 12.8 years. After adjustment for potential confounders (birth cohort, prematurity, birth weight and length, father's income index, body silhouette in childhood, food deprivation during World War II, population of birthplace, number of siblings, breastfeeding exposure and indoor exposure to passive smoking during childhood), latitude and UVR dose (annual or spring/summer) in county of birth were significantly associated with age at menarche (P(trend) < 0.0001). Women born at lower latitudes or in regions with higher annual or spring/summer UVR dose had a 3- to 4-month earlier menarche than women born at higher latitudes or in regions with lower UVR. On a continuous scale, a 1° increment in latitude resulted in a 0.04-year older age at menarche [95% confidence interval (CI): 0.03, 0.05], whereas a 1-kJ/m(2) increment in annual UVR dose resulted in a 0.42-year younger age at menarche (95% CI: -0.55, -0.29).

CONCLUSION

These data further suggest that light exposure in childhood may influence sexual maturation in women.

Contemporary clinical management of endometrial cancer

Although the contemporary management of endometrial cancer is straightforward in many ways, novel data has emerged over the past decade that has altered the clinical standards of care while generating new controversies that will require further investigation. Fortunately most cases are diagnosed at early stages, but high-risk histologies and poorly differentiated tumors have high metastatic potential with a significantly worse prognosis. Initial management typically requires surgery, but the role and extent of lymphadenectomy are debated especially with well-differentiated tumors. With the changes in surgical staging, prognosis correlates more closely with stage, and the importance of cytology has been questioned and is under evaluation. The roles of radiation in intermediate-risk patients and chemotherapy in high-risk patients are emerging. The therapeutic index of brachytherapy needs to be considered, and the best sequencing of combined modalities needs to balance efficacy and toxicities. Additionally novel targeted therapies show promise, and further studies are needed to determine the appropriate use of these new agents. Management of endometrial cancer will continue to evolve as clinical trials continue to answer unsolved clinical questions.

The pleiomorphic actions of vitamin D and its importance for children

Knowledge regarding the physiological role and dietary requirements of vitamin D has dramatically expanded over the past several decades. The "new" vitamin D is not only a mediator of calcium homeostasis, it also has important immunomodulatory, antimicrobial, and antiproliferative actions. In spite of the interest in vitamin D as a mediator in many chronic diseases of adulthood such as cancer and type II diabetes, less attention has been given to the implications of the new understanding of vitamin D for child and adolescent health. Recently, rickets caused by vitamin D deficiency is resurging in developed countries. Therefore, pharmacokinetic studies and epidemiologic research that incorporates clinical and functional outcomes are needed to clarify the role of vitamin D in growth and development in Korean children and adolescents and to determine vitamin D dietary requirements.