Maximizing resources to study an uncommon cancer: E2C2--Epidemiology of Endometrial Cancer Consortium

Hypertension and Risk of Endometrial Cancer: A Pooled Analysis in the Epidemiology of Endometrial Cancer Consortium (E2C2)

BACKGROUND

The incidence rates of endometrial cancer are increasing, which may partly be explained by the rising prevalence of obesity, an established risk factor for endometrial cancer. Hypertension, another component of metabolic syndrome, is also increasing in prevalence, and emerging evidence suggests that it may be associated with the development of certain cancers. The role of hypertension independent of other components of metabolic syndrome in the etiology of endometrial cancer remains unclear. In this study, we evaluated hypertension as an independent risk factor for endometrial cancer and whether this association is modified by other established risk factors.

METHODS

We included 15,631 endometrial cancer cases and 42,239 controls matched on age, race, and study-specific factors from 29 studies in the Epidemiology of Endometrial Cancer Consortium. We used multivariable unconditional logistic regression models to estimate ORs and 95% confidence intervals (CI) to evaluate the association between hypertension and endometrial cancer and whether this association differed by study design, race/ethnicity, body mass index, diabetes status, smoking status, or reproductive factors.

RESULTS

Hypertension was associated with an increased risk of endometrial cancer (OR, 1.14; 95% CI, 1.09-1.19). There was significant heterogeneity by study design (Phet < 0.01), with a stronger magnitude of association observed among case-control versus cohort studies. Stronger associations were also noted for pre-/perimenopausal women and never users of postmenopausal hormone therapy.

CONCLUSIONS

Hypertension is associated with endometrial cancer risk independently from known risk factors. Future research should focus on biologic mechanisms underlying this association.

IMPACT

This study provides evidence that hypertension may be an independent risk factor for endometrial cancer.

Night shift work, sleep duration and endometrial cancer risk: A pooled analysis from the Epidemiology of Endometrial Cancer Consortium (E2C2)

Data on the role of circadian related factors in the etiology of endometrial cancer are scarce. We collected individual data on night shift work or daily sleep duration from 7,207 cases and 22,027 controls participating in 11 studies from the Epidemiology of Endometrial Cancer Consortium (E2C2). Main analyses were performed among postmenopausal women: 6,335 endometrial cancer cases and 18,453 controls. Using individual data, study-specific odd ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated with logistic regression and pooled analyses were conducted using random-effects meta-analyses. A non-significant inverse association was observed between endometrial cancer and night shift work (OR=0.89, 95%CI=0.72-1.09; I2=0.0%, Pheterogeneity=0.676). Associations did not vary by shift type (permanent or rotating), or duration of night work. Categorizations of short (<7h) or long (≥9h) sleep duration were not associated with endometrial cancer risk (ORshort=1.02, 95%CI=0.95-1.10; I2=55.3%, Pheterogeneity=0.022; ORlong=0.93, 95%CI=0.81-1.06; I2=11.5%, Pheterogeneity=0.339). No associations were observed per 1-h increment of sleep (OR=0.98, 95%CI=0.95-1.01; I2=46.1%, Pheterogeneity=0.063), but an inverse association was identified among obese women (OR=0.93, 95%CI=0.89-0.98 per 1-h increment; I2=12.7%, Pheterogeneity=0.329). Overall, these pooled analyses provide evidence that night shift work and sleep duration are not strong risk factors for endometrial cancer in postmenopausal women.

Risk prediction models for endometrial cancer: development and validation in an international consortium

BACKGROUND

Endometrial cancer risk stratification may help target interventions, screening, or prophylactic hysterectomy to mitigate the rising burden of this cancer. However, existing prediction models have been developed in select cohorts and have not considered genetic factors.

METHODS

We developed endometrial cancer risk prediction models using data on postmenopausal White women aged 45-85 years from 19 case-control studies in the Epidemiology of Endometrial Cancer Consortium (E2C2). Relative risk estimates for predictors were combined with age-specific endometrial cancer incidence rates and estimates for the underlying risk factor distribution. We externally validated the models in 3 cohorts: Nurses' Health Study (NHS), NHS II, and the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.

RESULTS

Area under the receiver operating characteristic curves for the epidemiologic model ranged from 0.64 (95% confidence interval [CI] = 0.62 to 0.67) to 0.69 (95% CI = 0.66 to 0.72). Improvements in discrimination from the addition of genetic factors were modest (no change in area under the receiver operating characteristic curves in NHS; PLCO = 0.64 to 0.66). The epidemiologic model was well calibrated in NHS II (overall expected-to-observed ratio [E/O] = 1.09, 95% CI = 0.98 to 1.22) and PLCO (overall E/O = 1.04, 95% CI = 0.95 to 1.13) but poorly calibrated in NHS (overall E/O = 0.55, 95% CI = 0.51 to 0.59).

CONCLUSIONS

Using data from the largest, most heterogeneous study population to date (to our knowledge), prediction models based on epidemiologic factors alone successfully identified women at high risk of endometrial cancer. Genetic factors offered limited improvements in discrimination. Further work is needed to refine this tool for clinical or public health practice and expand these models to multiethnic populations.

Dietary omega-3 fatty acids and endometrial cancer risk in the Epidemiology of Endometrial Cancer Consortium: An individual-participant meta-analysis

BACKGROUND

Limited data from prospective studies suggest that higher dietary intake of long-chain omega-3 polyunsaturated fatty acids (LCn3PUFA), which hold anti-inflammatory properties, may reduce endometrial cancer risk; particularly among certain subgroups characterized by body mass and tumor pathology.

MATERIALS AND METHODS

Data from 12 prospective cohort studies participating in the Epidemiology of Endometrial Cancer Consortium were harmonized as nested case-control studies, including 7268 endometrial cancer cases and 26,133 controls. Habitual diet was assessed by food frequency questionnaire, from which fatty acid intakes were estimated. Two-stage individual-participant data mixed effects meta-analysis estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) through logistic regression for associations between study-specific energy-adjusted quartiles of LCn3PUFA and endometrial cancer risk.

RESULTS

Women with the highest versus lowest estimated dietary intakes of docosahexaenoic acid, the most abundant LCn3PUFA in diet, had a 9% increased endometrial cancer risk (Quartile 4 vs. Quartile 1: OR 1.09, 95% CI: 1.01-1.19; P trend = 0.04). Similar elevated risks were observed for the summary measure of total LCn3PUFA (OR 1.07, 95% CI: 0.99-1.16; P trend = 0.06). Stratified by body mass index, higher intakes of LCn3PUFA were associated with 12-19% increased endometrial cancer risk among overweight/obese women and no increased risk among normal-weight women. Higher associations appeared restricted to White women. The results did not differ by cancer grade.

CONCLUSION

Higher dietary intakes of LCn3PUFA are unlikely to reduce endometrial cancer incidence; rather, they may be associated with small to moderate increases in risk in some subgroups of women, particularly overweight/obese women.

Risk factors for endometrial cancer in Black women

PURPOSE

The incidence of endometrial cancer (EC) has been increasing faster among Black women than among other racial/ethnic groups in the United States. Although the mortality rate is nearly twice as high among Black than White women, there is a paucity of literature on risk factors for EC among Black women, particularly regarding menopausal hormone use and severe obesity.

METHODS

We pooled questionnaire data on 811 EC cases and 3,124 controls from eight studies with data on self-identified Black women (4 case-control and 4 cohort studies). We analyzed cohort studies as nested case-control studies with up to 4 controls selected per case. We used logistic regression to estimate multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We observed a positive association between BMI and EC incidence (P_trend < 0.0001) The OR comparing BMI ≥ 40 vs. < 25 kg/m² was 3.92 (95% CI 2.91, 5.27). Abdominal obesity among those with BMI < 30 kg/m² was not appreciably associated with EC risk (OR 1.21, 95% CI 0.74, 1.99). Associations of reproductive history with EC were similar to those observed in studies of White women. Long-term use of estrogen-only menopausal hormones was associated with an increased risk of EC (≥ 5 years vs. never use: OR 2.08, 95% CI: 1.06, 4.06).

CONCLUSIONS

Our results suggest that the associations of established risk factors with EC are similar between Black and White women. Other explanations, such as differences in the prevalence of known risk factors or previously unidentified risk factors likely underlie the recent increases in EC incidence among Black women.

Coffee consumption and risk of endometrial cancer: a pooled analysis of individual participant data in the Epidemiology of Endometrial Cancer Consortium (E2C2)

BACKGROUND

Epidemiologic studies suggest that coffee consumption may be inversely associated with risk of endometrial cancer (EC), the most common gynecological malignancy in developed countries. Furthermore, coffee consumption may lower circulating concentrations of estrogen and insulin, hormones implicated in endometrial carcinogenesis. Antioxidants and other chemopreventive compounds in coffee may have anticarcinogenic effects. Based on available meta-analyses, the World Cancer Research Fund (WCRF) concluded that consumption of coffee probably protects against EC.

OBJECTIVES

Our main aim was to examine the association between coffee consumption and EC risk by combining individual-level data in a pooled analysis. We also sought to evaluate potential effect modification by other risk factors for EC.

METHODS

We combined individual-level data from 19 epidemiologic studies (6 cohort, 13 case-control) of 12,159 EC cases and 27,479 controls from the Epidemiology of Endometrial Cancer Consortium (E2C2). Logistic regression was used to calculate ORs and their corresponding 95% CIs. All models were adjusted for potential confounders including age, race, BMI, smoking status, diabetes status, study design, and study site.

RESULTS

Coffee drinkers had a lower risk of EC than non-coffee drinkers (multiadjusted OR: 0.87; 95% CI: 0.79, 0.95). There was a dose-response relation between higher coffee consumption and lower risk of EC: compared with non-coffee drinkers, the adjusted pooled ORs for those who drank 1, 2-3, and >4 cups/d were 0.90 (95% CI: 0.82, 1.00), 0.86 (95% CI: 0.78, 0.95), and 0.76 (95% CI: 0.66, 0.87), respectively (P-trend < 0.001). The inverse association between coffee consumption and EC risk was stronger in participants with BMI > 25 kg/m2.

CONCLUSIONS

The results of the largest analysis to date pooling individual-level data further support the potentially beneficial health effects of coffee consumption in relation to EC, especially among females with higher BMI.

Estimating Additive Interaction Effect in Stratified Two-Phase Case-Control Design

BACKGROUND AND AIMS

There is considerable interest in epidemiology to estimate an additive interaction effect between two risk factors in case-control studies. An additive interaction is defined as the differential reduction in absolute risk associated with one factor between different levels of the other factor. A stratified two-phase case-control design is commonly used in epidemiology to reduce the cost of assembling covariates. It is crucial to obtain valid estimates of the model parameters by accounting for the underlying stratification scheme to obtain accurate and precise estimates of additive interaction effects. The aim of this paper is to examine the properties of different methods for estimating model parameters and additive interaction effects under a stratified two-phase case-control design.

METHODS

Using simulations, we investigate the properties of three existing methods, namely stratum-specific offset, inverse-probability weighting, and multiple imputation for estimating model parameters and additive interaction effects. We also illustrate these properties using data from two published epidemiology studies.

RESULTS

Simulation studies show that the multiple imputation method performs well when both the true and analysis models are additive (i.e., does not include multiplicative interaction terms) but does not provide a discernible advantage over the offset method when the analysis models are non-additive (i.e., includes multiplicative interaction terms). The offset method exhibits the best overall properties when the analysis model contains multiplicative interaction effects.

CONCLUSION

When estimating additive interaction between risk factors in stratified two-phase case-control studies, we recommend estimating model parameters using multiple imputation when the analysis model is additive, and we recommend the offset method when the analysis model is non-additive.

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.

GWAS meta-analysis of 16 852 women identifies new susceptibility locus for endometrial cancer

Endometrial cancer is the most common gynecological malignancy in the developed world. Although there is evidence of genetic predisposition to the disease, most of the genetic risk remains unexplained. We present the meta-analysis results of four genome-wide association studies (4907 cases and 11 945 controls total) in women of European ancestry. We describe one new locus reaching genome-wide significance (P < 5 × 10 -8) at 6p22.3 (rs1740828; P = 2.29 × 10 -8, OR = 1.20), providing evidence of an additional region of interest for genetic susceptibility to endometrial cancer.

Identification of a preoperative predictive factor for lymph node metastasis in uterine papillary serous carcinoma: long-term results from a single institution

OBJECTIVE

The purpose of this study was to identify preoperative clinicopathological predictive factors for lymph node (LN) metastasis in women diagnosed with uterine papillary serous carcinoma (UPSC).

METHODS

Women diagnosed with UPSC in our institution from 1997 to 2012 were identified. All patients underwent hysterectomy and bilateral salpingo-oophorectomy plus pelvic and/or para-aortic lymphadenectomy. The predictive values of the risk factors for LN metastasis were analyzed using χ and multivariate logistic regression analyses.

RESULTS

A total of 94 patients met our study criteria. A CA-125 cutoff of 47.5 IU/mL on the receiver operating characteristic curve provided the best sensitivity and specificity (56.5% vs 90.1%, respectively) for LN metastasis prediction. The sensitivities and specificities of old age (≥60 years), body mass index of 25 kg/m or greater, deep myometrial invasion, tumor size greater than 2 cm, tumor size greater than 4 cm, preoperative CA-125 greater than 47.5 IU/mL, LN metastasis on imaging, and extrauterine spread on imaging for the presence of a positive LN were 39.1%, 34.8%, 30.4%, 34.8%, 21.7%, 56.5%, 43.5%, and 52.2%, and 52.1%, 45.1%, 78.9%, 57.7%, 83.1%, 90.1%, 93.0%, and 90.1%, respectively. Preoperative CA-125 (P < 0.001), LN metastasis on preoperative imaging (P < 0.001), and extrauterine spread on preoperative imaging (P = 0.009) were risk factors for LN metastasis on univariate analysis. Multivariate analysis revealed that preoperative CA-125 (P = 0.001) was the only independent risk factor for LN metastasis.

CONCLUSIONS

Preoperative CA-125 is a preoperative predictive factor for LN metastasis in UPSC.

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.

Screening for germline phosphatase and tensin homolog-mutations in suspected Cowden syndrome and Cowden syndrome-like families among uterine cancer patients

Cowden syndrome (CS) is an autosomal dominant disorder characterized by multiple hamartomas in the breast, thyroid and endometrium, with a prevalence of 1 per 250,000. Females with CS have a 21-28% lifetime risk of developing uterine cancer. Germline mutations in the phosphatase and tensin homolog (PTEN) gene, a tumor suppressor gene, are responsible for 30-80% of CS cases. PTEN is a nine-exon gene, located on chromosome 10q23.3, which encodes the 403 amino acid PTEN protein. It negatively regulates the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin pathway, affecting various cellular processes and signaling pathways. The present study examined whether PTEN mutations are present in CS-like families with uterine cancer (UC). UC patients underwent surgery at Karolinska University Hospital, Stockholm, Sweden (2008-2012). Pedigrees were analyzed and 54 unrelated CS-like families were identified. CS-like families were defined as having at least one occurrence of uterine cancer and one of breast cancer, as well as at least one additional Cowden-associated tumor (uterine, breast, thyroid, colon or kidney cancer) in the same individual or in first-degree relatives. Genomic DNA was amplified using polymerase chain reaction, and DNA sequencing analysis of all nine exons of the PTEN gene was conducted. No germline PTEN mutations or polymorphisms were identified. Germline PTEN mutations are rare in CS-like families with uterine cancer, therefore, genetic screening must be restricted to patients that meet the strict National Comprehensive Cancer Network criteria. Gynecologists must be aware of the CS criteria and identify potential cases of CS in females where uterine cancer is the sentinel cancer.

Intrauterine devices and endometrial cancer risk: a pooled analysis of the Epidemiology of Endometrial Cancer Consortium

Intrauterine devices (IUDs), long-acting and reversible contraceptives, induce a number of immunological and biochemical changes in the uterine environment that could affect endometrial cancer (EC) risk. We addressed this relationship through a pooled analysis of data collected in the Epidemiology of Endometrial Cancer Consortium. We combined individual-level data from 4 cohort and 14 case-control studies, in total 8,801 EC cases and 15,357 controls. Using multivariable logistic regression, we estimated pooled odds ratios (pooled-ORs) and 95% confidence intervals (CIs) for EC risk associated with ever use, type of device, ages at first and last use, duration of use and time since last use, stratified by study and adjusted for confounders. Ever use of IUDs was inversely related to EC risk (pooled-OR = 0.81, 95% CI = 0.74-0.90). Compared with never use, reduced risk of EC was observed for inert IUDs (pooled-OR = 0.69, 95% CI = 0.58-0.82), older age at first use (≥ 35 years pooled-OR = 0.53, 95% CI = 0.43-0.67), older age at last use (≥ 45 years pooled-OR = 0.60, 95% CI = 0.50-0.72), longer duration of use (≥ 10 years pooled-OR = 0.61, 95% CI = 0.52-0.71) and recent use (within 1 year of study entry pooled-OR = 0.39, 95% CI = 0.30-0.49). Future studies are needed to assess the respective roles of detection biases and biologic effects related to foreign body responses in the endometrium, heavier bleeding (and increased clearance of carcinogenic cells) and localized hormonal changes.

Cross-cancer pleiotropic analysis of endometrial cancer: PAGE and E2C2 consortia

Genome-wide association studies (GWAS) have identified a large number of cancer-associated single nucleotide polymorphisms (SNPs), several of which have been associated with multiple cancer sites suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesized that SNPs associated with other cancers may be additionally associated with endometrial cancer. We examined 213 SNPs previously associated with 14 other cancers for their associations with endometrial cancer in 3758 endometrial cancer cases and 5966 controls of European ancestry from two consortia: Population Architecture Using Genomics and Epidemiology and the Epidemiology of Endometrial Cancer Consortium. Study-specific logistic regression estimates adjusted for age, body mass index and the most significant principal components of genetic ancestry were combined using fixed-effect meta-analysis to evaluate the association between each SNP and endometrial cancer risk. A Bonferroni-corrected P value of 2.35×10(-4) was used to determine statistical significance of the associations. SNP rs7679673, ~6.3kb upstream of TET2 and previously reported to be associated with prostate cancer risk, was associated with endometrial cancer risk in the direction opposite to that for prostate cancer [meta-analysis odds ratio = 0.87 (per copy of the C allele), 95% confidence interval = 0.81, 0.93; P = 7.37×10(-5)] with no evidence of heterogeneity across studies (P heterogeneity = 0.66). This pleiotropic analysis is the first to suggest TET2 as a susceptibility locus for endometrial cancer.

Exome-wide association study of endometrial cancer in a multiethnic population

Endometrial cancer (EC) contributes substantially to total burden of cancer morbidity and mortality in the United States. Family history is a known risk factor for EC, thus genetic factors may play a role in EC pathogenesis. Three previous genome-wide association studies (GWAS) have found only one locus associated with EC, suggesting that common variants with large effects may not contribute greatly to EC risk. Alternatively, we hypothesize that rare variants may contribute to EC risk. We conducted an exome-wide association study (EXWAS) of EC using the Infinium HumanExome BeadChip in order to identify rare variants associated with EC risk. We successfully genotyped 177,139 variants in a multiethnic population of 1,055 cases and 1,778 controls from four studies that were part of the Epidemiology of Endometrial Cancer Consortium (E2C2). No variants reached global significance in the study, suggesting that more power is needed to detect modest associations between rare genetic variants and risk of EC.

Familial cancer among consecutive uterine cancer patients in Sweden

Background

Uterine cancer (UC) represents 5.1% of all female malignancies in Sweden. Accumulation of UC in families occurs in around 5% of cases. We wanted to identify any familial association between UC and other selected cancers and to study the frequency of Lynch,Cowden and cancer syndromes among consecutive UC patients in Sweden.

Methods

481 UC patients were included. Information on the cancer diagnoses of their relatives (first- (FDRs) and second-degree (SDRs) relatives and first cousins) was obtained. The relative frequencies of different cancers among relatives were compared to those in the Swedish general cancer population in 1970 and 2010. Families that fulfilled the criteria for hereditary cancer syndromes were tested for mutations in the causative genes. Families with at least one case of UC in addition to the index patient were compared to families with no additional cases to investigate possible characteristics of putative hereditary cancer syndromes.

Results

There was an increased prevalence of UC in our study population compared to the Swedish general cancer population in 1970 and 2010 (6% vs. 4% and 3%, respectively). Seven families had Lynch Syndrome according to the Amsterdam II criteria. No families fulfilled the criteria for Cowden syndrome. In total 13% of index patients had at least one relative with UC and these families tended to have more cases of early onset cancer among family members. In addition, 16% of index patients were diagnosed with at least one other cancer. No families fulfilled the criteria for Cowden syndrome.

Conclusion

We showed a familial clustering of UC among relatives of our index patients. Of the seven families with mutation-verified Lynch Syndrome, only one had been previously diagnosed, highlighting the need to increase gynecologists’ awareness of the importance of taking family history. Our data on multiple cancers and young age of onset in families with uterine cancer is compatible with the existence of additional hereditary uterine cancer syndromes.

The occurrence of fetal microchimeric cells in endometrial tissues is a very common phenomenon in benign uterine disorders, and the lower prevalence of fetal microchimerism is associated with better uterine cancer prognoses

This is the first study carried out to describe the role of fetal microchimerism (FM) in the pathogenesis of uterine cancer. The prevalence and concentration of male fetal microchimeric cells (FMCs) were examined in endometrial tissues in relation to subtypes of uterine cancer, and the histological grade and stage of the tumor. FM occurrence was analyzed in relation to risk factors, including hypertension, obesity, type 2 diabetes, dyslipidemia, age at cancer diagnosis, and patient pregnancy history. The prevalence and concentration of FMCs were examined in endometrial tissues using real-time polymerase chain reaction, SRY and β-globin sequences as markers for male fetal FMCs and total DNA. The studied group involved 47 type 1 endometrial cancers, 28 type 2 endometrial cancers, and 41 benign uterine diseases. While the prevalence of FM was decreased only in type 1 endometrial cancer, compared with benign uterine disorders (38.3% vs.70.7%; odds ratio [OR]=0.257, 95% confidence interval [CI]: 0.105 to 0.628, p=0.003), FMC concentrations did not differ within examined groups. The lower FM prevalence was detected in low-grade (grade 1 and grade 2) endometrioid cancer (38.3% vs. 70.7%, OR=0.256, 95% CI: 0.105 to 0.627, p=0.003) and in FIGO 1 tumors (40.7% vs. 70.7%, OR=0.285, 95% CI: 0.120 to 0.675, p=0.004). No correlation between FM prevalence or FMC concentrations and risk factors was demonstrated. A lower prevalence of male FM seemed to be associated with better prognoses in uterine cancer based on tumor subtype, histological grade, and stage of the tumor.

Collaborative cancer epidemiology in the 21st century: the model of cancer consortia

During the last two decades, epidemiology has undergone a rapid evolution toward collaborative research. The proliferation of multi-institutional, interdisciplinary consortia has acquired particular prominence in cancer research. Herein, we describe the characteristics of a network of 49 established cancer epidemiology consortia (CEC) currently supported by the Epidemiology and Genomics Research Program (EGRP) at the National Cancer Institute (NCI). This collection represents the largest disease-based research network for collaborative cancer research established in population sciences. We describe the funding trends, geographic distribution, and areas of research focus. The CEC have been partially supported by 201 grants and yielded 3,876 publications between 1995 and 2011. We describe this output in terms of interdisciplinary collaboration and translational evolution. We discuss challenges and future opportunities in the establishment and conduct of large-scale team science within the framework of CEC, review future prospects for this approach to large-scale, interdisciplinary cancer research, and describe a model for the evolution of an integrated Network of Cancer Consortia optimally suited to address and support 21st-century epidemiology.

Type I and II endometrial cancers: have they different risk factors?

PURPOSE

Endometrial cancers have long been divided into estrogen-dependent type I and the less common clinically aggressive estrogen-independent type II. Little is known about risk factors for type II tumors because most studies lack sufficient cases to study these much less common tumors separately. We examined whether so-called classical endometrial cancer risk factors also influence the risk of type II tumors.

PATIENTS AND METHODS

Individual-level data from 10 cohort and 14 case-control studies from the Epidemiology of Endometrial Cancer Consortium were pooled. A total of 14,069 endometrial cancer cases and 35,312 controls were included. We classified endometrioid (n = 7,246), adenocarcinoma not otherwise specified (n = 4,830), and adenocarcinoma with squamous differentiation (n = 777) as type I tumors and serous (n = 508) and mixed cell (n = 346) as type II tumors.

RESULTS

Parity, oral contraceptive use, cigarette smoking, age at menarche, and diabetes were associated with type I and type II tumors to similar extents. Body mass index, however, had a greater effect on type I tumors than on type II tumors: odds ratio (OR) per 2 kg/m(2) increase was 1.20 (95% CI, 1.19 to 1.21) for type I and 1.12 (95% CI, 1.09 to 1.14) for type II tumors (P heterogeneity < .0001). Risk factor patterns for high-grade endometrioid tumors and type II tumors were similar.

CONCLUSION

The results of this pooled analysis suggest that the two endometrial cancer types share many common etiologic factors. The etiology of type II tumors may, therefore, not be completely estrogen independent, as previously believed.

The etiology of uterine sarcomas: a pooled analysis of the epidemiology of endometrial cancer consortium

BACKGROUND

Uterine sarcomas are characterised by early age at diagnosis, poor prognosis, and higher incidence among Black compared with White women, but their aetiology is poorly understood. Therefore, we performed a pooled analysis of data collected in the Epidemiology of Endometrial Cancer Consortium. We also examined risk factor associations for malignant mixed mullerian tumours (MMMTs) and endometrioid endometrial carcinomas (EECs) for comparison purposes.

METHODS

We pooled data on 229 uterine sarcomas, 244 MMMTs, 7623 EEC cases, and 28,829 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) for risk factors associated with uterine sarcoma, MMMT, and EEC were estimated with polytomous logistic regression. We also examined associations between epidemiological factors and histological subtypes of uterine sarcoma.

RESULTS

Significant risk factors for uterine sarcoma included obesity (body mass index (BMI)≥30 vs BMI<25 kg m(-2) (OR: 1.73, 95% CI: 1.22-2.46), P-trend=0.008) and history of diabetes (OR: 2.33, 95% CI: 1.41-3.83). Older age at menarche was inversely associated with uterine sarcoma risk (≥15 years vs <11 years (OR: 0.70, 95% CI: 0.34-1.44), P-trend: 0.04). BMI was significantly, but less strongly related to uterine sarcomas compared with EECs (OR: 3.03, 95% CI: 2.82-3.26) or MMMTs (OR: 2.25, 95% CI: 1.60-3.15, P-heterogeneity=0.01).

CONCLUSION

In the largest aetiological study of uterine sarcomas, associations between menstrual, hormonal, and anthropometric risk factors and uterine sarcoma were similar to those identified for EEC. Further exploration of factors that might explain patterns of age- and race-specific incidence rates for uterine sarcoma are needed.

Age at last birth in relation to risk of endometrial cancer: pooled analysis in the epidemiology of endometrial cancer consortium

Childbearing at an older age has been associated with a lower risk of endometrial cancer, but whether the association is independent of the number of births or other factors remains unclear. Individual-level data from 4 cohort and 13 case-control studies in the Epidemiology of Endometrial Cancer Consortium were pooled. A total of 8,671 cases of endometrial cancer and 16,562 controls were included in the analysis. After adjustment for known risk factors, endometrial cancer risk declined with increasing age at last birth (P(trend) < 0.0001). The pooled odds ratio per 5-year increase in age at last birth was 0.87 (95% confidence interval: 0.85, 0.90). Women who last gave birth at 40 years of age or older had a 44% decreased risk compared with women who had their last birth under the age of 25 years (95% confidence interval: 47, 66). The protective association was similar across the different age-at-diagnosis groups and for the 2 major tumor histologic subtypes (type I and type II). No effect modification was observed by body mass index, parity, or exogenous hormone use. In this large pooled analysis, late age at last birth was independently associated with a reduced risk of endometrial cancer, and the reduced risk persisted for many years.

The obesity-associated polymorphisms FTO rs9939609 and MC4R rs17782313 and endometrial cancer risk in non-Hispanic white women

Overweight and obesity are strongly associated with endometrial cancer. Several independent genome-wide association studies recently identified two common polymorphisms, FTO rs9939609 and MC4R rs17782313, that are linked to increased body weight and obesity. We examined the association of FTO rs9939609 and MC4R rs17782313 with endometrial cancer risk in a pooled analysis of nine case-control studies within the Epidemiology of Endometrial Cancer Consortium (E2C2). This analysis included 3601 non-Hispanic white women with histologically-confirmed endometrial carcinoma and 5275 frequency-matched controls. Unconditional logistic regression models were used to assess the relation of FTO rs9939609 and MC4R rs17782313 genotypes to the risk of endometrial cancer. Among control women, both the FTO rs9939609 A and MC4R rs17782313 C alleles were associated with a 16% increased risk of being overweight (p = 0.001 and p = 0.004, respectively). In case-control analyses, carriers of the FTO rs9939609 AA genotype were at increased risk of endometrial carcinoma compared to women with the TT genotype [odds ratio (OR)  = 1.17; 95% confidence interval (CI): 1.03–1.32, p = 0.01]. However, this association was no longer apparent after adjusting for body mass index (BMI), suggesting mediation of the gene-disease effect through body weight. The MC4R rs17782313 polymorphism was not related to endometrial cancer risk (per allele OR = 0.98; 95% CI: 0.91–1.06; p = 0.68). FTO rs9939609 is a susceptibility marker for white non-Hispanic women at higher risk of endometrial cancer. Although FTO rs9939609 alone might have limited clinical or public health significance for identifying women at high risk for endometrial cancer beyond that of excess body weight, further investigation of obesity-related genetic markers might help to identify the pathways that influence endometrial carcinogenesis.