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

Mutations in cancer-relevant genes are ubiquitous in histologically normal endometrial tissue

OBJECTIVE

Endometrial cancer (EndoCA) is the most common gynecologic cancer and incidence and mortality rate continue to increase. Despite well-characterized knowledge of EndoCA-defining mutations, no effective diagnostic or screening tests exist. To lay the foundation for testing development, our study focused on defining the prevalence of somatic mutations present in non-cancerous uterine tissue.

METHODS

We obtained ≥8 uterine samplings, including separate endometrial and myometrial layers, from each of 22 women undergoing hysterectomy for non-cancer conditions. We ultra-deep sequenced (>2000× coverage) samples using a 125 cancer-relevant gene panel.

RESULTS

All women harbored complex mutation patterns. In total, 308 somatic mutations were identified with mutant allele frequencies ranging up to 96.0%. These encompassed 56 unique mutations from 24 genes. The majority of samples possessed predicted functional cancer mutations but curiously no growth advantage over non-functional mutations was detected. Functional mutations were enriched with increasing patient age (p = 0.045) and BMI (p = 0.0007) and in endometrial versus myometrial layers (68% vs 39%, p = 0.0002). Finally, while the somatic mutation landscape shared similar mutation prevalence in key TCGA-defined EndoCA genes, notably PIK3CA, significant differences were identified, including NOTCH1 (77% vs 10%), PTEN (9% vs 61%), TP53 (0% vs 37%) and CTNNB1 (0% vs 26%).

CONCLUSIONS

An important caveat for future liquid biopsy/DNA-based cancer diagnostics is the repertoire of shared and distinct mutation profiles between histologically unremarkable and EndoCA tissues. The lack of selection pressure between functional and non-functional mutations in histologically unremarkable uterine tissue may offer a glimpse into an unrecognized EndoCA protective mechanism.

Development of a long term, ex vivo, patient-derived explant model of endometrial cancer

Incidence of endometrial cancer (EC) is rising in the developed world. The current standard of care, hysterectomy, is often infeasible for younger patients and those with high body mass index. There are limited non-surgical treatment options and a lack of biologically relevant research models to investigate novel alternatives to surgery for EC. The aim of the present study was to develop a long-term, patient-derived explant (PDE) model of early-stage EC and demonstrate its use for investigating predictive biomarkers for a current non-surgical treatment option, the levonorgestrel intra-uterine system (LNG-IUS). Fresh tumour specimens were obtained from patients with early-stage endometrioid EC. Tumours were cut into explants, cultured on media-soaked gelatin sponges for up to 21 days and treated with LNG. Formalin-fixed, paraffin embedded (FFPE) blocks were generated for each explant after 21 days in culture. Tumour architecture and integrity were assessed by haematoxylin and eosin (H&E) and immunohistochemistry (IHC). IHC was additionally performed for the expression of five candidate biomarkers of LNG resistance. The developed ex vivo PDE model is capable of culturing explants from early-stage EC tumours long-term (21 Days). This model can complement existing models and may serve as a tool to validate results obtained in higher-throughput in vitro studies. Our study provides the foundation to validate the extent to which EC PDEs reflect patient response in future research.

The risk factors for premalignant and malignant endometrial polyps in premenopausal and postmenopausal women and trends over the past decade: A retrospective study in a single center, South Korea

OBJECTIVES

To assess the prevalence and risk factors for premalignancy and malignancy in endometrial polyps and to evaluate trends over the past decade.

STUDY DESIGN

This was a retrospective study of patients who underwent hysteroscopic polypectomy at Inha University Hospital, South Korea between January 2013 and June 2023. The demographic and clinical characteristics of the patients reviewed to identify risk factors for premalignancy and malignancy in endometrial polyps included the following: age, parity, body mass index, menopausal status, abnormal uterine bleeding symptoms, diabetes mellitus, hypertension, polycystic ovarian syndrome, use of menopausal hormonal therapy or oral contraceptives, tamoxifen treatment in patients with breast cancer, and the number of polyps.

RESULTS

In total, 725 patients were enrolled, among whom 52 (7.2 %) had premalignant and malignant lesions. In logistic regression analysis, menopause (OR: 8.37, 95 % CI [3.33-21.04]), abnormal uterine bleeding (OR: 7.42, 95 % CI [2.13-25.86]), obesity (OR: 3.22, 95 % CI [1.53-6.77]), multiple polyps (OR: 2.86, 95 % CI [1.39-5.88]) and nulliparity (OR: 2.64, 95 % CI [1.13-6.19]) were significantly associated with premalignancy and malignancy in polyps. Annual trends during the study period showed an increase in the number of patients with three of the five risk factors (obesity, multiple polyps, and nulliparity) and an increase in the prevalence of premalignancy and malignancy in polyps.

CONCLUSIONS

Menopause, abnormal uterine bleeding, obesity, multiple polyps, and nulliparity increase the risk of premalignancy and malignancy in endometrial polyps. The prevalence of premalignant and malignant polyps has been increasing over the past decade. The risk factors that have contributed to this trend were obesity, nulliparity, and multiple polyps.

XRCC1 and hOGG1 polymorphisms and endometrial carcinoma: A meta-analysis

Endometrial carcinoma's (EC) etiology is complex and involves DNA repair gene polymorphisms like XRCC1-Arg399Gln and hOGG1-Ser326Cys, but their association with the disease is unclear. Following PRISMA, we conducted a systematic review and meta-analysis, collecting data from four databases. The studies needed to be population-based case-control studies examining the association between the named polymorphisms and EC. Quality was assessed with the Newcastle-Ottawa Scale. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated, and subgroup analyses were conducted based on ethnicity. Seven studies were included. Both polymorphisms were found to significantly increase EC risk, particularly in Caucasians. XRCC1-Arg399Gln showed a dominant model OR of 1.14 (95% CI: 1.01-1.29) and a homozygous model OR of 1.59 (95% CI: 1.12-2.25). The heterozygote model OR for hOGG1-Ser326Cys was 1.29 (95% CI: 1.02-1.63), and the allele OR was 1.31 (95% CI: 1.07-1.60). XRCC1-Arg399Gln and hOGG1-Ser326Cys may increase EC risk, primarily in Caucasian women, emphasizing the role of DNA repair in disease susceptibility. More extensive studies are needed to validate these findings in diverse ethnicities and investigate other DNA repair gene polymorphisms.

A comprehensive analysis of immunotherapy in advanced endometrial cancer (Review)

The morbidity and mortality rates of endometrial cancer (EC) are increasing yearly. Early-stage EC can be effectively treated through surgery or surgery combined with radiotherapy and chemotherapy. Advanced and recurrent EC is treated with chemotherapy and comprehensive treatment; however, the prognosis for patients at this disease stage is poor. Consequently, novel and effective treatment strategies are urgently required for these patients. Breakthrough progress has been made with the use of immunosuppressants in the treatment of EC, which have been included in treatment guidelines. In the present review, the etiology and classification of EC was outlined and the relevant scientific basis for the application of immunosuppressants in advanced and recurrent EC was discussed. The relevant published and ongoing clinical trials are also summarized. As such, the present review aimed to provide a scientific summary of immunotherapy of EC.

Risk-stratification machine learning model using demographic factors, gynaecological symptoms and β-catenin for endometrial hyperplasia and carcinoma: a cross-sectional study

BACKGROUND

Demographic features, suggestive gynaecological symptoms, and immunohistochemical expression of endometrial β-catenin have a prognostic capacity for endometrial hyperplasia and carcinoma. This study assessed the interaction of all variables and developed risk stratification for endometrial hyperplasia and carcinoma.

METHODS

This cross-sectional study was conducted from January 2023 to July 2023 at two teaching hospitals in Makassar Indonesia. Patients (< 70 years old) with suggestive symptoms of endometrial hyperplasia or carcinoma or being referred with disease code N.85 who underwent curettage and/or surgery for pathology assessment except those receiving radiotherapy, or chemotherapy, presence of another carcinoma, coagulation disorder, and history of anti-inflammatory drug use and unreadable samples. Demographic, and clinical symptoms were collected from medical records. Immunohistochemistry staining using mouse-monoclonal antibodies determined the β-catenin expression (percentage, intensity, and H-score) in endometrial tissues. Ordinal and Binary Logistic regression identified the potential predictors to be included in neural networks and decision tree models of histopathological grading according to the World Health Organization/WHO grading classification.

RESULTS

Abdominal enlargement was associated with worse pathological grading (adjusted odds ratio/aOR 6.7 95% CI 1.8-24.8). Increasing age (aOR 1.1 95% CI 1.03-1.2) and uterus bleeding (aOR 5.3 95% CI 1.3-21.6) were associated with carcinoma but not with %β-catenin and H-Score. However, adjusted by vaginal bleeding and body mass index, lower %β-catenin (aOR 1.03 95% 1.01-1.05) was associated with non-atypical hyperplasia, as well as H-Score (aOR 1.01 95% CI 1.01-1.02). Neural networks and Decision tree risk stratification showed a sensitivity of 80-94.8% and a specificity of 40.6-60% in differentiating non-atypical from atypical and carcinoma. A cutoff of 55% β-catenin area and H-Score of 110, along with other predictors could distinguish non-atypical samples from atypical and carcinoma.

CONCLUSION

Risk stratification based on demographics, clinical symptoms, and β-catenin possesses a good performance in differentiating non-atypical hyperplasia with later stages.

Occupational exposure to pesticides and endometrial cancer in the Screenwide case-control study

BACKGROUND

Endometrial cancer is the most common gynaecological tumour in developed countries and disease burden is expected to increase over the years. Identifying modifiable risk factors may help developing strategies to reduce the expected increasing incidence of these neoplasms.

OBJECTIVE

This study evaluates the association between occupational exposure to pesticides and endometrial cancer using data from a recent case-control study in Spain.

METHODS

The analyses included data from 174 consecutive incident endometrial cancer cases and 216 hospital controls frequency-matched by age. Data were collected through structured epidemiological questionnaires and exposure to pesticides was assessed using a Spanish job-exposure matrix (MatEmESp).

RESULTS

Overall, 12% of controls and 18% of cases were occupationally exposed to pesticides. We observed a positive association between occupational exposure to pesticides and endometrial cancer (OR = 2.08; 95% CI = 1.13-3.88 compared to non-exposed). In general, exposures that occurred farther in the past were significantly associated with endometrial cancer. Exposure to insecticides, fungicides and herbicides were positively associated with endometrial cancer (OR = 2.08; 95% CI = 1.13-3.88, OR = 4.40; 95% CI = 1.65-13.33, and OR = 5.25; 95% CI = 1.84-17.67, respectively). The agricultural, poultry and livestock activities scenario was associated with endometrial cancer (OR = 4.16; 95% CI = 1.59-12.32), while the cleaning exposure scenario was not (OR = 1.22; 95% CI = 0.55-2.67).

CONCLUSIONS

Assessment of occupational exposure to pesticides assessed using a Spanish job-exposure matrix revealed a positive association with endometrial cancer. The elucidation of the role of pesticide compounds on endometrial cancer should shed a light on the aetiology of this tumour.

Reproductive Factors and Endometrial Cancer Risk Among Women

Importance

Despite evidence of an association between reproductive factors and endometrial cancer risk, prospective studies have been conducted mainly in non-Asian countries.

Objective

To assess the association between reproductive factors, such as number of deliveries, age at menarche, or menopause, and endometrial cancer risk.

Design, Setting, and Participants

This cohort study used pooled individual data from 13 prospective cohort studies conducted between 1963 and 2014 in the Asia Cohort Consortium. Participants were Asian women. Data analysis was conducted from September 2019 to April 2023.

Exposures

Reproductive factors were assessed using a questionnaire in each cohort.

Main Outcomes and Measures

The main outcome was time to incidence of endometrial cancer. A Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% CIs.

Results

A total of 1005 endometrial cancer cases were detected among 332 625 women (mean [SD] age, 54.3 [10.4] years) during a mean (SD) of 16.5 (6.4) years of follow-up. Increasing number of deliveries was associated with a decreased endometrial cancer risk in a dose-response manner (≥5 deliveries vs nulliparous [reference]: HR, 0.37; 95% CI, 0.26-0.53; P for trend < .001). Compared with menarche at younger than 13 years, menarche at 17 years or older had an HR of 0.64 (95% CI, 0.48-0.86; P for trend < .001). Late menopause (age ≥55 years) showed an HR of 2.84 (95% CI, 1.78-4.55; P for trend < .001) compared with the youngest age category for menopause (<45 years). Age at first delivery, hormone therapy, and breastfeeding were not associated with endometrial cancer risk.

Conclusions and Relevance

This large pooled study of individual participant data found that late menarche, early menopause, and a higher number of deliveries were significantly associated with a lower risk of endometrial cancer. These convincing results from Asian prospective studies add to the growing body of evidence for the association between reproductive factors and endometrial cancer.

Women's health, hormonal balance, and personal autonomy

Hormone-based contraception disrupts hormonal balance, creating artificial states of anovulation and threatening women's health. We reviewed its main adverse effects and mechanisms on accelerated ovarian aging, mental health (emotional disruptions, depression, and suicide), sexuality (reduced libido), cardiovascular (brain stroke, myocardial infarction, hypertension, and thrombosis), and oncological (breast, cervical, and endometrial cancers). Other "collateral damage" includes negative effects on communication, scientific mistrust, poor physician-patient relationships, increased patient burden, economic drain on the healthcare system, and environmental pollution. Hormone-sensitive tumors present a dilemma owing to their potential dual effects: preventing some cancers vs. higher risk for others remains controversial, with denial or dismissal as non-relevant adverse effects, information avoidance, and modification of scientific criteria. This lack of clinical assessment poses challenges to women's health and their right to autonomy. Overcoming these challenges requires an anthropological integration of sexuality, as the focus on genital bodily union alone fails to encompass the intimate relational expression of individuals, complete sexual satisfaction, and the intertwined feelings of trust, safety, tenderness, and endorsement of women's femininity.

Age-specific trend and birth cohort effect on different histologic types of uterine corpus cancers

To evaluate the uterine corpus cancer incidence rates, age-specific trends, and birth cohort patterns by different histologic types. We conducted a retrospective cohort study of uterine cancer patients (n = 28,769) of all ages from the National Cancer Registry of Taiwan between 1998 and 2017. We estimated the incidence trends, average annual percent changes (AAPCs), and cancer-specific survival (CSS) rate for the two main subtypes (endometrioid and nonendometrioid) of uterine cancer in Taiwan. During the study period, uterine corpus cancer incidence rates increased over time from 5.3 to 15.21 per 100,000 women. Incidence trends for endometrioid carcinoma increased in all age groups (positive AAPCs > 5% for each age group), and the rise was steeper among women aged 50 years and younger. For nonendometrioid carcinomas, incidence rates increased among women over 50 years. The CSS rate improved among women with stage I (hazard ratio [HR] 0.63, 95% confidence interval [CI] 0.49-0.81) and stage III (HR 0.72, 95% CI 0.58-0.90) endometrioid carcinomas after 2013 compared with those during 2009-2012. However, the CSS rate remained unchanged for nonendometrioid carcinomas. Age, diagnostic period, stage and histologic types were significant factors associated with the 5-year CSS rate. We found that the incidences of both endometrioid and nonendometrioid carcinomas continued to increase among contemporary birth cohorts. Etiologic research is needed to explain the causes of these trends.

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.

Ion Channels in Endometrial Cancer

Simple Summary

Uterine or endometrial cancer is one of the most common types of cancer among the female population. Different alterations of molecules are related to many types of cancer. Some molecules called ion channels have been described as involved in the development of cancer, including endometrial cancer. We review the scientific evidence about the involvement of the ion channels in endometrial cancer and how some treatments can be developed with these molecules as a target. Even though they are involved in the progression of endometrial cancer, since they are present throughout the whole body, some possible treatments based on these could be studied.

Abstract

Uterine or endometrial cancer (EC) is the sixth most common neoplasia among women worldwide. Cancer can originate from a myriad of causes, and increasing evidence suggests that ion channels (IC) play an important role in the process of carcinogenesis, taking part in many pathways such as self-sufficiency in growth signals, proliferation, evasion of programmed cell death (apoptosis), angiogenesis, cell differentiation, migration, adhesion, and metastasis. Hormones and growth factors are well-known to be involved in the development and/or progression of many cancers and can also regulate some ion channels and pumps. Since the endometrium is responsive and regulated by these factors, the ICs could make an important contribution to the development and progression of endometrial cancer. In this review, we explore what is beyond (ion) flow regulation by investigating the role of the main families of ICs in EC, including as possible targets for EC treatment.

Retrospective analysis of endometrial cancer among Afro-Caribbean women in Barbados 2008-2017

Endometrial cancer data amongst Barbadian women was collected, to inform screening and management in this under-studied population. We analysed all recorded primary cases between January 1st 2008, and December 31st, 2017. Age-specific incidence, and crude mortality rates were calculated. Descriptive statistics characterized demographics, risk factors, prescription data and histopathology. Log-rank tests assessed simple group differences by EC type. Survival analysis based on tumour type was plotted using Kaplein-Meir curves. There were 270 recorded cases of EC, averaging 66 (8.8) years old (SD 8.75), with parity of 3.60 (2.3). Cases were postmenopausal with 257 (95%) experiencing postmenopausal bleeding. Of the 270 cases, 113 (42%) had type 1 tumours and 157(58%) had type 2 tumours. Weak evidence suggests the latter imparted worse survival (log rank test = 0.02). Estimated crude incidence rate was 18.64 per 100,000 women. Crude mortality rate from EC between January 1st, 2008 and December 31st, 2019 was 27%.

Extraterrestrial Gynecology: Could Spaceflight Increase the Risk of Developing Cancer in Female Astronauts? An Updated Review

Outer space is an extremely hostile environment for human life, with ionizing radiation from galactic cosmic rays and microgravity posing the most significant hazards to the health of astronauts. Spaceflight has also been shown to have an impact on established cancer hallmarks, possibly increasing carcinogenic risk. Terrestrially, women have a higher incidence of radiation-induced cancers, largely driven by lung, thyroid, breast, and ovarian cancers, and therefore, historically, they have been permitted to spend significantly less time in space than men. In the present review, we focus on the effects of microgravity and radiation on the female reproductive system, particularly gynecological cancer. The aim is to provide a summary of the research that has been carried out related to the risk of gynecological cancer, highlighting what further studies are needed to pave the way for safer exploration class missions, as well as postflight screening and management of women astronauts following long-duration spaceflight.

The Double Engines and Single Checkpoint Theory of Endometriosis

Endometriosis is a chronic disease characterized by the ectopic localization of the endometrial tissue in the peritoneal cavity. Consequently, it causes local pathological changes and systemic symptoms, affecting at least one in every ten women. This disease is difficult to diagnose early, it is prone to dissemination, is difficult to eradicate, tends to recur, and is regarded as “a cancer of no kill”. Indeed, the development of endometriosis closely resembles that of cancer in the way of mutagenesis, pelvic spreading, and immunological adaptation. While retrograde menstruation has been regarded as the primary cause of endometriosis, the role of ovulation and menstrual stimuli in the development of endometriosis has long been overlooked. The development of ovarian and peritoneal endometrioses, similar to the development of high-grade serous carcinoma in the fallopian tube fimbriae with intraperitoneal metastasis, depends highly on the carcinogens released during ovulation. Moreover, endometriosis carries an extremely hypermutated genome, which is non-inferior to the ultra-mutated endometrial cancer. The hypermutation would lead to an overproduction of new proteins or neoantigens. Because of this, the developing endometriosis may have to turn on the PD-1/PDL-1 “self-tolerance” checkpoint to evade immune surveillance, leaving an Achilles tendon for an immune checkpoint blockade. In this review, we present the double engines and single checkpoint theory of the genesis of endometriosis, provide the current pieces of evidence supporting the hypothesis, and discuss the new directions of prevention and treatment.

Executive Summary of the Uterine Cancer Evidence Review Conference

Evidence for uterine cancer prevention, diagnosis, and special issues from the Uterine Cancer Evidence Review Conference is summarized.

The Centers for Disease Control and Prevention recognized the need for educational materials for clinicians on the prevention and early diagnosis of gynecologic cancers. The American College of Obstetricians and Gynecologists convened a panel of experts in evidence review from the Society for Academic Specialists in General Obstetrics and Gynecology and content experts from the Society of Gynecologic Oncology to review relevant literature, best practices, and existing practice guidelines as a first step toward developing evidence-based educational materials for women's health care clinicians about uterine cancer. Panel members conducted structured literature reviews, which were then reviewed by other panel members and discussed at a virtual meeting of stakeholder professional and patient advocacy organizations in January 2021. This article is the evidence summary of the relevant literature and existing recommendations to guide clinicians in the prevention, early diagnosis, and special considerations of uterine cancer. Substantive knowledge gaps are noted and summarized to provide guidance for future research.

Somatic Mosaicism in Biology and Disease

Contrary to earlier beliefs, every cell in the individual is genetically different due to somatic mutations. Consequently, tissues become a mixture of cells with distinct genomes, a phenomenon termed somatic mosaicism. Recent advances in genome sequencing technology have unveiled possible causes of mutations and how they shape the unique mutational landscape of the tissues. Moreover, the analysis of sequencing data in combination with clinical information has revealed the impacts of somatic mosaicism on disease processes. In this review, we discuss somatic mosaicism in various tissues and its clinical implications for human disease.

Biology and pathology of the uterine microenvironment and its natural killer cells

Tissues are the new frontier of discoveries in immunology. Cells of the immune system are an integral part of tissue physiology and immunity. Determining how immune cells inhabit, housekeep, and defend gut, lung, brain, liver, uterus, and other organs helps revealing the intimate details of tissue physiology and may offer new therapeutic targets to treat pathologies. The uterine microenvironment modulates the development and function of innate lymphoid cells [ILC, largely represented by natural killer (NK) cells], macrophages, T cells, and dendritic cells. These immune cells, in turn, contribute to tissue homeostasis. Regulated by ovarian hormones, the human uterine mucosa (endometrium) undergoes ~400 monthly cycles of breakdown and regeneration from menarche to menopause, with its fibroblasts, glands, blood vessels, and immune cells remodeling the tissue into the transient decidua. Even more transformative changes occur upon blastocyst implantation. Before the placenta is formed, the endometrial glands feed the embryo by histiotrophic nutrition while the uterine spiral arteries are stripped of their endothelial layer and smooth muscle actin. This arterial remodeling is carried out by invading fetal trophoblast and maternal immune cells, chiefly uterine NK (uNK) cells, which also assist fetal growth. The transformed arteries no longer respond to maternal stimuli and meet the increasing demands of the growing fetus. This review focuses on how the everchanging uterine microenvironment affects uNK cells and how uNK cells regulate homeostasis of the decidua, placenta development, and fetal growth. Determining these pathways will help understand the causes of major pregnancy complications.

Pathology findings among women with alterations in uterine bleeding patterns in cameroon

PURPOSE

Endometrial cancer is on the rise in high-income countries but it has not been adequately studied in low-and-middle income countries especially in sub-Saharan Africa (SSA), likely due to scarce pathology facilities. The purpose of this study was to characterize and quantify the prevalence of endometrial hyperplasia or cancer in a cohort of women with abnormal uterine bleeding (AUB) who underwent endometrial biopsy in Cameroon.

METHODS

We designed a cross-sectional study using medical records to characterize women who underwent endometrial biopsy in the Cameroon Baptist Convention Health Services (CBCHS) from 2008 to 2019. Pathologic diagnoses were classified as either endometrial hyperplasia, endometrial cancer, or no endometrial hyperplasia/cancer. We reported the overall prevalence of endometrial hyperplasia or cancer. Bivariate analyses compared patient characteristics between women with endometrial cancer, endometrial hyperplasia, and neither.

RESULTS

The average age was 46.2 years and women had an average of 5.1 parity. We found that, 61 [(36.7% of 166 women; 95% CI (27.6-47.0%)] had endometrial hyperplasia or cancer. There were no cases of hyperplasia with atypia and 13 women had endometrial cancer. The remainder were comprised of benign or infectious pathologic findings. In bivariate analysis, mean ages were statistically different among the three groups (hyperplasia, cancer, and no hyperplasia/cancer), p < 0.001, and women with cancer had the highest age. Parity was statistically significantly different among the three groups (p = 0.002) and women with endometrial cancer had higher parity.

CONCLUSION

We found that just over 1 in 3 women with AUB who underwent endometrial biopsy at a health system in SSA were found to have pathologic findings of endometrial hyperplasia or cancer, with no cases of hyperplasia with atypia. Women with endometrial cancer had higher mean age and parity.

Diabetes Risk Reduction Diet and Endometrial Cancer Risk

Diabetes increases endometrial cancer risk. We investigated the role of a diabetes risk reduction diet (DRRD) on the risk of endometrial cancer using data from a multicentric, Italian hospital-based case-control study (1992-2006) enrolling 454 histologically confirmed cases of endometrial cancer and 908 controls matched by age and center. We derived a DRRD score assigning higher scores for higher intakes of cereal fiber, fruit, coffee, polyunsaturated:saturated fatty acid ratio, and nuts and for lower glycemic load and lower intakes of red/processed meat and sugar-sweetened beverages/fruit juices. The odds ratios (OR) of endometrial cancer according to the DRRD score were derived by multiple conditional logistic regression models. The OR for high (DRRD score >24, i.e., third tertile) versus medium-low adherence to the DRRD was 0.73 (95% confidence interval, CI, 0.55-0.97). Similar results were observed after the exclusion of diabetic women (OR 0.75; 95% CI, 0.56-1.00) and allowance for total vegetable consumption (OR 0.80; 95% CI, 0.60-1.07). Inverse associations were observed in most of the analyzed subgroups. The OR for high DRRD combined with high vegetable consumption was 0.45 (95% CI, 0.28-0.73). Our results suggest that diets able to reduce diabetes risk may also reduce endometrial cancer risk. High vegetable consumption combined with high adherence to the DRRD may provide additional benefit in endometrial cancer prevention.

Statistical Meta-Analysis of Risk Factors for Endometrial Cancer and Development of a Risk Prediction Model Using an Artificial Neural Network Algorithm

Simple Summary

A robust and comprehensive meta-analysis, for the first time, identified definitely that BMI is by far the most influential risk factor in endometrial cancer. Risk factors were previously only studied individually and or in smaller meta-analysis studies which grouped some factors together. BMI was shown to be an important risk factor with other factors less so, but no rank order was established. This work also offers, for the first time, a neural network computer model to predict the overall increase or decreased risk of cancer for individual patients, which is 98.6% accurate. This prediction can be used as a tool to determine if a patient should be considered for testing and to predict diagnosis, as well as to suggest prevention measures to patients.

Abstract

Objectives: In this study we wished to determine the rank order of risk factors for endometrial cancer and calculate a pooled risk and percentage risk for each factor using a statistical meta-analysis approach. The next step was to design a neural network computer model to predict the overall increase or decreased risk of cancer for individual patients. This would help to determine whether this prediction could be used as a tool to decide if a patient should be considered for testing and to predict diagnosis, as well as to suggest prevention measures to patients. Design: A meta-analysis of existing data was carried out to calculate relative risk, followed by design and implementation of a risk prediction computational model based on a neural network algorithm. Setting: Meta-analysis data were collated from various settings from around the world. Primary data to test the model were collected from a hospital clinic setting. Participants: Data from 40 patients notes currently suspected of having endometrial cancer and undergoing investigations and treatment were collected to test the software with their cancer diagnosis not revealed to the software developers. Main outcome measures: The forest plots allowed an overall relative risk and percentage risk to be calculated from all the risk data gathered from the studies. A neural network computational model to determine percentage risk for individual patients was developed, implemented, and evaluated. Results: The results show that the greatest percentage increased risk was due to BMI being above 25, with the risk increasing as BMI increases. A BMI of 25 or over gave an increased risk of 2.01%, a BMI of 30 or over gave an increase of 5.24%, and a BMI of 40 or over led to an increase of 6.9%. PCOS was the second highest increased risk at 4.2%. Diabetes, which is incidentally also linked to an increased BMI, gave a significant increased risk along with null parity and noncontinuous HRT of 1.54%, 1.2%, and 0.56% respectively. Decreased risk due to contraception was greatest with IUD (intrauterine device) and IUPD (intrauterine progesterone device) at −1.34% compared to −0.9% with oral. Continuous HRT at −0.75% and parity at −0.9% also decreased the risk. Using open-source patient data to test our computational model to determine risk, our results showed that the model is 98.6% accurate with an algorithm sensitivity 75% on average. Conclusions: In this study, we successfully determined the rank order of risk factors for endometrial cancer and calculated a pooled risk and risk percentage for each factor using a statistical meta-analysis approach. Then, using a computer neural network model system, we were able to model the overall increase or decreased risk of cancer and predict the cancer diagnosis for particular patients to an accuracy of over 98%. The neural network model developed in this study was shown to be a potentially useful tool in determining the percentage risk and predicting the possibility of a given patient developing endometrial cancer. As such, it could be a useful tool for clinicians to use in conjunction with other biomarkers in determining which patients warrant further preventative interventions to avert progressing to endometrial cancer. This result would allow for a reduction in the number of unnecessary invasive tests on patients. The model may also be used to suggest interventions to decrease the risk for a particular patient. The sensitivity of the model limits it at this stage due to the small percentage of positive cases in the datasets; however, since this model utilizes a neural network machine learning algorithm, it can be further improved by providing the system with more and larger datasets to allow further refinement of the neural network.

Cigarette Smoking and Estrogen-Related Cancer

Cigarette smoking is a known cause of many cancers, yet epidemiologic studies have found protective associations with the risk of four "estrogen-related" malignancies: endometrial cancer, endometrioid and clear cell ovarian cancers, and thyroid cancer. This review considers epidemiologic and biological aspects of these associations, focusing particularly on estrogen signaling, and contrasts them with those for breast cancer, another estrogen-related malignancy. The observational findings regarding the inverse associations are consistent and remain after adjustment for possible confounding factors. In general, women who smoke do not have lower circulating estrogen levels than nonsmokers, eliminating one possible explanation for reduced risks of these malignancies. For endometrial and endometrioid ovarian cancer, the negative associations could plausibly be explained by interference with signaling through the estrogen receptor α. However, this is unlikely to explain the lower risks of thyroid and clear cell ovarian cancers. For thyroid cancer, an anti-inflammatory effect of nicotine and reduced TSH levels from smoking have been proposed explanations for the inverse association, but both lack convincing evidence. While the overall impact of cigarette smoking is overwhelmingly negative, protective associations such as those discussed here can provide potential clues to disease etiology, treatment, and prevention.

Fertility-Sparing Treatment for Atypical Endometrial Hyperplasia and Endometrial Cancer: A Cochrane Systematic Review Protocol

INTRODUCTION

Endometrial cancer is the fifth most common cancer in women and atypical endometrial hyperplasia is a precancerous lesion. Obesity is an important risk factor for endometrioid endometrial adenocarcinoma and endometrial hyperplasia. Progesterone is recommended as first-line treatment in endometrial cancer or atypical endometrial hyperplasia in women who wish to preserve fertility, but optimal treatment schedules have not been defined. Metformin or bariatric surgery may also be useful in these women. The effectiveness and safety of fertility-preserving treatments being used for women with atypical endometrial hyperplasia and stage IA grade 1 endometrial cancer is unclear. Therefore, the systematic review aims to determine this point.

METHODS

We will search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, trial registers, conference proceedings, abstracts, cooperative trial groups and reference lists. We will include randomised controlled trials (RCTs) that compare fertility-preserving therapy including orally administered progesterone versus a levonorgestrel-releasing intrauterine system (IUS), metformin, other pharmacological interventions or bariatric surgery, and any of these interventions with womb-removing surgery. Quasi-randomised trials, non-randomised trials and cohort studies will be included. Two review authors will independently assess study eligibility and risk of bias and extract data. The primary outcomes are complete pathologic response and live birth rate. Secondary outcomes include overall survival, progression-free survival, pregnancy rate, need for hysterectomy, adverse events, psychological symptoms and quality of life.

PLANNED OUTCOMES

This review aims to clarify the effectiveness and risks of fertility-preserving treatments, including complete pathologic response rate, live birth rates, need for surgical treatment, adverse events, psychological symptoms and quality of life. The broad scope of the review includes the use of progesterone, metformin to reverse insulin resistance, and bariatric surgery or operative hysteroscopy.

RESULTS

The results may help to determine the optimal fertility-sparing treatment in endometrial cancer and atypical endometrial hyperplasia.

SYSTEMATIC REVIEW REGISTRATION

Prospero 2019 number CRD42019145991.

Number of parity/live birth(s) and cardiovascular disease among Iranian women and men: results of over 15 years of follow-up

Background

Most previous studies conducted in non-Middle Eastern populations have suggested that an increase in the number of parity/live birth(s) leads to cardiovascular disease (CVD) development, although their findings were inconclusive on this issue for both sexes. Biologic and socioeconomic pathways were suggested to explain this association. We studied this issue among urban Iranian men and women.

Methods

In this population-based cohort study, which included 3929 women and 2571 men aged ≥30 years, data for the number of parity/live birth(s) were obtained by a standard questionnaire. Participants were then annually followed for CVD events. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the number of parity/live birth(s) and other traditional CVD risk factors.

Results

During more than 15 years of follow-up, 456 and 524 CVD events have occurred among women and men, respectively. Among women, a J-shaped association was found between the number of live births and incident CVD with the lowest risk for women with two live births. Among women in multivariable analyses, each unit increase in parity had a HR of 1.05 (CI: 1.01–1.10), and having ≥4 parity was associated with a HR of 1.86 (0.97–3.56, p-value = 0.061). Among men, in comparison with participants who had 1 child, multivariable HRs of having 2, 3, and ≥ 4 children were 1.97 (1.24–3.12), 2.08 (1.31–3.31), and 2.08 (1.30–3.34), respectively.

Conclusion

To the best of our knowledge, the current study is the first report on this issue in the Middle East and North Africa region, a region with a high burden of CVD. It can now be suggested that the number of parity/live birth(s) is linked to CVD among the Iranian population, with this issue being more prominent among men. Further research is needed to support our results and clarify the pathways between the number of parity/live birth(s) and CVD development among Iranian populations by considering potential risk factors, especially psycho-socio-economic risk factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03499-2.

Serum potassium levels and mortality of patients with acute myocardial infarction: A systematic review and meta-analysis of cohort studies

BACKGROUND

The evidence of current epidemiological studies investigating the association between serum potassium levels and mortality of acute myocardial infarction (AMI) patients is controversial and inadequate.

DESIGN

Systematic review and meta-analysis.

METHODS

Two researchers independently searched the PubMed, EMBASE and Web of Science databases to identify observational studies published prior to 31 October 2017. Similarly, two researchers separately extracted data and any differences were resolved by discussion. Pooled relative risks and 95% confidence intervals (CIs) were computed with an inverse variance-weighted random-effects model. Heterogeneity among studies was assessed with the I² statistic.

RESULTS

Seven cohort studies were included for analysis. Compared with the reference group (3.5 to <4.0 mEq/L), the pooled relative risks of mortality were 1.15 (95% CI = 1.00-1.32), 1.09 (95% CI = 0.97-1.24), 1.42 (95% CI = 1.19-1.70) and 1.85 (95% CI = 1.39-2.47) for AMI patients with a potassium level of<3.5, 4.0 to <4.5, 4.5 to <5.0, and ≥5.0 mEq/L, respectively. For admission and post-admission potassium, although J-shaped associations were also indicated, non-significant results were observed for AMI patients with potassium levels of <3.5 mEq/L when compared with the reference group. Notably, in subgroup analyses of study characteristics, stratified by study quality, geographic location, type of outcome, number of cases, type of AMI, and adjustment for potential confounders, the findings were broadly consistent across strata.

CONCLUSIONS

These findings indicate that both lower (<3.5 mEq/L) and higher (≥4.5 mEq/L) serum potassium levels are associated with an increased risk of mortality of patients with AMI.

The mutational landscape of normal human endometrial epithelium

All normal somatic cells are thought to acquire mutations, but understanding of the rates, patterns, causes and consequences of somatic mutations in normal cells is limited. The uterine endometrium adopts multiple physiological states over a lifetime and is lined by a gland-forming epithelium1,2. Here, using whole-genome sequencing, we show that normal human endometrial glands are clonal cell populations with total mutation burdens that increase at about 29 base substitutions per year and that are many-fold lower than those of endometrial cancers. Normal endometrial glands frequently carry 'driver' mutations in cancer genes, the burden of which increases with age and decreases with parity. Cell clones with drivers often originate during the first decades of life and subsequently progressively colonize the epithelial lining of the endometrium. Our results show that mutational landscapes differ markedly between normal tissues-perhaps shaped by differences in their structure and physiology-and indicate that the procession of neoplastic change that leads to endometrial cancer is initiated early in life.

Risk factors for endometrial cancer: An umbrella review of the literature

Although many risk factors could have causal association with endometrial cancer, they are also prone to residual confounding or other biases which could lead to over- or underestimation. This umbrella review evaluates the strength and validity of evidence pertaining risk factors for endometrial cancer. Systematic reviews or meta-analyses of observational studies evaluating the association between non-genetic risk factors and risk of developing or dying from endometrial cancer were identified from inception to April 2018 using PubMed, the Cochrane database and manual reference screening. Evidence was graded strong, highly suggestive, suggestive or weak based on statistical significance of random-effects summary estimate, largest study included, number of cases, between-study heterogeneity, 95% prediction intervals, small study effects, excess significance bias and sensitivity analysis with credibility ceilings. We identified 171 meta-analyses investigating associations between 53 risk factors and endometrial cancer incidence and mortality. Risk factors were categorised: anthropometric indices, dietary intake, physical activity, medical conditions, hormonal therapy use, biochemical markers, gynaecological history and smoking. Of 127 meta-analyses including cohort studies, three associations were graded with strong evidence. Body mass index and waist-to-hip ratio were associated with increased cancer risk in premenopausal women (RR per 5 kg/m2 1.49; CI 1.39-1.61) and for total endometrial cancer (RR per 0.1unit 1.21; CI 1.13-1.29), respectively. Parity reduced risk of disease (RR 0.66, CI 0.60-0.74). Of many proposed risk factors, only three had strong association without hints of bias. Identification of genuine risk factors associated with endometrial cancer may assist in developing targeted prevention strategies for women at high risk.

Changing Incidence of Uterine Cancer in Rural Egypt: Possible Impact of Nutritional and Epidemiologic Transitions

PURPOSE

Uterine cancer is a top-ranking women's cancer worldwide, with wide incidence variations across countries and by rural and urban areas. Hormonal exposures and access to health care vary between rural and urban areas, globally. Egypt has an overall low incidence of uterine cancer but variable rural and urban lifestyles. Are there changes in the incidence of uterine cancer in rural and urban areas in middle-income countries such as Egypt? No previous studies have addressed this question from a well-characterized and validated population-based cancer registry resource in middle-income countries. The aim of this study was to explore the differences in clinical and demographic characteristics of uterine cancer over the period of 1999 to 2010 in rural and urban Gharbiah province, Egypt.

METHODS

Data were abstracted for all 660 patients with uterine cancer included in the Gharbiah Population-based Cancer Registry. Clinical variables included tumor location, histopathologic diagnosis, stage, grade, and treatment. Demographic variables included age, rural or urban residence, parity, and occupation. Crude and age-adjusted incidence rates (IRs) and rate ratios by rural or urban residence were calculated.

RESULTS

No significant differences were observed in most clinical and demographic characteristics between rural and urban patients. The age standardized IR (ASR) was 2.5 times higher in urban than in rural areas (6.9 and 2.8 per 100,000 in urban and rural areas, respectively). The rate ratio showed that the IR in urban areas was 2.46 times the rate in rural areas.

CONCLUSION

This study showed that the disease IR in rural areas has increased in the past decade but is still low compared with the incidence in urban areas in Egypt, which did not show a significant increase in incidence. Nutritional transitions, obesity, and epidemiologic and lifestyle changes toward Westernization may have led to IRs increasing more in rural than in urban areas in Egypt. This pattern of increasing incidence in Egypt, which used to have a low incidence of uterine cancer, may appear in other middle-income countries that experience emerging nutritional and epidemiologic transitions. The rate of uterine cancer in urban areas in Gharbiah is almost similar to the corresponding rates globally. However, the rate in rural areas in this population has increased over the past decade but is still lower than the corresponding global rates. Future studies should examine the etiologic factors related to increasing rates in rural areas and quantify the improvement in rural case finding.

Age at Menopause and Risk of Developing Endometrial Cancer: A Meta-Analysis

Object

The association of age at menopause with endometrial cancer remains controversial. Therefore, we quantitatively summarized the evidence from observational studies with a meta-analysis.

Methods

We searched PubMed, Web of Science, Embase, Medline, Chinese National Knowledge Infrastructure (CNKI), and Wan Fang Med online up to March 2019, and all eligible case-control and cohort studies were included in the study. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using the random-effects model. The dose-response relationship was assessed by restricted cubic spline model. The heterogeneity among studies was evaluated by I². Metaregression was used to explore the potential sources of between-study heterogeneity. Egger's test was used to estimate publication bias.

Results

Eighteen articles including 957242 subjects with 4781 cases were included in the meta-analysis. The pooled RR (95%CI) of endometrial cancer for the highest versus the lowest age at menopause was 1.89 (95%CI: 1.58-2.26). For dose-response analysis, a nonlinear relationship was found between age at menopause and endometrial cancer, and the positive association became statistically significant when age at menopause was greater than 46.5 years old.

Conclusions

This meta-analysis suggested that age at menopause was positively associated with endometrial cancer. For women whose menopausal age over 46.5 years old, the risk of endometrial cancer increased with the age at menopause.

Long-term effect of pregnancy-related factors on the development of endometrial neoplasia: A nationwide retrospective cohort study

Objective

By identifying pregnancy-related risk factors for endometrial neoplasia, women’s risk of developing this disease after childbirth can be predicted and high-risk women can be screened for early detection.

Methods

Study data from women who gave birth in Korea in 2007 were collected from the Korea National Health Insurance (KNHI) claims database between 2007 and 2015. The adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the development of endometrial neoplasia were estimated by multivariate Cox proportional hazards models.

Results

Data from 386,614 women were collected for this study. By 2015, 3,370 women from the initial cohort had been diagnosed with endometrial neoplasia secondary to delivery. Multivariate Cox proportional hazards regression revealed that preeclampsia (HR 1.55, 95% CI 1.29, 1.86), advanced maternal age (≥ 35; HR 1.52, 95% CI 1.39, 1.66), multifetal pregnancy (HR 1.81, 95% CI 1.46, 2.23), multiparity (HR 1.16, 95% CI 1.08, 1.24), cesarean section (HR 1.15, 95% CI 1.07, 1.23) and delivery of a large-for-gestational-age infant (HR 1.19, 95% CI 1.02, 1.39) were independent risk factors for future endometrial neoplasia. The risk for endometrial neoplasia increased as the number of risk factors increased (risk factors ≥3: HR 2.11, 95% CI 1.86–2.40).

Conclusion

This study showed that six pregnancy-related factors—advanced maternal age, multiparity, multifetal pregnancy, cesarean section, delivery of a large-for-gestational-age infant, and preeclampsia—are positively correlated with future development of endometrial neoplasia, including endometrial hyperplasia or cancer. Close observation and surveillance are warranted to enable early diagnosis of endometrial diseases, including endometrial cancer after pregnancy in high-risk women. However, due to unavailability of clinical information, many clinical/epidemiological factors can become confounders. Further research is needed on factors associated with the risk of endometrial neoplasia.

Cholesterol consumption and risk of endometrial cancer: a systematic review and dose-response meta-analysis of observational studies

In vivo and in vitro studies have indicated the link of cholesterol consumption and endometrial cancer risk, however, previous observational studies have yielded inconsistent results. Additionally, a previous meta-analysis published in 2007 found limited evidence of aforementioned association. Therefore, we performed the dose-response meta-analysis to address this concern. Studies were identified using the PubMed, EMBASE and Web of Science databases from the database inception to the end of June 2015 as well as by examining the references of retrieved articles. Two authors independently performed the eligibility evaluation and data extraction. The summary risk estimates and 95% confidence intervals (CIs) were summarized by the random-effects models. One cohort and nine case-control studies were included in the dose-response analyses. Risk of endometrial cancer increased by 6% for 100 mg/day increment in the dietary consumption of cholesterol (Odds ratio (OR) = 1.06; 95% CI = 1.00–1.12), with significant heterogeneity (I² = 64.2, P = 0.003). When stratified by study design, the result was significant in case-control studies (OR = 1.07; 95% CI = 1.01–1.13). Additionally, although the direction of the associations were consistent in the subgroup analyses stratified by study characteristics and adjustment for potential confounders, not all of them showed statistical significance. In summary, findings of the present dose-response meta-analysis partly support the positive association between dietary cholesterol consumption and risk of endometrial cancer. Since only one cohort study was included, more prospective studies and pooled analysis of observational studies are warranted to confirm our findings in the future.

Relationship between initiation time of adjuvant chemotherapy and survival in ovarian cancer patients: a dose-response meta-analysis of cohort studies

Although several studies have previously investigated the association between the initiation time of adjuvant chemotherapy and survival in ovarian cancer, inconsistencies remain about the issue. We searched PubMed and Web of Science through the May 24, 2017 to identify cohort studies that investigated the aforementioned topic. Fourteen studies with 59,569 ovarian cancer patients were included in this meta-analysis. We conducted meta-analyses comparing the longest and shortest initiation time of adjuvant chemotherapy and dose-response analyses to estimate summary hazards ratios (HRs) and 95% confidence intervals (CIs). A random-effects model was used to estimate HRs with 95% CIs. When comparing the longest with the shortest category of initiation time of adjuvant chemotherapy, the summary HR was 1.18 (95% CI: 1.06–1.32; I² = 17.6; n = 7) for overall survival. Additionally, significant dose-response association for overall survival was observed for each week delay (HR = 1.04; 95% CI: 1.00–1.09; I² = 9.05; n = 5). Notably, these findings were robust in prospective designed cohort studies as well as studies with advanced stage (FIGO III-IV) patients. No evidence of publication bias was observed. In conclusion, prolonged initiation time of adjuvant chemotherapy is associated with a decreased overall survival rate of ovarian cancer, especially in patients with advanced stage ovarian cancer.

Number of parity and the risk of rheumatoid arthritis in women: A dose-response meta-analysis of observational studies

AIM

The association between parity and rheumatoid arthritis (RA) risk has been investigated, but results are controversial. Thus, our aim was to systematically analyze the effect of number of parity on the risk of RA in women.

METHODS

Relevant published studies were identified using PubMed and embase databases through 1 April 2016. We pooled the relative risks (RR) and 95% confidence intervals (CI) using random-effects models.

RESULTS

In all, 12 studies with a total of 2 497 580 participants and 11 521 RA cases were included. A borderline significant inverse association was observed when we compared parity with nulliparity for RA, with summarized RR = 0.90 (95%CI: 0.79-1.02; I²  = 58.5%, P_{heterogeneity}  = 0.010). In dose-response analysis, we observed a significant nonlinear (P_nonlinearity  = 0.000) relation between parity number and the risk of RA. Compared with null parity, the pooled RR of RA were 0.89 (95%CI: 0.86-0.93), 0.84 (95%CI: 0.79-0.89), 0.85 (95%CI: 0.79-0.90), 0.88 (95%CI: 0.81-0.95), 0.90 (95%CI: 0.83-0.97), 0.92 (95%CI: 0.84-1.02), and 0.94 (95%CI: 0.83-1.07) for 1, 2, 3, 4, 5, 6, and 7 live births, respectively. Subgroup and sensitivity analyses showed similar associations. No publication bias was found.

CONCLUSION

The findings from the current meta-analysis indicate that parity was related to decreased risk of RA. The greatest risk reduction appeared when the parity number reached two. Further studies are warranted to confirm our findings.

Dietary n-3 polyunsaturated fatty acids, fish consumption, and endometrial cancer risk: a meta-analysis of epidemiological studies

The relationship between intake of fish and n-3 fatty acids and endometrial cancer risk has not been consistent across epidemiological studies. We quantitatively assessed the aforementioned association through a systematic review and meta-analysis. PubMed and Embase were searched through March 2017 for eligible epidemiological studies. Fixed or random-effects models were used to pool relative risks (RRs) and 95% confidence intervals (CIs). The dose-response relationship was also evaluated. Based on the literature search, five prospective studies and 11 case-control studies were identified. All 16 studies were categorized as high-quality studies. After pooling available risk estimates, no significant association was detected between overall fish intake and endometrial cancer risk. In subgroup analyses, every one additional serving/week of fish intake was significantly associated with inversed endometrial cancer risk in studies adjusted for smoking (RR (95% CI): 0.95 (0.91-1.00)), or studies performed in Europe (RR (95% CI): 0.90 (0.84-0.97)), but not in other tested subgroups. In studies conducted in Asia, there was significant positive association (RR (95% CI): 1.15 (1.10-1.21)). Regarding n-3 PUFA intake, marginally inverse associations of high EPA or DHA intake were detected (EPA: RR (95% CI) = 0.79 (0.61-1.04); DHA: RR (95% CI) = 0.85 (0.64-1.11)). Dose-response analyses suggested a significant nonlinear relationship between DHA intake and endometrial cancer risk (p: 0.04). Overall, this meta-analysis suggests that intake of n-3 PUFA may be inversely associated with endometrial cancer risk at some level of evidence, although the exact relationship, especially for fish intake, needs further characterization. Further well-designed studies are warranted.

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.

Sertraline use in the first trimester and risk of congenital anomalies: a systemic review and meta-analysis of cohort studies

AIM

To perform a meta-analysis of available cohort studies on the association between sertraline use by pregnant women in the first trimester and the findings of congenital anomalies in infants.

METHODS

A comprehensive search of articles published from the index date up to 31st December 2015 investigating the aforementioned associations was conducted on PubMed and Web of Science. Mesh headings used included the terms "serotonin reuptake inhibitor," "sertraline," "congenital anomalies" and "obstetrical outcome."

RESULTS

Twelve cohort studies that involved 6 468 241 pregnant women were identified. We summarized odds ratios (ORs) and 95% confidence intervals (CIs) of congenital anomalies using the random-effects model. Pregnant women who used sertraline in the first trimester had a statistically significant increased risk of infant cardiovascular-related malformations (OR = 1.36; 95% CI = 1.06-1.74; I2  = 64.4%; n = 12) as well as atrial and/or ventricular septal defects (OR = 1.36, 95% CI = 1.06-1.76; I2  = 62.2%; n = 8). Additionally, positive but nonsignificant associations between sertraline use and congenital anomalies of the nervous system (OR = 1.39; 95% CI = 0.83-2.32; I2  = 0%; n = 5), digestive system (OR = 1.23; 95% CI = 0.76-1.98; I2  = 0%; n = 5), eye, ear, face and neck (OR = 1.08; 95% CI = 0.33-3.55; I2  = 32.1%; n = 3), urogenital system (OR = 1.03; 95% CI = 0.73-1.46; I2  = 0%; n = 5), and musculoskeletal system (OR = 0.97; 95% CI = 0.69-1.36; I2  = 0%; n = 5) were observed.

CONCLUSION

This meta-analysis suggested that the use of sertraline use by pregnant women in the first trimester had an increased risk of cardiovascular-related malformations as well as atrial and/or ventricular septal defects in infants. Meanwhile, nonsignificant associations between sertraline use and other congenital anomalies were found. More cohort studies are warranted to provide detailed results of other congenital anomalies.

Cancer: A disease at the crossroads of trade-offs

Central to evolutionary theory is the idea that living organisms face phenotypic and/or genetic trade-offs when allocating resources to competing life-history demands, such as growth, survival, and reproduction. These trade-offs are increasingly considered to be crucial to further our understanding of cancer. First, evidences suggest that neoplastic cells, as any living entities subject to natural selection, are governed by trade-offs such as between survival and proliferation. Second, selection might also have shaped trade-offs at the organismal level, especially regarding protective mechanisms against cancer. Cancer can also emerge as a consequence of additional trade-offs in organisms (e.g., eco-immunological trade-offs). Here, we review the wide range of trade-offs that occur at different scales and their relevance for understanding cancer dynamics. We also discuss how acknowledging these phenomena, in light of human evolutionary history, may suggest new guidelines for preventive and therapeutic strategies.

Premenopausal abnormal uterine bleeding and risk of endometrial cancer

BACKGROUND

Endometrial biopsies are undertaken in premenopausal women with abnormal uterine bleeding but the risk of endometrial cancer or atypical hyperplasia is unclear.

OBJECTIVES

To conduct a systematic literature review to establish the risk of endometrial cancer and atypical hyperplasia in premenopausal women with abnormal uterine bleeding.

SEARCH STRATEGY

Search of PubMed, Embase and the Cochrane Library from database inception to August 2015.

SELECTION CRITERIA

Studies reporting rates of endometrial cancer and/or atypical hyperplasia in women with premenopausal abnormal uterine bleeding.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two reviewers and cross-checked. For each outcome, the risk and a 95% CI were estimated using logistic regression with robust standard errors to account for clustering by study.

MAIN RESULTS

Sixty-five articles contributed to the analysis. Risk of endometrial cancer was 0.33% (95% CI 0.23-0.48%, n = 29 059; 97 cases) and risk of endometrial cancer or atypical hyperplasia was 1.31% (95% CI 0.96-1.80, n = 15 772; 207 cases). Risk of endometrial cancer was lower in women with heavy menstrual bleeding (HMB) (0.11%, 95% CI 0.04-0.32%, n = 8352; 9 cases) compared with inter-menstrual bleeding (IMB) (0.52%, 95% CI 0.23-1.16%, n = 3109; 14 cases). Of five studies reporting the rate of atypical hyperplasia in women with HMB, none identified any cases.

CONCLUSIONS

The risk of endometrial cancer or atypical hyperplasia in premenopausal women with abnormal uterine bleeding is low. Premenopausal women with abnormal uterine bleeding should first undergo conventional medical management. Where this fails, the presence of IMB and older age may be indicators for further investigation. Further research into the risks associated with age and the cumulative risk of co-morbidities is needed.

TWEETABLE ABSTRACT

Contrary to practice, premenopausal women with heavy periods or inter-menstrual bleeding rarely require biopsy.

Cigarette smoking during pregnancy and preeclampsia risk: a systematic review and meta-analysis of prospective studies

Although evidence from epidemiological studies evaluating the association between cigarette smoking during pregnancy and preeclampsia risk has been systematically reviewed, the findings have been out of date. To further clarify the relationship, we conducted this comprehensive meta-analysis of prospective studies. We searched PubMed and Web of Science up to August 2015 to identify prospective studies that evaluated the association between cigarette smoking during pregnancy and preeclampsia risk. Random-effects models were used to estimate summarized relative risk (RR) and 95% confidence intervals (CIs). Seventeen prospective studies involving 62,089 preeclampsia patients from a total of approximately 1.8 million subjects were included. Overall, there was a significant negative association between smoking during pregnancy and incidence of preeclampsia (RR = 0.67, 95% CI: 0.60–0.75), with significant heterogeneity (I² = 91.7%). Such an inverse association was also detected in strata of subgroup analyses according to study location, study sample size, parity of populations, singleton pregnancy, and adjustment for potential confounders including maternal age, diabetes mellitus, chronic hypertension, body mass index, and gender of infant. In summary, this meta-analysis suggests that smoking during pregnancy is inversely associated with incidence of preeclampsia. Further large scale multi-center prospective studies are warranted to validate our findings.

Effect of assisted hatching on pregnancy outcomes: a systematic review and meta-analysis of randomized controlled trials

Emerging evidence suggests that assisted hatching (AH) techniques may improve clinical pregnancy rates, particularly in poor prognosis patients; however, there still remains considerable uncertainty. We conducted a meta-analysis to verify the effect of AH on pregnancy outcomes. We searched for related studies published in PubMed, Web of Science, and Cochrane library databases from start dates to October 10, 2015. Totally, 36 randomized controlled trials with 6459 participants were included. Summary odds ratios (ORs) with 95% confidence intervals (CIs) for whether by AH or not were estimated. We found a significant increase in clinical pregnancy (OR = 1.16, 95% CI = 1.00–1.36, I² = 48.3%) and multiple pregnancy rates (OR = 1.50, 95% CI = 1.11–2.01, I² = 44.0%) with AH when compared to the control. Numerous subgroup analyses stratified by hatching method, conception mode, extent of AH, embryos transfer status, and previous failure history were also carried out. Interestingly, significant results of clinical pregnancy as well as multiple pregnancy rates were observed among women who received intracytoplasmic sperm injection, and who received AH which the zona were completely removed. In summary, this meta-analysis supports that AH was associated with an increased chance of achieving clinical pregnancy and multiple pregnancy. Whether AH significantly changes live birth and miscarriage rates needs further investigations.

Associations between Passive Maternal Smoking during Pregnancy and Preterm Birth: Evidence from a Meta-Analysis of Observational Studies

Previous studies investigating the relationship between passive maternal smoking and preterm birth reveal inconsistent results. We conducted the current meta-analysis of observational studies to evaluate the relationship between passive maternal smoking and preterm birth. We identified relevant studies by searching PubMed, EMBASE, and ISI Web of Science databases. We used random-effects models to estimate summary odds ratios (SORs) and 95% confidence intervals (CIs) for aforementioned association. For the analysis, we included 24 studies that involved a total of 5607 women who experienced preterm birth. Overall, the SORs of preterm birth for women who were ever exposed to passive smoking versus women who had never been exposed to passive smoking at any place and at home were 1.20 (95%CI = 1.07-1.34,I(2) = 36.1%) and 1.16 (95%CI = 1.04-1.30,I(2) = 4.4%), respectively. When we conducted a stratified analysis according to study design, the risk estimate was slightly weaker in cohort studies (SOR = 1.10, 95%CI = 1.00-1.21,n = 16) than in cross-sectional studies (SOR = 1.47, 95%CI = 1.23-1.74,n = 5). Additionally, the associations between passive maternal smoking and preterm birth were statistically significant for studies conducted in Asia (SOR = 1.26, 95%CI = 1.05-1.52), for studies including more than 100 cases of preterm birth (SOR = 1.22, 95%CI = 1.05-1.41), and for studies adjusted for maternal age (SOR = 1.27,95%CI = 1.09-1.47), socioeconomic status and/or education (SOR = 1.28, 95%CI = 1.10-1.49), body mass index (SOR = 1.33, 95%CI = 1.04-1.71), and parity (SOR = 1.27, 95%CI = 1.13-1.43). Our findings demonstrate that passive maternal smoking is associated with an increased risk of preterm birth. Future prospective cohort studies are warranted to provide more detailed results stratified by passive maternal smoking during different trimesters of pregnancy and by different types and causes of preterm birth.

Parity and gastric cancer risk: a systematic review and dose-response meta-analysis of prospective cohort studies

We performed this meta-analysis of epidemiological studies to comprehensively assess the association between parity and gastric cancer risk, because previous studies have shown conflicting results regarding this topic. Relevant prospective studies were identified by searching the following databases: PubMed, EMBASE, and Web of Science, and random-effects models were used to estimate summary relative risks (SRRs) and 95% confidence intervals (CIs). Our search yielded 10 prospective cohort studies involving a total of 6624 gastric cancer cases and 5,559,695 non-cases. The SRRs for ever parity vs. nulliparous and highest vs. lowest parity number were 0.96 (95%CI = 0.87–1.05, I² = 0%) and 1.03 (95%CI = 0.94–1.13, I² = 0%), respectively. Additionally, the SRR for an increment of one live birth was 1.00 (95%CI = 0.97–1.03, I² = 18.6%). These non-significant associations were observed in all subgroups as stratified by the number of gastric cases, follow-up years, geographic location, menopausal status, anatomic subsite of gastric cancer, and adjustment for potential confounders, as well as in sensitivity analyses. Our meta-analysis found no significant association between parity and gastric cancer risk. However, further studies should be conducted to validate our findings and could provide more detailed results by stratifying their findings by Lauren’s subtype, histology, and anatomic site, as well as fully adjusting for potential confounding factors.

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

Although observational studies have assessed the relationship between parity and thyroid cancer risk, the findings are inconsistent. To quantitatively assess the association, we conducted a systematic review and meta-analysis. PubMed and Embase were searched up to January 2015. Prospective or case-control studies that evaluated the association between parity and thyroid cancer risk were included. We used the fixed-effects model to pool risk estimates. After literature search, 10 prospective studies, 12 case-control studies and 1 pooled analysis of 14 case-control studies including 8860 patients were identified. The studies had fair methodological quality. Pooled analysis suggested that there was a significant association between parity and risk of thyroid cancer (RR for parous versus nulliparous: 1.09, 95% CI 1.03-1.15; I2=33.4%). The positive association persisted in almost all strata of subgroup analyses based on study design, location, study quality, type of controls, and confounder adjustment, although in some strata statistical significance was not detected. By evaluating the number of parity, we identified that both parity number of 2 versus nulliparous and parity number of 3 versus nulliparous demonstrated significant positive associations (RR=1.11, 95% CI 1.01-1.22; I2=31.1% and RR=1.16, 95% CI 1.01-1.33; I2=19.6% respectively). The dose-response analysis suggested neither a non-linear nor linear relationship between the number of parity and thyroid cancer risk. In conclusion, this meta-analysis suggests a potential association between parity and risk of thyroid cancer in females. However, the lack of detection of a dose-response relationship suggests that further studies are needed to better understand the relationship.

Breastfeeding and thyroid cancer risk in women: A dose-response meta-analysis of epidemiological studies

BACKGROUND & AIMS

The association between breastfeeding and thyroid cancer risk is not consistent from epidemiological studies. To better clarify the association including assessing a potential dose-response relationship, we conducted a comprehensive meta-analysis.

METHODS

We searched PubMed (MEDLINE) up to November 2015 for prospective studies or case-control studies that evaluated the association between breastfeeding and risk of thyroid cancer. Effect estimates were pooled using a fixed-effects model.

RESULTS

Nine reports (2 prospective studies, 6 case-control studies and 1 pooled analysis of 14 case-control studies) involving 2423 cases and 350,081 non-cases were identified. After pooling relevant studies, there was a significant inverse association between ever breastfeeding and risk of thyroid cancer (RR = 0.91, 95% CI 0.83-0.99), with minor heterogeneity (I(2) = 10.1%). The dose-response analysis revealed a significant linear relationship between the duration of breastfeeding and risk of thyroid cancer. The summary RR for an increment of 1 month of breastfeeding with risk of thyroid cancer was 0.983 (95% CI 0.98-0.99). When focusing on cohort studies, a more prominent linear dose-response relationship was detected, with the combined RR for every increment of 1 month of breastfeeding to be 0.965 (95% CI 0.96-0.97).

CONCLUSIONS

This meta-analysis suggests that breastfeeding is potentially inversely associated with thyroid cancer risk. Also longer duration of breastfeeding may further decreases thyroid cancer risk. If validated in large-scale prospective studies, our findings may have implications for impacting women's decision in breastfeeding.

Dietary fat intake and endometrial cancer risk: dose-response meta-analysis of epidemiological studies

Epidemiological studies have provided controversial evidence of the association between dietary fat intake and endometrial cancer (EC) risk. To address this inconsistency, we conducted this dose-response meta-analysis by total dietary fat intake, based on epidemiological studies published up to the end of June 2015 identified from PubMed, EMBASE and Web of Science. Two authors (RH and Q-JW) independently performed the eligibility evaluation and data extraction. All differences were resolved by discussion with the third investigator (LJ). Random-effects models were used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). Overall, the search yielded 16 studies (6 cohort and 10 case-control studies) that involved a total of 7556 EC cases and 563,781 non-cases. The summary RR for EC for each 30g/day increment intake was 0.98 (95%CI = 0.95–1.001; I² = 0%; n = 11) for total dietary fat. Non-significant results were observed in plant-based fat (summary RR = 1.05, 95%CI = 0.94–1.18; I² = 0%; n = 5) and animal-based fat (summary RR = 1.17, 95%CI = 0.92–1.36; I² = 85.0%; n = 6). Additionally, the null associations were observed in almost all the subgroup and sensitivity analyses. In conclusion, findings of the present meta-analysis suggested a lack of association between total dietary fat intake and EC risk. Further studies, especially prospective designed studies are warranted to confirm our findings.