Oral contraceptive and IUD use and endometrial cancer: a population-based case-control study in Shanghai, China

Association between intrauterine device use and endometrial, cervical, and ovarian cancer: an expert review

The intrauterine device is one of the most effective forms of contraception. Use of the intrauterine device has increased in the United States over the last 2 decades. Two formulations are commercially available in the United States: the levonorgestrel-releasing intrauterine device and the copper intrauterine device. The levonorgestrel intrauterine device releases progestin, causing endometrial suppression and cervical mucus thickening, whereas the primary mechanism of action of the copper intrauterine device is to create a local inflammatory response to prevent fertilization. Whereas the protective effects of combined hormonal contraception against ovarian and endometrial cancer, and of tubal sterilization against ovarian cancer are generally accepted, less is known about the effects of modern intrauterine devices on the development of gynecologic malignancies. The best evidence for a protective effect of intrauterine device use against cancer incidence pertains to levonorgestrel intrauterine devices and endometrial cancer, although studies suggest that both copper intrauterine devices and levonorgestrel intrauterine devices reduce endometrial cancer risk. This is supported by the proposed dual mechanisms of action including both endometrial suppression and a local inflammatory response. Studies on the relationship between intrauterine device use and ovarian cancer risk show conflicting results, although most data suggest reduced risk of ovarian cancer in intrauterine device users. The proposed biological mechanisms of ovarian cancer reduction (foreign-body inflammatory response, increased pH, antiestrogenic effect, ovulation suppression) vary by type of intrauterine device. Whereas it has been well established that use of copper intrauterine devices confers a lower risk of cervical intraepithelial neoplasms, the effect of levonorgestrel intrauterine device use on cervical cancer remains unclear. Older studies have linked its use to a higher incidence of cervical dysplasia, but more recent literature has found a decrease in cervical cancer with intrauterine device use. Various mechanisms of protection are postulated, including device-related inflammatory response in the endocervical canal and prostaglandin-mediated immunosurveillance. Overall, the available evidence suggests that both levonorgestrel intrauterine devices and copper intrauterine devices reduce gynecologic cancer risk. Whereas there is support for the reduction of endometrial cancer risk with hormonal and copper intrauterine device use, and reduction of cervical cancer risk with copper intrauterine device use, evidence in support of risk reduction with levonorgestrel intrauterine device use for cervical and ovarian cancers is less consistent.

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.

The levonorgestrel intrauterine system for prevention of endometrial cancer in women with obesity: A cost-effectiveness study

OBJECTIVE

To estimate the cost-effectiveness of the levonorgestrel intrauterine system (LNG-IUS) as an endometrial cancer prevention strategy in women with obesity.

METHODS

A Markov decision-analytic model was used to compare 5 strategies in women with a body mass index of 30 or greater: 1) Usual care 2) LNG-IUS for 5 years 3) LNG-IUS for 7 years 4) LNG-IUS for 5 years, replaced once for a total of 10 years 5) LNG-IUS for 7 years, replaced once for a total of 14 years. Obesity was presumed to be associated with a 3-fold relative risk of endometrial cancer incidence and a 2.65-fold disease-specific mortality. The LNG-IUS was assumed to confer a 50% reduction in cancer incidence over the period of the LNG-IUS insertion. Outcomes were incremental cost-effectiveness ratios, calculated in 2019 Canadian dollars (CAD) per year of life saved. One-way and two-way sensitivity analyses were performed.

RESULTS

The LNG-IUS strategy was considered cost-effective if the cost of the intervention is less than $66,400 CAD ($50,000 US dollars) per year of life saved. The strategy becomes cost-effective if the LNG-IUS is inserted at age 57 (strategy #2), at age 52 for strategy #3, at age 51 for strategy #4 and at age 45 for strategy #5, when compared to usual care. The results are stable to variations in cost but sensitive to the estimated risk reduction of the LNG-IUS and the impact of obesity on endometrial cancer incidence and disease-specific mortality.

CONCLUSION

The LNG-IUS is a cost-effective method of endometrial cancer prevention in women with obesity.

Endometrial cancer prevention in high-risk women

Endometrial cancer (EC) is the most common gynaecological malignancy, and its incidence is rising alongside the growing prevalence of obesity. Effective risk-reducing interventions hijacking the key mechanisms driving endometrial carcinogenesis may affect EC diagnoses if aimed at those at greatest risk. An understanding of the key risk factors and their role in tumourigenesis is critical in developing such prevention strategies. In this review, we summarise the major risk factors for EC and the evidence for available risk-reducing interventions in high-risk women. We suggest potential prevention strategies and make a case for the need for risk prediction models that identify specific groups of women at a particularly high risk of EC for whom risk-reducing interventions are likely to have a significant impact.

Association of Combined Estrogen-Progestogen and Progestogen-Only Contraceptives with the Development of Cancer

Combined estrogen-progestogen contraceptives (oral contraceptives or OCs) and progestogen-only contraceptives (POCs) are synthetic steroids that bind to steroid hormone receptors, which are widespread throughout the body. They have a profound effect on cellular physiology. Combined OCs have been classified by the International Agency for Research on Cancer (IARC) as Group 1 carcinogens, but their findings have not been updated recently. In order to update the information and better understand the impact that OCs and POCs have on the risk of development of cancers, a comprehensive literature search was undertaken, focusing on more recently published papers. In agreement with the IARC, the recent literature confirms an increased risk of breast cancer and cervical cancer with the use of OCs. The recent literature also confirms the IARC conclusion that OCs decrease the risk of ovarian and endometrial cancers. However, there is little support from recent studies for the IARC conclusion that OCs decrease the risk of colorectal cancer or increase the risk of liver cancer. For liver cancer, this may be due to the recent studies having been performed in areas where hepatitis is endemic. In one large observational study, POCs also appear to increase the overall risk of developing cancer. OCs and POCs appear to increase the overall risk of cancer when carefully performed studies with the least intrinsic bias are considered.

Summary

OCs have been classified as cancer-causing agents, especially leading to increases in breast cancer and cervical cancer. A review of the recent scientific literature was performed to see whether this still appears to be the case. The recent literature supports the cancer-causing role of OCs especially for breast cancer and cervical cancer. Studies also indicate that progesterone-only contraceptives (such as implants and vaginal rings) also can cause cancer. This is especially true for breast cancer and cervical cancer.

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

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

Endometrial cancer and oral contraceptives: an individual participant meta-analysis of 27 276 women with endometrial cancer from 36 epidemiological studies

BACKGROUND

Oral contraceptives are known to reduce the incidence rate of endometrial cancer, but it is uncertain how long this effect lasts after use ceases, or whether it is modified by other factors.

METHODS

Individual participant datasets were sought from principal investigators and provided centrally for 27 276 women with endometrial cancer (cases) and 115 743 without endometrial cancer (controls) from 36 epidemiological studies. The relative risks (RRs) of endometrial cancer associated with oral contraceptive use were estimated using logistic regression, stratified by study, age, parity, body-mass index, smoking, and use of menopausal hormone therapy.

FINDINGS

The median age of cases was 63 years (IQR 57-68) and the median year of cancer diagnosis was 2001 (IQR 1994-2005). 9459 (35%) of 27 276 cases and 45 625 (39%) of 115 743 controls had ever used oral contraceptives, for median durations of 3·0 years (IQR 1-7) and 4·4 years (IQR 2-9), respectively. The longer that women had used oral contraceptives, the greater the reduction in risk of endometrial cancer; every 5 years of use was associated with a risk ratio of 0·76 (95% CI 0·73-0·78; p<0·0001). This reduction in risk persisted for more than 30 years after oral contraceptive use had ceased, with no apparent decrease between the RRs for use during the 1960s, 1970s, and 1980s, despite higher oestrogen doses in pills used in the early years. However, the reduction in risk associated with ever having used oral contraceptives differed by tumour type, being stronger for carcinomas (RR 0·69, 95% CI 0·66-0·71) than sarcomas (0·83, 0·67-1·04; case-case comparison: p=0·02). In high-income countries, 10 years use of oral contraceptives was estimated to reduce the absolute risk of endometrial cancer arising before age 75 years from 2·3 to 1·3 per 100 women.

INTERPRETATION

Use of oral contraceptives confers long-term protection against endometrial cancer. These results suggest that, in developed countries, about 400 000 cases of endometrial cancer before the age of 75 years have been prevented over the past 50 years (1965-2014) by oral contraceptives, including 200 000 in the past decade (2005-14).

FUNDING

Medical Research Council, Cancer Research UK.

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.

Oral contraceptive use and risk of breast, cervical, colorectal, and endometrial cancers: a systematic review

Oral contraceptives may influence the risk of certain cancers. As part of the AHRQ Evidence Report, Oral Contraceptive Use for the Primary Prevention of Ovarian Cancer, we conducted a systematic review to estimate associations between oral contraceptive use and breast, cervical, colorectal, and endometrial cancer incidence. We searched PubMed, Embase, and Cochrane Database of Systematic Reviews. Study inclusion criteria were women taking oral contraceptives for contraception or ovarian cancer prevention; includes comparison group with no oral contraceptive use; study reports quantitative associations between oral contraceptive exposure and relevant cancers; controlled study or pooled patient-level meta-analyses; sample size for nonrandomized studies ≥100; peer-reviewed, English-language; published from January 1, 2000 forward. Random-effects meta-analyses were conducted by estimating pooled ORs with 95% confidence intervals (CIs). We included 44 breast, 12 cervical, 11 colorectal, and 9 endometrial cancers studies. Breast cancer incidence was slightly but significantly increased in users (OR, 1.08; CI, 1.00-1.17); results show a higher risk associated with more recent use of oral contraceptives. Risk of cervical cancer was increased with duration of oral contraceptive use in women with human papillomavirus infection; heterogeneity prevented meta-analysis. Colorectal cancer (OR, 0.86; CI, 0.79-0.95) and endometrial cancer incidences (OR, 0.57; CI, 0.43-0.77) were significantly reduced by oral contraceptive use. Compared with never use, ever use of oral contraceptives is significantly associated with decreases in colorectal and endometrial cancers and increases in breast cancers. Although elevated breast cancer risk was small, relatively high incidence of breast cancers means that oral contraceptives may contribute to a substantial number of cases.

Safety, Efficacy, and Patient Acceptability of the Copper T-380A Intrauterine Contraceptive Device

The ParaGard Copper T 380A intrauterine device (CuT380A) provides reversible contraception that is as effective as sterilization for up to 20 years. The CuT380A is a mainstream, first-line contraceptive option for most healthy women, including nulligravid women, as well as many women who have serious medical problems. Because it is the most cost-effective method of birth control, the CuT380A is the preferred IUD, except for women who desire lighter or no menstrual blood loss. Surveys reveal that 95% of US CuT380A users are “very” or “somewhat” satisfied with their method. This article describes current candidates for IUD use, discusses the mechanisms of action of the CuT380A, provides guidance to reduce barriers to IUD access, suggests counseling points for patients, and outlines techniques to reduce the risks and side effects that can be associated with use of the CuT380A.

DNA methylation in endometrial cancer

Endometrial cancer is the most commonly diagnosed gynecological cancer, and it has been shown to be a complex disease driven by abnormal genetic, and epigenetic alterations, as well as environmental factors. Epigenetic changes resulting in aberrant gene expression are dynamic and modifiable features of many cancer types. A significant epigenetic change is aberrant DNA methylation. In this review, we review evidence on the role of aberrant DNA methylation, examining changes in relation to endometrial carcinogenesis, and report on recent advances in the understanding of the contribution of aberrant DNA methylation to endometrial cancer with the emphasis on the role of dietary/ lifestyle and environmental factors, as well as opportunities and challenges of DNA methylation in endometrial cancer management and prevention.

Copper containing intra-uterine devices versus depot progestogens for contraception

BACKGROUND

Highly effective contraception is essential to reduce unintended pregnancies and the effect these have on individuals, society and public health resources. Intrauterine devices (IUDs) and depot progestogens are two commonly used long-acting, reversible contraceptive methods with different risk and benefit profiles.

OBJECTIVES

To compare the contraceptive and non-contraceptive benefits and risks of using the copper-containing IUD versus depot progestogens for contraception.

SEARCH STRATEGY

In June 2009 we searched the Cochrane Pregnancy and Childbirth Group Trials Register, the Cochrane Central Register of Controlled Trials, Pubmed, Popline, Clinical Trials.gov, the Current Controlled Trials metaRegister, EMBASE and LILACS, and contacted study authors.

SELECTION CRITERIA

Randomized trials comparing women using copper-containing IUDs with women using depot progestogens.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality, extracted and double-entered data.

MAIN RESULTS

Two studies were included in the review. In the one study in HIV infected women, the IUD was compared with depot progestogen or the oral contraceptive, according to the women's choice. As the majority of women chose depot progestogen, we have included this study in the review, within a mixed hormonal contraception sub-group.Overall, the copper IUD was more effective than depot progestogens/hormonal contraception at preventing pregnancy (risk ratio (RR) 0.45; 95% confidence interval (CI) 0.24 to 0.84). HIV disease progression was reduced in the IUD group (RR 0.58; 95% CI 0.39 to 0.87). There was no significant difference in pelvic inflammatory disease rates between the two groups. Discontinuation of the allocated method was less frequent with the IUD in one study, and less frequent with hormonal contraception in the other study (in which women were allowed to switch between various hormonal methods).

AUTHORS' CONCLUSIONS

In the populations studied, the IUD was more effective than hormonal contraception with respect to pregnancy prevention. High quality research is urgently needed to compare the effects, if any, of these two commonly used contraception methods on HIV acquisition/seroconversion and HIV/AIDS disease progression.

Use of oral contraceptives, intrauterine devices and tubal sterilization and cancer risk in a large prospective study, from 1996 to 2006

The association of contraceptive methods, including oral contraceptives (OC), intrauterine devices (IUD) and tubal sterilization (TS), with overall and site-specific cancer were prospectively investigated in a cohort of 66,661 Chinese women in Shanghai, 76.7% of whom used contraception. During a median follow-up time of 7.5 years, 2,250 women were diagnosed with cancer. Ever-use of any contraceptive method was not associated with overall cancer risk [adjusted hazard ratio (HR(adj)) = 1.02, 95% CI, 0.92-1.12]. Use of any contraceptive method was associated with increased risk of rectal cancer (HR(adj) = 1.68, 95% CI, 1.08-2.62) and reduced risk of thyroid cancer (HR(adj) = 0.63, 95% CI, 0.38-1.04). Risk of gallbladder cancer increased with ever use of OC (HR(adj) = 2.38, 95% CI, 1.26-4.49). IUD use was associated with a possible reduced risk of thyroid cancer (HR(adj) = 0.64, 95% CI, 0.38-1.07). Longer duration of IUD use decreased risk for breast, thyroid and lung cancers. Ever having a TS was associated with increased uterine body cancer (HR(adj) = 2.50, 95% CI, 1.47-4.25) and decreased risk of stomach cancer (HR(adj) = 0.59, 95% CI, 0.39-0.91). We did not find any contraceptive method to be related to the risk of ovarian cancer but the analyses were based on few events. Although chance findings are a likely explanation for some of the associations found in our study, these findings suggest that various contraceptive methods or reproductive patterns may play a role in the etiology of cancer.

Non-contraceptive benefits of oral contraceptives

BACKGROUND

There is increasing awareness of the opportunity that many contraceptive interventions may provide for additional health benefits. However, treatment of medical problems with oral contraceptives (OCs) is often an 'off-label' practice.

OBJECTIVE

The aim of this review is to summarize available data on non-contraceptive benefits of OCs.

METHODS

Review of the literature.

RESULTS

OCs have been shown to reduce the risk of ovarian, endometrial, and colorectal cancer. It has been suggested that OCs may be used in treatment of endometriosis, menorrhagia, and uterine leiomyomas. Pelvic inflammatory disease, dysmenorrhea, premenstrual syndrome, and acne have been shown to improve under OCs.

CONCLUSION

OCs are important for global and female health. Besides contraception, non-contraceptive effects of OCs are evidence based, well established, and commonly used in clinical practice.

Cost-effectiveness analysis of prevention strategies for gynecologic cancers in Lynch syndrome

BACKGROUND

Women with Lynch syndrome (hereditary nonpolyposis colorectal cancer) have an increased lifetime risk for endometrial and ovarian cancer. Screening and prophylactic surgery have been recommended as prevention strategies. In this study, the authors estimated the net health benefits and cost-effectiveness of these strategies in a Markov decision-analytic model.

METHODS

Five strategies were compared for a hypothetical cohort of women with Lynch syndrome: 1) no prevention ('reference'); 2) prophylactic surgery (hysterectomy and bilateral salpingo-oophorectomy) at age 30 years; 3) prophylactic surgery at age 40 years; 4) annual screening with endometrial biopsy, transvaginal ultrasound, and CA 125 from age 30 years; and 5) annual screening from age 30 years until prophylactic surgery at age 40 years (combined strategy). Net health benefit was measured in quality-adjusted life years (QALYs), and the primary outcome measured was the incremental cost-effectiveness ratio (ICER). Baseline and transition probabilities were obtained from published literature, and costs were from the U.S. Department of Health and Human Services and Agency for Health Care Quality and Research. Sensitivity analyses were performed for uncertainty around various parameters.

RESULTS

The combined strategy provided the highest net health benefit (18.98 QALYs) but had an ICER of $194,650 per QALY relative to the next best strategy (prophylactic surgery at age 40 years). Prophylactic surgery at age 30 years and annual screening were dominated by alternate strategies.

CONCLUSIONS

Annual screening followed by prophylactic surgery at age 40 years was the most effective gynecologic cancer prevention strategy, but the incremental benefit over prophylactic surgery alone was attained at substantial cost. The ICER would become favorable by improving the effectiveness and reducing the costs of screening in this population.

Meta-analysis of intrauterine device use and risk of endometrial cancer

PURPOSE

We sought to study the association between intrauterine device (IUD) use and endometrial cancer.

METHODS

A comprehensive search of literature published through April 2007 was conducted, studies reviewed, and data abstracted. Data from ten studies were pooled and analyzed using both fixed- and random-effects models to examine the association of ever use of an IUD and endometrial cancer.

RESULTS

Based on the random effects model, a protective crude association between IUD use and endometrial cancer was observed (odds ratio [OR] = 0.39; 95% confidence interval [CI] = 0.29-0.51; heterogeneity p < 0.001) with a pooled adjusted risk of OR = 0.54 (95% CI, 0.47-0.63; heterogeneity p = 0.40). A decreased risk of endometrial cancer also was seen for increased years of IUD use (OR for 5 years of use 0.88; 95% CI = 0.84-0.92; n = 5; heterogeneity p = 0.14), increased years since last IUD use (OR for 5 years of use 0.91; 95% CI, 0.86-0.95; n = 4; heterogeneity p = 0.02), and increased years since first IUD use (OR for 5 years of use 0.89; 95% CI, 0.83-0.95; n = 4; heterogeneity p = 0.04).

CONCLUSIONS

Our results suggest that nonhormonal IUD use may be associated with a decreased risk for endometrial cancer; however, the exact mechanism for this association is unclear. Future investigations should address the difference in the proposed association by specific type of IUDs.

Copper IUD and LNG IUS compared with tubal occlusion

This article will cover current contraceptive use around the world, then examine the advantages and disadvantages of female sterilization, the hormonal intrauterine system and the copper intrauterine device. Finally, the need for contraceptive choice will be discussed along with a discussion on the cost-effectiveness of these methods.

The promise and reality of the intrauterine route for hormone delivery for prevention and therapy of gynecological disease

CONTEXT

Progestins delivered by a variety of routes have been demonstrated, in addition to their high contraceptive effect, to have substantial benefits in the treatment of various gynecological disorders, and the intrauterine route has particular efficacy in treating endometrial and myometrial disorders. It should be possible to extend this to prevention of disease.

THERAPY OF GYNECOLOGICAL DISEASE

Those conditions for which there is most evidence of therapeutic benefit from intrauterine release of progestins include heavy menstrual bleeding (due to most causes), endometrial hyperplasia, endometriosis and adenomyosis.

PREVENTION OF GYNECOLOGICAL DISEASE

Reasonable evidence exists to support the findings that intrauterine levonorgestrel helps to prevent the development of uterine fibroids, endometriosis, endometrial hyperplasia, acute episodes of pelvic infection and a wide range of menstrual symptoms. There is also promise of prevention of endometrial carcinoma, endometrial polyps, infertility and perhaps adenomyosis.

CONCLUSIONS

There is a need for specific studies to further explore the prevention of these gynecological conditions which can cause major health disturbances and community distress.

Neoplasia with use of intrauterine devices

BACKGROUND

One of the mechanisms by which intrauterine devices (IUDs) prevent pregnancy is the creation of a sterile inflammatory response in the endometrium. Additionally, hormone-releasing IUDs or intrauterine systems (IUSs) release progestins or progesterone into the uterus. Both of these mechanisms may affect users' risk for neoplasia.

STUDY DESIGN

We searched the PubMed database for studies on IUD use and risk for neoplasia conducted between 1960 and September 2006 and published in all languages. We excluded case reports and case series. For the association between ever using an IUD and risk for endometrial cancer, we conducted a meta-analysis using a Bayesian random-effects model to account for between-study heterogeneity.

RESULTS

We found no evidence of increased risk for neoplasia with IUD use. Nine case-control studies and one cohort study found reduced risks for endometrial cancer with having ever used an IUD (pooled adjusted odds ratio=0.6, 95% confidence interval=0.4-0.7). No trend in associations was observed with characteristics of IUD use, type of IUD and histologic type of cancer. Four case-control studies found no association between IUD use and risk for cervical cancer. One study found no increased incidence of breast cancer among levonorgestrel-releasing IUS users as compared with the general population in Finland. Finally, three studies found no association between IUD use and occurrence of hydatidiform moles or malignant sequelae.

CONCLUSIONS

Use of an IUD does not appear to increase the risk for neoplasia. While nearly all studies found that IUD use was associated with a decreased risk for endometrial cancer, it remains unclear whether this association is causal.