Oral Contraceptive Use and Breast Cancer Risk Assessment: A Systematic Review and Meta-Analysis of Case-Control Studies, 2009-2020

A Global Regional Comparison of the Risk of Breast Cancer in Woman Using Oral Contraceptives-Systematic Review and Meta-Analysis

Background: Incidence of breast cancer (BrCa) may be correlated with country development, with a rise in cases anticipated in regions of the world that are currently undergoing an economic transformation. Herein, differences with regard to the occurrence of breast cancer between individual countries may depend on the distribution of risk factors, the level of early detection, also ethnicity and race, as well as clinical characteristics. The aim of our study was to identify and then investigate observational studies in which the risk of breast cancer was associated with the use of oral hormonal contraceptives (OCs), with particular emphasis on geographic region, and to conduct a systematic review and meta-analysis of the obtained data. Methods: RR (relative risk) was calculated and displayed in forest plots for visual interpretation. Accordingly, 74 studies involving a total of 198,579 women were eligible for inclusion in the meta-analysis. This is the first meta-analysis to comprehensively summarize the evidence between OC use and BrCa risk in connection with geographical region. Results: The cumulative results of the meta-analysis for specific parts of the world are: Africa (RR = 1.16, p = 0.216) and the Americas (RR = 1.03, p = 0.597); Asia (RR = 1.29, p = 0.014); European countries (RR = 1.01, p = 0.904); and Middle East countries (RR = 1.29, p = 0.043). Subgroup analyses showed an increased risk of BrCa for the analyzed variables that depended upon the geographical region. Conclusions: Our meta-analysis suggests that OC use may be associated with a higher BrCa risk, although a statistically significant association was not found for all geographical regions of the world.

Epidemiological breast cancer prediction by country: A novel machine learning approach

Breast cancer remains a significant contributor to cancer-related deaths among women globally. We seek for this study to examine the correlation between the incidence rates of breast cancer and newly identified risk factors. Additionally, we aim to utilize machine learning models to predict breast cancer incidence at a country level. Following an extensive review of the available literature, we have identified a range of recently studied risk factors associated with breast cancer. Subsequently, we gathered data on these factors and breast cancer incidence rates from numerous online sources encompassing 151 countries. To evaluate the relationship between these factors and breast cancer incidence, we assessed the normality of the data and conducted Spearman's correlation test. Furthermore, we refined six regression models to forecast future breast cancer incidence rates. Our findings indicate that the incidence of breast cancer is most positively correlated with the average age of women in a country, as well as factors such as meat consumption, CO2 emissions, depression, sugar consumption, tobacco use, milk intake, mobile cells, alcohol consumption, pesticides, and oral contraceptive use. As for prediction, the CatBoost Regressor successfully predicted future breast cancer incidence with an R squared value of 0.84 ± 0.03. An increased incidence of breast cancer is mainly associated with dietary habits and lifestyle. Our findings and recommendations can serve as a baseline for developing educational programs intended to heighten awareness amongst women in countries with heightened risk.

Impact of khat (Catha edulis) and oral contraceptive use on telomerase levels and tumor suppressor genes p53 and p21 in normal subjects and breast cancer patients

This study aimed to evaluate the effects of oral contraceptive (OC) use, khat chewing, and their combined effect on telomerase level and tumor suppressor genes, p53 and p21 in breast cancer (BC) patients and normal volunteers. 140 Yemeni women aged 25-40 years old enrolled, 60 newly diagnosed pretreated BC patients, and 80 control subjects. Venous blood (5 ml) was collected and the results showed BC patients to have significantly raised levels of telomerase, p53, and p21 compared to the control group. The use of OCs significantly raised telomerase in control group with no effect in BC patients; whereas p53 and p21 were significantly increased in BC patients. On the other hand, khat chewing significantly increased p53 in controls and BC patients, whereas p21 was significantly raised in BC patients. The combined use of OCs and khat chewing significantly increased telomerase and p53 in control group, and significantly increased p53 and p21 in BC patients. Telomerase was shown to be a risk factor (OR 4.4) for BC, and the use of OCs was a high-risk factor for increasing telomerase (OR 27.8) in normal subjects. In contrast, khat chewing was shown to be protective (OR 0.142), and the combined use of OCs and khat chewing decreased the risk factor of telomerase from OR 27.8 to 2.1.

Optimising health after early menopause

The typical age at menopause is 50-51 years in high-income countries. However, early menopause is common, with around 8% of women in high-income countries and 12% of women globally experiencing menopause between the ages of 40 years and 44 years. Menopause before age 40 years (premature ovarian insufficiency) affects an additional 2-4% of women. Both early menopause and premature ovarian insufficiency can herald an increased risk of chronic disease, including osteoporosis and cardiovascular disease. People who enter menopause at younger ages might also experience distress and feel less supported than those who reach menopause at the average age. Clinical practice guidelines are available for the diagnosis and management of premature ovarian insufficiency, but there is a gap in clinical guidance for early menopause. We argue that instead of distinct age thresholds being applied, early menopause should be seen on a spectrum between premature ovarian insufficiency and menopause at the average age. This Series paper presents evidence for the short-term and long-term consequences of early menopause. We offer a practical framework for clinicians to guide diagnosis and management of early menopause, which considers the nature and severity of symptoms, age and medical history, and the individual's wishes and priorities to optimise their quality of life and short-term and long-term health. We conclude with recommendations for future research to address key gaps in the current evidence.

Association of microRNA-21 expression with breast cancer subtypes and its potential as an early biomarker

Breast cancer has become the most diagnosed cancer worldwide in 2020 with high morbidity and mortality rates. The alarming increase in breast cancer incidence has sprung many researchers to focus on developing novel screening tests to identify early breast cancer which will allow clinicians to provide timely and effective treatments. With much evidence supporting the notion that the deregulation of miRNAs (a class of non-coding RNA) greatly contributes to cancer initiation and progression, the promising role of miRNAs as cancer biomarkers is gaining traction in the research world. Among the upregulated miRNAs identified in breast carcinogenesis, miR-21 was shown to be significantly expressed in breast cancer tissues and bodily fluids of breast cancer patients. Therein, this review paper aims to provide an overview of breast cancer, the role and significance of miR-21 in breast cancer pathogenesis, and its potential as a breast cancer biomarker. The paper also discusses the current types of tumor biomarkers and their limitations, the presence of miR-21 in extracellular vesicles and plasma, screening methods available for miRNA detection along with some challenges faced in developing diagnostic miR-21 testing for breast cancer to provide readers with a comprehensive outlook based on using miR-21 in clinical settings.

Contraceptive use with breast cancer incidence in Indonesia

INTRODUCTION

Breast cancer is the most common cancer in women worldwide and is a significant threat to public health. This study aims to conduct a systematic review of the relationship between hormonal contraceptive use and breast cancer incidence.

METHODS

The search was conducted using Google Scholar, Proquest, Pubmed and one Indonesian database, Garuda, using English and Indonesian keywords. The inclusion criteria in this study were the publication year of the last five years, namely 2019-2023, English and Indonesian language, case-control observational research, using the Indonesian population, and full-text access.

RESULTS

A total of 165 studies were obtained from the Google Scholar database, including 104 studies. The overall multivariate analysis revealed that there was a statistically significant association of hormonal contraception with the incidence of breast cancer with OR values in the range of 2-6.

CONCLUSIONS

The findings of this systematic study suggest that the use of hormones can contribute to hormonal imbalances that further increase breast cell proliferation and disrupt gene expression, resulting in uncontrolled cell development/cancer. In addition, the findings recommend increasing the number of studies on this topic to obtain more adequate and possibly more diverse information.

The role of probiotics in improving menstrual health in women with primary dysmenorrhoea: A randomized, double-blind, placebo-controlled trial (the PERIOD study)

BACKGROUND

Primary dysmenorrhea is associated with poorer quality of life; however, the causal mechanism remains unclear. A vast body of literature supports the use of oral probiotics for relief from the symptoms of endometriosis; however, to our knowledge, no study has prescribed probiotics for primary dysmenorrhea.

OBJECTIVE

The aim of this study is to investigate the effects of 3-month supplementation with oral probiotics on quality of life and inflammatory markers in women with primary dysmenorrhea.

DESIGN

Randomized placebo-controlled trial.

METHODS

A total of 72 patients (36 patients in each arm) were randomized to receive either oral sachets containing 5 billion colony-forming units each of Lactobacillus acidophilus BCMC (BCrobes Microbial Cells) 12130, Lactobacillus casei subsp BCMC 12313, Lactobacillus lactis BCMC 12451, Bifidobacterium bifidum BCMC 02290, Bifidobacterium longum BCMC 02120, and Bifidobacterium infantis BCMC 02129 each or placebo twice daily for 3 months. Main outcome measures were visual analog scale, verbal rating scale, physical and mental health scores using Short-Form 12-Item version 2 questionnaire, frequency of nonsteroidal anti-inflammatory drug use, and changes in inflammatory markers (interleukin-6, interleukin-8, and tumor necrosis factor alpha) before and after treatment.

RESULTS

There was no significant difference in the quality of life scores between the probiotic and placebo groups. Both groups showed significant improvement in pain (visual analog scale) and severity (verbal rating scale) scores but the probiotic group had much lower nonsteroidal anti-inflammatory drug use (odds ratio: 0.69, 95% confidence interval: 0.26-1.83) and better mental health scores (mean change: 6.5, p = 0.03 versus 6.1, p = 0.08) than the placebo group. There was a significant confounding effect of nonsteroidal anti-inflammatory drug use on quality of life scores. No significant difference was found in inflammatory cytokines.

CONCLUSION

Tested oral probiotics improved mental health and potentially reduced the use of nonsteroidal anti-inflammatory drugs; however, there was no significant change in inflammatory markers. Further research with a larger sample size is needed to confirm the findings.

REGISTRATION

This study is registered under ClinicalTrials.gov (NCT04119011).

Estrogens and the risk of breast cancer: A narrative review of literature

In female mammals, the development and regulation of the reproductive system and non-reproductive system are significantly influenced by estrogens (oestrogens). In addition, lipid metabolism is another physiological role of estrogens. Estrogens act through different types of receptors to introduce signals to the target cell by affecting many estrogen response elements. Breast cancer is considered mostly a hormone-dependent disease. Approximately 70% of breast cancers express progesterone receptors and/or estrogen receptors, and they are a good marker for cancer prognosis. This review will discuss estrogen metabolism and the interaction of estrogen metabolites with breast cancer. The carcinogenic role of estrogen is discussed in light of both conventional and atypical cancers susceptible to hormones, such as prostate, endometrial, and lung cancer, as we examine how estrogen contributes to the formation and activation of breast cancer. In addition, this review will discuss other factors that can be associated with estrogen-driven breast cancer.

Risk of Gynecological Cancers in Women With Polycystic Ovary Syndrome and the Pathophysiology of Association

Polycystic ovary syndrome (PCOS) is an endocrine disorder increasingly affecting women in the reproductive age group. The women usually present with menstruation irregularities, hirsutism, weight gain, and acne. There has been ongoing research about the increased risk of gynecological cancers in women with polycystic ovary syndrome compared to those without it. This review aimed to understand the risk of gynecological cancers, endometrial, ovarian, and breast cancer in PCOS, and to study in detail the underlying mechanisms involved. We searched PubMed and Google Scholar databases for studies and selected 10 articles from a total of 19,388 relevant articles. We found an increased risk of endometrial cancer in women with PCOS whereas the risk of ovarian and breast cancer was not increased. A recent study has even reported a reduced risk of ovarian cancer in genetically predicted PCOS. In understanding various medical conditions possibly leading to cancer in these women we found that hyperandrogenism, hyperinsulinemia, unopposed estrogen action, chronic inflammation, and dyslipidemia were major contributors. There is a need for more large-scale cohort studies which will take into consideration other factors leading to cancers in women with PCOS, such as smoking, alcohol, and family history, to substantiate the significance of these associations further. The interventions used to treat PCOS might also affect the risk of cancer and require further probing. This review is an attempt to analyze the risk of cancers of the reproductive system in females with PCOS in coherence with understanding the mechanisms leading to the respective cancers.

Breast Cancer: Risk Assessment, Screening, and Primary Prevention

This review provides an outline of a risk-based approach to breast cancer screening and prevention. All women should be assessed for breast cancer risk starting at age 18 with identification of modifiable and non-modifiable risk factors. Patients can then be stratified into average, moderate, and high-risk groups with personalized screening and prevention plans. Counseling on breast awareness and lifestyle changes is recommended for all women, regardless of risk category. High-risk individuals may benefit from additional screening modalities such as MRI and chemoprevention and should be managed closely by a multidisciplinary team.

The impact of endocrine disrupting compounds and carcinogens in wastewater: Implications for breast cancer

The incidence of breast cancer is often associated with geographic variation which indicates that a person's surrounding environment can be an important etiological factor in cancer development. Environmental risk factors can include exposure to sewage- or wastewater, which consist of a complex mixture of pathogens, mutagens and carcinogens. Wastewater contains primarily carbonaceous, nitrogenous and phosphorus compounds, however it can also contain trace amounts of chemical pollutants including toxic metal cations, hydrocarbons and pesticides. More importantly, the contamination of drinking water by wastewater is a potential source of exposure to mammary carcinogens and endocrine disrupting compounds. Organic solvents and other pollutants often found in wastewater have been detected in various tissues, including breast and adipose tissues. Furthermore, these pollutants such as phenolic compounds in some detergents and plastics, as well as parabens and pesticides can mimic estrogen. High estrogen levels are a well-established risk factor for estrogen-receptor (ER) positive breast cancer. Therefore, exposure to wastewater is a risk factor for the initiation, progression and metastasis of breast cancer. Carcinogens present in wastewater can promote tumourigenesis through various mechanisms, including the formation of DNA adducts, gene mutations and oxidative stress. Lastly, the presence of endocrine disrupting compounds in wastewater can have negative implications for ER-positive breast cancers, where these molecules can activate ERα to promote cell proliferation, survival and metastasis. As such, strategies should be implemented to limit exposure, such as providing funding into treatment technologies and implementation of regulations that limit the production and use of these potentially harmful chemicals.

Oral Contraceptive Use and Assessment of Breast Cancer Risk among Premenopausal Women via Molecular Characteristics: Systematic Review with Meta-Analysis

Breast cancer is divided into four molecular subtypes. Each one has distinct clinical features. The aim of this study was to assess individual breast cancer subtype risk in premenopausal women taking oral contraceptives (OCs). Databases (MEDLINE; PubMed, EMBASE, and the Cochrane Library) were searched to January 2022 to identify case-control studies meeting the inclusion criteria. The influence of OCs intake on the risk of ER-positive breast cancer (ER+BC) was revealed to be non-significant with regard to reduction: OR = 0.9134, 95% CI: 0.8128 to 1.0265, p = 0.128. Assessment of ER-negative subtype breast cancer (ER-BC) risk indicated that OCs use significantly increased the risk: OR = 1.3079, 95% CI: 1.0003 to 1.7100, p = 0.050. Analysis for HER2-positive breast cancer (HER2+BC) risk showed that OCs use statistically non-significantly lowered the risk: OR = 0.8810, 95% CI: 0.5977 to 1.2984, p = 0.522. Meta-analysis with regard to Triplet-negative breast cancer (TNBC) risk showed non-statistically significant increased risk: OR = 1.553, 95% CI: 0.99 to 2.43, p = 0.055. The findings of the meta-analysis suggest that breast cancer risk in premenopausal women may vary with respect to molecular subtypes. Extensive scientific work is still necessary in order to understand the impact of OCs use on breast cancer risk in young women.

Oral Contraceptive Use and Breast Cancer Risk for BRCA1 and BRCA2 Mutation Carriers: Systematic Review and Meta-Analysis of Case–Control Studies

Oral contraceptive use is one of the major modifiable risk factors for breast cancer. To investigate the effect of oral contraceptive taking on breast cancer risk by BRCA 1 and BRCA 2 mutation status, we conducted a systematic review and meta-analysis of case-controlled studies. Therefore, English language articles were retrieved by searching MEDLINE (PubMed), EMBASE and the Cochrane Library up to August 2021. Data were pooled from none case–control studies, comprising a total of 33,162 subjects, including 23,453 who had never used oral contraceptives. Overall meta-analysis indicated a statistically insignificant risk reduction: OR = 0.86, 95% CI: 0.70 to 1.06, p = 0.1594. However, increased breast cancer risk was associated with age at first use of OCs ≥20 years: OR = 1.21, 95% CI:1.07 to 1.36, p = 0.002. Multivariable meta-regression with covariates of age of first OC use (β = 0.21, 95% CI: −0.25 to 0.67, p = 0.3767), duration of OC use (β = −0.08, 95% CI; −0.51 to 0.34, p = 0.7093), and time since last OC use (β = 0.32, 95% CI: −0.22 to 0.85, p = 0.2461) did not have a significant effect on the breast cancer risk. This meta-analysis suggests a diverse effect of oral contraceptive use against breast cancer in BRCA carrier mutation. The association between OC use and breast and ovarian cancers needs more investigation.

How hormonal contraceptives shape brain and behavior: A review of preclinical studies

Steroid hormones influence different aspects of brain function, including development, neurogenesis, neuronal excitability, and plasticity, thus affecting emotional states, cognition, sociality, and reward. In women, their levels fluctuate across the lifespan and through the reproductive stages but are also altered by exogenous administration of hormonal contraceptives (HC). HC are widely used by women throughout their fertile life both for contraceptive and therapeutic benefits. However, awareness of their effects on brain function and behavior is still poorly appreciated, despite the emerging evidence of their action at the level of the central nervous system. Here, we summarize results obtained in preclinical studies, mostly conducted in intact female rodents, aimed at investigating the neurobiological effects of HC. HC can alter neuroactive hormones, neurotransmitters, neuropeptides, as well as emotional states, cognition, social and sexual behaviors. Animal studies provide insights into the neurobiological effects of HC with the aim to improve women's health and well-being.

Oral Contraceptive Use and Breast Cancer Risk According to Molecular Subtypes Status: A Systematic Review and Meta-Analysis of Case-Control Studies

We conducted a systematic review and meta-analysis to investigate the effect of oral contraceptives (OCs) on risk of breast cancer (BrCa) by status of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). We searched the MEDLINE (PubMed), Embase and the Cochrane Library database and bibliographies of pertinent articles published up to 2020. Therein, we identified nineteen eligible case-control studies which provided data by breast cancer subtypes: ER-positive (ER+), ER-negative (ER−), HER2-positive (HER2+) and Triplet-negative (TN). Summary risk estimates (pooled OR [pOR]) and 95% confidence intervals (CIs) were calculated using fixed/random effects models. The summary meta-analysis showed that over-use of OCs led to significant increased risk of TNBrCa (OR = 1.37, 95% CI; 1.13 to 1.67, p = 0.002), as well as of ER−BrCa (OR = 1.20, 95% CI: 1.03 to 1.40, p = 0.019). There was also a significant reduction in the risk of ER+BrCa (OR = O.92, 95% CI: 0.86 to 0.99, p = 0.026,) and a slight reduction in the risk of HER2+BrCa (OR = 0.95, 95% CI; 0.79 to 1.14, p = 0.561) after taking OCs. Meta-analysis indicated that OC use has different impacts on risk of breast cancer subtypes defined by receptor status. The identified differences between individual subtypes of breast cancer may reflect different mechanisms of carcinogenesis.