Association of reproductive risk factors and breast cancer molecular subtypes: a systematic review and meta-analysis

Trends in breast cancer among elderly women: Development in estrogen and HER2 subtypes in the last ten years

BACKGROUND

Increasing life expectancy increases breast cancer (BC) rates in elderly, where better health allows for improved tolerance of treatments. We assessed trends in BC incidence of tumor subtypes for women with focus on the elderly.

METHODS

Changes in BC incidence in women by age from 2012 to 2021 were assessed using data from the Nordic countries. We calculated the incidence of BC subtypes by age group using data from the Danish Breast Cancer Group (DBCG) database. We used generalized linear models assuming a Poisson distribution.

RESULTS

In the Nordic countries, 205 305 women were diagnosed with BC between 2012 and 2021. In Denmark, 50 858 BC patients were diagnosed between 2012 and 2022, identified with tumor characteristics. Incidence of BC among women aged 80+ increased significantly across the Nordic Countries, with 1.24 % per year (95 % CI: 0.07 %: 2.41 %). In Denmark, in the 80+ group, the ER+/HER2- subtype had the highest increase, with 1.98 % per year (95 % CI: 1.10 %: 2.87 %).

CONCLUSION

Across the Nordic countries, incidence of BC in women aged 80+ increased. In Denmark, rising incidence of BC is driven by the ER+/HER2- subtype in the 80+ group, which has the best prognosis and gentle treatments. More elderly BC patients will require treatment and follow-up in the future.

Risk factors for breast cancer subtypes by race and ethnicity: a scoping review

BACKGROUND

Breast cancer consists of distinct molecular subtypes. Studies have reported differences in risk factor associations with breast cancer subtypes, especially by tumor estrogen receptor (ER) status, but their consistency across racial and ethnic populations has not been comprehensively evaluated.

METHODS

We conducted a qualitative, scoping literature review using the Preferred Reporting Items for Systematic Reviews and Meta-analysis, extension for Scoping Reviews to investigate consistencies in associations between 18 breast cancer risk factors (reproductive, anthropometric, lifestyle, and medical history) and risk of ER-defined subtypes in women who self-identify as Asian, Black or African American, Hispanic or Latina, or White. We reviewed publications between January 1, 1990 and July 1, 2022. Etiologic heterogeneity evidence (convincing, suggestive, none, or inconclusive) was determined by expert consensus.

RESULTS

Publications per risk factor ranged from 14 (benign breast disease history) to 66 (parity). Publications were most abundant for White women, followed by Asian, Black or African American, and Hispanic or Latina women. Etiologic heterogeneity evidence was strongest for parity, followed by age at first birth, postmenopausal body mass index, oral contraceptive use, and estrogen-only and combined menopausal hormone therapy. Evidence was limited for other risk factors. Findings were consistent across racial and ethnic groups, although the strength of evidence varied.

CONCLUSION

The literature supports etiologic heterogeneity by ER for some established risk factors that are consistent across race and ethnicity groups. However, in non-White populations evidence is limited. Larger, more comparable data in diverse populations are needed to better characterize breast cancer etiologic heterogeneity.

Reproductive factors and mammographic density within the International Consortium of Mammographic Density: A cross-sectional study

BACKGROUND

Elevated mammographic density (MD) for a woman's age and body mass index (BMI) is an established breast cancer risk factor. The relationship of parity, age at first birth, and breastfeeding with MD is less clear. We examined the associations of these factors with MD within the International Consortium of Mammographic Density (ICMD).

METHODS

ICMD is a consortium of 27 studies with pooled individual-level epidemiological and MD data from 11,755 women without breast cancer aged 35-85 years from 22 countries, capturing 40 country-& ethnicity-specific population groups. MD was measured using the area-based tool Cumulus. Meta-analyses across population groups and pooled analyses were used to examine linear regression associations of square-root (√) transformed MD measures (percent MD (PMD), dense area (DA), and non-dense area (NDA)) with parity, age at first birth, ever/never breastfed and lifetime breastfeeding duration. Models were adjusted for age at mammogram, age at menarche, BMI, menopausal status, use of hormone replacement therapy, calibration method, mammogram view and reader, and parity and age at first birth when not the association of interest.

RESULTS

Among 10,988 women included in these analyses, 90.1% (n = 9,895) were parous, of whom 13% (n = 1,286) had ≥ five births. The mean age at first birth was 24.3 years (Standard deviation = 5.1). Increasing parity (per birth) was inversely associated with √PMD (β: - 0.05, 95% confidence interval (CI): - 0.07, - 0.03) and √DA (β: - 0.08, 95% CI: - 0.12, - 0.05) with this trend evident until at least nine births. Women who were older at first birth (per five-year increase) had higher √PMD (β:0.06, 95% CI:0.03, 0.10) and √DA (β:0.06, 95% CI:0.02, 0.10), and lower √NDA (β: - 0.06, 95% CI: - 0.11, - 0.01). In stratified analyses, this association was only evident in women who were post-menopausal at MD assessment. Among parous women, no associations were found between ever/never breastfed or lifetime breastfeeding duration (per six-month increase) and √MD.

CONCLUSIONS

Associations with higher parity and older age at first birth with √MD were consistent with the direction of their respective associations with breast cancer risk. Further research is needed to understand reproductive factor-related differences in the composition of breast tissue and their associations with breast cancer risk.

Epidemiology and prognostic nomogram for invasive breast cancer aged 85 years and older in the USA

The available data on epidemiology and prognostic factors of female patients with breast cancer aged 85 years and older in the USA are limited, especially regarding molecular-level heterogeneity. Relevant data were extracted from the surveillance, epidemiology, and end-result database. The incidence rate and the annual prevalence rate were determined. The annual percent change (APC) of incidence was measured to determine the gradual trends or changes in rates. A visual nomogram was constructed to predict the 3-year overall survival (OS). The Kaplan-Meier method and log-rank test were performed for survival analysis. In total, 18,137 female patients with invasive breast cancer aged 85 years and older were included. Among these patients, patients with HR+/HER2- accounted for 68.7%, followed by HR-/HER2- (9.3%), HR+/HER2+ (7.4%), and HR-/HER2+ (3.1%). The overall incidence rate among this population was 181.82 (95% CI 179.18-184.49) per 100,000 women. This decreased from 184.73 to 177.71 per 100,000 women from 2010 to 2019, with an APC of - 1.0 (95% CI - 1.8 to - 0.1, P = 0.036). The incidence rate varied across receptor subtypes and races and was higher in patients with HR+/HER2- or the black population. The most common treatment regime was breast-conserving surgery. Approximately 29.2% of all patients were categorized as receiving no treatment. A nomogram for predicting 3-year overall survival was constructed, with a consistency index of 0.71. Furthermore, the calibration curves showed consistency. In this study, we have presented the epidemiological data of invasive breast cancer in females aged 85 years and older in the USA. The developed predictive nomogram can effectively identify patients with poor survival.

Beyond Milk and Nurture: Breastfeeding's Powerful Impact on Breast Cancer

Breast cancer (BC) stands as a global concern, given its high incidence and impact on women's mortality. This complex disease has roots in various risk factors, some modifiable and others not. Understanding and identifying these factors can be instrumental in both preventing BC and improving survival rates. Remarkably, women's reproductive behaviors have emerged as critical determinants of BC susceptibility. Numerous studies have shed light on how aspects including age of menarche, first pregnancy and menopause along with number of pregnancies, hormone replacement therapies, can influence one's risk of developing BC. Furthermore, the act of breastfeeding and its duration have shown an inverse relationship with BC risk. This review delves into the biological and molecular mechanisms associated with breastfeeding that contribute to BC protection. It highlights the role of endocrine processes triggered by suckling stimulation, the gradual onset of lactational amenorrhea, delayed weaning, reduced lifetime menstrual cycles, chromosomal repair mechanisms, and immunological events throughout the lactation cycle. These insights provide a potential explanation for the protective effects conferred by breastfeeding against breast carcinomas.

Reproductive characteristics, menopausal status, race and ethnicity, and risk of breast cancer subtypes defined by ER, PR and HER2 status: the Breast Cancer Etiology in Minorities study

BACKGROUND

Associations between reproductive factors and risk of breast cancer differ by subtype defined by joint estrogen receptor (ER), progesterone receptor (PR), and HER2 expression status. Racial and ethnic differences in the incidence of breast cancer subtypes suggest etiologic heterogeneity, yet data are limited because most studies have included non-Hispanic White women only.

METHODS

We analyzed harmonized data for 2,794 breast cancer cases and 4,579 controls, of whom 90% self-identified as African American, Asian American or Hispanic. Questionnaire data were pooled from three population-based studies conducted in California and data on tumor characteristics were obtained from the California Cancer Registry. The study sample included 1,530 luminal A (ER-positive and/or PR-positive, HER2-negative), 442 luminal B (ER-positive and/or PR-positive, HER2-positive), 578 triple-negative (TN; ER-negative, PR-negative, HER2-negative), and 244 HER2-enriched (ER-negative, PR-negative, HER2-positive) cases. We used multivariable unconditional logistic regression models to estimate subtype-specific ORs and 95% confidence intervals associated with parity, breast-feeding, and other reproductive characteristics by menopausal status and race and ethnicity.

RESULTS

Subtype-specific associations with reproductive factors revealed some notable differences by menopausal status and race and ethnicity. Specifically, higher parity without breast-feeding was associated with higher risk of luminal A and TN subtypes among premenopausal African American women. In contrast, among Asian American and Hispanic women, regardless of menopausal status, higher parity with a breast-feeding history was associated with lower risk of luminal A subtype. Among premenopausal women only, luminal A subtype was associated with older age at first full-term pregnancy (FTP), longer interval between menarche and first FTP, and shorter interval since last FTP, with similar OR estimates across the three racial and ethnic groups.

CONCLUSIONS

Subtype-specific associations with reproductive factors overall and by menopausal status, and race and ethnicity, showed some differences, underscoring that understanding etiologic heterogeneity in racially and ethnically diverse study samples is essential. Breast-feeding is likely the only reproductive factor that is potentially modifiable. Targeted efforts to promote and facilitate breast-feeding could help mitigate the adverse effects of higher parity among premenopausal African American women.

Clustering of HR + /HER2- breast cancer in an Asian cohort is driven by immune phenotypes

Breast cancer exhibits significant heterogeneity, manifesting in various subtypes that are critical in guiding treatment decisions. This study aimed to investigate the existence of distinct subtypes of breast cancer within the Asian population, by analysing the transcriptomic profiles of 934 breast cancer patients from a Malaysian cohort. Our findings reveal that the HR + /HER2- breast cancer samples display a distinct clustering pattern based on immune phenotypes, rather than conforming to the conventional luminal A-luminal B paradigm previously reported in breast cancers from women of European descent. This suggests that the activation of the immune system may play a more important role in Asian HR + /HER2- breast cancer than has been previously recognized. Analysis of somatic mutations by whole exome sequencing showed that counter-intuitively, the cluster of HR + /HER2- samples exhibiting higher immune scores was associated with lower tumour mutational burden, lower homologous recombination deficiency scores, and fewer copy number aberrations, implicating the involvement of non-canonical tumour immune pathways. Further investigations are warranted to determine the underlying mechanisms of these pathways, with the potential to develop innovative immunotherapeutic approaches tailored to this specific patient population.

A contemporary review of breast cancer risk factors and the role of artificial intelligence

Background

Breast cancer continues to be a significant global health issue, necessitating advancements in prevention and early detection strategies. This review aims to assess and synthesize research conducted from 2020 to the present, focusing on breast cancer risk factors, including genetic, lifestyle, and environmental aspects, as well as the innovative role of artificial intelligence (AI) in prediction and diagnostics.

Methods

A comprehensive literature search, covering studies from 2020 to the present, was conducted to evaluate the diversity of breast cancer risk factors and the latest advances in Artificial Intelligence (AI) in this field. The review prioritized high-quality peer-reviewed research articles and meta-analyses.

Results

Our analysis reveals a complex interplay of genetic, lifestyle, and environmental risk factors for breast cancer, with significant variability across different populations. Furthermore, AI has emerged as a promising tool in enhancing the accuracy of breast cancer risk prediction and the personalization of prevention strategies.

Conclusion

The review highlights the necessity for personalized breast cancer prevention and detection approaches that account for individual risk factor profiles. It underscores the potential of AI to revolutionize these strategies, offering clear recommendations for future research directions and clinical practice improvements.

Tissue Expression of Growth Differentiation Factor 11 in Patients with Breast Cancer

Protein growth differentiation factor 11 (GDF11) plays crucial roles in cellular processes, including differentiation and development; however, its clinical relevance in breast cancer patients is poorly understood. We enrolled 68 breast cancer patients who underwent surgery at our hospital and assessed the expression of GDF11 in tumorous, ductal carcinoma in situ (DCIS), and non-tumorous tissues using immunohistochemical staining, with interpretation based on histochemical scoring (H-score). Our results indicated higher GDF11 expressions in DCIS and normal tissues compared to tumorous tissues. In addition, the GDF11 H-score was lower in the patients with a tumor size ≥ 2 cm, pathologic T3 + T4 stages, AJCC III-IV stages, Ki67 ≥ 14% status, HER2-negative, and specific molecular tumor subtypes. Notably, the patients with triple-negative breast cancer exhibited a loss of GDF11 expression. Spearman correlation analysis revealed associations between GDF11 expression and various clinicopathological characteristics, including tumor size, stage, Ki67, and molecular subtypes. Furthermore, GDF11 expression was positively correlated with mean corpuscular hemoglobin concentration and negatively correlated with neutrophil count, as well as standard deviation and coefficient of variation of red cell distribution width. These findings suggest that a decreased GDF11 expression may play a role in breast cancer pathogenesis.

Risk factors for breast cancer subtypes by race and ethnicity: A scoping review of the literature

Background

Breast cancer is comprised of distinct molecular subtypes. Studies have reported differences in risk factor associations with breast cancer subtypes, especially by tumor estrogen receptor (ER) status, but their consistency across racial and ethnic populations has not been comprehensively evaluated.

Methods

We conducted a qualitative, scoping literature review using the Preferred Reporting Items for Systematic Reviews and Meta-analysis, extension for Scoping Reviews to investigate consistencies in associations between 18 breast cancer risk factors (reproductive, anthropometric, lifestyle, and medical history) and risk of ER-defined subtypes in women who self-identify as Asian, Black or African American, Hispanic or Latina, or White. We reviewed publications between January 1, 1990 and July 1, 2022. Etiologic heterogeneity evidence (convincing, suggestive, none, or inconclusive) was determined by expert consensus.

Results

Publications per risk factor ranged from 14 (benign breast disease history) to 66 (parity). Publications were most abundant for White women, followed by Asian, Black or African American, and Hispanic or Latina women. Etiologic heterogeneity evidence was strongest for parity, followed by age at first birth, post-menopausal BMI, oral contraceptive use, and estrogen-only and combined menopausal hormone therapy. Evidence was limited for other risk factors. Findings were consistent across racial and ethnic groups, although the strength of evidence varied.

Conclusion

The literature supports etiologic heterogeneity by ER for some established risk factors that are consistent across race and ethnicity groups. However, in non-White populations evidence is limited. Larger, more comparable data in diverse populations is needed to better characterize breast cancer etiologic heterogeneity.

Comparative analysis of breast cancer characteristics in young premenopausal and postmenopausal women in Ghana

Breast cancer is increasingly common among young women in Ghana. BCa is heterogeneous with unique traits that impact causes, prognostic, and predictive outcomes of patients before and after menopause. However, limited evidence exists on differences between young premenopausal (YPM) and postmenopausal cases in Ghana. This study compared breast tumour characteristics between YPM women (under 35 years) and postmenopausal women. We conducted a prospective cross-sectional study involving 140 BCa-diagnosed women at the Breast Care Clinic of Komfo Anokye Teaching Hospital (KATH), Kumasi from November 2019 to June 2021. Thirty-one (22.1%) of participants were YPM and 109 (77.9%) were postmenopausal. The median ages for YPM and postmenopausal were 32.0 (range: 25.0-35.0) and 57.0 (48.0-86.0) respectively. Invasive carcinoma was the most common histological type (97.1%). Left tumour location was the most frequent in both groups (51.6% for YPM and 51.8% for postmenopausal). Lumps detected were frequently in the outer upper quadrant in both groups (61.3% and 56.0%). The majority of the YPM women (80.7%) and postmenopausal women (87.0%) had stage III and IV diseases. Most YPM (64.5%) and postmenopausal women (64.4%) exhibited triple-negative breast cancer (TNBC). Both YPM 13 (56.6%) and postmenopausal participants 40 (56.3%) exhibited a predominantly partial response to neo-adjuvant chemotherapy but YPM women (21.7%) experienced disease progression than the postmenopausal women (12.7%). The study highlights consistent tumour characteristics and advanced clinical stages at diagnosis in both groups with a higher prevalence of TNBC. TNBC and HER2+ subtypes respond better to Anthracycline-based neoadjuvant chemotherapy. Establishing Breast Care Clinics in district and regional hospitals for early detection is crucial and further studies are warranted to understand the higher TNBC prevalence in black Africans and re-evaluate breast education programs to address the persistently late presentations.

Breast cancer: Epidemiology, risk factors and screening

Breast cancer is a global health concern with a significant impact on the well-being of women. Worldwide, the past several decades have witnessed changes in the incidence and mortality of breast cancer. Additionally, epidemiological data reveal distinct geographic and demographic disparities globally. A range of modifiable and non-modifiable risk factors are established as being associated with an increased risk of developing breast cancer. This review discusses genetic, hormonal, behavioral, environmental, and breast-related risk factors. Screening plays a critical role in the effective management of breast cancer. Various screening modalities, including mammography, ultrasound, magnetic resonance imaging (MRI), and physical examination, have different applications, and a combination of these modalities is applied in practice. Current screening recommendations are based on factors including age and risk, with a significant emphasis on minimizing potential harms to achieve an optimal benefits-to-harms ratio. This review provides a comprehensive insight into the epidemiology, risk factors, and screening of breast cancer. Understanding these elements is crucial for improving breast cancer management and reducing its burden on affected individuals and healthcare systems.

Hormonal Contraception and the Risk of Breast Cancer in Women of Reproductive Age: A Meta-Analysis

This study aims to summarize evidence from observational studies about the lifetime use of HC and the risk of BC in women of reproductive age. The PubMed, Cochrane, and EMBASE databases were searched for observational studies published from 2015 to February 2022. Meta-analyses were performed using adjusted odds ratios and relative risks with a random-effects model using the I2 statistic to quantify the heterogeneity among studies. Of the 724 studies identified, 650 were screened for title/abstract selection, 60 were selected for full-text revision, and 22 were included in the meta-analysis. Of these, 19 were case-control studies and 3 were cohort studies. The results of the meta-analysis indicate a significantly higher risk of developing BC in ever users of HC (pooled OR = 1.33; 95% CI = 1.19 to 1.49). This effect is larger in the subgroups of case-control studies (pooled OR = 1.44, 95% CI = 1.21 to 1.70) and in the subgroup of studies that strictly define menopausal status (pooled OR = 1.48; 95% CI, 1.10 to 2.00). Although our meta-analysis of observational studies (cohort and case-control) suggests a significantly increased overall risk of BC in users or ever-users of modern hormonal contraceptives, the high heterogeneity among studies (>70%) related to differences in study design, measurement of variables, confounders, among other factors, as well as publication biases should be considered when interpreting our results.