Increased risk for invasive breast cancer associated with hormonal therapy: a nation-wide random sample of 65,723 women followed from 1997 to 2008

Systematic Review and Meta-Analysis of Lifestyle and Reproductive Factors Associated with Risk of Breast Cancer in Asian Women

BACKGROUND

Assessing breast cancer risks from lifestyle and reproductive factors is critical for developing population-specific risk prediction tools. However, limited studies have evaluated these risks in recent Asian birth cohorts.

METHODS

We systematically reviewed articles published from January 2010 to December 2023, examining breast cancer risk factors in Asian women. Data were described narratively, estimates pooled, and prevalence and attributable proportions compared across Asian populations.

RESULTS

Of the 128 studies reviewed, 103 reported adjusted effect sizes for meta-analysis. Lifestyle and reproductive factors were predictive of breast cancer risk in Asian women, with varying impacts on premenopausal and postmenopausal women. Relative risks were similar within Asian populations and in comparison to European populations, except for menarche, menopause, and hormone receptor therapy. However, risk factor distributions differed across populations. While alcohol intake (21%) and oral contraceptive use (20%) emerged as the most attributable modifiable risk factors in Europeans, passive smoking (24%) and higher BMI (17%, ≥24 kg/m2 among postmenopausal women) were predominant in Asians.

CONCLUSIONS

Our study shows that while the effects of lifestyle and reproductive breast cancer risk factors are largely similar across different populations, their distributions vary.

IMPACT

Our analysis underscores the importance of considering population-specific risk factor distributions when developing risk prediction tools for Asian populations.

Prescription of Chinese herbal products is associated with a decreased risk of uterine fibroids: A population-based cohort study

The finding of a decrease in subsequent fibroid-related operation following the use of Chinese herbal products (CHPs) has led to speculation that CHPs might play a role in uterine fibroids prevention.This study provides an overview of uterine fibroids incidence, comparing CHP users with those who do not use CHPs, referred to as non-CHP users. The results can provide information to clinicians for counseling women about the preventive use of CHPs.A total of 52,151 women (20-45 years of age) were recruited from a nationwide 1-million-person representative sample of those covered by National Health Insurance in Taiwan and were followed from 2000 to 2013. Exact matching was performed for comparative analysis. The age-specific hazard ratios (HRs) of uterine fibroids in relation to either CHP or the phytoestrogen use were calculated with multivariate Cox proportional hazard regression.More than 71% of patients had used a CHP at some point previously. The overall incidence density rate of uterine fibroids for non-CHP users was estimated at 27.5 per 1000 patient-years. The corresponding values for CHP and the phytoestrogen users were lower than those of the non-CHP group (CHP group = 15.5; the phytoestrogen group = 12.5 per 1000 patient-years). The covariate adjusted HRs for uterine fibroid were 0.73 (95% confidence interval [CI] 0.63-0.85) and 0.65 (95% CI 0.52-0.82) in women using CHPs and the phytoestrogen, respectively.CHPs seem to contribute to a decreased risk in developing uterine fibroids. Although the mechanism of action of these products is unclear, their use as a preventive agent for uterine fibroids might be taken into consideration.

Chinese herbal products and the reduction of risk of breast cancer among females with type 2 diabetes in Taiwan: A case-control study

Women with type 2 diabetes have a higher risk of developing breast cancer. In Taiwan, traditional Chinese medicine is widely used to treat diabetes; however, its precise influence has not been empirically tested.The objective of the case-control study is to estimate the effect on the risk of breast cancer of using traditional Chinese medicine for women with type 2 diabetes.More than 80% of women with type 2 diabetes have used traditional Chinese medicine. The most commonly prescribed drug was metformin and the herbal formulas were the Di Huang Wan series, including Liu Wei Di Huang Wan, Qi Ju Di Huang Wan, and Zhi Bai Di Huang Wan, followed by Bai Hu Jia Ren Shen Tang and Yu Quan Wan. For the effect of metformin, women who used traditional Chinese medicine including Di Huang series have a lower risk of breast cancer HR: 0.35 (95%CI: 0.23-0.51) in women younger than 55 and HR: 0.54 (95%CI: 0.37-0.79) in women older than 55.The protective effect of the Di Huang Wan series may be due to the synergetic effect of reducing blood glucose or increasing insulin sensitivity and delaying the insulin resistance of cells. The relationship between the Di Huang Wan series and breast cancer of women with type 2 diabetes requires further investigation.

The sociocultural effects on orthopedic surgeries in Taiwan

Various sociocultural factors affect healthcare-seeking behaviors. In Taiwanese society, superstitions and lunar festivals play important roles in people’s lives. We investigated the impact of “Ghost Month” (the 7^th lunar month) and Chinese New Year (the 12^th lunar month and the 1^st lunar month of the following year) on the number of elective surgeries and emergent surgeries in Taiwan. The number of total knee replacement (TKR) surgeries and proximal femur fracture (PFF) surgeries in each lunar month from 2000 to 2011 were extracted from the Taiwan National Health Insurance Database, a computerized and population-based database. Patients were then sorted by location of residence or gender. The average number of TKR surgeries performed was significantly lower during the 1^st, 7^th, and 12^th lunar months in urban areas, whereas in rural areas this trend was only evident in the 7^th and 12^th lunar months. There was however, no significant difference in the average number of PFF surgeries in each lunar month except for an increase seen in the 1^st lunar month in rural patients (p<0.05). When sorted by gender, the average number of TKR surgeries was significantly decreased in the 7^th and 12^th lunar months in male patients, and decreased in the 1^st, 7^th, and 12^th lunar months in female patients. In contrast, there was no difference in the average numbers of PFF surgeries in the 7^th and 12^th lunar months either in male or female patients. We proposed that the timing of elective surgeries such as TKR might be influenced by Ghost Month and Chinese New Year; however, emergent PFF surgeries were not significantly influenced by sociocultural beliefs and taboos in Taiwan.

Prescription of Chinese herbal products is associated with a decreased risk of invasive breast cancer

The finding of a decrease in endometrial cancer incidence among breast cancer survivors following the use of Chinese herbal products (CHPs) has led to speculation that CHPs might play a role in breast cancer prevention.This study provides an overview of breast cancer incidence, comparing CHP users with those who do not use traditional Chinese medicine (TCM), referred to as non-TCM users. The results can provide information to clinicians for counseling women about the preventive use of TCM.A total of 184,386 women (20-79 years of age) were recruited from a nationwide 1-million-person representative sample of those covered by National Health Insurance in Taiwan and were followed from 1999 to 2012. A total of 1853 incidents of invasive breast cancer were diagnosed. The person-year approach with the Poisson assumption was used to estimate the incidence density rate. The age-specific hazard ratios of breast cancer in relation to either CHP or siwutang (SWT) use were calculated with multivariate Cox proportional hazard regression.More than 78% of patients had used a CHP at some point previously. The overall incidence density rate of breast cancer for non-TCM users was estimated at 1.73 per 10,000 patient-years. The corresponding values for CHP and SWT users were lower than those of the non-TCM group (CHP group = 0.85; SWT group = 0.63 per 10,000 patient-years). The covariate adjusted HRs for breast cancer were 0.57 (95% confidence interval [CI] 0.50-0.65) and 0.36 (95% CI 0.28-0.46) in women using CHPs and SWT, respectively. The findings were confirmed using propensity score matching.Consumption of CHPs reduces the incidence of invasive breast cancer. Although the mechanism of action of these products is unclear, their use as a preventive agent for breast cancer is appropriate for many women at an increased risk of breast cancer.

Change in risk of breast cancer after receiving hormone replacement therapy by considering effect-modifiers: a systematic review and dose-response meta-analysis of prospective studies

We synthesize the current literatures and use the power of meta-analysis to examine trends on association between hormone replacement therapy (HRT) and the risk of breast cancer (BC). We performed a comprehensive literature search using PubMed, EMBASE, and Web of Science from their inception until Jan 2017. Prospective studies that provided adjusted risk estimates of HRT and BC risk were eligible. Categorical and dose-response meta-analyses followed the PRISMA were conducted using random effects model and restricted cubic spline model, respectively. Forty-seven publications from thirty-five unique studies were included, involving 3,898,376 of participants and 87,845 of BC cases. Compared with non-users, RR for current estrogen-only therapy (ET) users was 1.14 (95% confidence interval (CI) = 1.05–1.22), and for per year increases was 1.02 (95% CI = 1.02–1.02). Moreover, RR for current estrogen plus progestin therapy (EPT) users was 1.76, (95% CI = 1.56–1.96), and for per year increases was 1.08 (95% CI = 1.08–1.08). Dose-response analyses revealed 8–10 years’ onset peaks, and indicated residual increased BC risk remained after stopping use of ET regimen rather than for EPT. Effect-modifiers like BMI, duration of use, race/ethnicity, routes of administration were recognized. In Conclusions, current use of EP or EPT and ever use of tibolone are associated with an elevated risk of BC. Compared with slim HRT users and non-users, lower BC risks were found among overweight/obese HRT users and former EPT users, respectively. Both ET and EPT users are associated with higher risk of lobular BC than ductal BC, and more ER-positive than negative BC cases were detected among EPT users.

Estetrol is a weak estrogen antagonizing estradiol-dependent mammary gland proliferation

Estetrol (E4) is a natural estrogen produced exclusively by the human fetal liver during pregnancy. Its physiological activity remains unknown. In contrast to ethinyl estradiol and estradiol (E2), E4 has a minimal impact on liver cell activity and could provide a better safety profile in contraception or hormone therapy. The aim of this study was to delineate if E4 exhibits an activity profile distinct from that of E2 on mammary gland. Compared with E2, E4 acted as a low-affinity estrogen in both human in vitro and murine in vivo models. E4 was 100 times less potent than E2 to stimulate the proliferation of human breast epithelial (HBE) cells and murine mammary gland in vitro and in vivo respectively. This effect was prevented by fulvestrant and tamoxifen, supporting the notion that ERα (ESR1) is the main mediator of the estrogenic effect of E4 on the breast. Interestingly, when E4 was administered along with E2, it significantly antagonized the strong stimulatory effect of E2 on HBE cell proliferation and on the growth of mammary ducts. This study characterizes for the first time the impact of E4 on mammary gland. Our results highlight that E4 is less potent than E2 and exhibits antagonistic properties toward the proliferative effect of E2 on breast epithelial cells. These data support E4 as a potential new estrogen for clinical use with a reduced impact on breast proliferation.

Concurrent Use in Taiwan of Chinese Herbal Medicine Therapies among Hormone Users Aged 55 Years to 79 Years and Its Association with Breast Cancer Risk: A Population-Based Study

Background. The purpose of the present study was to analyze the concurrent use of Chinese herbal products (CHPs) among women aged 55 to 79 years who had also been prescribed hormonal therapies (HT) and its association with breast cancer risk. Methods. The use, frequency of service, and CHP prescribed among 17,583 HT users were evaluated from a random sample of 1 million beneficiaries from the National Health Insurance Research Database. A logistic regression method was used to identify the factors that were associated with the coprescription of a CHP and HT. Cox proportional hazards regressions were performed to calculate the hazard ratios (HRs) of breast cancer between the TCM nonusers and women who had undergone coadministration of HT and a CHP or CHPs. Results. More than one out of every five study subjects used a CHP concurrently with HT (CHTCHP patients). Shu-Jing-Huo-Xie-Tang was the most commonly used CHP coadministered with HT. In comparison to HT-alone users, the HRs for invasive breast cancer among CHTCHP patients were not significantly increased either in E-alone group or in mixed regimen group. Conclusions. The coadministration of hormone regimen and CHPs did not increase the risk of breast cancer.

CYP2W1, CYP4F11 and CYP8A1 polymorphisms and interaction of CYP2W1 genotypes with risk factors in Mexican women with breast cancer

Breast cancer (BCa) is the leading type of cancer in Mexican women. Genetic factors, such as single nucleotide polymorphisms (SNP) of P450 system, have been reported in BCa. In this report, and for the first time in the literature, we analyzed the rs3735684 (7021 G>A), rs11553651 (15016 G>T) and rs56195291 (60020 C>G) polymorphisms in the CYP2W1, 4F11 and 8A1 genes in patients with BCa and in healthy Mexican women to identify a potential association between these polymorphisms and BCa risk. Patients and controls were used for polymorphism analysis using an allelic discrimination assay with TaqMan probes and confirmed by DNA sequencing. Links with clinic-pathological characteristics were also analyzed. Statistical analysis was performed using the standard χ2 or Fisher exact test statistic. No significant differences were observed in the distributions of CYP2W1 (OR 8.6, 95%CI 0.43-172.5 P>0.05; OR 2.0, 95%CI 0.76-5.4, P>0.05) and CYP4F11 (OR 0.3, 95%CI 0.01-8.4 P>0.05) genotypes between the patients and controls. Only the CYP8A1 CC genotype was detected in patients with BCa and the controls. All polymorphism frequencies were in Hardy-Weinberg Equilibrium (HWE) in the controls (P>0.05). We found a significant association between BCa risk and smoking, use of oral contraceptives or hormonal replacement therapy (HRT), obesity, hyperglycemia, chronic diseases, family history of cancer and menopausal status in the population studied (P<0.05). Tobacco, oral contraceptive or HRT, chronic diseases and obesity or overweight were strongly associated with almost eight, thirty-five, nine and five-fold increased risk for BCa. Tobaco, obesity and hyperglycemia significantly increased the risk of BCa in the patients carrying variant genotypes of CYP2W1 (P<0.05). These results indicate that the CYP2W1 rs3735684, CYP4F11 rs11553651 and CYP8A1 rs56195291 SNPs are not a key risk factor for BCa in Mexican women. This study did not detect an association between the CYP2W1, 4F11 and 8A1 genes polymorphisms and BCa risk in a Mexican population. However, some clinico-pathological risk factors interact with CYP2W1 genotypes and modifies susceptibility to BCa.

Higher parity and earlier age at first birth are associated with lower risk of death from colon cancer

This study was undertaken to examine whether there is an association between parity and age at first birth and risk of colon cancer. The study cohort consisted of 1,292,462 women who had a first and singleton childbirth between 1978 and 1987. We tracked each woman from the time of their first childbirth to December 31, 2009, and their vital status was ascertained by linking records with the computerized mortality database. We used the Cox proportional hazards model with time-dependent covariates to estimate the hazard ratios (HR) of death from colon cancer associated with parity and age at first birth. We limited eligible colon cancer deaths to those who were 45 years old or more to exclude possible heredity colon cancer cases, which usually occur at an early age. There were 670 colon cancer deaths during 34,980,246 person-years of follow-up. The colon cancer death rate was 1.96 cases per 100,000 person-years. The adjusted HR was 2.76 (95% CI = 1.60-4.75) for women who gave birth between 20 and 24 years and 7.35 (95% CI = 4.28-12.62) for women who gave birth after 24 years of age when compared with women who gave birth at younger than 20 years. A rising risk of colon cancer was seen with increasing age at first birth. The adjusted HR were 0.81 (95% CI = 0.65-1.02) among women with two live births, 0.93 (95% CI = 0.74-1.18) among women with three live births and 0.72 (95% CI = 0.51-1.00) for women with four or more births when compared with women who had given birth to only one child. The present study provides evidence that reproductive factors (parity and early age at first birth) may confer a protective effect on the risk of colon cancer.

Exposure to ionizing radiation causes long-term increase in serum estradiol and activation of PI3K-Akt signaling pathway in mouse mammary gland

PURPOSE

Exposure to ionizing radiation is an established risk factor for breast cancer. Radiation exposure during infancy, childhood, and adolescence confers the highest risk. Although radiation is a proven mammary carcinogen, it remains unclear where it acts in the complex multistage process of breast cancer development. In this study, we investigated the long-term pathophysiologic effects of ionizing radiation at a dose (2 Gy) relevant to fractionated radiotherapy.

METHODS AND MATERIALS

Adolescent (6-8 weeks old; n = 10) female C57BL/6J mice were exposed to 2 Gy total body γ-radiation, the mammary glands were surgically removed, and serum and urine samples were collected 2 and 12 months after exposure. Molecular pathways involving estrogen receptor-α (ERα) and phosphatidylinositol-3-OH kinase (PI3K)-Akt signaling were investigated by immunohistochemistry and Western blot.

RESULTS

Serum estrogen and urinary levels of the oncogenic estrogen metabolite (16αOHE1) were significantly increased in irradiated animals. Immunostaining for the cellular proliferative marker Ki-67 and cyclin-D1 showed increased nuclear accumulation in sections of mammary glands from irradiated vs. control mice. Marked increase in p85α, a regulatory sub-unit of the PI3K was associated with increase in Akt, phospho-Akt, phospho-BAD, phospho-mTOR, and c-Myc in irradiated samples. Persistent increase in nuclear ERα in mammary tissues 2 and 12 months after radiation exposure was also observed.

CONCLUSIONS

Taken together, our data not only support epidemiologic observations associating radiation and breast cancer but also, specify molecular events that could be involved in radiation-induced breast cancer.

Diabetic patients with severe sepsis admitted to intensive care unit do not fare worse than non-diabetic patients: a nationwide population-based cohort study

BACKGROUND

We sought to examine whether type 2 diabetes increases the risk of acute organ dysfunction and of hospital mortality following severe sepsis that requires admission to an intensive care unit (ICU).

METHODS

Nationwide population-based retrospective cohort study of 16,497 subjects with severe sepsis who had been admitted for the first time to an ICU during the period of 1998-2008. A diabetic cohort (n = 4573) and a non-diabetic cohort (n = 11924) were then created. Relative risk (RR) of organ dysfunctions, length of hospital stay (LOS), 90-days hospital mortality, ICU resource utilization and hazard ratio (HR) of mortality adjusted for age, gender, Charlson-Deyo comorbidity index score, surgical condition and number of acute organ dysfunction, were compared across patients with severe sepsis with or without diabetes.

RESULTS

Diabetic patients with sepsis had a higher risk of developing acute kidney injury (RR, 1.54; 95% confidence interval (CI), 1.44-1.63) and were more likely to be undergoing hemodialysis (15.55% vs. 7.24%) in the ICU. However, the diabetic cohort had a lower risk of developing acute respiratory dysfunction (RR = 0.96, 0.94-0.97), hematological dysfunction (RR = 0.70, 0.56-0.89), and hepatic dysfunction (RR = 0.77, 0.63-0.93). In terms of adjusted HR for 90-days hospital mortality, the diabetic patients with severe sepsis did not fare significantly worse when afflicted with cardiovascular, respiratory, hepatic, renal and/or neurologic organ dysfunction and by numbers of organ dysfunction. There was no statistically significant difference in LOS between the two cohorts (median 17 vs. 16 days, interquartile range (IQR) 8-30 days, p = 0.11). Multiple logistic regression analysis to predict the occurrence of mortality shows that being diabetic was not a predictive factor with an odds ratio of 0.972, 95% CI 0.890-1.061, p = 0.5203.

INTERPRETATION

This large nationwide population-based cohort study suggests that diabetic patients do not fare worse than non-diabetic patients when suffering from severe sepsis that requires ICU admission.