Reproductive and hormonal risk factors for ductal carcinoma in situ of the breast

Investigating the trends of incidence rates of breast cancer in Southern Iran: a population based survey

BACKGROUND

The overall incidence of breast cancer is different all over the world and even within a nation. The present study aims to investigate the stratum-specific incidence trends of breast cancer in southern Iran.

METHODS

In this retrospective cohort study, the data of Fars Population-Based Cancer Registry was used during 2001-2018. New cancer cases with ICD-O-3 codes C50.0 to C50.9 were categorized based on age group, morphology, and topography. Age-specific incidence rates of breast cancer were calculated during 2001-2018. Annual overall and truncated age-standardized incidence rates and their 95% Confidence Intervals (CIs) were also calculated. Afterward, the Annual Percentage Changes (APCs) of the age-specific and age-standardized incidence rates of breast cancer during 2001-2018 were calculated using Joinpoint regression software.

RESULTS

An increasing trend was observed in the incidence of breast cancer among women during 2001-2018 (APC of age-standardized incidence rates: 9.5 (95% CI: 7.5, 11.5)).However, the trend was increasing less during the recent years. The APC of age-standardized rates decreased from 15.03 (95% CI: 10.4, 19.8) in 2007 to 6.15(95% CI: 4.0, 8.4) in 2018. The most common morphology of breast cancer was invasive ductal carcinoma (77.3% in females and 75.1% in males) and its trend was similar to the general trend of different types of breast cancer. The most common site of breast cancer was the upper outer quadrant. Most breast cancer cases were female and males accounted for 2.45% of the cases. Among females, 40-55 was the most prevalent age group.

CONCLUSION

The incidence of breast cancer among women living in southern Iran showed an increasing trend from 2001 to 2018. However, the rate of increase exhibited a milder slope during the more recent years. Based on the higher prevalence of breast cancer in the 40-55 age group observed in the present study, it offers valuable insight into the potential reduction of the breast cancer screening age from 50 to 40 years for healthy Iranian women. However, before implementing such a policy change, it is crucial to conduct additional studies that specifically examine the cost-effectiveness, as well as the potential benefits and risks associated with this alteration.

DCIS and LCIS: Are the Risk Factors for Developing In Situ Breast Cancer Different?

Ductal carcinoma in situ (DCIS) is widely accepted as a precursor of invasive ductal carcinoma (IDC). Lobular carcinoma in situ (LCIS) is considered a risk factor for invasive lobular carcinoma (ILC), and it is unclear whether LCIS is also a precursor. Therefore, it would be expected that similar risk factors predispose to both DCIS and IDC, but not necessarily LCIS and ILC. This study examined associations with risk factors using data from 3075 DCIS cases, 338 LCIS cases, and 1584 controls aged 35-60, recruited from the UK-based GLACIER and ICICLE case-control studies between 2007 and 2012. Analysis showed that breastfeeding in parous women was protective against DCIS and LCIS, which is consistent with research on invasive breast cancer (IBC). Additionally, long-term use of HRT in post-menopausal women increased the risk of DCIS and LCIS, with a stronger association in LCIS, similar to the association with ILC. Contrary to findings with IBC, parity and the number of births were not protective against DCIS or LCIS, while oral contraceptives showed an unexpected protective effect. These findings suggest both similarities and differences in risk factors for DCIS and LCIS compared to IBC and that there may be justification for increased breast surveillance in post-menopausal women taking long-term HRT.

Distinct Reproductive Risk Profiles for Intrinsic-Like Breast Cancer Subtypes: Pooled Analysis of Population-Based Studies

BACKGROUND

Reproductive factors have been shown to be differentially associated with risk of estrogen receptor (ER)-positive and ER-negative breast cancer. However, their associations with intrinsic-like subtypes are less clear.

METHODS

Analyses included up to 23 353 cases and 71 072 controls pooled from 31 population-based case-control or cohort studies in the Breast Cancer Association Consortium across 16 countries on 4 continents. Polytomous logistic regression was used to estimate the association between reproductive factors and risk of breast cancer by intrinsic-like subtypes (luminal A-like, luminal B-like, luminal B-HER2-like, HER2-enriched-like, and triple-negative breast cancer) and by invasiveness. All statistical tests were 2-sided.

RESULTS

Compared with nulliparous women, parous women had a lower risk of luminal A-like, luminal B-like, luminal B-HER2-like, and HER2-enriched-like disease. This association was apparent only after approximately 10 years since last birth and became stronger with increasing time (odds ratio [OR] = 0.59, 95% confidence interval [CI] = 0.49 to 0.71; and OR = 0.36, 95% CI = 0.28 to 0.46 for multiparous women with luminal A-like tumors 20 to less than 25 years after last birth and 45 to less than 50 years after last birth, respectively). In contrast, parous women had a higher risk of triple-negative breast cancer right after their last birth (for multiparous women: OR = 3.12, 95% CI = 2.02 to 4.83) that was attenuated with time but persisted for decades (OR = 1.03, 95% CI = 0.79 to 1.34, for multiparous women 25 to less than 30 years after last birth). Older age at first birth (Pheterogeneity < .001 for triple-negative compared with luminal A-like breast cancer) and breastfeeding (Pheterogeneity < .001 for triple-negative compared with luminal A-like breast cancer) were associated with lower risk of triple-negative breast cancer but not with other disease subtypes. Younger age at menarche was associated with higher risk of all subtypes; older age at menopause was associated with higher risk of luminal A-like but not triple-negative breast cancer. Associations for in situ tumors were similar to luminal A-like.

CONCLUSIONS

This large and comprehensive study demonstrates a distinct reproductive risk factor profile for triple-negative breast cancer compared with other subtypes, with implications for the understanding of disease etiology and risk prediction.

Obesity and breast cancer risk for pre- and postmenopausal women among over 6 million Korean women

PURPOSE

To examine the association between obesity measured by body mass index (BMI) and waist circumference (WC) according to menopausal status in Korean women.

METHODS

We identified 6,467,388 women, using the Korean National Health Insurance System Cohort. Cox-proportional hazard models were used to generate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for breast cancer risk in relation to BMI and WC.

RESULTS

In postmenopausal women, the risk of breast cancer increased with BMI. Compared to women with a BMI of 18.5-23 kg/m two, the risk of invasive breast cancer was lower in patients with BMI < 18.5 (aHR 0.82, 95% CI 0.75-0.89), while it increased linearly in those with BMI 23-25 (1.11, 1.08-1.14), BMI 25-30 (1.28, 1.25-1.32), and BMI ≥ 30 (1.54,1.47-1.62). In contrast, the risk of breast cancer decreased with BMI in premenopausal women. Compared to women with a BMI of 18.5-23, the risk of IBC was similar in those with a BMI < 18.5 (1.02, 0.94-1.11) and BMI 23-25 (1.01, 0.97-1.05), but was significantly lower in those with a BMI 25-30 (0.95, 0.91-0.98) and BMI ≥ 30 (0.90, 0.82-0.98). A relative increase with BMI was less profound for carcinoma in situ in postmenopausal women, and a relative decrease was more profound in premenopausal women. An analysis using WC showed almost identical results.

CONCLUSIONS

There was a positive relationship between obesity and breast cancer in postmenopausal women, and an inverse association in premenopausal women.

Integrating biology and access to care in addressing breast cancer disparities: 25 years' research experience in the Carolina Breast Cancer Study

Purpose of Review

To review research on breast cancer mortality disparities, emphasizing research conducted in the Carolina Breast Cancer Study, with a focus on challenges and opportunities for integration of tumor biology and access characteristics across the cancer care continuum.

Recent Findings

Black women experience higher mortality following breast cancer diagnosis, despite lower incidence compared to white women. Biological factors, such as stage at diagnosis and breast cancer subtypes, play a role in these disparities. Simultaneously, social, behavioral, environmental, and access to care factors are important. However, integrated studies of biology and access are challenging and it is uncommon to have both data types available in the same study population. The central emphasis of Phase 3 of the Carolina Breast Cancer Study, initiated in 2008, was to collect rich data on biology (including germline and tumor genomics and pathology) and health care access in a diverse study population, with the long term goal of defining intervention opportunities to reduce disparities across the cancer care continuum.

Summary

Early and ongoing research from CBCS has identified important interactions between biology and access, leading to opportunities to build greater equity. However, sample size, population-specific relationships among variables, and complexities of treatment paths along the care continuum pose important research challenges. Interdisciplinary teams, including experts in novel data integration and causal inference, are needed to address gaps in our understanding of breast cancer disparities.

The impact of ductal carcinoma in situ on health services utilization

PURPOSE

To determine the intermediate-term impact of diagnosis and treatment of ductal carcinoma in situ of the breast (DCIS) on health services utilization, we compared utilization by cases of DCIS to unaffected controls.

METHODS

We identified a population-based cohort of Ontario females diagnosed with DCIS between 2010 and 2015. We matched 5 controls without any history of cancer to each case, on the date of diagnosis of the case (the index date), by age, annual mammography history, socioeconomic status, and comorbidity. We identified billing claims and hospital records, during the interval 13 to 60 months prior to, and subsequent to the index date, and computed rates per 100 person-years during both intervals, to conduct a difference-in-differences analysis. We used negative binomial regression to test if the change in rates in health services differed between cases and controls.

RESULTS

Visits with a breast diagnosis code, and claims for breast surgery and imaging, were significantly increased among cases compared to controls (all p values < 0.0001) after DCIS;however, there was no increase in visits for anxiety or depression (RR 1.13 (95% CI 0.97, 1.32, p = 0.11), visits to psychiatrists (RR 1.07 (95% CI 0.82, 1.40) p = 0.6), or hospital procedures other than breast surgery (RR 1.10 (95% CI 0.88, 1.37) p = 0.4).

CONCLUSIONS

DCIS is associated with more visits and procedures related to the breast compared to controls following diagnosis and treatment, but other health services utilization and visits related to anxiety and depression were not increased.

Risk factors for estrogen receptor positive ductal carcinoma in situ of the breast in African American women

BACKGROUND

Compared to U.S. white women, African American women are more likely to die from ductal carcinoma in situ (DCIS). Elucidation of risk factors for DCIS in African American women may provide opportunities for risk reduction.

METHODS

We used data from three epidemiologic studies in the African American Breast Cancer Epidemiology and Risk Consortium to study risk factors for estrogen receptor (ER) positive DCIS (488 cases; 13,830 controls). Results were compared to associations observed for ER+ invasive breast cancer (n = 2,099).

RESULTS

First degree family history of breast cancer was associated with increased risk of ER+ DCIS [odds ratio (OR): 1.69, 95% confidence interval (CI): 1.31, 2.17]. Oral contraceptive use within the past 10 years (vs. never) was also associated with increased risk (OR: 1.43, 95%CI: 1.03, 1.97), as was late age at first birth (≥25 years vs. <20 years) (OR: 1.26, 95%CI: 0.96, 1.67). Risk was reduced in women with older age at menarche (≥15 years vs. <11 years) (OR: 0.62, 95%CI: 0.42, 0.93) and higher body mass index (BMI) in early adulthood (≥25 vs. <20 kg/m2 at age 18 or 21) (OR: 0.75, 95%CI: 0.55, 1.01). There was a positive association of recent BMI with risk in postmenopausal women only. In general, associations of risk factors for ER+ DCIS were similar in magnitude and direction to those for invasive ER+ breast cancer.

CONCLUSIONS

Our findings suggest that most risk factors for invasive ER+ breast cancer are also associated with increased risk of ER+ DCIS among African American women.

Risk factors for ductal carcinoma in situ of the breast in the UK Biobank cohort study

Ductal carcinoma in situ of the breast (DCIS) is considered to be a non-obligate precursor of invasive breast cancer (IBC). This suggests that risk factors for DCIS should be a subset of those for IBC. To this end, we investigated whether demographic, lifestyle, and reproductive factors that have been linked to IBC risk are also associated with DCIS risk. This study was conducted in 263,788 women aged 40-69 years at enrolment into the UK Biobank population-based cohort. Information on demographic, reproductive and health factors was collected at baseline using computerized questionnaires, while incident DCIS was ascertained through linkage to UK cancer registries. Age-adjusted and multivariable hazard ratios were estimated using Cox proportional hazards models in the total sample and by menopausal status. During an average of 7 years of follow-up, 1,016 women developed DCIS. Multivariable analysis indicated that age, physical activity, height, family history of breast cancer, menopausal status, parity, and years between menarche and first live birth had associations with DCIS risk. Among post-menopausal women not using hormone replacement therapy, body mass index ≥30 kg/m² was associated with increased DCIS risk. This study, the largest to date including both pre-menopausal and post-menopausal women, confirms previous findings indicating correspondence between risk factors for DCIS and IBC and highlights the potential contribution to DCIS risk of anthropometric measures not previously reported to be associated with the disease, such as height and BMI amongst post-menopausal women.

Epidemiologic risk factors for in situ and invasive ductal breast cancer among regularly screened postmenopausal women by grade in the Cancer Prevention Study-II Nutrition Cohort

PURPOSE

Histopathologic grade provides an integrated measure of biologic features which affects cancer prognosis. In invasive ductal breast cancer (IDBC), the grade of the ductal carcinoma in situ (DCIS) and invasive components are usually concordant, suggesting grade is established early in tumorigenesis and may be linked to etiologic factors. In this study, we used prospectively collected data from postmenopausal women in the Cancer Prevention Study-II (CPS-II) Nutrition Cohort to compare risk factor associations among low-grade and high-grade DCIS, as well as low-grade and high-grade IDBC.

METHODS

Among 73,825 cancer-free women at enrollment in the CPS-II Nutrition Cohort in 1992-1993 (mean age: 62.1 years), we verified 802 diagnosed with DCIS (C50 8500/2; n = 430 low-grade and 372 high-grade) and 3,125 with IDBC (C50 8500/3; n = 2,221 low-grade and 904 high-grade) through June 2013. Person-time contribution was conditional on screening mammograms self-reported on biennial surveys. Multivariable-adjusted joint Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

A personal history of benign breast disease was more strongly associated with higher risk of low-grade DCIS (HR = 2.20, 95% CI 1.81-2.67; p for heterogeneity = 0.0004) than high-grade DCIS. Consumption of two or more alcoholic drinks/day was only associated with a higher risk of low-grade IDBC (HR = 1.58, 95% CI 1.33-1.88; p for heterogeneity = 0.005).

CONCLUSIONS

These results suggest heterogeneity by grade for breast cancer etiology. Identification of potential risk factor differences among low-grade and high-grade DCIS and IDBC may help to clarify associations, and ultimately, improve breast cancer risk prediction models.

Risk factors for Luminal A ductal carcinoma in situ (DCIS) and invasive breast cancer in the Carolina Breast Cancer Study

Purpose

Invasive breast cancers are thought to arise from in situ lesions, but some ductal carcinoma in situ (DCIS) are indolent with low likelihood of progressing to invasive carcinoma. Comparison of risk factor associations between DCIS and invasive disease may elucidate which factors influence early versus late stages of carcinogenesis. Therefore, we determined whether there were differences in risk factor profiles for screen-detected DCIS and invasive breast cancer among Luminal A lesions.

Methods

We conducted a case-control analysis using data from the Carolina Breast Cancer Study (1993–2001). Analyses were restricted to Luminal A tumors and screen-detected tumors among mammography-eligible women, to limit confounding by mode of detection (N = 108 DCIS; N = 203 invasive). Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between risk factors and lesion type.

Results

In stratified analyses, we observed qualitative differences in the direction of association for ever smoking, obese BMI, high waist-to-hip-ratio (WHR), and ≥10 years of oral contraceptive use between DCIS and invasive disease. Breastfeeding was inversely associated with invasive disease and was not associated with DCIS. Interaction tests for risk factor associations between Luminal A DCIS and invasive breast cancer were not statistically significant (p>0.05).

Conclusions

Among Luminal A tumors, established breast cancer risk factors may exert stronger effects on progression of early lesions to invasive disease, with lesser effects on risk of DCIS.

Epidemiologic Risk Factors for In Situ and Invasive Breast Cancers Among Postmenopausal Women in the National Institutes of Health-AARP Diet and Health Study

Comparing risk factor associations between invasive breast cancers and possible precursors may further our understanding of factors related to initiation versus progression. Accordingly, among 190,325 postmenopausal participants in the National Institutes of Health-AARP Diet and Health Study (1995-2011), we compared the association between risk factors and incident ductal carcinoma in situ (DCIS; n = 1,453) with that of risk factors and invasive ductal carcinomas (n = 7,525); in addition, we compared the association between risk factors and lobular carcinoma in situ (LCIS; n = 186) with that of risk factors and invasive lobular carcinomas (n = 1,191). Hazard ratios and 95% confidence intervals were estimated from multivariable Cox proportional hazards regression models. We used case-only multivariable logistic regression to test for heterogeneity in associations. Younger age at menopause was associated with a higher risk of DCIS but lower risks of LCIS and invasive ductal carcinomas (P for heterogeneity < 0.01). Prior breast biopsy was more strongly associated with the risk of LCIS than the risk of DCIS (P for heterogeneity = 0.04). Increased risks associated with use of menopausal hormone therapy were stronger for LCIS than DCIS (P for heterogeneity = 0.03) and invasive lobular carcinomas (P for heterogeneity < 0.01). Associations were similar for race, age at menarche, age at first birth, family history, alcohol consumption, and smoking status, which suggests that most risk factor associations are similar for in situ and invasive cancers and may influence early stages of tumorigenesis. The differential associations observed for various factors may provide important clues for understanding the etiology of certain breast cancers.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

Breastfeeding Mode and Risk of Breast Cancer: A Dose-Response Meta-Analysis

BACKGROUND

Breastfeeding reduces women's risk of breast cancer. Since exclusive breastfeeding has a stronger hormonal effect, it could theoretically result in a greater reduction in breast cancer risk than any breastfeeding mode. No meta-analysis has examined breast cancer risk by breastfeeding mode. Research aim: The authors conducted a meta-analysis for breast cancer risk in parous women who breastfed exclusively or in any mode versus parous women who formula fed their infants, and they estimated the summary dose-response association by the accumulated duration of any breastfeeding mode.

METHODS

A systematic review of studies published between 2005 and 2015 analyzing breastfeeding and breast cancer risk in women was conducted in PubMed and EBSCOhost. A meta-analysis ( n = 65 studies) with fixed effects (or random effects, if heterogeneity existed) was carried out stratified by breastfeeding mode and menopausal and parity status. A summary dose-response association was estimated using the generalized least-squares method.

RESULTS

The summary relative risk (SRR) for breast cancer in parous women who breastfed exclusively was 0.72, 95% confidence interval (CI) [0.58, 0.90], versus parous women who had never breastfed. For parous women who breastfed in any mode, the SRR was lower in both premenopausal women (0.86, 95% CI [0.80, 0.93]) and postmenopausal women (0.89, 95% CI [0.83, 0.95]). There was no heterogeneity or publication bias. There is weak evidence of a difference between exclusive and any breastfeeding mode ( p = .08). The summary dose-response curve was nonlinear ( p < .001).

CONCLUSION

Exclusive breastfeeding among parous women reduces the risk of breast cancer compared with parous women who do not breastfeed exclusively.

Risk factors for young-onset invasive and in situ breast cancer

PURPOSE

Young-onset breast cancers tend to be more aggressive than later-onset tumors and may have different risk factor profiles. Among young-onset cases, there may also be etiologic differences between ductal carcinomas in situ (DCIS) and invasive breast cancer, particularly if some factors promote malignant transformation.

METHODS

We evaluated the association between several potential risk factors and young-onset breast cancer in the Two Sister Study (2008-2010), a sister-matched case-control study involving 1,406 women diagnosed with breast cancer before age 50 (1,185 invasive, 221 DCIS) and 1,648 controls.

RESULTS

Older age at menarche, younger age at menopause, premenopausal hysterectomy, early age at first-term pregnancy, obesity, and consumption of alcohol were associated with reduced risk of young-onset breast cancer. These patterns remained when we limited analysis to invasive breast cancers. In general, effect estimates were similar for young-onset invasive breast cancer and DCIS, although the number of DCIS cases was small.

CONCLUSIONS

In this sister-matched case-control study of young-onset breast cancer, many of the studied risk factors were associated with young-onset invasive breast cancer. There were few discernable differences in risk factors for young-onset DCIS versus young-onset invasive breast cancer.

Breast cancer subtypes and previously established genetic risk factors: a bayesian approach

BACKGROUND

Gene expression analyses indicate that breast cancer is a heterogeneous disease with at least five immunohistologic subtypes. Despite growing evidence that these subtypes are etiologically and prognostically distinct, few studies have investigated whether they have divergent genetic risk factors. To help fill in this gap in our understanding, we examined associations between breast cancer subtypes and previously established susceptibility loci among white and African-American women in the Carolina Breast Cancer Study.

METHODS

We used Bayesian polytomous logistic regression to estimate ORs and 95% posterior intervals for the association between each of 78 single nucleotide polymorphisms (SNP) and five breast cancer subtypes. Subtypes were defined using five immunohistochemical markers: estrogen receptors (ER), progesterone receptors (PR), human epidermal growth factor receptors 1 and 2 (HER1/2), and cytokeratin (CK) 5/6.

RESULTS

Several SNPs in TNRC9/TOX3 were associated with luminal A (ER/PR+, HER2-) or basal-like breast cancer (ER-, PR-, HER2-, HER1, or CK 5/6+), and one SNP (rs3104746) was associated with both. SNPs in FGFR2 were associated with luminal A, luminal B (ER/PR+, HER2+), or HER2+/ER- disease, but none were associated with basal-like disease. We also observed subtype differences in the effects of SNPs in 2q35, 4p, TLR1, MAP3K1, ESR1, CDKN2A/B, ANKRD16, and ZM1Z1.

CONCLUSION AND IMPACT

We found evidence that genetic risk factors for breast cancer vary by subtype and further clarified the role of several key susceptibility genes. .

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.

Risk factors of breast cancer: a systematic review and meta-analysis

The etiology of breast cancer might be explained by 2 mechanisms, namely, differentiation and proliferation of breast epithelial cells mediated by hormonal factors. We performed a systematic review and meta-analysis to update effects of risk factors for both mechanisms. MEDLINE and EMBASE were searched up to January 2011. Studies that assessed association between oral contraceptives (OC), hormonal replacement therapy (HRT), diabetes mellitus (DM), or breastfeeding and breast cancer were eligible. Relative risks with their confidence intervals (CIs) were extracted. A random-effects method was applied for pooling the effect size. The pooled odds ratios of OC, HRT, and DM were 1.10 (95% CI = 1.03-1.18), 1.23 (95% CI = 1.21-1.25), and 1.14 (95% CI = 1.09-1.19), respectively, whereas the pooled odds ratio of ever-breastfeeding was 0.72 (95% CI = 0.58-0.89). Our study suggests that OC, HRT, and DM might increase risks, whereas breastfeeding might lower risks of breast cancer.

Effects of menopausal hormone therapy on ductal carcinoma in situ of the breast

Post-menopausal hormone therapy with estrogen plus progestin is consistently reported to be associated with an increased risk of invasive breast cancer. However, findings on an association between hormone use and ductal carcinoma in situ of the breast (DCIS), a possible precursor lesion of invasive breast cancer, are sparse and inconsistent. Women's Health Initiative data were used to assess the effects of hormone therapy on the risk of DCIS in two clinical trials of hormone therapy (16,276 women enrolled in the trial of daily conjugated equine estrogens plus medroxyprogesterone acetate (CEE + MPA) vs placebo; 10,187 women enrolled in the trial of CEE-alone vs placebo). The effects of hormone therapy on DCIS in clinical trial participants were assessed during the intervention, post-intervention, and entire followup periods, and in the observational study (OS; 30,421 CEE + MPA users and non-users and 18,657 CEE-alone users and non-users who met eligibility criteria similar to the clinical trial). Compared to placebo, CEE + MPA was non-significantly associated with higher risk of DCIS over approximate average of 11 years of follow-up (HR = 1.23; 95 % CI: 0.91-1.64). No statistical difference was detected between intervention and post-intervention phases (p = 0.32). Corresponding OS results supported an increased risk for DCIS in CEE + MPA users compared to women who were non-users (HR = 1.65; 95 % CI: 1.25-2.19) after adjusting for potential confounders. There was no clear association between CEE-alone use and risk of DCIS. CEE-alone trial data showed that the risk of DCIS was non-significantly lower in the treatment than in the placebo group, while analysis of the corresponding OS showed a non-significantly higher risk of DCIS in the CEE-alone users than non-users. Our analysis suggests that combined estrogen plus progestin use in post-menopausal women may increase risk of DCIS. Whether estrogen-alone use is associated with DCIS requires further investigation.

Ductal carcinoma in situ: recent advances and future prospects

Introduction. This article reviews current management strategies for DCIS in the context of recent randomised trials, including the role of sentinel lymph node biopsy (SLNB), adjuvant radiotherapy (RT) and endocrine treatment. Methods. Literature review facilitated by Medline, PubMed, Embase and Cochrane databases. Results. DCIS should be managed in the context of a multidisciplinary team. Local control depends upon clear surgical margins (at least 2 mm is generally acceptable). SLNB is not routine, but can be considered in patients undergoing mastectomy (Mx) with risk factors for occult invasion. RT following BCS significantly reduces local recurrence (LR), particularly in those at high-risk. There remains a lack of level-1 evidence supporting omission of adjuvant RT in selected low-risk cases. Large, multi-centric or recurrent lesions should be treated by Mx and immediate reconstruction should be discussed. Adjuvant hormonal treatment may reduce the risk of LR in selected cases with hormone sensitive disease. Conclusion. Further research is required to determine the role of new RT regimes and endocrine therapies. Biological profiling and molecular analysis represent an opportunity to improve our understanding of tumour biology in DCIS to rationalise treatment. Reliable identification of low-risk lesions could allow treatment to be less radical.

Postmenopausal hormone therapy and ductal carcinoma in situ: a population-based case-control study

BACKGROUND AND AIM

The relationship between hormone therapy (HT) and invasive breast cancer has been extensively investigated, but the relationship between HT and in situ breast cancer has received relatively little attention. We examined the relationship between HT and ductal carcinoma in situ (DCIS) among postmenopausal women who participated in a population-based case-control study in Connecticut, USA.

METHODS

This analysis included 1179 post-menopausal women (603 controls and 576 cases), who comprised a subset of a population-based case-control study that included all incident cases of breast carcinoma in situ (BCIS) in Connecticut and frequency-matched controls by 5-year age intervals.

RESULTS

We found no association between DCIS and ever use of any HT (adjusted odds ratio (OR)=0.85, 95% confidence interval (CI): 0.65-1.11); of estrogen alone (adjusted OR=0.93; 95% CI: 0.68-1.29) or of estrogen and progesterone (adjusted OR=0.75; 95% CI: 0.52-1.08). There was also no association between DCIS and current use of these hormones. In addition, estimated risk of DCIS did not increase with duration of use of these preparations.

CONCLUSIONS

These results add to a small literature that remains inconclusive. To determine whether HT poses risk of in situ breast cancer, larger studies with greater power and precise control of important covariates (e.g., mammography screening) are needed, as are meta-analyses of available data.

Reproductive and menstrual factors and risk of ductal carcinoma in situ of the breast in a cohort of postmenopausal women

PURPOSE

The contribution of menstrual and reproductive factors to risk of ductal carcinoma (DCIS) of the breast is poorly understood.

METHODS

The association between menstrual and reproductive factors and subsequent DCIS risk was examined in Women's Health Initiative (WHI) clinical trial participants, in which mammography was protocol mandated. The cohort consisted of 64,060 women, among whom 664 cases of DCIS were ascertained over a median follow-up of 12.0 years. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

After adjustment for covariates, only older age at menopause (HR ≥ 55 vs. 45-54 : 1.39, 95% CI 1.08-1.79) was significantly associated with risk; however, greater parity (HR ≥ 5 live births vs. 0: 0.70, 95% CI 0.47-1.03), among parous women, and age at first live birth (HR ≥ 30 years relative to <20 years: 1.32, 95% CI 0.92-1.90) were of borderline significance. Age at menarche and months of breast-feeding were not associated with risk. Associations did not differ between high- and low-/moderate-grade DCIS, or by level of body mass index or family history of breast cancer; however, there was a suggestion that the associations of age at menopause, parity, and age at first live birth were limited to women who had ever used hormone therapy.

CONCLUSIONS

Findings from this large cohort of postmenopausal women suggest that age at menopause, and possibly, age at first live birth, and parity are associated with risk of DCIS, whereas age at menarche and duration of breast-feeding are not.

Metastatic invasive breast cancer recurrence following curative-intent therapy for ductal carcinoma in situ

BACKGROUND

The development of an invasive breast cancer recurrence outside of the breast parenchyma following curative-intent therapy for ductal carcinoma in situ (DCIS) is rare. We describe the patient and tumor characteristics associated with such recurrences.

METHODS

A retrospective review was conducted of 621 patients who were treated for DCIS between 2004 and 2009. Patient, tumor, and treatment characteristics were collected. Descriptive statistics were utilized for data summary and data were compared using χ(2), where appropriate.

RESULTS

Of 621 patients who underwent curative-intent therapy for DCIS, 12 (1.9%) developed an invasive metastatic recurrence. Primary local therapy at the time of the initial DCIS diagnosis included 11 patients who underwent mastectomy and one who had lumpectomy and adjuvant radiotherapy. The metastatic recurrences were in chest wall and/or ipsilateral axillary lymph nodes only (n = 6) or distant sites with or without ipsilateral axillary or supraclavicular lymph nodes (n = 6). Of the 12 patients with invasive recurrence, eight had high grade DCIS with comedo necrosis at initial diagnosis. The biomarker profiles of the invasive recurrences included 55% estrogen receptor positivity, 45% progesterone receptor positivity, and 73% Her2/neu amplification. Patient age, tumor grade, presence of comedo necrosis, biomarker profile, and surgical treatment were not predictive of recurrence.

CONCLUSION

Invasive metastatic recurrence following adequate local therapy for DCIS is uncommon and likely represents progression of unidentified invasive disease at the time of diagnosis. The majority of invasive recurrences were Her2/neu amplified. Further studies are necessary to determine if such a unique biomarker profile correlates with metastatic recurrence.

Ductal carcinoma in-situ: an update for clinical practice

INTRODUCTION

Ductal carcinoma in-situ (DCIS) is a heterogeneous entity with an elusive natural history. The objective of radiological, histological and molecular characterisation remains to reliably predict the biological behaviour and optimise clinical management strategies. Increases in diagnostic frequency have followed the introduction of mammographic screening and increased utility of magnetic resonance imaging. However, progress remains limited in distinguishing non-progressive incidental lesions from their progressive and clinically relevant counterparts. This article reviews current management strategies for DCIS in the context of recent randomized trials, including the role of sentinel lymph node biopsy (SLNB), adjuvant radiotherapy (RT) and endocrine treatment.

METHODS

Literature review facilitated by Medline, PubMed, Embase and Cochrane databases.

RESULTS

DCIS should be managed in the context of a multidisciplinary team. Local control depends upon adequate surgical clearance with margins of at least 2 mm. SLNB is not routinely indicated and should be reserved for those with concurrent or recurrent invasive disease. SLNB can be considered in patients undergoing mastectomy (MX) and those with risk factors for invasion such as palpability, comedo morphology, necrosis or recurrent disease. RT following BCS significantly reduces local recurrence (LR), particularly in those at high-risk. There remains a lack of level-1 evidence supporting the omission of adjuvant RT in selected low-risk cases. Large, multi-centric or recurrent lesions (particularly in cases of prior RT) should be treated by MX with the opportunity for immediate reconstruction. Adjuvant Tamoxifen may reduce the risk of LR in selected cases with hormone sensitive disease.

CONCLUSION

Further research is required to determine the role of contemporary RT regimes and endocrine therapies. Biological profiling and molecular analysis represent an opportunity to improve our understanding of the tumour biology of this condition and rationalise its treatment. Reliable identification of low-risk lesions could allow treatment to be less radical or safely omitted.

Breastfeeding and prognostic markers in breast cancer

BACKGROUND

Several studies suggest that total breastfeeding time reduces breast cancer risk. The underlying mechanisms are unclear. Whether breastfeeding also affects the prognosis is not yet investigated. A number of tumour characteristics, i.e. histological type of cancer, grade, tumour size, Nottingham prognostic index, vascular invasion and DNA-ploidy, have been demonstrated to be of prognostic value.

METHODS

We have searched for a possible link between these prognostic markers and breastfeeding time, age at first child and number of children. 250 women treated for breast cancer have answered a questionnaire.

RESULTS

No significant interactions were found possibly with one exception, LVI vs. age at first child. We found, significant correlations between lobular cancer, and thereby also DNA-ploidy, and age at first childbirth.

CONCLUSIONS

We have found that lobular cancer (and thereby also diploid tumours) are connected, independently, to age at first childbirth and possibly also to number of children but no other correlations between reproductive data, breastfeeding included, and prognostic markers used in this study were found.

Epidemiology of ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) is a relatively common diagnosis among women undergoing screening mammography. The greatest increases in DCIS incidence have been in non-comedo subtypes of DCIS that are not associated with subsequent invasive cancer. After a 500% increase in DCIS from 1983 to 2003, the incidence of DCIS declined in women aged 50 years and older, whereas the incidence in women younger than age 50 continues to increase. Having undergone mammography is one of the strongest and most prevalent risk factors associated with a diagnosis of DCIS. Other risk factors for DCIS are similar to that for invasive cancer including increasing age, family history of breast cancer, high mammographic breast density, and postmenopausal hormone therapy use. Treatment for DCIS is relatively aggressive with the use of both surgery and radiation therapy and most recently adjuvant hormonal therapy. Breast cancer mortality is low and similar with all types of treatment. New information regarding incidence of DCIS and subtypes of DCIS according to frequency of mammography and risk factors could lead to insights into the biology of DCIS.