Hormones and mammographic breast density

Severity and risk factors of interval breast cancer in Queensland, Australia: a population-based study

BACKGROUND

Interval breast cancers (BC) are those diagnosed within 24 months of a negative mammogram. This study estimates the odds of being diagnosed with high-severity BC among screen-detected, interval, and other symptom-detected BC (no screening history within 2 years); and explores factors associated with being diagnosed with interval BC.

METHODS

Telephone interviews and self-administered questionnaires were conducted among women (n = 3,326) diagnosed with BC in 2010-2013 in Queensland. Respondents were categorised into screen-detected, interval, and other symptom-detected BCs. Data were analysed using logistic regressions with multiple imputation.

RESULTS

Compared with screen-detected BC, interval BC had higher odds of late-stage (OR = 3.50, 2.9-4.3), high-grade (OR = 2.36, 1.9-2.9) and triple-negative cancers (OR = 2.55, 1.9-3.5). Compared with other symptom-detected BC, interval BC had lower odds of late stage (OR = 0.75, 0.6-0.9), but higher odds of triple-negative cancers (OR = 1.68, 1.2-2.3). Among women who had a negative mammogram (n = 2,145), 69.8% were diagnosed at their next mammogram, while 30.2% were diagnosed with an interval cancer. Those with an interval cancer were more likely to have healthy weight (OR = 1.37, 1.1-1.7), received hormone replacement therapy (2-10 years: OR = 1.33, 1.0-1.7; > 10 years: OR = 1.55, 1.1-2.2), conducted monthly breast self-examinations (BSE) (OR = 1.66, 1.2-2.3) and had previous mammogram in a public facility (OR = 1.52, 1.2-2.0).

CONCLUSION

These results highlight the benefits of screening even among those with an interval cancer. Women-conducted BSE were more likely to have interval BC which may reflect their increased ability to notice symptoms between screening intervals.

OUP accepted manuscript

In screening for breast cancer (BC), mammographic breast density (MBD) is a powerful risk factor that increases breast carcinogenesis and synergistically reduces the sensitivity of mammography. It also reduces specificity of lesion identification, leading to recalls, additional testing, and delayed and later-stage diagnoses, which result in increased health care costs. These findings provide the foundation for dense breast notification laws and lead to the increase in patient and provider interest in MBD. However, unlike other risk factors for BC, MBD is dynamic through a woman’s lifetime and is modifiable. Although MBD is known to change as a result of factors such as reproductive history and hormonal status, few conclusions have been reached for lifestyle factors such as alcohol, diet, physical activity, smoking, body mass index (BMI), and some commonly used medications. Our review examines the emerging evidence for the association of modifiable factors on MBD and the influence of MBD on BC risk. There are clear associations between alcohol use and menopausal hormone therapy and increased MBD. Physical activity and the Mediterranean diet lower the risk of BC without significant effect on MBD. Although high BMI and smoking are known risk factors for BC, they have been found to decrease MBD. The influence of several other factors, including caffeine intake, nonhormonal medications, and vitamins, on MBD is unclear. We recommend counseling patients on these modifiable risk factors and using this knowledge to help with informed decision making for tailored BC prevention strategies.

Supplemental Cancer Screening for Women With Dense Breasts: Guidance for Health Care Professionals

Mammography is the standard for breast cancer screening. The sensitivity of mammography in identifying breast cancer, however, is reduced for women with dense breasts. Thirty-eight states have passed laws requiring that all women be notified of breast tissue density results in their mammogram report. The notification includes a statement that differs by state, encouraging women to discuss supplemental screening options with their health care professionals (HCPs). Several supplemental screening tests are available for women with dense breast tissue, but no established guidelines exist to direct HCPs in their recommendation of preferred supplemental screening test. Tailored screening, which takes into consideration the patient's mammographic breast density and lifetime breast cancer risk, can guide breast cancer screening strategies that are more comprehensive. This review describes the benefits and limitations of the various available supplemental screening tests to guide HCPs and patients in choosing the appropriate breast cancer screening.

Association between alcohol consumption and mammographic density: a hospital-based cross-sectional study

BACKGROUND

Mammographic density (MD), the proportion of radiological dense breast, has been reported to be a strong risk factor for breast cancer in many studies. Epidemiological evidence indicates that alcohol consumption increases the risk of breast cancer. In Western countries, a positive association between alcohol consumption and MD has been reported.

METHODS

To investigate the effect of alcohol consumption on MD, we conducted a cross-sectional analysis of healthy women enrolled in a breast cancer screening program at the Ebina Health Service Center, Japan, in 2012, comprising 477 premenopausal women and 308 postmenopausal women. Alcohol consumption was assessed using a self-report questionnaire. Unconditional logistic regression was applied to calculate the odds ratio (OR) and 95% confidence intervals (CI) while adjusting for confounders.

RESULTS

The study included 497 women with high breast density (HD group) and 288 women with low breast density (LD group). In all women, multivariate analysis revealed that the OR for HD was significantly increased among women with the highest alcohol intake (≥ 140 g/week of ethanol) compared with abstainers (OR 2.1, 95% CI 1.2-3.9 p = 0.01). The linear trend with increasing alcohol consumption was statistically significant (p = 0.009).

CONCLUSION

MD was positively associated with alcohol consumption in Japanese women.

Correlation Between Mammographic Breast Density, Breast Tissue Type in Ultrasonography, Fibroglandular Tissue, and Background Parenchymal Enhancement in Magnetic Resonance Imaging

Objective

Breast cancer is the most common malignancy in the female population, and imaging studies play a critical role for its early detection. Mammographic breast density (MBD) is one of the markers used to predict the risk stratification of breast cancer in patients. We aimed to assess the correlations among MBD, ultrasound breast composition (USBC), fibroglandular tissue (FGT), and the amount of background parenchymal enhancement (BPE) in magnetic resonance imaging, after considering the subjects' menopausal status.

Methods

In this retrospective cross-sectional study, the medical records' archives in a tertiary referral hospital were reviewed. Data including age, menopausal status, their mammograms, and ultrasound assessments were extracted from their records. All of their imaging studies were reviewed, and MBD, USBC, FGT, and BPE were determined, recorded, and entered into SPSS software for analysis.

Results

A total of 121 women (mean age = 42.7 ± 11.0 years) were included, of which 35 out of 115 (30.4%) had reached menopause. Using the Jonckheere-Terpstra test for evaluating the trends among above mentioned 4 radiologic characteristics in the total sample population, a significant positive relation was found between each of these paired variables: (1) USBC-MBD (P = .006), (2) FGT-MBD (P = .001), (3) USBC-BPE (P = .046), (4) USBC-FGT (P = .036), and (5) BPE-FGT (P < .001). These trends were not found to be significant among premenopausal subjects.

Conclusions

Considering the trends between different measures of breast density in the 3 radiologic modalities, these factors can be used interchangeably in certain settings.

Breast tissue density change after oophorectomy in BRCA mutation carrier patients using visual and volumetric analysis

OBJECTIVE

BRCA1/2 mutations account for 30-50% of hereditary breast cancers and bilateral oophorectomy is associated with a reduced risk of breast cancer in these patients. Breast density is a well-established breast cancer risk factor and is also associated with increased risk in BRCA carriers. The aim of the study was to evaluate the impact of oophorectomy on mammographic breast density and to assess which method of breast density assessment is more sensitive to change over time.

METHODS

Retrospective study of 50 BRCA1/2 patients who underwent bilateral oophorectomy and had at least a baseline and post-surgery mammogram. Mammographic breast density was determined by Volpara and consensus visual assessment by two radiologists. The primary endpoint was change in density between baseline and the first mammogram post-surgery.

RESULTS

At baseline, there was a non-significant trend for decreased density with increasing age. Volumetric breast density (VBD) significantly decreased after oophorectomy from a median VBD of 12.5% at baseline to 10.2% post-surgery which was driven by a reduction in fibroglandular volume. There was a higher absolute decrease in VBD in patients aged between 40-50 (p < 0.01). Using Volpara Density Grades (analogous to BI-RADS 4th edition density categories), 84% of females displayed a decrease in density category over the study period compared to only 76% using the radiologists' visual classification (p < 0.001) Conclusion: Oophorectomy is associated with a decrease in breast density and younger patients exhibit a larger absolute decrease. Volpara is more sensitive to identify change over time compared to visual assessment. Advances in knowledge: Oophorectomy is associated with a significant decrease in VBD in patients with BRCA mutations and Volpara Density Grades were more sensitive to identify decreases in density compared to visually assessed BI-RADS categories. Decreases in breast density following oophorectomy surgery in BRCA patients may be one of the mechanisms contributing to the observed decreased breast cancer risk after surgery. However, further studies are needed to investigate the relationship between breast density, oophorectomy and breast cancer risk in BRCA patients.

Breast Density and Breast Cancer Incidence in the Lebanese Population: Results from a Retrospective Multicenter Study

Purpose

To study the distribution of breast mammogram density in Lebanese women and correlate it with breast cancer (BC) incidence.

Methods

Data from 1,049 women who had screening or diagnostic mammography were retrospectively reviewed. Age, menopausal status, contraceptives or hormonal replacement therapy (HRT), parity, breastfeeding, history of BC, breast mammogram density, and final BI-RADS assessment were collected. Breast density was analyzed in each age category and compared according to factors that could influence breast density and BC incidence.

Results

120 (11.4%) patients had BC personal history with radiation and/or chemotherapy; 66 patients were postmenopausal under HRT. Mean age was 52.58 ± 11.90 years. 76.4% of the patients (30–39 years) had dense breasts. Parity, age, and menopausal status were correlated to breast density whereas breastfeeding and personal/family history of BC and HRT were not. In multivariate analysis, it was shown that the risk of breast cancer significantly increases 3.3% with age (P = 0.005), 2.5 times in case of menopause (P = 0.004), and 1.4 times when breast density increases (P = 0.014).

Conclusion

Breast density distribution in Lebanon is similar to the western society. Similarly to other studies, it was shown that high breast density was statistically related to breast cancer, especially in older and menopausal women.

Factors Associated with Mammographic Density in Postmenopausal Women

Objectives

Breast density increases the risk of breast cancer, but also in the interpretation of mammography is also important. This study examine the risk factors affecting breast density in postmenopausal women.

Methods

Between January 2013 and January 2014, 215 patients admitted to The Clinics of Gynecology and Obstetrics with complaints of menopause were taken. According to the results of mammography, Group I (non-dense, n = 175) and Group II (dense, n = 40) were created. The informations of the caseswere analyzed retrospectively.

Results

In Group I, body mass index (BMI), number of pregnancies, parity were significantly higher than group II (P < 0.05). In group II, the withdrawal period of menstruation and progesterone levels were significantly higher (P < 0.05). In logistic regression analysis, BMI for dense breasts and number of pregnancies were found to be an independent risk factor (P < 0.05).

Conclusion

Increased BMI, pregnancy and parity, result of reduction in density , but longer duration of menopause and increased progesterone cause an increase in density. BMI and the number of pregnancy was found to be independent risk factors for reducing breast density.

Mammographic breast density: Predictive value for pathological response to neoadjuvant chemotherapy in breast cancer patients

BACKGROUND

This study aims to evaluate the relation between mammographic breast density (BD) and pathological response to neoadjuvant chemotherapy.

METHODS

In this retrospective study, 241 breast cancer patients who received neoadjuvant chemotherapy were included. BD was assessed in mammograms already performed at diagnosis. Pathological complete response (pCR) and pathological stage were correlated with BD, tumour phenotype and other clinico-pathological factors.

RESULTS

Patients with low BD had better pCR compared to those with high density (30.5% vs 19.5% respectively, OR = 1.8, 95% CI = 0.98-3.3, p = 0.056) which was more pronounced after adjustment with body mass index (BMI) (OR = 2.4, 95% CI = 1.2-4.8, p = 0.011). HER2-positive disease (32.5% vs. 18.4%, OR = 2.2, 95% = 1.2-4.0, p = 0.01), lower BMI (OR = 1.1, 95% CI = 1.03-1.15, p = 0.004) and lower clinical stage (p = 0.002) were significant predictors of pCR in univariate analysis. In multivariate analysis, low BD (OR = 2.7, 95% CI = 1.3-5.5, p = 0.006) and lower BMI (OR = 1.1, 95% CI = 1.03-1.17, p = 0.003) were independent predictors of better pCR, while early clinical stage (I, II) was of borderline significance (OR = 2.6, 95% CI = 0.99-6.7, p = 0.052). High BD (OR = 1.8, 95% CI = 1.1-3.2, p = 0.03), advanced clinical stage (III) (OR = 1.5, 95% CI = 1.03-2.1, p = 0.03) and higher BMI (OR = 1.06, 95% CI = 1.02-1.11, p = 0.006) were significant predictors of advanced pathological stage.

CONCLUSION

Low mammographic BD, low BMI and early clinical stage were associated with improved pCR rate and lower pathological stage after neoadjuvant chemotherapy. BD had more pronounced association with response to chemotherapy after adjustment with BMI.

Relationship between breast cancer risk factors and mammographic breast density in the Fernald Community Cohort

Background:

We investigated associations of known breast cancer risk factors with breast density, a well-established and very strong predictor of breast cancer risk.

Methods:

This nested case–control study included breast cancer-free women, 265 with high and 860 with low breast density. Women were required to be 40–80 years old and should have a body mass index (BMI) <35 at the time of the index mammogram. Information on covariates was obtained from annual questionnaires.

Results:

In the overall analysis, breast density was inversely associated with BMI at mammogram (P for trend<0.001), and parity (P for trend=0.02) and positively associated with alcohol consumption (ever vs never: odds ratio 2.0, 95% confidence interval 1.4–2.8). Alcohol consumption was positively associated with density, and the association was stronger in women with a family history of breast cancer (P<0.001) and in women with hormone replacement therapy (HRT) history (P<0.001). Parity was inversely associated with density in all subsets, except premenopausal women and women without a family history. The association of parity with density was stronger in women with HRT history (P<0.001).

Conclusion:

The associations of alcohol and parity with breast density appear to be in reverse direction, but stronger in women with a family history of breast cancer and women who ever used HRT.

Androgens and breast cancer

The role of androgens on breast cancer development and progression has not been fully elucidated. Several in vivo and in vitro studies demonstrate that androgens have an inhibitory effect on the mammary epithelium, whereas the majority of epidemiological studies report a positive association between high androgen levels and risk of breast cancer. Expression of the androgen receptor is a positive prognostic factor. Understanding the role of androgens in breast carcinogenesis is important because many women use testosterone replacement for the alleviation of symptoms brought on by menopause, in particular high-risk women who undergo surgical menopause at an early age. We overview the literature examining a role of androgens in the etiology of breast cancer.

Assessment of mammographic density before and after first full-term pregnancy

Mammographic density (MD) has consistently been found as one of the strongest breast cancer risk factors. In our study, both qualitative and quantitative density measurements were performed in a hospital-based group of premenopausal women before and after first full-term pregnancy providing an opportunity for direct evaluation of the effects of one pregnancy on MD. Mammograms were obtained from 23 women before and after first full-term pregnancy and from 28 nulliparous controls. MD was determined by a standard qualitative assessment method using the Breast Imaging Reporting and Data System, and a quantitative computer-based threshold method (0-100%). The mean age at mammography before and after pregnancy was 31 and 34 years, respectively, with a mean difference of 40 months between mammographies. The quantitative density assessment showed a significant reduction in relative MD after pregnancy of 12 percentage points (8.6-15.4), compared with 3.1 (0.0-6.2) in the nulliparous control group (P<0.001). A reduction in MD of more than 10% was seen in 52% of the patients, compared with 18% of the controls. The qualitative density assessment confirmed a reduction in MD after pregnancy by one Breast Imaging Reporting and Data System category (P=0.02). This longitudinal study showed that MD can be influenced by one full-term pregnancy. This effect was seen with both quantitative and qualitative assessment methods. It may be hypothesized that breast cancer risk reduction associated with pregnancy is mediated through a direct reduction of MD, and MD assessment might be incorporated in individualizing risk assessment and prevention.

Hot flushes: are there effective alternatives to estrogen?

Hot flushes are the most common indication for the prescription of hormone replacement therapy (HRT) since it is effective in over 80% of cases. In 1995, 37% of American women took HRT, principally for this purpose. However, over the last five years, publications such as those from the Women's Health Initiative (WHI) have caused concern among women since they perceive that the risks outweigh the benefits. Following this publication, half of the women taking HRT in the UK, USA and New Zealand discontinued HRT. With the discontinuation of estrogen many women re-developed hot flushes; however only a small number (18%) of women report restarting hormone therapy. The majority of these (76%) for the recurrence of severe hot flushes or night sweats. Alternatives are available, but limited knowledge on aetiology and mechanisms of hot flushing represents a major obstacle for the development of new, targeted, non-hormonal treatments, and no current alternatives are as effective as estrogen.

Breast density in women with premature ovarian failure or postmenopausal women using hormone therapy: analytical cross-sectional study

CONTEXT AND OBJECTIVE

Studies on postmenopausal women have reported increased risk of breast cancer relating to the type and duration of hormone therapy (HT) used. Women with premature ovarian failure (POF) represent a challenge, since they require prolonged HT. Little is known about the impact of prolonged HT use on these women's breasts. This study aimed to evaluate the effects of one type of HT on the breast density of women with POF, compared with postmenopausal women.

DESIGN AND SETTING

Cross-sectional study at the Department of Obstetrics and Gynecology, Universidade Estadual de Campinas (Unicamp).

METHODS

31 women with POF and 31 postmenopausal women, all using HT consisting of conjugated equine estrogen combined with medroxyprogesterone acetate, and matched according to HT duration, were studied. Mammography was performed on all subjects and was analyzed by means of digitization or Wolfe's classification, stratified into two categories: non-dense (N1 and P1 patterns) and dense (P2 and Dy).

RESULTS

No significant difference in breast density was found between the two groups through digitization or Wolfe's classification. From digitization, the mean breast density was 24.1% ± 14.6 and 18.1% ± 17.2 in the POF and postmenopausal groups, respectively (P = 0.15). Wolfe's classification identified dense breasts in 51.6% and 29.0%, respectively (P = 0.171).

CONCLUSION

There was no difference in breast density between the women with POF and postmenopausal women, who had used HT for the same length of time. These results may help towards compliance with HT use among women with POF.

Recording of hormone therapy and breast density in breast screening programs: summary and recommendations of the International Cancer Screening Network

Breast density and the use of hormone therapy (HT) for menopausal symptoms alter the risk of breast cancer and both factors influence screening mammography performance. The International Cancer Screening Network (ICSN) surveyed its 29 member countries and found that few programs record breast density or the use of HT among screening participants. This may affect the ability of programs to assess their effectiveness in reducing breast cancer mortality. Seven countries recorded the use of HT at screening, and some were able to link screening records to individual prescribing records of HT. Eight countries reported recording breast density at screening mammography for some or all women screened. The recommendations of the ICSN for recording information about breast density and HT are presented.

The effect of transdermal testosterone on mammographic density in postmenopausal women not receiving systemic estrogen therapy

CONTEXT

Greater mammographic density is associated with increased breast cancer risk and reduced diagnostic mammographic sensitivity and may be seen with estrogen/progestin therapy (EPT). The effects of testosterone therapy on mammographic density in postmenopausal women not on EPT are not known.

OBJECTIVE

Our objective was to compare effects of two doses of the testosterone transdermal patch (TTP) with placebo in postmenopausal women without concomitant EPT on mammographic density over 52 wk.

DESIGN

We conducted a randomized, double-blind, placebo-controlled, parallel-group, multinational trial.

PATIENTS

Patients included 279 postmenopausal women participating in a testosterone and sexual function study with paired mammograms for baseline and 52 wk/exit.

INTERVENTIONS

Patients were randomized to placebo, TTP 150 microg/d, or TTP 300 microg/d, stratified by menopause type (natural or surgical).

MAIN OUTCOME MEASURES

Change from baseline to wk 52 in the percentage of dense tissue (PD) on digital mammograms.

RESULTS

A total of 250 women with paired mammograms for study baseline and wk 52 were included in the primary analysis. Mean age was 54.6 yr, baseline body mass index was 27.5 kg/m(2), and 78% were naturally menopausal. There were no baseline differences between groups. Mean changes from baseline (+/-SEM) in PD for placebo, TTP 150 microg/d and TTP 300 microg/d were small (0.05 +/- 0.16, 0.06 +/- 0.19, and 0.21 +/- 0.17%) and not significantly different. There were no statistically significant differences from placebo for total dense or nondense area and no significant relationships between hormone levels and PD after adjustment for body mass index.

CONCLUSION

TTP therapy over 52 wk appears to have no significant effect on digitally quantified absolute or percent dense mammographic area in postmenopausal women not using EPT.

Testosterone addition during menopausal hormone therapy: effects on mammographic breast density

OBJECTIVE

To study the effect on mammographic breast density of testosterone addition during combined estrogen/progestogen therapy in postmenopausal women.

METHODS

A prospective, randomized, double-blind, placebo-controlled trial. A total of 99 women were given 2 mg 17beta-estradiol and 1 mg norethisterone acetate in combination with either a testosterone patch (300 mug/24 h) or a placebo patch. Mammographic breast density at baseline and after 6 months was assessed by visual classification scales and by digitized quantification. A standardized questionnaire was used to quantify subjective breast symptoms.

RESULTS

Visual classifications showed an increase in mammographic density in 18-30% of the women, with no significant differences between the treatment groups. The mean increase of the area of dense breast during treatment according to digitized assessment was 7.4% in the placebo group and 5.4% in the testosterone group. Breast symptoms showed a positive association with the increase in density (r(s) = 0.34; p < 0.01). Symptoms were most pronounced at 2 months of treatment. Density, both at baseline (r(s) = -0.35; p < 0.01) and change during treatment (r(s) = -0.28; p < 0.01) showed a negative association with free testosterone levels.

CONCLUSION

The addition of testosterone does not appear to influence mammographic breast density in women concurrently treated with a common oral estrogen/progestogen regimen for a period of 6 months.

Expression of syndecan-1 in histologically normal breast tissue from postmenopausal women with breast cancer according to mammographic density

OBJECTIVE

To analyze the expression of Syndecan-1 in dense and non-dense human breast tissue.

METHODS

Specimens of histologically normal tissue were obtained from postmenopausal women undergoing surgery for breast cancer. Each tissue block was subject to radiological examination and pair-wise samples of dense and non-dense tissue were collected. Semi-quantitative assessment of immunohistochemical staining intensity for Syndecan-1 and estrogen receptor subtypes was performed.

RESULTS

The expression of Syndecan-1 in all tissue compartments was significantly higher in dense than in non-dense specimens. The strongest staining was recorded in stromal tissue. There was a strong correlation between epithelial estrogen receptor alpha and stromal cell Syndecan-1 expression in dense tissue (rs = 0.7; p = 0.02). This association was absent in non-dense tissue.

CONCLUSION

An increase of Syndecan-1 in all tissue compartments and a redistribution from epithelium to stroma may be a characteristic feature for dense breast tissue.

Neutral effect of ultra-low-dose continuous combined estradiol and norethisterone acetate on mammographic breast density

OBJECTIVE

To compare the effects of two different ultra-low doses of continuous combined hormone therapy and placebo on mammographic breast density in postmenopausal women.

METHODS

A subpopulation of 255 postmenopausal women from the CHOICE trial were randomly assigned to 0.5 mg 17beta-estradiol (E2) + 0.25 mg norethisterone acetate (NETA), 0.5 mg E2 + 0.1 mg NETA, or placebo. Women using hormone replacement therapy (HRT) up to 2 months prior to the study were excluded; 154 women fulfilled the inclusion criteria. Mammograms were performed at baseline and after 6 months. Breast density was evaluated by visual classification scales and a computer-assisted digitized technique.

RESULTS

No significant differences were detected between the active treatment groups and the placebo group in the digitized quantification. The mean baseline values for density around 20% were unchanged after 6 months. Also, visual classifications showed no increase in breast density in any study group.

CONCLUSION

In contrast to currently available bleed-free regimens, the new ultra-low-dose combination of 0.5 mg E2 and 0.1 mg NETA seems to have very little or even a neutral effect on the breast. Both digitized quantification and visual assessment of breast density were unchanged after 6 months. Larger prospective studies should be performed to confirm this new finding.

Breast cancer and hormonal therapy

Valid evidence from randomized-controlled trials indicates that breast cancer risk is increased with combined estrogen/progestogen use and that such treatment implies a risk greater than that of estrogen alone. Overall, risk estimates from observational studies are somewhat higher than in randomized-controlled trials but remain modest as compared with other risk factors even after long-term treatment. For combined estrogen/progestogen therapy, risk increases gradually to reach statistical significance after 4 to 5 years. Apart from its many beneficial health effects, the safety data for use of estrogen alone are quite reassuring. The only justifications for progestogen addition are for bleeding control and endometrial protection. At present, there are several new therapeutic compounds and concepts in development, which hold promise to provide both endometrial protection and breast safety.

Mammographic density using two computer-based methods in an isoflavone trial

OBJECTIVES

Mammographic density is a useful biomarker of breast cancer risk. Computer-based methods can provide continuous data suitable for analysis. This study aimed to compare a semi-automated computer-assisted method (Cumulus) and a fully automated volumetric computer method (standard mammogram form (SMF)) for assessing mammographic density using data from a previously conducted randomised placebo-controlled trial of an isoflavone supplement.

METHODS

Mammograms were obtained from participants in the intervention study. A total of 177 women completed the study. Baseline and follow-up mammograms were digitised and density was estimated using Cumulus (read by two readers) and SMF. Left-right correlation, changes in density over time, and difference between intervention and control groups were evaluated. Changes of density over time, and changes between intervention group and control group were examined using paired t-test and Student's t-test, respectively.

RESULTS

Inter-reader correlation coefficient by Cumulus was 0.90 for dense area, and 0.86 for percentage density. Left-right correlation of percent density was lower in SMF than in Cumulus. Among all women, percentage density by Cumulus decreased significantly over time, but no change was seen for SMF percentage density. The intervention group showed marginally significant greater reduction of percent density by Cumulus compared to controls (p=0.04), but the difference became weak after adjustment for baseline percent density (p=0.06). No other measurement demonstrated significant difference between intervention and control groups.

CONCLUSIONS

This comparison suggests that slightly different conclusions could be drawn from different methods used to assess breast density. The development of a more robust fully automated method is awaited.

Mammographic density, breast cancer risk and risk prediction

In this review, we examine the evidence for mammographic density as an independent risk factor for breast cancer, describe the risk prediction models that have incorporated density, and discuss the current and future implications of using mammographic density in clinical practice. Mammographic density is a consistent and strong risk factor for breast cancer in several populations and across age at mammogram. Recently, this risk factor has been added to existing breast cancer risk prediction models, increasing the discriminatory accuracy with its inclusion, albeit slightly. With validation, these models may replace the existing Gail model for clinical risk assessment. However, absolute risk estimates resulting from these improved models are still limited in their ability to characterize an individual's probability of developing cancer. Promising new measures of mammographic density, including volumetric density, which can be standardized using full-field digital mammography, will likely result in a stronger risk factor and improve accuracy of risk prediction models.

Role of androgens, progestins and tibolone in the treatment of menopausal symptoms: a review of the clinical evidence

Estrogen-containing hormone therapy (HT) is the most widely prescribed and well-established treatment for menopausal symptoms. High quality evidence confirms that estrogen effectively treats hot flushes, night sweats and vaginal dryness. Progestins are combined with estrogen to prevent endometrial hyperplasia and are sometimes used alone for hot flushes, but are less effective than estrogen for this purpose. Data are conflicting regarding the role of androgens for improving libido and well-being. The synthetic steroid tibolone is widely used in Europe and Australasia and effectively treats hot flushes and vaginal dryness. Tibolone may improve libido more effectively than estrogen containing HT in some women. We summarize the data from studies addressing the efficacy, benefits, and risks of androgens, progestins and tibolone in the treatment of menopausal symptoms.

Breast density in women with premature ovarian failure using hormone therapy

BACKGROUND

Women with premature ovarian failure (POF) are treated with estrogen-progestin therapy; however, doubts remain regarding the effect of this therapy on the breasts of women with POF.

OBJECTIVE

To evaluate the breast density of women with POF using estrogen-progestin therapy compared with normally menstruating women.

METHODS

A cross-sectional study was performed in 31 women with POF using conjugated equine estrogens and medroxyprogesterone acetate and a control group of 31 normally menstruating women, paired by age. All underwent mammography, analyzed by digitization and Wolfe's classification, the latter defined as non-dense (N1 and P1) or dense (P2 and Dy). Parity, breastfeeding and body mass index were evaluated, as well as duration of hormone use and ovarian failure in the POF group.

RESULTS

Digitization revealed no difference in mean breast density between the groups: 24.1+/-14.6% and 21.8+/-11.3% for POF and control groups, respectively. The Wolfe classification also failed to detect any significant difference between the groups, dense breasts being detected in 51.6% and 35.5% of cases in the POF and control groups, respectively.

CONCLUSION

Periods of hypoestrogenism followed by hormone therapy resulted in no changes in breast density in women with POF, compared with normally menstruating women of the same age.

Breast cancer risk factors and a novel measure of volumetric breast density: cross-sectional study

We conducted a cross-sectional study nested within a prospective cohort of breast cancer risk factors and two novel measures of breast density volume among 590 women who had attended Glasgow University (1948–1968), replied to a postal questionnaire (2001) and attended breast screening in Scotland (1989–2002). Volumetric breast density was estimated using a fully automated computer programme applied to digitised film-screen mammograms, from medio-lateral oblique mammograms at the first-screening visit. This measured the proportion of the breast volume composed of dense (non-fatty) tissue (Standard Mammogram Form (SMF)%) and the absolute volume of this tissue (SMF volume, cm³). Median age at first screening was 54.1 years (range: 40.0–71.5), median SMF volume 70.25 cm³ (interquartile range: 51.0–103.0) and mean SMF% 26.3%, s.d.=8.0% (range: 12.7–58.8%). Age-adjusted logistic regression models showed a positive relationship between age at last menstrual period and SMF%, odds ratio (OR) per year later: 1.05 (95% confidence interval: 1.01–1.08, P=0.004). Number of pregnancies was inversely related to SMF volume, OR per extra pregnancy: 0.78 (0.70–0.86, P<0.001). There was a suggestion of a quadratic relationship between birthweight and SMF%, with lowest risks in women born under 2.5 and over 4 kg. Body mass index (BMI) at university (median age 19) and in 2001 (median age 62) were positively related to SMF volume, OR per extra kg m⁻² 1.21 (1.15–1.28) and 1.17 (1.09–1.26), respectively, and inversely related to SMF%, OR per extra kg m⁻² 0.83 (0.79–0.88) and 0.82 (0.76–0.88), respectively, P<0.001. Standard Mammogram Form% and absolute SMF volume are related to several, but not all, breast cancer risk factors. In particular, the positive relationship between BMI and SMF volume suggests that volume of dense breast tissue will be a useful marker in breast cancer studies.

Reproducibility of visual assessment on mammographic density

BACKGROUND

High mammographic density was an independent risk factor for breast cancer and has a higher associated risk than most other known risk factors. The reproducibility remains a major issue in assessment of breast parenchymal patterns. Misclassification of mammographic pattern can lead to significant underestimation of risk estimates. The purpose of this study was to assess the inter-rater and intra-rater reliability based on visual subjective mammographic density measurements.

METHOD

Three density measures, Wolfe parenchymal pattern, Boyd classification scale, and a percentage of densities in total breast, were investigated. The study included 101 women who were participants of the International Breast Cancer Intervention Study I (IBIS I) for up to 7 years. Seven sets of mammograms were collected for each woman. Left breast mediolateral oblique films were digitized, and the scanned images were independently reviewed by two readers. These images were reassessed by one reader after a year. The agreements of measures were evaluated by Kappa statistics (Wolfe and Boyd scale) and intraclass correlation coefficient (percentage densities).

RESULTS

For the inter-rater agreement, Weighted Kappa for Wolfe scale was 0.89 (P < 0.0001) and for Boyd scale was 0.84 (P < 0.0001). The intraclass correlation coefficient was 0.94 for percentage densities. For the intra-rater agreement, Weighted Kappa for Wolfe scale was 0.87 (P < 0.0001) and for Boyd scale was 0.86 (P < 0.0001). The intraclass correlation coefficient was 0.96 for percentage densities.

CONCLUSION

The study concludes that both visual qualitative and quantitative measurements on mammographic density are highly reproducible in the breast cancer research studies if appropriate training is provided. The method is appropriate for risk assessment in a prevention trial.

Mammographic breast density as a general marker of breast cancer risk

Mammographic breast density is a strong risk factor for breast cancer but whether breast density is a general marker of susceptibility or is specific to the location of the eventual cancer is unknown. A study of 372 incident breast cancer cases and 713 matched controls was conducted within the Mayo Clinic mammography screening practice. Mammograms on average 7 years before breast cancer were digitized, and quantitative measures of percentage density and dense area from each side and view were estimated. A regional density estimate accounting for overall percentage density was calculated from both mammogram views. Location of breast cancer and potential confounders were abstracted from medical records. Conditional logistic regression was used to estimate associations, and C-statistics were used to evaluate the strength of risk prediction. There were increasing trends in breast cancer risk with increasing quartiles of percentage density and dense area, irrespective of the side of the breast with cancer (P(trends) < 0.001). Percentage density from the ipsilateral side [craniocaudal (CC): odds ratios (ORs), 1.0 (ref), 1.7, 3.1, and 3.1; mediolateral oblique (MLO): ORs, 1.0 (ref), 1.5, 2.2, and 2.8] and the contralateral side [CC: ORs, 1.0 (ref), 1.8, 2.2, and 3.7; MLO: ORs, 1.0 (ref), 1.6, 1.9, and 2.5] similarly predicted case-control status (C-statistics, 0.64-65). Accounting for overall percentage density, density in the region where the cancer subsequently developed was not a significant risk factor [CC: 1.0 (ref), 1.3, 1.0, and 1.2; MLO: 1.0 (ref), 1.1, 1.0, and 1.1 for increasing quartiles]. Results did not change when examining mammograms 3 years on average before the cancer. Overall mammographic density seems to represent a general marker of breast cancer risk that is not specific to breast side or location of the eventual cancer.

Longitudinal Trends in Mammographic Percent Density and Breast Cancer Risk

BACKGROUND

Mammographic density is a strong risk factor for breast cancer. However, whether changes in mammographic density are associated with risk remains unclear.

MATERIALS AND METHODS

A study of 372 incident breast cancer cases and 713 matched controls was conducted within the Mayo Clinic mammography screening practice. Controls were matched on age, exam date, residence, menopause, interval between, and number of mammograms. All serial craniocaudal mammograms 10 years before ascertainment were digitized, and quantitative measures of percent density (PD) were estimated using a thresholding method. Data on potential confounders were abstracted from medical records. Logistic regression models with generalized estimating equations were used to evaluate the interactions among PD at earliest mammogram, time from earliest to each serial mammogram, and absolute change in PD between the earliest and subsequent mammograms. Analyses were done separately for PD measures from the ipsilateral and contralateral breast and also by use of hormone therapy (HT).

RESULTS

Subjects had an average of five mammograms available, were primarily postmenopausal (83%), and averaged 61 years at the earliest mammogram. Mean PD at earliest mammogram was higher for cases (31%) than controls (27%; ipsilateral side). There was no evidence of an association between change in PD and breast cancer risk by time. Compared with no change, an overall reduction of 10% PD (lowest quartile of change) was associated with an odds ratio of 0.9997 and an increase of 6.5% PD (highest quartile of change) with an odds ratio of 1.002. The same results held within the group of 220 cases and 340 controls never using HT. Among the 124 cases and 337 controls known to use HT during the interval, there was a statistically significant interaction between change in PD and time since the earliest mammogram (P = 0.01). However, in all groups, the risk associated with the earliest PD remained a stronger predictor of risk than change in PD.

CONCLUSION

We observed no association between change in PD with breast cancer risk among all women and those never using HT. However, the interaction between change in PD and time should be evaluated in other populations.

Androgens and the breast

There is increasing interest in the role of androgens in the treatment of women but little is known about their long-term safety. There are also very few studies on testosterone therapy and breast cancer risk. However, some observations support the concept that androgens may counteract the stimulatory effects of estrogen and progestogen in the mammary gland. Mammographic breast density and breast cell proliferation could be regarded as surrogate markers for the risk of breast cancer. Recently the addition of testosterone to a common estrogen/progestogen regimen was found to inhibit the stimulatory effects of hormones on breast cell proliferation. The effects of testosterone alone on the postmenopausal breast remain to be investigated.

Different types of postmenopausal hormone therapy and mammographic density in Norwegian women

Postmenopausal hormone therapy (HT) is associated with increased risk of breast cancer. The HTs used in Scandinavia is associated with higher risk estimates than those used in most other countries. Mammographic density is one of the strongest risk factors for breast cancer, and possibly an intermediate marker for breast cancer. We decided to examine the relationship between use of different types of HT and mammographic density in Norwegian women. Altogether, 1,007 postmenopausal participants in the governmental mammographic screening program were asked about current and previous HT use. Mammograms were classified according to percent and absolute mammographic density. Overall, current users of HT had on average 3.6% higher mean percent mammographic density when compared with never users (p < 0.001). After adjustment for age at screening, number of children and BMI in a multivariate model, women using the continuous estradiol (E(2)) plus norethisterone acetate (NETA) combination had a mean percent mammographic density significantly higher than never users (6.1% absolute difference). Those using the continuous E(2) plus NETA combination had an 4.8% (absolute difference) higher mean percent mammographic density after <5 years of use when compared with never users, while the corresponding number for >or=5 years of use was 7% (p-trend < 0.001). We found similar associations when absolute mammographic density was used as the outcome variable. In summary, our study shows a statistical significant positive dose-response association between current use of the continuous E(2) plus NETA combination and both measures of mammographic density.

Addressing the soy and breast cancer relationship: review, commentary, and workshop proceedings

The impact of soyfood intake on breast cancer risk has been investigated extensively. Much of this focus can be attributed to the soybean being a dietary source that is uniquely rich in isoflavones. The chemical structure of isoflavones is similar to that of estrogen, and isoflavones bind to both estrogen receptors (ER alpha and ER beta) (although they preferentially bind to and activate ER beta) and exert estrogen-like effects under some experimental conditions. Isoflavones also possess nonhormonal properties that are associated with the inhibition of cancer cell growth. Thus, there are several possible mechanisms by which soy may reduce the risk of breast cancer. However, the role of isoflavones in breast cancer has become controversial because, in contrast to the possible beneficial effects, some data from in vitro and animal studies suggest that isoflavones, especially genistein, the aglycone of the main soybean isoflavone genistin, may stimulate the growth of estrogen-sensitive tumors. Limited human data directly address the tumor-promoting effects of isoflavones and soy. Because the use of soyfoods and isoflavone supplements is increasing, it is important from a public health perspective to understand the impact of these products on breast cancer risk in women at high risk of the disease and on the survival of breast cancer patients. To this end, a workshop was held in November 2005 to review the existing literature and to make research recommendations. This paper summarizes the workshop findings and recommendations. The primary research recommendation is that the impact of isoflavones on breast tissue needs to be evaluated at the cellular level in women at high risk for breast cancer.

Physical activity in relation to mammographic density in the dutch prospect-European prospective investigation into cancer and nutrition cohort

BACKGROUND

Evidence accumulates that physical inactivity is one of the few modifiable risk factors for breast cancer. The mechanism through which physical inactivity affects breast cancer risk is not clear. The study aim was to investigate the association between physical activity and breast density because mammographic density is strongly associated with breast cancer risk.

METHODS

We did a cross-sectional study in 620 women, of ages 49 to 68 years and participants of the Dutch Prospect-European Prospective Investigation into Cancer and Nutrition cohort. A self-administered questionnaire was used to obtain information on duration and intensity of physical activity (recreational, household, and occupational) during the year preceding study recruitment. A total activity index (inactive, moderately inactive, moderately active, and active) was estimated by combining all activity types. Percent and absolute breast density were determined on screening mammograms using a computer-aided method. Multivariate linear regression was used to examine the association between physical activity and breast density.

RESULTS

Mean percent density was 35.3% [95% confidence interval (95% CI), 31.8-38.8] for the inactive category compared with 36.1% (95% CI, 33.0-39.2) for the active category. Mean absolute density values for the inactive and active category were 45.8 cm(2) (95% CI, 40.9-50.7) and 42.6 cm(2) (95% CI, 38.3-47.0), respectively. Subgroup analysis for postmenopausal women showed similar results, as did separate analyses for recreational and household activity.

CONCLUSIONS

The result does not support a relation between current physical activity and mammographic density in postmenopausal women.

Influence of menopausal status and use of hormone replacement therapy on radiation dose from mammography in routine breast screening

Menopausal status and hormone replacement therapy (HRT) cause alterations in breast structure which can affect mammographic image quality. Here we present the results of a study to discover the effect of menopausal status and HRT use on breast dose. Women attending routine screening completed questionnaires which included questions regarding menopausal status and HRT use. Details of the radiographic technique factors were recorded, from which the mean glandular dose (MGD) per film for each woman was calculated. MGD values were analysed with regard to the woman's menopausal status and HRT use. The data from 516 women were analysed. Among the women who had never used HRT, women who had not undergone the menopause had a mean MGD of 2.94 mGy per film, whereas post-menopausal women had a lower mean MGD of 2.52 mGy per film: a difference which was found to be highly significant (p = 0.0045). Post-menopausal women who had never used HRT and those who had previously used HRT, but had ceased using it, had identical mean MGDs (2.54 mGy per film), whereas current HRT users had a significantly greater mean MGD (2.89 mGy per film, p = 0.003). Women currently using HRT receive a statistically significantly larger radiation dose from routine breast screening than other women. However, this effect is small and only occurs during the period of HRT use. Women who have ceased using HRT show no difference in MGD compared with women who have never taken HRT.

Digitized assessment of mammographic breast density in patients who received low-dose intrauterine levonorgestrel in continuous combination with oral estradiol valerate: a pilot study

OBJECTIVE

To perform a pilot study of the effects on the breast by low-dose intrauterine progestogen combined with estrogen.

DESIGN

A prospective pilot study.

SETTING

University hospital.

PATIENT(S)

Twenty postmenopausal women without any previous breast disorder.

INTERVENTION(S)

Women were treated with a low-dose intrauterine system releasing 20 microg/24 hours of levonorgestrel in continuous combination with 2 mg of oral E2 valerate. The effects on mammographic breast density, breast cell proliferation, and hormonal levels were followed for 18 months.

MAIN OUTCOME MEASURE(S)

Change in mammographic breast density and breast cell proliferation. Correlations with levels of hormones, growth factors, and binding proteins.

RESULT(S)

Three women showed an apparent increase in density. For the remaining 17 women the changes were only a few percent. Digitized assessment of density showed strong correlations with visual classification scales (rs = 0.96-0.97). There was no increase in proliferation as expressed by the percentage of MIB-1-positive breast cells in fine-needle aspiration biopsies. Increase in breast density displayed a positive correlation with patients age (rs = 0.52) and an inverse relationship with levels of E2 (rs = -0.50) and free T (rs = -0.50).

CONCLUSION(S)

Low-dose intrauterine administration progestogen may develop into an attractive alternative for hormonal therapy in postmenopausal women as endometrial protection may be achieved at very low systemic levels.

The effect of low dose hormone therapy on mammographic breast density

OBJECTIVES

To evaluate the effect of two standard and one low dose continuous hormone therapy regimens on mammography.

METHODS

One hundred and thirty-two non-hysterectomized postmenopausal women were randomly allocated either to conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, n=38), 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA, n=44) or 17beta-estradiol 1 mg plus norethisterone acetate 0.5 mg (low E2/NETA, n=50). Treatment was continuous and the study period lasted 12 months. Main outcome measures were the changes according to Wolfe classification between baseline and 12-month mammograms.

RESULTS

Five (13.2%) women in the CEE/MPA group showed an increase in breast density. Fourteen (31.8%) women on E2/NETA and 6 (12.2%) on low E2/NETA treatment revealed an increase in breast density. No woman exhibited an involution of fibroglandular tissue.

CONCLUSIONS

Different hormone therapy regimens have a variable impact on breast density probably depending on the steroid used. Low dose hormone therapy associates with significantly lesser increase in breast density.

Mammographic Density and Breast Cancer Risk in BRCA1 and BRCA2 Mutation Carriers

High breast density as measured on mammograms is a strong risk factor for breast cancer in the general population, but its effect in carriers of germline BRCA1 and BRCA2 mutations is unclear. We obtained mammograms from 206 female carriers of BRCA1 or BRCA2 mutations, 96 of whom were subsequently diagnosed with breast cancer and 136 relatives of carriers who were themselves noncarriers. We compared the mammographic densities of affected carriers (cases) and unaffected carriers (controls), and of mutation carriers and noncarriers, using a computer-assisted method of measurement and visual assessment by two observers. Analyses were adjusted for age, parity, body mass index, menopausal status, and hormone replacement therapy use. There was no difference in the mean percent density between noncarriers and carriers. Among carriers, increasing mammographic density was associated with an increased risk of breast cancer (P(trend) = 0.024). The odds ratio (OR; 95% confidence interval) for breast cancer associated with a density of > or =50% was 2.29 (1.23-4.26; P = 0.009). The OR did not differ between BRCA1 and BRCA2 carriers or between premenopausal and postmenopausal carriers. The results suggest that the distribution of breast density in BRCA1 and BRCA2 carriers is similar to that in non-carriers. High breast density in carriers is associated with an increased risk of breast cancer, with the relative risk being similar to that observed in the general population. Use of mammographic density could improve individual risk prediction in carriers.

Optical transillumination spectroscopy to quantify parenchymal tissue density: an indicator for breast cancer risk

Mammographic screening for early detection of breast cancer has proven valuable in improving breast cancer survival. However, breast cancer incidence is still increasing, and thus preventative oncology needs to receive more attention, with the goal of identifying women with increased risk of developing breast cancer in the future and offering them risk reduction interventions. Mammogram derived parenchymal density pattern has been shown by various authors to provide a high odds ratio for breast cancer. Near-infrared optical transillumination spectroscopy was employed to determine physiological properties of the breast tissue to quantify differences in women with low or high breast cancer risk. Specifically in this study, women who had a recent mammogram underwent examination of their breast tissue by optical transillumination spectroscopy. Areas of adipose and glandular tissues which give rise to mammographic density patterns also have characteristic optical transillumination spectra. Correlation between optical transillumination spectroscopy and mammographic density pattern was established using partial least squares analysis. Results show that predicted tissue density based on optical transillumination spectroscopy correlates with mammographic observed tissue density, with a Spearman Rank correlation coefficient of 0.72. This suggests that optical transillumination spectroscopy may be a promising tool to quantify and monitor changes in breast cancer risk.

What is breast density?

Although having increased breast density is one of the strongest risk factors for breast cancer other than increased age and having a BRCA1 or BRCA2 mutation, it is still not clearly understood what that measure of risk is reflecting biologically. It has long been presumed based on indirect evidence that breast density is an indicator of cumulative hormone, particularly estrogen, exposure throughout one's life. However, there is growing evidence that the story may not be that simple. Recent studies suggest that stromal and epithelial proliferation and interaction, and the IGH-axis may all be involved in explaining the breast density and breast cancer risk association. Clearly for breast cancer research to advance it will be necessary to think beyond the presumed association that explains breast density only through estrogen pathways.