Temporal changes in mammographic breast density and breast cancer risk among women with benign breast disease.

INTRODUCTION: Benign breast disease (BBD) and high mammographic breast density (MBD) are prevalent and independent risk factors for invasive breast cancer. It has been suggested that temporal changes in MBD may impact future invasive breast cancer risk, but this has not been studied among women with BBD. METHODS: We undertook a nested case-control study within a cohort of 15,395 women with BBD in Kaiser Permanente Northwest (KPNW; 1970-2012, followed through mid-2015). Cases (n = 261) developed invasive breast cancer > 1 year after BBD diagnosis, whereas controls (n = 249) did not have breast cancer by the case diagnosis date. Cases and controls were individually matched on BBD diagnosis age and plan membership duration. Standardized %MBD change (per 2 years), categorized as stable/any increase (≥ 0%), minimal decrease of less than 5% or a decrease greater than or equal to 5%, was determined from baseline and follow-up mammograms. Associations between MBD change and breast cancer risk were examined using adjusted unconditional logistic regression. RESULTS: Overall, 64.5% (n = 329) of BBD patients had non-proliferative and 35.5% (n = 181) had proliferative disease with/without atypia. Women with an MBD decrease (≤ - 5%) were less likely to develop breast cancer (Odds Ratio (OR) 0.64; 95% Confidence Interval (CI) 0.38, 1.07) compared with women with minimal decreases. Associations were stronger among women ≥ 50 years at BBD diagnosis (OR 0.48; 95% CI 0.25, 0.92) and with proliferative BBD (OR 0.32; 95% CI 0.11, 0.99). DISCUSSION: Assessment of temporal MBD changes may inform risk monitoring among women with BBD, and strategies to actively reduce MBD may help decrease future breast cancer risk.

Associations of tubal ligation and hysterectomy with serum androgen and estrogen metabolites among postmenopausal women in the Women's Health Initiative Observational Study.

PURPOSE: Hysterectomy is associated with subsequent changes in circulating hormone levels, but the evidence of an association for tubal ligation is unclear. We evaluated whether circulating concentrations of androgens and estrogens differ by tubal ligation or hysterectomy status in postmenopausal women from the Women's Health Initiative (WHI)-Observational Study (OS). METHODS: Serum androgens and estrogens were measured in 920 postmenopausal women who did not use menopausal hormone therapy at the time of blood draw, of whom 139 self-reported a history of tubal ligation and 102 reported hysterectomy (with intact ovaries). Geometric mean hormone concentrations (GMs) and 95% confidence intervals (CIs) associated with a history of tubal ligation or hysterectomy (ever/never), as well as time since procedures, were estimated using adjusted linear regression with inverse probability of sampling weights to account for selection. RESULTS: Circulating levels of 12 androgen/androgen metabolites and 20 estrogen/estrogen metabolites did not differ by tubal ligation status. Among women reporting prior hysterectomy compared to women without hysterectomy, we observed lower levels of several androgens (e.g., testosterone (nmol/L): GMyes 0.46 [95% CI:0.37-0.57] vs. GMno 0.62 [95% CI:0.53-0.72]) and higher levels of estrogen metabolites, for example, 2-hydroxyestrone-3-methyl ether (GMyes 11.1 [95% CI:8.95-13.9] pmol/L vs. GMno 8.70 [95% CI:7.38-10.3]) and 4-methoxyestrone (GMyes 6.50 [95% CI:5.05-8.37] vs. GMno 4.92 [95% CI:4.00-6.05]). CONCLUSION: While we did not observe associations between prior tubal ligation and postmenopausal circulating hormone levels, our findings support that prior hysterectomy was associated with lower circulating testosterone levels and higher levels of some estrogen metabolites, which may have implications for future hormone-related disease risks.

Measured body size and serum estrogen metabolism in postmenopausal women: the Ghana Breast Health Study.

BACKGROUND: Several anthropometric measures have been associated with hormone-related cancers, and it has been shown that estrogen metabolism in postmenopausal women plays an important role in these relationships. However, little is known about circulating estrogen levels in African women, and the relevance to breast cancer or breast cancer risk factors. To shed further light on the relationship of anthropometric factors and estrogen levels in African women, we examined whether measured body mass index (BMI), waist-to-hip ratio (WHR), height, and self-reported body size were associated with serum estrogens/estrogen metabolites in a cross-sectional analysis among postmenopausal population-based controls of the Ghana Breast Health Study. METHODS: Fifteen estrogens/estrogen metabolites were quantified using liquid chromatography-tandem mass spectrometry in serum samples collected from postmenopausal female controls enrolled in the Ghana Breast Health Study, a population-based case-control study conducted in Accra and Kumasi. Geometric means (GMs) of estrogens/estrogen metabolites were estimated using linear regression, adjusting for potential confounders. RESULTS: Measured BMI (≥ 30 vs. 18.5-24.9 kg/m2) was positively associated with parent estrogens (multivariable adjusted GM for unconjugated estrone: 78.90 (66.57-93.53) vs. 50.89 (43.47-59.59), p-value < 0.0001; and unconjugated estradiol: 27.83 (21.47-36.07) vs. 13.26 (10.37-16.95), p-value < 0.0001). Independent of unconjugated estradiol, measured BMI was associated with lower levels of 2-pathway metabolites and higher levels of 16-ketoestradriol. Similar patterns of association were found with WHR; however, the associations were not entirely independent of BMI. Height was not associated with postmenopausal estrogens/estrogen metabolite levels in African women. CONCLUSIONS: We observed strong associations between measured BMI and parent estrogens and estrogen metabolite patterns that largely mirrored relations that have previously been associated with higher breast cancer risk in postmenopausal White women. The consistency of the BMI-estrogen metabolism associations in our study with those previously noted among White women suggests that estrogens likely explain part of the BMI-postmenopausal breast cancer risk in both groups. These findings merit evaluation in Black women, including prospective studies.

Effect of risk-reducing salpingo-oophorectomy on sex steroid hormone serum levels among postmenopausal women: an NRG Oncology/Gynecologic Oncology Group study.

BACKGROUND: Risk-reducing salpingo-oophorectomy is an effective ovarian cancer risk reduction strategy. However, bilateral oophorectomy has also been associated with increased long-term nonneoplastic sequelae, effects suggested to be mediated through reductions in systemic sex steroid hormone levels. Currently, it is unclear whether the postmenopausal ovary contributes to the systemic hormonal milieu or whether postmenopausal ovarian volume or other factors, such as body mass index and age, affect systemic hormone levels. OBJECTIVE: We examined the impact of oophorectomy on sex steroid hormone levels in postmenopausal women. Furthermore, we explored how well ovarian volume measured by transvaginal ultrasound correlated with direct ovarian measures obtained during surgical pathology evaluation and investigated the association between hormone levels and ovarian volumes. STUDY DESIGN: Postmenopausal women who underwent risk-reducing salpingo-oophorectomy (180 cases) or ovarian cancer screening (38 controls) enrolled in an international, prospective study of risk-reducing salpingo-oophorectomy and risk of ovarian cancer algorithm-based screening among women at increased risk of ovarian cancer (Gynecologic Oncology Group-0199) were included in this analysis. Controls were frequency matched to the cases on age at menopause, age at study entry, and time interval between blood draws. Ovarian volume was calculated using measurements obtained from transvaginal ultrasound in both cases and controls and measurements recorded in surgical pathology reports from cases. Serum hormone levels of testosterone, androstenedione, androstenediol, dihydrotestosterone, androsterone, dehydroepiandrosterone, estrone, estradiol, and sex hormone-binding globulin were measured at baseline and follow-up. Spearman correlation coefficients were used to compare ovarian volumes as measured on transvaginal ultrasound and pathology examinations. Correlations between ovarian volumes by transvaginal ultrasound and measured hormone levels were examined using linear regression models. All models were adjusted for age. Paired t tests were performed to evaluate individual differences in hormone levels before and after risk-reducing salpingo-oophorectomy. RESULTS: Ovarian volumes measured by transvaginal ultrasound were only moderately correlated with those reported on pathology reports (Spearman rho [ρ]=0.42). The median time interval between risk-reducing salpingo-oophorectomy and follow-up for the cases was 13.3 months (range, 6.0-19.3), and the median time interval between baseline and follow-up for the controls was 12.7 months (range, 8.7-13.4). Sex steroid levels decreased with age but were not correlated with transvaginal ultrasound ovarian volume, body mass index, or time since menopause. Estradiol levels were significantly lower after risk-reducing salpingo-oophorectomy (percentage change, -61.9 post-risk-reducing salpingo-oophorectomy vs +15.2 in controls; P=.02), but no significant differences were seen for the other hormones. CONCLUSION: Ovarian volumes measured by transvaginal ultrasound were moderately correlated with volumes directly measured on pathology specimens and were not correlated with sex steroid hormone levels in postmenopausal women. Estradiol was the only hormone that declined significantly after risk-reducing salpingo-oophorectomy. Thus, it remains unclear whether the limited post-risk-reducing salpingo-oophorectomy changes in sex steroid hormones among postmenopausal women impact long-term adverse outcomes.

Risk factors for breast cancer development by tumor characteristics among women with benign breast disease.

BACKGROUND: Among women diagnosed with invasive breast cancer, 30% have a prior diagnosis of benign breast disease (BBD). Thus, it is important to identify factors among BBD patients that elevate invasive cancer risk. In the general population, risk factors differ in their associations by clinical pathologic features; however, whether women with BBD show etiologic heterogeneity in the types of breast cancers they develop remains unknown. METHODS: Using a nested case-control study of BBD and breast cancer risk conducted in a community healthcare plan (Kaiser Permanente Northwest), we assessed relationships of histologic features in BBD biopsies and patient characteristics with subsequent breast cancer risk and tested for heterogeneity of associations by estrogen receptor (ER) status, tumor grade, and size. The study included 514 invasive breast cancer cases (median follow-up of 9 years post-BBD diagnosis) and 514 matched controls, diagnosed with proliferative or non-proliferative BBD between 1971 and 2006, with follow-up through mid-2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using multivariable polytomous logistic regression models. RESULTS: Breast cancers were predominantly ER-positive (86%), well or moderately differentiated (73%), small (74% < 20 mm), and stage I/II (91%). Compared to patients with non-proliferative BBD, proliferative BBD with atypia conferred increased risk for ER-positive cancer (OR = 5.48, 95% CI = 2.14-14.01) with only one ER-negative case, P-heterogeneity = 0.45. The presence of columnar cell lesions (CCLs) at BBD diagnosis was associated with a 1.5-fold increase in the risk of both ER-positive and ER-negative tumors, with a 2-fold increase (95% CI = 1.21-3.58) observed among postmenopausal women (56%), independent of proliferative BBD status with and without atypia. We did not identify statistically significant differences in risk factor associations by tumor grade or size. CONCLUSION: Most tumors that developed after a BBD diagnosis in this cohort were highly treatable low-stage ER-positive tumors. CCL in BBD biopsies may be associated with moderately increased risk, independent of BBD histology, and irrespective of ER status.

Use of postmenopausal hormone therapies and risk of histology- and hormone receptor-defined breast cancer: results from a 15-year prospective analysis of NIH-AARP cohort.

BACKGROUND: Menopausal hormone therapy (MHT) increases breast cancer (BC) risk, but cohort studies largely consider use only at enrollment. Evidence is limited on how changes in MHT use alter the magnitude of risk, and whether risk varies between invasive and in situ cancer, by histology or by hormone receptor status. METHODS: We investigated the roles of estrogen-alone therapy (ET) and estrogen plus progestin therapy (EPT) on BC risk overall, by histology and estrogen receptor (ER) and progesterone receptor (PR) status, and on incidence of in situ disease, in the NIH-AARP cohort. Participants included 118,760 postmenopausal women (50-71 years), of whom 63.5% (n = 75,398) provided MHT use information at baseline in 1996 and in a follow-up survey in 2004, subsequent to the dissemination in 2002 of the Women's Health Initiative trial safety concerns regarding EPT. ET analyses included 50,476 women with hysterectomy (31,439 with follow-up data); EPT analyses included 68,284 women with intact uteri (43,959 with follow-up data). Adjusted hazard ratios (HRs) were estimated using Cox proportional hazards models using age as the time metric with follow-up through 2011. RESULTS: Eight thousand three hundred thirty-three incident BC cases were accrued, 2479 in women with follow-up data. BC risk was not elevated in current ET users at baseline (HR = 1.05, 95% confidence interval [CI] CI = 0.95-1.16) but was higher in women continuing use through 2004 (HR = 1.35, 95% CI = 1.04-1.75). Ever EPT use at baseline was associated with elevated BC risk overall (HR = 1.54 (1.44-1.64), with a doubling in risk for women with 10 or more years of use, for in situ disease, and across subtypes defined by histology and ER/PR status (all p < 0.004). Risk persisted in women who continued EPT through 2004 (HR = 1.80, 95% CI = 1.39-2.32). In contrast, no association was seen in women who discontinued EPT before 2004 (HR = 1.14, 95% CI = 0.99-1.30). CONCLUSIONS: ET use was not associated with BC risk in this cohort, although excess risk was suggested in women who continued use through 2004. EPT use was linked to elevated in situ and invasive BC risk, and elevated risk across invasive BC histologic and hormone receptor-defined subtypes, with the highest risk for women who continued use through the 2004 follow-up survey.

Relationship of circulating insulin-like growth factor-I and binding proteins 1-7 with mammographic density among women undergoing image-guided diagnostic breast biopsy.

BACKGROUND: Mammographic density (MD) is a strong breast cancer risk factor that reflects fibroglandular and adipose tissue composition, but its biologic underpinnings are poorly understood. Insulin-like growth factor binding proteins (IGFBPs) are markers that may be associated with MD given their hypothesized role in breast carcinogenesis. IGFBPs sequester IGF-I, limiting its bioavailability. Prior studies have found positive associations between circulating IGF-I and the IGF-I:IGFBP-3 ratio and breast cancer risk. We evaluated the associations of IGF-I, IGFBP-3, and six other IGFBPs with MD. METHODS: Serum IGF measures were quantified in 296 women, ages 40-65, undergoing diagnostic image-guided breast biopsy. Volumetric density measures (MD-V) were assessed in pre-biopsy digital mammograms using single X-ray absorptiometry. Area density measures (MD-A) were estimated by computer-assisted thresholding software. Age, body mass index (BMI), and BMI2-adjusted linear regression models were used to examine associations of serum IGF measures with MD. Effect modification by BMI was also assessed. RESULTS: IGF-I and IGFBP-3 were not strongly associated with MD after BMI adjustment. In multivariable analyses among premenopausal women, IGFBP-2 was positively associated with both percent MD-V (ß = 1.49, p value = 0.02) and MD-A (ß = 1.55, p value = 0.05). Among postmenopausal women, positive relationships between IGFBP-2 and percent MD-V (ß = 2.04, p = 0.003) were observed; the positive associations between IGFBP-2 and percent MD-V were stronger among lean women (BMI < 25 kg/m2) (ß = 5.32, p = 0.0002; p interaction = 0.0003). CONCLUSIONS: In this comprehensive study of IGFBPs and MD, we observed a novel positive association between IGFBP-2 and MD, particularly among women with lower BMI. In concert with in vitro studies suggesting a dual role of IGFBP-2 on breast tissue, promoting cell proliferation as well as inhibiting tumorigenesis, our findings suggest that further studies assessing the role of IGFBP-2 in breast tissue composition, in addition to IGF-1 and IGFBP-3, are warranted.

Breast cancer risk prediction in women aged 35-50 years: impact of including sex hormone concentrations in the Gail model.

BACKGROUND: Models that accurately predict risk of breast cancer are needed to help younger women make decisions about when to begin screening. Premenopausal concentrations of circulating anti-Müllerian hormone (AMH), a biomarker of ovarian reserve, and testosterone have been positively associated with breast cancer risk in prospective studies. We assessed whether adding AMH and/or testosterone to the Gail model improves its prediction performance for women aged 35-50. METHODS: In a nested case-control study including ten prospective cohorts (1762 invasive cases/1890 matched controls) with pre-diagnostic serum/plasma samples, we estimated relative risks (RR) for the biomarkers and Gail risk factors using conditional logistic regression and random-effects meta-analysis. Absolute risk models were developed using these RR estimates, attributable risk fractions calculated using the distributions of the risk factors in the cases from the consortium, and population-based incidence and mortality rates. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminatory accuracy of the models with and without biomarkers. RESULTS: The AUC for invasive breast cancer including only the Gail risk factor variables was 55.3 (95% CI 53.4, 57.1). The AUC increased moderately with the addition of AMH (AUC 57.6, 95% CI 55.7, 59.5), testosterone (AUC 56.2, 95% CI 54.4, 58.1), or both (AUC 58.1, 95% CI 56.2, 59.9). The largest AUC improvement (4.0) was among women without a family history of breast cancer. CONCLUSIONS: AMH and testosterone moderately increase the discriminatory accuracy of the Gail model among women aged 35-50. We observed the largest AUC increase for women without a family history of breast cancer, the group that would benefit most from improved risk prediction because early screening is already recommended for women with a family history.

Circulating androgens and postmenopausal ovarian cancer risk in the Women's Health Initiative Observational Study.

Our knowledge of epidemiologic risk factors for ovarian cancer supports a role for androgens in the pathogenesis of this disease; however, few studies have examined associations between circulating androgens and ovarian cancer risk. Using highly sensitive LC-MS/MS assays, we evaluated associations between pre-diagnostic serum levels of 12 androgens, including novel androgen metabolites that reflect androgen activity in tissues, and ovarian cancer risk among postmenopausal women in a nested case-control study in the Women's Health Initiative (WHI) Observational Study (OS). We frequency-matched 169 ovarian cancer cases to 410 controls from women enrolled in WHI-OS who were not using menopausal hormones at enrollment/blood draw. We estimated associations overall and by subtype (n = 102 serous/67 non-serous) using multivariable adjusted logistic regression. Androgen/androgen metabolite levels were not associated with overall ovarian cancer risk. In analyses by subtype, women with increased levels of androsterone-glucuronide (ADT-G) and total 5-α reduced glucuronide metabolites (markers of tissue-level androgenic activity) were at increased risk of developing non-serous ovarian cancer: ADT-G tertile (T)3 versus T1 odds ratio [OR] (95% confidence interval [CI]) 4.36 (1.68-11.32), p-heterogeneity 0.002; total glucuronide metabolites 3.63 (1.47-8.95), 0.002. Risk of developing serous tumors was unrelated to these markers. ADT-G and total glucuronide metabolites, better markers of tissue-level androgenic activity in women than testosterone, were associated with an increased risk of developing non-serous ovarian cancer. Our work demonstrates that sex steroid metabolism is important in the etiology of non-serous ovarian cancers and supports a heterogeneous hormonal etiology across histologic subtypes of ovarian cancer.

Estrogen metabolism in menopausal hormone users in the women's health initiative observational study: Does it differ between estrogen plus progestin and estrogen alone?

The WHI found an unexpected reduced breast cancer risk in women using CEE alone. We hypothesized CEE alone induces estrogen hydroxylation along the 2-pathway rather than the competing 16-pathway, a pattern linked to reduced postmenopausal breast cancer risk. One thousand eight hundred and sixty-four women in a WHIOS case-control study of estrogen metabolism and ovarian and endometrial cancer were studied of whom 609 were current E + P users (351 used CEE + MPA), while 272 used E alone (162 used CEE). Fifteen EM were measured, and analyses were conducted for each metabolite, hydroxylation pathway (2-, 4-, or 16-pathway) and ratios of pathway concentrations using inverse probability weighted linear regression. Compared to E + P users, all EM were higher in E alone users (significant for unconjugated estrone, total/conjugated estradiol, total/unconjugated 2-methoxyestrone, 4-methoxyestrone and unconjugated estriol). The relative concentrations of 2- and 4-pathway EM did not differ between the MHT users (2-pathway EM comprised 15% and 4-pathway EM <2% of the total), but 16-pathway EM were lower in E alone users (p = 0.036). Ratios of 2- and 4-pathway EM compared to 16-pathway EM were significantly higher in E alone compared to E + P users. Similar but not significant patterns were observed in CEE-alone and CEE + MPA users. Our data suggest that compared to E + P users, women using E alone have more extensive metabolism via the 2- vs. the competing 16-pathway. This is consistent with epidemiologic evidence of reduced postmenopausal breast cancer risk associated with this metabolic profile and may provide a clue to the breast cancer risk reduction in CEE alone users during the WHI.